What are the blood groups for human beings?

What are the blood groups for human beings?

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Human blood groups are of 4 types with negative and positive of each types (Wikipedia). But according to this forum thread there are some other types too:


I'm going to make software for blood donation, where I need to put a dropdown list of actual blood types. I had intended to use:

[ Select Blood Group V ] [ O Negative ] [ O Positive ] [ A Negative ] [ A Positive ] [ B Negative ] [ B Positive ] [ AB Negative ] [ AB Positive ]

But now I am uncertain whether this is appropriate. What is the most suitable list of blood types for donors?

As far as I am aware it is the RhD and ABO blood groups that matter with blood donation - though you may wish to contact a blood donation organisation for more specific information on how they handle & categorise the blood.

But using just RhD and ABO gives 8 combinations, positive and negative of A, B, AB, and O. You can find out more about the blood groups, blood donation, and the characteristics of blood groups here.

The subgroups you allude to are due to differences in the number of the antigens on the surface of the blood cell, for example the A1 group have ~1,000,000 A antigens per cell whereas A2 variants have ~250,000. The A group has ~20 subgroups, the vast majority of people are A1 (~80%) or A2 (~20%), and the other groups make up less than 1% of the population.

These two subgroups are interchangeable as far as transfusion is concerned, but complications can sometimes arise in rare cases when typing the blood.

If the blood donor is filling out the info, I recommend you have one dropdown that offers: A, B, O, AB, don't know… And a second dropdown that offers Rh +, Rh -, don't know. And be aware that the average person is not likely to correctly know their blood type.

Actual laboratory blood typing checks for a large number of possible differences between blood cells beyond just ABO types. The clinician or technician will not use anything as simple as either your drop-down OR the slightly more complex drop-down in the referenced forum post.

If you still want to know more about "what the actual blood types are," recognize that there are LOTS of blood types, including the MNS system, the Kell system, and the Lewis system:

The Mystery of Human Blood Types

Blood banks run blood type tests before blood is sent to hospitals for transfusions. Image: U.S. Navy photo by Mass Communication Specialist 3rd Class Jake Berenguer/Wikicommons

Everyone’s heard of the A, B, AB and O blood types. When you get a blood transfusion, doctors have to make sure a donor’s blood type is compatible with the recipient’s blood, otherwise the recipient can die. The ABO blood group, as the blood types are collectively known, are ancient. Humans and all other apes share this trait, inheriting these blood types from a common ancestor at least 20 million years ago and maybe even earlier, claims a new study published online today in Proceedings of the National Academy of Sciences. But why humans and apes have these blood types is still a scientific mystery.

The ABO blood group was discovered in the first decade of the 1900s by Austrian physician Karl Landsteiner. Through a series of experiments, Landsteiner classified blood into the four well-known types. The “type” actually refers to the presence of a particular type of antigen sticking up from the surface of a red blood cell. An antigen is anything that elicits a response from an immune cell called an antibody. Antibodies latch onto foreign substances that enter the body, such as bacteria and viruses, and clump them together for removal by other parts of the immune system. The human body naturally makes antibodies that will attack certain types of red-blood-cell antigens. For example, people with type A blood have A antigens on their red blood cells and make antibodies that attack B antigens people with type B blood have B antigens on their red blood cells and make antibodies that attack A antigens. So, type A people can’t donate their blood to type B people and vice versa. People who are type AB have both A and B antigens on their red blood cells and therefore don’t make any A or B antibodies while people who are type O have no A or B antigens and make both A and B antibodies. (This is hard to keep track of, so I hope the chart below helps!)

After Landsteiner determined the pattern of the ABO blood group, he realized blood types are inherited, and blood typing became one of the first ways to test paternity. Later, researchers learned ABO blood types are governed by  a single gene that comes in three varieties: A, B and O. (People who are type AB inherit an A gene from one parent and a B gene from the other.)

This chart lists the antigens and antibodies made by the different ABO blood types. Image: InvictaHOG/Wikicommons

More than a hundred years after Landsteiner’s Nobel Prize-winning work, scientists still have no idea what function these blood antigens serve. Clearly, people who are type O—the most common blood type—do just fine without them. What scientists have found in the last century, however, are some interesting associations between blood types and disease. In some infectious diseases, bacteria may closely resemble certain blood antigens, making it difficult for antibodies to detect the difference between foreign invaders and the body’s own blood. People who are type A, for instance, seem more susceptible to smallpox, while people who are type B appear more affected by some E. coli infections.

Over the last hundred years, scientists have also discovered that the ABO blood group is just one of more than 20 human blood groups. The Rh factor is another well known blood group, referring to the “positive” or “negative” in blood types, such as A-positive or B-negative. (The Rh refers to Rhesus macaques, which were used in early studies of the blood group.) People who are Rh-positive have Rh antigens on their red blood cells people who are Rh-negative don’t and produce antibodies that will attack Rh antigens. The Rh blood group plays a role in the sometimes fatal blood disease erythroblastosis fetalis that can develop in newborns if an Rh-negative women gives birth to an Rh-positive baby and her antibodies attack her child.

Most people have never heard of the numerous other blood groups—such as the MN, Diego, Kidd and Kell—probably because they trigger smaller or less frequent immune reactions. And in some cases, like the MN blood group, humans don’t produce antibodies against the antigens. One “minor” blood type that does have medical significance is the Duffy blood group. Plasmodium vivax, one of the parasites that causes malaria, latches onto the Duffy antigen when it invades the body’s red blood cells. People who lack the Duffy antigens, therefore, tend to be immune to this form of malaria.

Although researchers have found these interesting associations between blood groups and disease, they still really don’t understand how and why such blood antigens evolved in the first place. These blood molecules stand as a reminder that we still have a lot to learn about human biology.

Blood contains cells, proteins, and sugars

The straw-colored fluid that forms the top layer is called plasma and forms about 60% of blood. The middle white layer is composed of white blood cells (WBCs) and platelets, and the bottom red layer is the red blood cells (RBCs). These bottom two layers of cells form about 40% of the blood.

Plasma is mainly water, but it also contains many important substances such as proteins (albumin, clotting factors, antibodies, enzymes, and hormones), sugars (glucose), and fat particles.

All of the cells found in the blood come from bone marrow. They begin their life as stem cells, and they mature into three main types of cells— RBCs, WBCs, and platelets. In turn, there are three types of WBC—lymphocytes, monocytes, and granulocytes𠅊nd three main types of granulocytes (neutrophils, eosinophils, and basophils). See them in action in "Meet the blood cells".

See a figure of all the cellular elements of blood in Janeway & Traver's Immunobiology

A sample of blood can be further separated into its individual components by spinning the sample in a centrifuge. The force of the spinning causes denser elements to sink, and further processing enables the isolation of a particular protein or the isolation of a particular type of blood cell. With the use of this method, antibodies and clotting factors can be harvested from the plasma to treat immune deficiencies and bleeding disorders, respectively. Likewise, RBCs can be harvested for blood transfusion.

Blood Types

Blood types are determined by the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body. Since some antigens can trigger a patient's immune system to attack the transfused blood, safe blood transfusions depend on careful blood typing and cross-matching. Do you know what blood type is safe for you if you need a transfusion?

There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells. In addition to the A and B antigens, there is a protein called the Rh factor, which can be either present (+) or absent (–), creating the 8 most common blood types (A+, A-, B+, B-, O+, O-, AB+, AB-).

Blood Types and Transfusion

There are very specific ways in which blood types must be matched for a safe transfusion. The right blood transfusion can mean the difference between life and death.

Every 2 seconds someone in the US needs a blood transfusion.

Use the interactive graphic below to learn more about matching blood types for transfusions.

Also, Rh-negative blood is given to Rh-negative patients, and Rh-positive or Rh-negative blood may be given to Rh-positive patients. The rules for plasma are the reverse.

  • The universal red cell donor has Type O negative blood.
  • The universal plasma donor has Type AB blood.

There are more than 600 other known antigens, the presence or absence of which creates "rare blood types." Certain blood types are unique to specific ethnic or racial groups. That’s why an African-American blood donation may be the best hope for the needs of patients with sickle cell disease, many of whom are of African descent. Learn about blood and diversity.

