- The B blood group is one of the four major types within the ABO blood group system, which classifies human blood based on specific antigens present on the surface of red blood cells (RBCs) and corresponding antibodies found in the plasma. Individuals with blood group B have the B antigen on the surface of their RBCs and produce anti-A antibodies in their plasma. These antibodies target and destroy any red cells that display the A antigen, making compatibility crucial during blood transfusions.
- There are two primary subtypes of the B blood group based on the Rhesus (Rh) factor:
- B positive (B⁺): This is the more common variant and means the person has both the B antigen and the Rh (D) antigen on their red cells.
- B negative (B⁻): This rarer subtype has the B antigen but lacks the Rh antigen.
- In transfusion medicine, a person with B-positive blood can receive B⁺, B⁻, O⁺, and O⁻ blood, while a B-negative individual can safely receive B⁻ and O⁻ blood. Transfusing blood that contains incompatible antigens (such as A or AB blood) into someone with B blood can trigger an immune response, potentially leading to serious complications such as hemolytic transfusion reactions.
- The inheritance of the B blood group follows Mendelian genetics, governed by the ABO gene located on chromosome 9. The gene has three alleles: A, B, and O. The B allele is co-dominant with the A allele and dominant over the O allele. Therefore, individuals with blood type B may have one of the following genotypes: BB (homozygous) or BO (heterozygous).
- Globally, the distribution of the B blood group varies widely. It is more prevalent in Asia, particularly in parts of India, China, and Central Asia, but is less common in Western Europe and the Americas. This uneven distribution has implications for blood bank inventories and population-based research.
- Some studies have explored possible links between blood group B and various health conditions, such as susceptibility to infections or cardiovascular disease, though findings are often inconclusive or influenced by other genetic and environmental factors.
