Prevalence and titre of ABO haemolysin antibodies in pregnant Nigerian women.

The prevalence and titre of anti-A and anti-B haemolysin antibodies was determined in pregnant and non-pregnant women in a Nigerian community. The results show that alpha haemolysin occurs less frequently than beta-haemolysin in both pregnant and non-pregnant subjects. However, the prevalence of alpha haemolysin was significantly higher in pregnant subjects than in the non-pregnant ones. Surprisingly, the prevalence of haemolysin was significantly lower among the pregnant group than the non-pregnant group. These findings seem to suggest that the foetus probably plays a dual role in alpha and beta-haemolysin production--it enhances the production of alpha-haemolysin while suppressing that of beta-haemolysin. These findings offer explanations for the usually observed low frequency of occurrence of haemolytic disease of the newborn due to ABO incompatibility.