What Is A Universal Blood Donor?

Universal donors are those with an O negative blood type. Why? O negative blood can be used in transfusions for any blood type.

Type O is routinely in short supply and in high demand by hospitals – both because it is the most common blood type and because type O negative blood is the universal blood type needed for emergency transfusions and for immune deficient infants.

Approximately 45 percent of Caucasians are type O (positive or negative), but 51 percent of African-Americans and 57 percent of Hispanics are type O. Minority and diverse populations, therefore, play a critical role in meeting the constant need for blood.

Types O negative and O positive are in high demand. Only 7% of the population are O negative. However, the need for O negative blood is the highest because it is used most often during emergencies. The need for O+ is high because it is the most frequently occurring blood type (37% of the population).

The universal red cell donor has Type O negative blood. The universal plasma donor has Type AB blood. For more about plasma donation, visit the plasma donation facts.


Because much of the research on blood antigens has focused on understanding blood transfusions, the antigens are commonly referred to as blood group antigens. 14 Blood group antigens are primarily tissue antigens, and are widely distributed throughout the body. The antigens evolved earlier in ectodermal and endodermal tissue than in RBCs and hematopoietic cells, and for this reason are also referred to as histo-blood group antigens. 14 Antibodies to these tissue antigens cause rejection of transplanted tissues and organs 11 and can cause spontaneous abortions. 14

Both the ABO and Rh blood groups systems have been associated with a number of diseases, but this is more likely related to the presence or absence of these tissue antigens throughout the body and not directly or primarily related to their presence on RBCs. 14 Although early research relied on using statistical methods to associate the blood groups with diseases such as infection, malignancy, and coagulation, these associations have more recently been given scientific validation through extensive research in infectious disease, tumor immunology, and membrane chemistry. 14

Some of the known associations between blood group antigens and disease are presented here and summarized in Table 2 . Research is complicated for several reasons: the ABO blood group system is highly polymorphic, with more than 20 distinct sub-groups study findings are usually related to ABO phenotype, but rarely to the ABO genotype, secretor status, and Lewis phenotype and animal models are unsatisfactory because their antigen glycosylation structure is different from humans. 15 Molecular biology techniques, transgenic animals, and computer modeling are being explored as possible investigative tools for studying the complex mechanisms and processes involved in glycosylation, and how glycosylation affects proteins and individual cells, as well as entire organisms the lack of adequately robust analytical tools is perhaps the biggest impediment faced by researchers. 15

Table 2

The Relationship of Blood Group with Disease Risks

DiseaseRisk FactorBlood Group/Antigens
Sickle cell anemia 16 Increased adhesionAdhesion Molecules
Hemolytic disease of the newborn 12, 17 Antibodies to RhDRhD
Chronic and autoimmune hemolytic anemias 13, 17 Rh nullRh, RhAG
Vascular disorders, venous and arterial thromboembolism, coronary heart disease, ischemic stroke, myocardial infarction 1, 11, 14, 18� Reduced clearance of von Willebrand factor and FVIIIGroups A > AB > B
Dementia, cognitive impairment 22, 23 Coagulation factorsGroups AB > B > A
Plague, cholera, tuberculosis, mumps 14 Antigen profileGroup O
Smallpox, Pseudomonas aeruginosa 14 Antigen profileGroup A
Gonorrhea, tuberculosis, S. pneumoniae, E. coli, salmonella 14 Antigen profileGroup B
Smallpox, E. coli, salmonella 14 Antigen profileGroup AB
N. meningitides, H. influenza, C. albicans, S. pneumoniae, E. coli urinary tract infections, S. pyogenes, V. cholera 1, 14, 24 Antigen profileNon-secretors
H. pylori 1, 11, 14, 25, 26 Strain-dependentGroup A 95% non-O
Peptic ulcers, gastroduodenal disease 11, 14, 25 Secretor status, H. pylori strainAll non-secretors Group O
Norovirus 1, 11, 27� Strain-dependentSecretors groups O, A
P. falciparum malaria 1, 11, 30 Receptor/antigen profileKnops antigens groups A, B
P. vivax malaria 30 Antigen profileDuffy FY antigens
Cholera 27 Severity differs by antigen profileLewis antigen non- secretors non-O groups
Bacterial Meningitis (N. meningitidis, H. influenza, S. pneumoniae) 31 Antigen profileNon-secretors A, AB, O blood groups
Cancer (tissue specific) 1, 11, 14, 32� Increased tumor antigens and ligandsA, B, H antigens lost 𠇊- like” antigens gained
Leukemia and Lymphoma 14, 38 RBC membrane changesA, B, H antigens lost
 Non-Hodgkin’s central nervous system lymphoma (primary and secondary) 39� Group O, B
 Hodgkin’s lymphoma 41 Group B
�ute lymphoblastic leukemia 41, 42 Group O
�ute myeloid leukemia 1, 41, 42 Group A
Stomach Cancer 20, 26, 43 H. pylori strainGroup A
Pancreatic Cancer 1, 11, 20, 44 H. pylori strainGroup B > AB > A
 Von Hippel-Lindau and Neuroendocrine 45 Multiple tumorsGroup O
Multiple Endocrine Neoplasia Type 1 46 Strongly associatedGroup O
Colon/Rectum Cancer 1, 47, 48 Type 1 and 2 chains Lewis antigensSecretors 𠇊-like” antigens expressed
Hypertension 15, 49� 3 phenotypes differGroup BϪ㺫
Hyperlipidemia 15, 49, 53� Low fat diet Ineffective
Intestinal ALP and apoB-48 vary by secretor status
LDL: Heterozygous MN Group A, B
ALP/apoB-48: Group O and B secretors
Type 2 Diabetes 15, 18, 49, 56� Rh group modifiesGroup AB > B > A
Type 1 Diabetes 29, 58, 59 FUT2 gene locusNon-secretors

The risk factors and blood groups or antigens associated with various diseases, based on the research presented in this review.

The role of cell adhesion molecules in disease

Although the exact mechanisms are not yet known that will explain all of the reported associations between blood group antigens and disease, what is known about their structure and functions provides some intriguing clues. An unexpected number of the antigenic structures found on RBCs act as cell adhesion molecules (CAMs) some contribute to normal RBC development and some play a role in human disease. 16, 60 These antigens can serve as receptors and ligands for microbes, and may play a role in movement of normal and malignant cells throughout the body. 14 CAM moieties include carbohydrates, glycosylphosphatidylinositol-anchored proteins, and transmembrane proteins, 16 and are grouped into 5 families: cadherins, selectins, integrins, the immunoglobulin superfamily (IgSF), and cell surface proteoglycans blood group antigens are associated with all but cadherins. 14 Selectins are expressed by leukocytes, platelets, and endothelial cells, and RBCs are capable of binding to them. 16 Selectins participate in attaching leukocytes to endothelial cells, and integrins participate in cell-to-cell and cell-to matrix communication. 14 Selectins, integrins, the IgSF, the cartilage link protein family, and sialomucins play a role in hematopoiesis. 16, 60

RBCs, especially sickled red cells, contain sialylated glycolipids and glycoproteins, which facilitate cell-cell interactions. 16 Sickle RBCs are strongly adherent to thrombospondin, fibronectin, and especially to laminin adhesion to endothelial cells induces pathological changes in them, especially cell retraction and upregulation of procoagulants and adhesion molecules. 16 RBCs are also responsive to epinephrine, with sickle RBCs showing significantly more responsiveness and greater adherence post-exposure. 16 The adhesion receptor CD44, a cartilage link protein, is primarily a receptor for hyaluronan, but also binds to fibronectin, osteopontin, and endothelial cells it mediates aggregation of leukocytes and T-cell activation, cooperates with integrin to bind erythroid progenitor cells to bone marrow matrix fibronectin, and anchors tumor cells during metastasis. 16

