Role of antibody dependent cell mediated cytotoxicity in ABO hemolytic disease of the newborn.

Study includes fifty O blood group mothers delivering A or B group infants suffering from jaundice and a control group consisting of thirty one O group mothers of non-jaundiced infants. Lytic ability of maternal IgG anti-A/anti-B was determined by 51Cr ADCC assay in which cord blood monocytes were used as effector cells. In control series mean% specific lysis (SL) was 18 +/- 3.1 for IgG anti-A and 17.9 +/- 3.1 for IgG anti-B. In jaundiced series IgG anti-A was more lytic than IgG anti-B. However, the increase in ADCC lysis was statistically insignificant. Even though > 1:32 titre was more often associated with > 35% SL, in general the immune A/B antibody titre showed poor correlation with ADCC lysis. Majority of the severe ABO-HDN cases had > 35% ADCC lysis.