The Blood Groups and Their Interactions
The human ABO blood group system is defined by the presence of specific carbohydrate antigens on the surface of red blood cells and the corresponding antibodies (isoagglutinins) circulating in the plasma. While primarily associated with blood transfusions, these antigens are also expressed on the endothelial, tubular, and glomerular cells of the kidney, making them critical factors in organ transplantation.
ABO Compatibility and Donation Table
The table below shows which blood groups can donate to one another under standard (compatible) conditions and which combinations are considered incompatible.
Donor Blood Group | Compatible Recipient Groups | Incompatible Recipient Groups (Requires ABOi Protocol) |
|---|---|---|
O | O, A, B, AB | None (Universal Donor) |
A | A, AB | O, B |
B | B, AB | O, A |
AB | AB | O, A, B |
3.Key Compatibility Principles
- The Universal Donor (Group O):
Individuals with blood group O lack both A and B antigens on their renal cells. This allows them to donate to any other blood group without triggering an antibody attack from the recipient. - The Universal Recipient (Group AB):
Individuals with blood group AB do not produce anti-A or anti-B isoagglutinins. As a result, they can safely receive a kidney from any donor group. - Blood Group O Recipients:
These patients face the greatest disadvantage because they can only receive kidneys from group O donors. Since group O kidneys are often allocated to non-O recipients who are highly sensitized, group O candidates frequently wait twice as long for a transplant. - A2 to B Interactions:
The A2 subgroup has weakened antigenicity (approximately 75% less expression). Therefore, transplants from A2 donors to B recipients are often feasible with standardized low-titer protocols, or sometimes even without desensitization if titers are ≤1:8.
Biological Variances:
Blood group O individuals naturally have about 25% lower levels of von Willebrand factor, which provides some protection against thrombosis but makes them more susceptible to bleeding complications.