Hemolytic diseases

In the early 1940s, maternal antibodies to the RhD antigen of the fetus were identified as the cause of hemolytic disease of the newborn (HDN), 12 which can now be prevented by administration of Ig anti-D to the RhD-negative mother upon delivery this prevents the formation of antibodies to RhD. 17 In addition to the RhD-negative genotype, there is an extremely rare Rh-null genotype, in which the RBCs lack all Rh antigens, resulting in membrane polypeptides that are missing or severely deficient, and abnormalities in RBC shape, membrane phospholipid organization, and cation transport. 13 There are two Rh-null types: the amorph type is associated with a silent allele due to a mutation of the RHCE gene in a RhD-negative person, while the regulator type is due to homozygosity of an autosomal suppressor gene unrelated to the RH locus. 17

All Rh antigens can potentially play a role in autoimmune hemolytic anemias as well as hemolytic reactions due to immune activation following pregnancy or transfusion, but Rh-null individuals experience chronic hemolytic anemias of non-immune origin. Further investigations into the Rh-null phenotype revealed that Rh antigens are part of a non-covalently-bound complex of proteins, with a core tetramer of two Rh and two Rh-associated glycoprotein (RhAG) subunits, and CD47, LW, and GPB accessory proteins this complex is anchored in the lipid bilayer by the N-terminal and C-terminal domains of the Rh and RhAG proteins. 17 This complex is linked to the actin-spectrin based cytoskeleton of the RBC through direct interaction with protein 4.2 and ankyrin, and with protein Band 3, the erythroid anion exchanger, through their common interaction with ankyrin when Rh or RhAG proteins are missing, this complex is not assembled or transported to the cell membrane, resulting in the characteristic osmotic fragility and RBC abnormalities found in chronic hemolytic anemia. 17

Circulatory diseases

Historically, non-O blood groups have been associated with greater incidence of vascular disorders such as cerebral arterial ischemia, venous thromboembolism, peripheral vascular disease, angina, and myocardial infarction, and these associations were confirmed in 2008 with a systematic review and meta-analysis, and further validated by subsequent GWAS studies. 1 Recent reviews of the published literature quantified the risk in non-O blood group individuals for venous thrombosis (OR=1.79), peripheral vascular disease (OR=1.45), coronary heart disease (OR=1.25), myocardial infarction (OR=1.25), and ischemic stroke (OR=1.14), as compared with blood group O individuals. 19, 21 Von Willebrand factor (vWF) and Factor VIII (FVIII) are plasma coagulation glycoproteins, which act by forming a non-covalently bound complex vWF stabilizes FVIII and transports it to the site of vascular injury, and then interacts with platelets as part of the clotting process. 1 vWF is partially regulated by the cleavage action of a metalloprotease, which clears it from the plasma it is thought that the A and B antigens interfere with access to the cleavage site, thereby reducing clearance of vWF. 1

FVIII and vWF are approximately 25%�% lower in the plasma of blood group O people (specifically, Bombay < O < B < A < AB, with A/O and B/O having less than A/A and B/B individuals), and group O individuals are therefore at lower risk for venous and arterial thromboembolism, but at greater risk of excessive bleeding than group A individuals. 1, 11, 14 Higher average levels of FVIII in blood group A individuals increase the risk of ischemic heart disease and venous thromboembolism, 11 and group A people are more likely to thrombose or have myocardial infarctions than group O individuals. 14 The risk for myocardial infarction in the presence of coronary atherosclerosis is 44% lower for group O individuals than for other blood groups. 11 Non-O blood group individuals have an 11% greater relative risk of developing coronary heart disease than blood group O individuals, 20 and group AB individuals have a high risk of stroke compared to group O individuals. 18 A recent report found that 60% of stroke risk in blood group AB individuals was associated with FVIII levels. 22

Cognitive Disorders

In addition to their association with circulatory diseases, higher levels of vWF and FVIII in non-O blood group individuals have been associated with increased risk of dementia and cognitive impairment, indicating that coagulation factors may play a role in these disorders. 23 A large prospective case-control study found an increased risk of cognitive impairment (OR = 1.82) in blood group AB individuals, which was independent of age, race, gender, or geographic region, and that FVIII levels differed significantly by blood group, with O < A < B < AB. 22 This study also found that hypertension, dyslipidemia, obesity, diabetes, and cardiovascular disease (CVD) were more prevalent in those with cognitive impairment, which indicates that a common etiology is likely blood group influences CVD risk and CVD risk factors are known to be associated with dementia and cognitive impairment. Interestingly, blood groups B and AB were more frequent in blacks (in both cases and controls), 22 which may be an overlooked factor in increased rates of stroke and CVD in this population.

Bacteria, viruses, and parasites

Epithelial cells express ABH and Lewis antigens, which are effectively cell-surface glycoconjugates used by parasites, bacteria, and viruses as receptors for attachment, resulting in different susceptibilities depending on the antigen profile of an individual. 11 By using the same blood group antigens as their host, certain microbial parasites utilize molecular mimicry as a defense against the host’s immune system. 11 The chemical signatures on the membranes of many gram-negative organisms such as Escherichia coli resemble A and B blood group antigens in vitro experiments have shown that anti-B antibodies kill E. coli, and anti-A and anti-B antibodies may therefore play a similar role in destroying gram-negative bacteria in vivo. 14

Type O blood group is associated with increased incidence of plague, cholera, mumps, and tuberculosis infections type A blood group is associated with increased incidence of smallpox and Pseudomonas aeruginosa infection type B blood group is associated with increased incidence of gonorrhea, tuberculosis, Streptococcus pneumoniae, E. coli, and salmonella infections and type AB blood group is associated with increased incidence of smallpox, E. coli, and salmonella infections. 14 Non-secretors have an increased incidence of Neisseria meningitides, Haemophilus influenza, Candida albicans, 14 S. pneumoniae, E. coli urinary tract infections, 1 Streptococcus pyogenes, and Vibrio cholerae. 24

H. pylori

In 1954, it was reported that the incidence of peptic ulcers (gastric and duodenal) was 20% higher for group O individuals than group A individuals, with the incidence of duodenal ulcers 35% higher in group O individuals than in group A, B, and AB individuals, and 50% higher in non-secretors (who make up 20% of the population). 14 For group A and B non-secretors, the relative risk was 1:6 for group O secretors, the relative risk was 1:35 and for group O non-secretors, the relative risk was 2:5. 14 Secretor status and H. pylori infection are independent and significant risk factors for gastroduodenal disease, with a relative risk of 1.9 for non-secretors vs secretors. 25 Although gastritis and gastric ulcers are associated with H. pylori infection, more recent studies have reported that different strains of H. pylori showed varying preferences for each blood group antigen, and in fact, 95% of the strains did not show a preference for blood group O antigens. 11 Interestingly, although only 5% of the strains prefer the H antigen in the general population, in those of American Indian heritage (a group O-dominant population), 60% of the strains show this preference. 11


The Norovirus appears to be another strain-dependent pathogen, but blood group B individuals have less risk of infection (OR, 0.096) and symptomatic disease (OR, 0), and group O individuals have a much greater risk of infection (OR, 11.8). 11 The Norovirus binds to difucosylated Lewis antigens (secretors) and to A and H antigens, and but not to B antigens, 27 while non-secretors appear to be resistant to symptomatic infection with most strains. 1 In 3 outbreaks in Sweden, 29% of non-secretors were asymptomatic, while among those with symptoms, none were non-secretors (se/se) 51% were heterozygous (Se/se) and 49% were homozygous (Se/Se). 1 However, recent research has shown that non-secretors are not immune to infection the genogroup and genotype of the Norovirus strains have different binding capacities due to extensive structural differences in certain domains of the capsid protein, which are critical for attachment to host cells and determine whether binding can occur in non-secretors. 28 Although non-secretor status provides resistance to Norovirus infection, it is thought to increase susceptibility to Crohn’s disease and to autoimmune gastritis, which increases the risk of malabsorption and deficiency of vitamin B12, and the risk of pernicious anemia. 29


There are 4 species of Plasmodium, but the most virulent is P. falciparum, which accounts for 50% of the cases and 80% of the deaths, while P. vivax accounts for another 40% of cases. 30 The Duffy blood group system, which has 6 discrete antigens, is involved in P. vivax infections mutations of the FY gene that result in RBCs without the Duffy antigen protect against infection by this strain of malaria. 30 The Knops blood group system, which has 9 discrete antigens, appears to play a role in the severity of P. falciparum infection mutations of several of these antigens appear to provide a protective effect in African blacks. 30

