Since the introduction of the ABO blood typing in 1900 by Karl Landsteiner, scientists to date still do not fully comprehend the role it plays in human physiology.

However, the consensus exists that it must play a role because such a blood typing exists even in ancient species, such as amphibians and reptiles, and in evolved species, such as rodents and primates.

Blood group serology

The fact that differing blood serology exists is testament to the fact that the blood antigens are being subject to active, intensive evolutionary selection pressure. The two most common methodologies for blood typing are the ABO, and Rhesus (Rh) blood typing.

• O+ : The most common globally (33.5%)
• A+ : Followed by a close second (25.5%)
• B+ : The third most common (27%)
• AB+ : The forth most common (6.5%), and rarest form of Rh positive blood typing
• The rarest blood types all belongs to the Rh negative, which are, also in the same order as the positive Rh blood typing (3.1%, 2.4%, 1.5%, 0.5%)

Rh negative are not only rare, occurring in approximately 7.5%, but also precious, as they are universal donors, meaning they can donate to individuals that are Rh positive, but only exclusively receive Rh negative blood.

Similarly, O blood type are universal donors, A can receive from A and O, B and receive from B and O, AB can receive from A, B, AB and O (they are thus the universal recipients).

The Bombay Blood Type (BBT): This serotype occurs in one in 10,000 Indians, or in one hundredth of a percent of people (0.01%). In Europeans, the occurrence is even rarer, at one in 1,000,000, or one ten thousandth of a percent (0.001%). Individuals with BBT do not have a ‘H’ antigen, and cannot make the ‘A’ and ‘B’ antigen. They can only accept similar blood, meaning those of the ABO serotype cannot donate their blood to them.

Various cancers and their blood type risk

Pancreatic cancer: Approximately 17% were attributable to a non-O blood group; there was a slight increase in the risk of pancreatic cancer for those with A, AB, or B. These results were corroborated by several other studies.

Stomach cancer: Blood group A is more susceptible to stomach/gastric cancer, and the least susceptible ones are those with blood group O. Those with AB blood had a higher chance, but the results were not statistically significant.

Non-melanoma skin cancer: Those with non-O blood had a lower chance of contracting this cancer.

Squamous cell carcinoma: Those with non-O blood also had a lower chance of contracting this cancer.

Ovarian cancer: Those with B and AB had an increased risk of contracting ovarian cancer.

Non-small cell lung cancer: It was found that those with A and AB had a higher mortality rate, when compared to those with B or O blood type.

Risks of strokes, and cardiovascular diseases

Deep-venous thromboembolism (DVT): Non-O blood types have been reported, by three meta-analyses, to have an increased risk of DVT.

Lower levels of circulating von Willebrand factor: Individuals with type O would have a higher level of this factor, which in turn reduced clotting risk. Thus, those with type O blood also exhibited lower levels of ischemic stroke, myocardial infraction, and peripheral artery disease.

Communicable diseases

Helicobacter pylori: The specific O sub-type, O Lewis b, has been associated with a higher risk of contracting this bacteria, which results in peptic ulcers. The hypothesised reason is that certain H. pyloristrains can bind O lewis b antigen much more strongly compared to A lewis b.

Vibrio cholera, E Coli, and Norovirus: Type O people are also more susceptible to severe infections of these three bacterial infection, than other blood serotypes.

Malaria: Those with blood serotype O have a better prognosis towards a malaria infection, which provides a compelling example of microbial selection pressure on evolution of blood group antigens. This has been supported experimentally, and througha Genome-wide association study. MIMS

Read more:
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Sources:
http://www.medicaldaily.com/people-same-blood-types-share-similarities-how-they-fight-diseases-401853
http://www.hmudq.edu.cn/zz/jy/UpFiles/news/201211/2012 ABO blood group 血液.pdf
http://www.rhesusnegative.net/themission/bloodtypefrequencies/
http://www.hsa.gov.sg/content/hsa/en/Blood_Services/Transfusion_Medicine/Blood_Safety/Blood_Group_Serology.html
http://jnci.oxfordjournals.org/content/101/6/424.full.pdf+html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2015995/pdf/brmedj03437-0015.pdf http://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-014-0237-8