From UPSC perspective, the following things are important :
Prelims level : Blood Groups
Mains level : Not Much
- Over the last two weeks, the “Bombay blood group”, a rare blood type, has been at the centre of attention in Mumbai’s healthcare scene.
- Demand for the blood type has coincidentally spiked at hospitals, but supply has been scarce.
Bombay blood group
- The four most common blood groups are A, B, AB and O.
- The rare, Bombay blood group was first discovered in Mumbai (then Bombay) in 1952.
- Each red blood cell has antigen over its surface, which helps determine which group it belongs to.
- The Bombay blood group, also called hh, is deficient in expressing antigen H, meaning the RBC has no antigen H.
- For instance, in the AB blood group, both antigens A and B are found. A will have A antigens; B will have B antigens. In hh, there are no A or B antigens.
Rare in India, rarer globally
- Globally, the hh blood type has an incidence of one in four million.
- It has a higher incidence in South Asia; in India, one in 7,600 to 10,000 are born with this type.
- This blood type is more common in South Asia than anywhere else because of inbreeding and close community marriages.
- It is genetically passed. Shared common ancestry among Indians, Sri Lankans, Pakistanis and Bangladeshis has led to more cases of hh blood phenotype in this region.
Testing for the group
- To test for hh blood, an Antigen H blood test is required.
- Often the hh blood group is confused with the O group.
- The difference is that the O group has Antigen H, while the hh group does not.
- If anyone lacks Antigen H, it does not mean he or she suffers from poor immunity or may be more prone to diseases.
- Their counts for haemoglobin, platelets, white blood cells and red blood cells are similar to the count of others based on their health index.
- Because of rarity, however, they do face problems during blood transfusion.
- The individuals with Bombay blood group can only be transfused autologous blood or blood from individuals of Bombay hh phenotype only which is very rare.
- Rejection may occur if they receive blood from A, B, AB or O blood group. In contrast, hh blood group can donate their blood to ABO blood types.