The severity of P. falciparum malaria is directly correlated with the presence or absence of blood group A and B antigens O blood group individuals tend to be less severely affected by malaria, while A and B blood group individuals are at greater risk of malarial anemia (OR, 1.18). 11 Infected RBCs express membrane proteins that bind the A antigen, and possibly to a lesser extent the B antigen, of uninfected RBCs, forming large clusters or rosettes RBCs with just the H antigen form smaller and less robust rosettes, 1 while RBCs with the A antigen form larger and stronger rosettes. 30 A and B antigens also act as adhesion molecules during sequestration, allowing infected RBCs to adhere to the microvascular endothelial cells, which remove them from circulation and protect the parasite from destruction, but also block circulation and reduce oxygen supply. 1, 11 Rosetting and sequestration correlate with the increased severity of malaria and contribute to the high mortality rate among children with cerebral malaria this is a major selection pressure behind the population distribution of those with blood group O relative to non-O in the areas of the world where malaria is still prevalent. 1, 11

Mosquito-Borne Diseases

Mosquito-borne diseases add layers of complexity to the efforts to correlate blood groups with disease risk, and highlight the need for interdisciplinary, collaborative research. The Aedes mosquito is the common vector for transmission of yellow fever, dengue fever, chikungunya, and zika viruses a common vector increases the risk of host co-infections, and the risk of genetic recombination and reassortment in these viruses. 61 Both dengue and chikungunya infections can be asymptomatic, mild, severe, or fatal, and similarity of symptoms results in misclassification without laboratory diagnosis. 62 Studies must also consider normal blood group distribution frequencies for affected populations, as well as the number of serotypes, topotypes, sub-types, clades, and strains for a given virus, especially if some are more virulent than others (as seen with malarial parasites). Even landing preferences and feeding patterns of mosquitoes may affect blood group infection rates Aedes mosquitoes were reported to be more attracted to some host blood types than others. 63, 64 There are no published studies correlating blood groups with zika virus, and only a few for dengue or chikungunya fever 65� the findings of one 68 are consistent with gene association studies, 70 which found that the AB blood group (which lacks antibodies to both A and B antigens) was independently associated with increased susceptibility to severe dengue hemorrhagic fever in secondary infections. Understanding how blood group antigens affect disease risk, prevalence, and severity will contribute to more effective prevention, improved treatments, and faster vaccine development. Time is of the essence, and right now, the mosquitoes are winning.


The predominant cause of endemic and epidemic cholera is the bacteria Vibrio cholera O1, which has been associated with a lower risk of colonization in exposed blood group O individuals, but a higher risk of more severe disease if colonized in those individuals. 27 A study in Bangladesh reported the distribution of O:A:B:AB blood groups in healthy controls as 28%, 23%, 38%, and 11%, respectively in patients as 43%, 19%, 34%, and 4%, respectively and in asymptomatic contacts as 47%, 18%, 27%, and 8%, respectively. 27 This study found that the Lewis antigen was significantly different in symptomatic cholera infections, when compared to controls and healthy contacts.

The overall distribution in the study participants was 28% Le(a+b–) or non-secretors with the Lewis antigen, 55% Le(a𠄻+) or secretors with the Lewis antigen, and 17% Le(a𠄻–), who do not express the Lewis antigen and can be either secretors or non-secretors. 27 Comparing cholera patients vs contacts/healthy controls, the distribution was 39% vs 25%/25% Le(a+b–), 40% vs 60%/58% Le(a𠄻+), and 21% vs 15%/17% Le(a𠄻–), indicating that non-secretors were more likely to get symptomatic cholera than contacts (OR, 1.91) and healthy controls (OR, 1.90), and that secretors were less likely than contacts (OR, 0.45) and healthy controls (OR, 0.48), while no difference was found in the Lewis-null group. 27

When comparing patients to contacts by blood group, within the A and B blood groups the secretor phenotype was significantly less common, while non-secretors and Lewis-null phenotypes were more common this difference was not seen in the O blood group individuals, but since this blood group is itself a risk factor for cholera, the Lewis blood group effect may have been masked. 27 Additionally, secretors required less intravenous fluid than non-secretors, which is consistent with the severity findings, and Lewis-null individuals had the longest duration of diarrhea and required the most intravenous fluids, suggesting an increased severity of infection if it occurs this may be related to the finding that the Lewis-null group also had the lowest IgA response to lipopolysaccharide antigens at day 7. 27

Bacterial Meningitis

Three species of bacteria, N. meningitides, H. influenza, and S. pneumoniae, cause about 75% of all bacterial meningitis the capsules of these bacteria contain polysaccharide antigens, which the immune defense of the host must recognize and respond to with the appropriate antibodies. 31 These bacteria can generate either A or B antigens, depending on the blood group environment in which they find themselves, and also contain an enzyme that can alter B antigen to A antigen perhaps not surprisingly, blood group B individuals have the lowest prevalence of infection by these bacteria because their anti-A antibodies respond as natural antibodies to the bacterial antigens. 31 In contrast, blood group A, AB, and O individuals must rely on specific anti-pneumococcal antibodies, which their immune system must generate in response to the invading organisms. 31 Non-secretors are significantly more susceptible to these bacteria than secretors non-secretors make up 20% to 25% of the general population of western Europe, but in several studies, the proportion of non-secretors in patients with these infections ranged from 47.0% to 73.3%. 31


Blood group antigens participate in cell signaling, cell recognition, and cell adhesion, and are therefore likely to play a role in tumorigenesis, metastasis, and prognosis. 46 During cellular differentiation, development, and aging, expression of ABH and related antigens varies this is particularly true during pathological phenomena and carcinogenesis. 11 The epithelial tissues of the mouth, gastrointestinal tract, lung, bladder, breast, uterine cervix, and prostate have ABH antigens, but these antigens are often missing from the glycoproteins and glycolipids of malignant tissues in these areas. 1 For example, it is thought that DNA methylation in the promoter region for the blood group A gene may inhibit transcription of the associated enzyme and therefore loss of the A antigen, but different mechanisms for reduction of mRNA have been found in A tumors, which appear to be specific to each tumor cell line. 35

Loss of A and B antigens precedes metastasis, results from down-regulated transcription of ABO with associated loss of A- or B-transferase activity, and increases accumulation of other antigens which act as ligands for selectins and facilitate the metastatic process. 1 As malignancy progresses, normal antigens are lost and so-called tumor antigens are acquired the decrease in A, B, and H antigens is inversely proportional to the metastatic potential of the tumor. 14 Blood group antigens are known to have procoagulant and angiogenic properties, act as ligands for selectins, increase cellular motility, and increase resistance to apoptosis these biological roles may facilitate tumor progression, and a model has been proposed that may account for the described associations between the presence or loss of these markers and the outcome of disease. 71

Some people who are not blood group A have tumors with true A antigens or with 𠇊-like” antigens that have very similar properties to A antigens in these people, the tumor antigens would be recognized as foreign and would interact with anti-A antibodies, resulting in attack of the tumor. 14 This may explain why blood group A people have a higher incidence of cancer than group O people the A or 𠇊-like” properties of these tumor antigens are not seen as foreign in blood group A people. 14 When compared to group O people, group A people have a higher incidence of cancer in the salivary glands (64%) stomach (22%) ovaries (28%) uterus (15%) cervix (13%) and colon/rectum (11%). 14 It should be noted that although ABO genotypes are significantly correlated with the risk of certain cancers, they do not cause cancer they only indicate susceptibility. 11 Conversely, lack of correlation does not confer protection: multiple studies have failed to find an association between blood type and breast cancer. 32�, 37

Leukemia and Lymphoma

In patients with acute leukemia, and sometimes in aplastic anemia, A and B antigens commonly decrease until they are undetectable as the patient’s condition improves, the antigens increase again to their former levels. 14 This loss of antigens may not be due to deficiency in transferase synthesis or activity, but instead may be due to an inhibitory factor related to antigen-antibody binding, or an abnormal distribution or density of antigen sites in the RBC membrane. 38 In patients with leukemia, between 17% and 37% had significantly lower expression of A, B, or H antigens when compared to healthy controls of A, B, or AB patients with myeloid malignancies, 55% had reduced expression of A or B antigens, and 21% of O patients had reduced H antigens, when compared with healthy controls of the same ABO genotype. 1

