The titre of IgG anti-A/B in the serum of group O mothers of incompatible infants with early neonatal jaundice.

The titre of IgG anti-A/B was determined by means of a 2-mercaptoethanol test in the serum of 80 blood group O mothers, who gave birth at term to A/B incompatible infants, who developed early neonatal jaundice with a serum bilirubin level of over 10 mg/100 ml. The titres were compared with the results of the direct antiglobulin test performed on the red cells from the cord blood and the necessity for exchange transfusion. Only in mothers of group A infants, a significant correlation was found between the titre of IgG anti-A and the occurrence of a positive antiglobulin test. In no case the need for an exchange transfusion was correlated with the IgG anti-A/B titre.