No abstract

Leukoagglutinins were shown to occur in sera from nontransfused gravid Negro, Caucasian and Asian women. Investigations into the relationship of parity to the incidence of leukoagglutinins indicated that two pregnancies were usually required before leukoagglutinins became demonstrable in the gravid women. In their second pregnancies, 13 of 68 women (19 per cent) possessed leukoagglutinins. In families with two children, the leukocytes of both offspring contained the potential antigenic stimulus for leukoagglutinin production. In this series with increasing parity, the proportion of women immunized did not significantly differ. The significance of the frequent leukocyte sensitization was discussed. Leukoagglutinins persisted in the sera of parous women for varying periods of time after parturition. The antibodies of 16 of 31 women could still be identified in their sera three years after delivery. The distribution of potentially stimulating leukocyte antigens in the offspring of two large families provided suggestive evidence that the formation of leukoagglutinins had persisted in the two women for eight years after sensitization. The leukoagglutinins found in gravid women had numerous specificities. Eighteen of the 40 specificities (agglutination patterns) of leukoagglutinins were observed in the sera of other women. With increasing time after delivery, the specificity of leukoagglutinating sera tended to become narrower than the serum sample obtained at parturition.