Non-Hodgkin’s primary central nervous system lymphoma (PCNSL) begins in and typically remains confined to the central nervous system (CNS), 40 while secondary central nervous system lymphoma (SCNSL) typically does not begin in the CNS but may later involve the CNS in 10% to 30% of cases. 39 A multi-center study of 36 patients with PCNSL reported that the incidence was 55.6% in blood group O, 8.3% in blood group A, 27.8% in blood group B, and 8.3% in blood group AB, 40 while a second study evaluated 202 patients with secondary central nervous system lymphoma (SCNSL), and reported that the incidence was 29.7% in blood group O, 5.0% in blood group A, 61.9% in blood group B, and 3.5% in blood group AB. 39 In both studies, the same population of healthy controls was used, in which the blood group proportions were 35.6% in blood group O, 37.1% in blood group A, 22.2% in blood group B, and 6.1% in blood group AB the dramatically lower incidence in blood group A in both studies is highly significant in light of the fact that blood group A is the most common blood group in Iran. 39, 40

There are very few studies of the association between ABO blood groups and children with leukemia and lymphoma. A ten-year retrospective study of pediatric patients with acute myeloid leukemia (AML n=116), acute lymphoblastic leukemia (ALL n=522), Hodgkin’s lymphoma (n=63), and non-Hodgkin’s lymphoma (n=78) reported significant differences in the overall distribution of blood groups when compared to the source population for all but the AML patients. 41 This study reported that the incidence of Hodgkin’s lymphoma was 45.6% higher in blood group B patients and 56.5% lower in blood group A patients the incidence of non-Hodgkin’s lymphoma was 52.9% lower in blood group A patients the incidence of ALL was 14.3% higher in blood group O patients but there was no difference in the distribution of blood groups in patients with AML. 41 A separate multi-center pediatric study of 682 patients with ALL and 224 patients with AML reported the incidence of ALL was 56.5% higher in blood group O patients, 35.8% lower in blood group A patients, and 26.9% lower in blood group B patients, while the incidence of AML was 28.8% higher in blood group A patients. 42

Stomach cancer

Worldwide, gastric cancer is the fourth most common type of cancer and the second leading cause of cancer deaths studies since the 1950s have consistently shown that blood group A individuals have about a 20% greater risk of stomach cancer than blood group O individuals. 20 A meta-analysis in 2012 gave group A individuals an odds ratio of 1.11 and group O individuals an odds ratio of 0.91 for gastric cancer, and also found that blood group A individuals had significantly higher rates of H. pylori infection that non-A blood group patients (OR=1.42). 43 This is significant because a recent investigation of ABO blood groups and H. pylori found that the risk of advanced precancerous gastric lesions was significantly affected by the presence or absence in the bacterial DNA of two SNPs in the cytotoxin-associated gene A (CagA), distinguished as CagA positive and CagA negative strains. 26

In individuals infected with CagA positive H. pylori, the risk was significantly higher in blood group A than in blood group O for intestinal metaplasia (OR=1.36) and dysplasia (OR=1.78), with a combined OR of 1.42, while in those with CagA negative strains or who were not infected with H. pylori, blood group A individuals had a significantly lower risk than blood group O individuals for intestinal metaplasia and dysplasia (OR=0.60). 26 Thus, ABO blood group is a risk factor in the development of precancerous lesions in individuals with CagA positive H. pylori infection ABO antigens on the gastric epithelium are binding sites for the H. pylori bacterium, which then injects CagA virulence protein into the cellular cytoplasm. 26 Both factors play a role in the severity of gastric precancerous lesions and progression to gastric cancer.

Pancreatic cancer

Pancreatic cancer is the seventh most frequent cause of cancer death worldwide, and is one of the most aggressive cancers, with mortality rates nearly equal to incidence rates. 20 Non-O individuals have a 25% greater risk of stomach and pancreatic cancer, with a 17% overall greater risk of pancreatic cancer alone when compared to blood group O, the risk of exocrine pancreatic cancer is highest in blood group B (OR, 1.72), and lower for blood groups AB (OR, 1.51) and A (OR, 1.32) 11 secretor status had no significant effect on this risk, but the behavior of H. pylori, which is also influenced by blood group, may have an influence on risk. 1 Non-O blood group individuals infected with CagA negative H. pylori have an even higher risk for pancreatic cancer (OR=2.78). 20 The higher rate of pancreatic cancer in non-O blood group individuals may have been explained by a genome-wide association study, which found that the SNP rs505922 mapped to the first intron of the ABO blood group gene in the 9q34 locus and was in complete linkage disequilibrium with the O/non-O allele. 44 Other studies have found that blood group O is strongly associated with pancreatic disease in patients with Von Hippel-Lindau (VHL) syndrome and is significantly correlated with solid pancreatic lesions in patients with pancreatic neuroendocrine tumors (PNETs) VHL patients have a high risk of developing multiple tumors throughout the body and their risk of developing both benign and malignant PNETs is 8% to 17%. 45

Multiple Endocrine Neoplasia Type I

In 105 patients diagnosed with multiple endocrine neoplasia type I (MENS-1), 46 (43.8%) were diagnosed with a neuroendocrine tumor of these 46 patients, 14 had more than one tumor for a total of 60 tumors, located in the duodenum (n=13), stomach (n=3), lung (n=5), pancreas (n=34), gallbladder (n=1), or thymus (n=4). 46 In patients with metastatic tumors, 16 of 17 (93.8%) had blood group O, while 32 of 43 (74.4%) with benign tumors were blood group O in patients with neuroendocrine tumors, 35 of 46 (76.1%) had blood group O, while only 31 of 59 (52.5%) with non-neuroendocrine tumors were blood group O. 46 Of the 59 patients with non-neuroendocrine tumors, 31 (52.5%) were blood group O, 15 (25.4%) were blood group A, 7 (11.9%) were group blood B, and 6 (10.2%) were blood group AB, while of the 46 patients with neuroendocrine tumors, 35 (76.1%) were blood group O, 9 (19.6%) were blood group A, 2 (4.3%) were blood group B, and none were blood group AB. 46 Blood group AB is found in 4% of the general population, and was found in 3.8% of the study cohort, so the absence of group AB in patients with neuroendocrine tumors was notable. 46

Cancer of the colon/rectum

Increased activity of the 㬑,2-fucosyltransferase of the FUT2 gene (Secretor) and the 㬑,4-fucosyltransferase of the FUT3 gene (Lewis) appear to be involved in the development and control of cancers of the distal colon Type 1 and Type 2 chains and Lewis antigens are normally present in the fetal colon and disappear in healthy adults, but they reappear in adults who have distal colon cancers. 1, 48 In the normal colon, only Type 1 chains are expressed by secretors, while no Type 1 or Type 2 chains are expressed by non-secretors in normal or cancerous colon tissue. 47 In normal colon and colon cancer tissue, secretor status also determines whether the H antigen (blood group O) expresses. 47 The secretory part of the goblet cells in the normal colon is responsible for expression of blood group antigens. 48 Blood group A antigen is sometimes expressed on malignant tumors of group O or group B individuals about 10% of colon tumors of homozygous type O people express A antigen and have N-acetylgalactosaminyltransferase activity. 1

Metabolic diseases

The role of blood groups in metabolic diseases is more complex this is most likely because they are multifactorial diseases that are not controlled by just one gene or antigen. However, some intriguing associations have been found which are presented here.


