Anti-A and anti-B haemolysins, dangerous universal blood donors and the risk of ABO antagonism in a Nigerian community.

Blood samples from 509 volunteers from a Nigerian community were tested for the presence of anti-A and anti-B hemolysins. Among the group 0 individuals in the study, 53.6% had anti-A hemolysins, 62.7% had anti-B hemolysins and 47.9% had both anti-A and anti-B hemolysins. Of the group A individuals 35.7% had anti-B hemolysins and none had anti-A hemolysins; 8.8% of the group B individuals had anti-A hemolysins and none had anti-B hemolysins. The high level of anti-A and anti-B hemolysins compared to the low levels in Europeans is discussed, particularly in relation to the preponderance of ABO incompatibility over Rh(D) incompatibility as a cause of hemolytic disease of the newborn in Nigerians in contrast to Europeans. The physiology of anti-A and anti-B hemolysins is reviewed and the fact that, unlike Europeans, many group O individuals in Nigeria are 'dangerous' rather than 'safe' universal blood donors is highlighted.