Hypertension can have many different causes, so it is not surprising that different studies have found different associations between blood group antigens and hypertension. One study found that the rate of hypertension was highest in blood group B, followed by blood group A, and that blood group AB had the lowest rate of hypertension, 49 while another study reported a link between blood group A and systolic blood pressure in Caucasians but not in Blacks. 15 In essential hypertension due to abnormal erythrocyte sodium and potassium transport, no association was found with the ABO, Rh, Duffy, Kidd, P, or MNS blood groups, or with the major histocompatibility HLA antigens. 50 In essential hypertension due to abnormal erythrocyte sodium-lithium countertransport, no association was found with the MNS blood group polymorphism. 52

Essential hypertension is diagnosed when secondary forms of hypertension can be ruled out, but it can also be diagnosed due to renal stenosis (renovascular hypertension), atherosclerotic or fibromuscular etiology, or primary aldosteronism associated with low plasma renin levels individuals with these conditions were compared to normotensive controls and to individuals with secondary hypertension, and no significant differences were found in ABO, Rh, Kidd, Kell, Duffy, P, haptoglobin, PGM-1, or acid phosphatase systems. 51 However, there were significant differences in the frequencies of the MNS blood group antigens when comparing normotensive controls with individuals who had essential or renovascular hypertension when compared to normotensives, essential hypertensives were significantly different among Whites, while a similar difference was not seen among Blacks. 51 Three distinctly different phenotypic frequencies were seen when individuals with atherosclerotic renovascular hypertension were compared to essential hypertensives and normotensives. 51


Studies since the early 1980s have investigated the genetic basis for differences in LDL cholesterol, HDL cholesterol, and triglycerides, and several have found an association between the MN blood group and LDL cholesterol levels. 53 Participants in a dietary intervention program with homozygous MM and NN genotypes (47%) had similar responses to a low-fat diet, which resulted in almost all of the reported reduction in LDL cholesterol in contrast, those with the heterozygous MN genotype (53%) had little or no response to the low-fat diet. 53 This finding is relevant when prescribing a low-fat diet for LDL cholesterol management because it indicates that about half of the general population at large would have a similar response to a low-fat diet. 53

Researchers have also investigated the association between ABO blood group antigens and hyperlipidemia. One study reported that total cholesterol, LDL cholesterol, and triglycerides were higher, and HDL cholesterol was lower, in blood groups A and B, and that blood group AB was protective for hyperlipidemia, 49 while another study reported that blood group A was associated with higher total cholesterol and LDL cholesterol, but reported no association with HDL cholesterol. 15

Perhaps the most interesting finding was the association of ABO and secretor blood groups with serum levels of intestinal alkaline phosphatase (I-ALP) and apolipoprotein B-48 (apo B-48) I-ALP is required for transport of chylomicrons from the intestines into the circulation and is therefore a marker for chylomicron absorption, and apo B-48 is a protein that stabilizes the chylomicron membrane, and is therefore a marker for chylomicron production. 55 There are significant differences in serum I-ALP and apo B-48 between blood group O and B secretors and all other blood groups the O and B secretors have very elevated serum levels of these markers compared with blood group A/AB secretors and non-secretors of all blood groups. 55

ABO non-secretors only have about 20% of the serum I-ALP of secretors, and among secretors, blood group A has very low activity (2.8 ± 1.1 IU/L mean ± SEM) compared to blood group B and O (14.1 ± 1.1 IU/L and 19.0 ± 2.5 IU/L, respectively). 54 It is thought that I-ALP binds with ABO antigens on RBCs of non-secretors and is also adsorbed by the A antigens of secretors, therefore being rapidly eliminated from circulation in these individuals, but the soluble circulating antigens of O and B secretors preferentially bind with I-ALP and prevent its elimination in these individuals. 55 Blood group A individuals also have lower serum apo B-48 levels, which may be due to a genetic down-regulation of I-ALP activity in their intestines, resulting in reduced chylomicron secretion 55 and possibly lower serum cholesterol levels.

Diabetes mellitus

A large prospective study in France found no association between risk of type 2 diabetes mellitus (T2DM) and Rh blood group, but those in blood group O had the lowest risk of T2DM while blood group B individuals were at the highest risk, followed by group AB and then group A people, but the risk for group AB individuals did not reach statistical significance. 18 When ABO and Rh groups were evaluated together, blood group B + individuals had the highest risk, followed by group AB + , then A – and then A + individuals, but no difference in risk was seen for the other groups. 18 When adjusted for metabolic covariates (fasting blood glucose and lipids), blood group AB individuals had the highest risk of T2DM (OR, 1.95), followed by group B (OR, 1.26) and group A (OR, 1.21) as compared with blood group O individuals, who had the lowest risk. 18

Other studies have reported contradictory results: a study in Yemen reported that the highest random blood sugar and insulin levels were found in blood group A, while blood group AB showed a protective effect 49 a study in Iraqi individuals reported higher total cholesterol, higher blood glucose, and higher blood pressure in blood group O individuals, followed by lower risk in group A, group B, and then group AB individuals, who had the lowest risk 18 a large study in Bangladesh reported no association between ABO blood groups and T2DM and a study in Malaysia found lower risk of T2DM in blood groups A and O. 56 It has also been reported that non-secretors are more likely to have T2DM. 15

Convincing evidence has been reported of a genetic association in those of European ancestry between non-secretor status (se/se homozygous for the A/A alleles of the FUT2 gene) and insulin-dependent type 1 diabetes mellitus (T1DM). In the case-control population, the odds ratio for non-secretor status was 1.29 (p=7.3 x 10 � ) in the diabetic family population, the relative risk for non-secretor status was 1.22 (p=6.8 x 10 𢄦 ) and the combined results clearly indicated a locus for T1DM in the FUT2 gene (p=4.3 x 10 � ). 29

The I-ALP findings by blood group for diabetes were similar to the findings for hyperlipidemia, with significantly higher serum I-ALP and total ALP levels in blood group B and O secretors (including controls) when compared to A secretors or ABO non-secretors, but no significant difference in serum I-ALP or total ALP between A secretors and ABO non-secretors (including controls). 59 However, when comparing blood group B and O secretor diabetics to controls, I-ALP activity was similar between type 1 and type 2 diabetics but significantly higher in both types than in the controls similarly, there was no significant difference in I-ALP activity between type 1 and type 2 diabetics in the A secretor and ABO non-secretor groups, but both types of diabetics had significantly higher I-ALP activity than the controls in these groups. 59

Additional comparisons were made between the diabetics and controls in the group B and O secretors: in most cases, fasting I-ALP activity was higher in the diabetics than in the controls both types of diabetics had significantly higher liver ALP activity than the controls type 2 diabetics had higher liver ALP than type 1 diabetics and type 2 diabetics also had more abnormal ALT and GGT values than type 1 diabetics. 59 Disturbed liver function could impair clearance of I-ALP by the liver and would explain the higher ALP levels found in the diabetics high I-ALP has been reported in patients with cirrhosis of the liver. 59

The Role of the Microbiome

Considerable research has focused on the role of intestinal bacteria in the development of diabetes. There are significant differences between the composition of the gut microbiome in healthy children and children with T1DM, and it is believed that T1DM occurs as a result of a pathogenic inflammatory response resulting in damage to the β-cells of the pancreas. 58 In addition, intestinal bacterial strains have been identified that can regulate the immune system and induce antigen-specific pathogenic T cells, which may be involved in the development of T1DM. 58 Differences were also found in both phylum and class levels for those with newly-diagnosed T2DM, those who were pre-diabetic, and those with normal glucose tolerance, indicating that the progression of glucose intolerance is associated with specific changes in the gut microbiome. 58

Obesity is strongly correlated with T2DM, but there are metabolically normal obese people who are insulin sensitive and euglycemic, and metabolically obese normal weight people who have metabolic syndrome despite maintaining a healthy weight. 57 In addition, discordance in obesity between monozygotic and dizygotic twins clearly indicates that other factors than genetics are involved in obesity fecal transplants between fat and thin mice have resulted in changes in metabolism, morphology, and composition of the gut microbiome to match the donor mouse. 58 There is a strong associate between obesity and alterations of the gut microbiome, but it is not known whether these changes are a consequence or a cause of obesity. 58

13.2: Organization of the Human Body

  • Contributed by CK-12: Biology Concepts
  • Sourced from CK-12 Foundation

How is the human body similar to a well-tuned machine?

Many people have compared the human body to a machine. Think about some common machines, such as drills and washing machines. Each machine consists of many parts, and each part does a specific job, yet all the parts work together to perform an overall function. The human body is like a machine in all these ways. In fact, it may be the most fantastic machine on Earth.

The human machine is organized at different levels, starting with the cell and ending with the entire organism (see Figure below). At each higher level of organization, there is a greater degree of complexity.

The human organism has several levels of organization.


The most basic parts of the human machine are cells&mdashan amazing 100 trillion of them by the time the average person reaches adulthood! Cells are the basic units of structure and function in the human body, as they are in all living things. Each cell carries out basic life processes that allow the body to survive. Many human cells are specialized in form and function, as shown in Figure below. Each type of cell in the figure plays a specific role. For example, nerve cells have long projections that help them carry electrical messages to other cells. Muscle cells have many mitochondria that provide the energy they need to move the body.

Different types of cells in the human body are specialized for specific jobs. Do you know the functions of any of the cell types shown here?


After the cell, the tissue is the next level of organization in the human body. A tissue is a group of connected cells that have a similar function. There are four basic types of human tissues: epithelial, muscle, nervous, and connective tissues. These four tissue types, which are shown in Figure below, make up all the organs of the human body.

The human body consists of these four tissue types.

  • Connective tissue is made up of cells that form the body&rsquos structure. Examples include bone and cartilage.
  • Epithelial tissue is made up of cells that line inner and outer body surfaces, such as the skin and the lining of the digestive tract. Epithelial tissue protects the body and its internal organs, secretes substances such as hormones, and absorbs substances such as nutrients.
  • Muscle tissue is made up of cells that have the unique ability to contract, or become shorter. Muscles attached to bones enable the body to move.
  • Nervous tissue is made up of neurons, or nerve cells, that carry electrical messages. Nervous tissue makes up the brain and the nerves that connect the brain to all parts of the body.

Organs and Organ Systems

After tissues, organs are the next level of organization of the human body. An organ is a structure that consists of two or more types of tissues that work together to do the same job. Examples of human organs include the brain, heart, lungs, skin, and kidneys. Human organs are organized into organ systems, many of which are shown in Figure below. An organ system is a group of organs that work together to carry out a complex overall function. Each organ of the system does part of the larger job.

Many of the organ systems that make up the human body are represented here. What is the overall function of each organ system?

Your body&rsquos 12 organ systems are shown below (Table below). Your organ systems do not work alone in your body. They must all be able to work together. For example, one of the most important functions of organ systems is to provide cells with oxygen and nutrients and to remove toxic waste products such as carbon dioxide. A number of organ systems, including the cardiovascular and respiratory systems, all work together to do this.


There are controversies regarding the best method for procurement of blood during elective and emergency situations: (a) It can be done by routinely asking for grouping and cross-matching in elective surgical patients. Many scientific articles disputed the relevance of preoperative arrangement of blood in surgeries where blood loss is not anticipated to be significant.[20,21] (b) Blood may be ordered without full set of investigations.[19] ABO-Rh typing alone results in a 99.8% chance of a compatible transfusion. Antibody screening increases this safety margin up to 99.94%, and an additional cross-match further increases the compatibility to 99.95%. In absence of cross-matching, there is a possibility of missing the antigens on donor cells, but in clinical practice, they are of less importance. Hence, “screening and typing” alone should be carried out. Other methods include “type and partial cross-match,” which includes the immediate phase of cross-match “type and uncross match,” for those recipients who have never been transfused before, the chance of detection of antibody with each cross-match is 1:1000 “type O Rh-negative uncross match,” it is performed in emergency situation when the time for these procedures is limited. In the latter condition, type O Rh-negative packed RBCs, that is, the universal donor can be used as they will have a negligible amount of hemolytic anti-A/anti-B antibodies against the recipient RBCs.

What blood type is the universal Donor ?

The universal donor blood type is O negative (O-). Donors having blood group or type O negative (O-) blood have the unique power to help anyone in emergency situation and need of a blood transfusion and help to save patients life.

But question is there how doctor should decide to transfusion only O negative blood group in emergency situation and why O negative blood group is known as blood Universal Donor.

What blood type is the universal Donor ?

Blood types

We know that there are different types of antigen on surface of red blood corpuscles who play key factors in deciding and finding of blood types which type of blood you have ? or deciding blood universal Donor type and blood universal receiver type.

Whether a person has blood type A positive (A+) or A negative (A-), blood type B positive (B+) or B negative (B-), blood type AB positive (AB+) or AB negative (AB-) and blood type O positive (O+) or O negative (O-). blood depends on the presence or absence of specific substance on the red blood cells.

There are two types of specific substance known as antigens present on the surface of red blood cells named antigen A and antigen B.

And other type of antigen is presence of RH factor or absence of RH factor. RH factor is present in red blood cells of patients then it is considered to be positive (+) blood group and if RH factor is absent in red blood cells of patients then it is considered to be negative (-) blood types.

The Rh blood group is one of the most complex blood groups known in humans. From its discovery some years ago where it was named after the Rhesus monkey, because RH factor was first found in rhesus monkey then further experiment and Research done on human beings. And discovery of RH factor become second in importance only to the ABO blood group in the field of transfusion medicine.

So there is two types of antigens — antigen A and antigen B and other RH factor deciding what kind of blood types you have.

And other factor responsible for deciding blood type either it will be Universal Donor blood type or Universal receiver blood type that is multiple alleles in ABO blood group systems. Now let us try to understand something about what is multiple alleles

Multiple alleles

In mendelian heredity characters are concerned with genes with two alternative forms or alleles. now it has been noticed that for many characters a genes for a character may exist in many alternative alleles. this forms of a genes are due to mutation of single wild type.

Definition of multiple alleles is when more than two allelic forms of wild types are located on same locus in given pair of chromosomes they are known to compose the series of multiple alleles. Actually grouping of all the different alleles that may be present in a gene pair is defined as systems of multiple alleles and multiple alleles posses the following characteristics

1) multiple alleles are located at the same locus in the chromosomes

2) multiple alleles regulate of particular character

3) process of crossing over is not exhibited by multiple alleles among themselves due to their location on same locus

4) multiple alleles shows the dominant or intermediate phenotypes while wild type of series is usually dominant. wild-type or dominant is represented by capital letters. while other alleles which are recessive are represented by lowercase letter.

And multiple alleles in ABO blood group systems there are group of three alleles regulate relating to the formation of 6 genotypes

Three different alleles in ABO blood group are following

1) Antigen A dominant allele and their genotypes is represented by IA

2) Antigen B dominant allele and there genotype is represented by IB

3) and blood group O have no antigen then it should be represented by iO that is recessive allele

According to Mendelian law of dominance out of two contrasting allelomorphic factor only one Express itself in an individual. The factor that expresses itself is known as dominant alleles while other which has not shown its effect or supress is termed as recessive alleles.

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blood type A :- there is two types of blood group A first is A positive (A+) and second one is A negative (A-). Thus a person having antigen A and presence of RH factor it is considered to be with blood type A Positive (A+) or person having antigen A and absence of RH factor it is considered to be with blood type A negative (A-).

What blood type is the universal Donor ?

blood type B :- there is two types of blood group B first is B positive (B+) and second one is B negative (B-). Thus a person having antigen B and presence of RH factor it is considered to be with blood type B Positive (B+) or person having antigen B and absence of RH factor it is considered to be with blood type B negative (B-).

blood type AB :- there is two types of blood group AB first is AB positive (AB+) and second one is AB negative (AB-). Thus a person having both antigen A and B and presence of RH factor it is considered to be with blood type AB Positive (AB+) or person having both antigen A and B and absence of RH factor it is considered to be with blood type AB negative (AB-).

blood type O :- there is two types of blood group O first is O positive (O+) and second one is O negative (O-). Thus a person having absence of antigen A or B or both and presence of RH factor it is considered to be with blood type O Positive (O+) or person having absence of antigen A or B or both and absence of RH factor it is considered to be with blood type O negative (O-).

Different blood types and their antibodies

Now understandings blood types and their antibodies. Antibodies are immunoglobulin protein secreted by B lymphocytes in several immune response when foreign particles like pathogens or something chemicals when inter inside our body, it neutralizes of it by the process of antigen antibody interaction. Antigen is foreign particles and antibody is immunoglobulin protein.

antigen-antibody reaction, is a specific chemical interaction between antibodies produced by B cells of the white blood cells and antigens during immune reaction. The antigens and antibodies combine by a process called agglutination.

● In our ABO blood group system person having blood type A have antibody B in their blood

● In our ABO blood group system person having blood type B have antibody A in their blood

● In our ABO blood group system person having blood type AB have no any antibody in their blood

● In our ABO blood group system person having blood type O have antibody A and B in their blood.

Now understand what blood type is universal Donor ? Universal Donor blood type is O negative represented by (O-). And why O negative blood type is considered as blood Universal Donor because it has no antigen A, B and RH factor and when it transfusion to patients then antibody present in blood of patients can not able to recognise for immune response due to absence of antigen in Donor blood group that is O negative blood group. Because antibody is specific to antigen then create immune response and if neither antigen is available nor antibody from B cell secreted. Thus O negative blood group is suitable for all patients which does not create any antigen antibody reaction in patients blood.

And I think you have found your answer what type of blood is the universal Donor correctly you say O negative (O-) blood group is universal Donor blood type.

Q1) what blood type is the universal Donor

Ans. option no. (B) you will have right answer what blood type is the universal Donor, O negative is blood Universal Donor type.

Red blood cells from O negative (O-) donors can be transfused to anyone, regardless of the person’s blood type. This is crucial with trauma patients in those early moments of an emergency where doctors will often depend on only O- blood to help save the person’s life.

Once the patient’s blood type is determined, doctors can switch to that blood type for future transfusions.

Universal receiver blood type

Blood type AB either it will be positive (AB+) or negative (AB-) both are known as universal receiver blood type. So universal receiver blood type AB have capable of taking blood from any other person having different types of blood group either it will be positive or negative like A+, A-, B+, B-, AB+, AB-, O+, O-

Why blood type AB known as universal receiver ?

Blood type AB is known as universal receiver because it has no antibody A and B production in their blood and when other blood group like A+, A-, B+, B-, AB+, AB-, O+, O- from other person get donating to person having blood type AB do not causes antigen- antibody immune response because of absence of antibody A and B in blood type AB

And antigen and antibody are always specific to one another in function it means antibody A is always recognise antigen A only not other type of antigen. The AB blood type means that both of the antigens for A and B blood are present. Since both A and B antigens are present in recipient and donor person with AB blood type the recipient won’t reject the blood. The body identifies that blood as “self” rather than “foreign.”

You are probably aware that giving a person a blood transfusion with the wrong type of blood can be lethal, leading to rejection and often death. But you may not be aware that individuals with type AB blood can safely receive blood from a donor with any blood type—O, A, B, or AB. This person who can accept a blood transfusion from any blood type is called a universal recipient.

Some Quick facts about O negative

1) 7% of the world population has O negative (O-) blood.

2)O negative (O-) blood is the blood type in the highest demand.

3) O negative (O-) blood is the preferred blood type for people with underdeveloped immune systems, including premature babies and cancer patients.

4) The preferred donation methods for O negative ( O- ) donors are Double Red Blood Cell and Whole Blood. These two donation types allow O negative O- donors to maximize their donation and make the largest impact for patients in need.

5) While O negative (O-) is the universal blood type for whole blood and red blood cell transfusions, it is not the rarest blood type nor is it the universal blood type for platelet or plasma transfusions.

6) Universal blood type for platelet transfusions
The universal blood type for platelet transfusions is AB positive (AB+). One of the rarest of all blood types, only 3% of the world population has this special blood type. Platelets from AB+ donors can be used for any patient in need. AB+ donors are encouraged to donate Plasma or Platelets.

7) Universal plasma donors
People with AB type blood (positive or negative) are universal plasma donors. Only 4% of the world population has type AB blood. Plasma from AB donors can be given to patients with any blood type, making it extremely important for those in need. AB donors are encouraged to donate Plasma or Platelets.

8) You can maximize your donation to make the largest impact. Schedule a donation appointment and give the gift of life in honor of National Donate Life Month!

9) Donors with type O negative (O-) red blood cells are referred to as universal donors and their red blood cells can be given to any other blood type

10) Donors with type AB positive (AB+) are referred to as universal recipients and can receive red blood cells from any other blood type

11) Donors with type AB negative (AB-) are universal plasma donors and can give plasma to any other blood type.

Biology chapter 6

A. are derived from the same original stem cell.

D. have mitochondria and other organelles.

A. neutrophils and basophils

B. lymphocytes and monocytes

C. eosinophils and monocytes

D. monocytes and neutrophils

B. megakaryocyte breakdown.

C. increase erythrocyte production.

B. infectious mononucleosis

A. It is caused by an Epstein-Barr virus.

B. Symptoms include fever, sore throat, and swollen lymph glands.

C. There is uncontrolled white blood cell proliferation.

D. Active EBV can be passed in saliva.

2. Eosinophils: use granular contents to digest large pathogens, such as worms, and reduce inflammation.

3. Basophils: promote blood flow to injured tissues and the inflammatory response.

4. Lymphocytes: responsible for specific immunity. B cells produce antibodies T cells destroy cancer and virus- infected cells.

2. Platelets and damaged tissue release prothrombin activator, which initiates a cascade of enzymatic reactions.

3. Prothrombin activator converts prothrombin into thrombin.

4. Thrombin severs two amino acid chains from fibrinogen.

5. The activated fragments form the fibrin thread.

6. Fibrin winds around the platelet plug providing a framework for the clot.

A. Formed elements and plasma would not remain in the blood.

B. Red blood cells would increase in concentration.
C. The Ca2+ concentration in the blood would increase.
D. The blood pressure of the individuals would increase.

Blood Types

Human blood is grouped into four types: A, B, AB, and O. Each letter refers to a kind of antigen, or protein, on the surface of red blood cells. For example, the surface of red blood cells in Type A blood has antigens known as A-antigens.

The Rh Factor

Each blood type is also grouped by its Rhesus factor, or Rh factor. Blood is either Rh positive (Rh+) or Rh negative (Rh-). About 85% of Americans have Rh+ blood.

Rhesus refers to another type of antigen, or protein, on the surface of red blood cells. The name Rhesus comes from Rhesus monkeys, in which the protein was first discovered.

Why Know Your Blood Type

Knowing a person's exact blood typeis criticalwhen a blood transfusion is necessary. Duringa blood transfusion, a patient must receive a blood type that is compatible with his or her own. If the blood types are not compatible, red blood cells will clump together, making clots that can block blood vessels and cause death.

People with Type Onegative blood are considered to be universal donorsbecause theycan donateto people of any blood type. Individuals with Type AB+ blood areconsidered the universal recipientsbecause people with that type can receive any blood type.

Blood Type Chart: Below is a chart listing blood types, the percentage of Americans with that type, and the types they can donate to.

Blood typePercent of Americans with this typeWho can receive this type?
O+37O+, A+, B+, AB+
O-6All blood types
A+34A+, AB+
A-6A+, A-, AB+, AB-
B+10B+, AB+
B-2B+, B-, AB+, AB-
AB-1AB+, AB-

Did You Know?

  • Blood type is inherited, just like eye color.
  • Certain blood types are more common in certain countries. In China, over 99 percentof the population has Rh+ blood.
  • Different kinds of animals have different kinds of blood. Dogs have 4 blood types cats have 11 cows have about 800.
  • Some people think blood type tells about personality. Legend has it that Type A is calm and trustworthy Type B is creative and excitable Type AB is thoughtful and emotional and Type O is a confident leader.
  • In Japan, the idea of blood type as personality type is so popular that Japanese ask "What's your blood type?" about as often as Americans ask "What's your sign?"

Blood Transfusions

A blood transfusion is the transfer of blood from one person to another. Blood that is lost through an injury, an illness or a surgery can be replaced through transfusion. Aside from transferring blood as a whole, parts of blood, such as red blood cells, plateletsor plasma can also be transferred to individuals.

Donor blood is tested for HIV, hepatitis, syphilis, West Nile virusand other diseases before transfusion. According to the Centers for Disease Control, there are more than 9.5 million blood donors in the United States and an estimated 5 million patients who receive blood annually, resulting in a total of 14.6 million transfusions per year.

The American Association of Blood Banks maintains a databaseof locations for individuals to donate blood. Many blood donation centers are run by the Red Cross.

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