Maternal alloimmunization to HLA, platelet and granulocyte-specific antigens during pregnancy: its influence on cord blood granulocyte and platelet counts.

In order to obtain an estimate of the frequency of platelet-specific and granulocyte-specific antibodies and of the effect of such antibodies on the platelet count and granulocyte count of the newborn infant, serum from 147 women in their second or subsequent pregnancies was tested. No platelet-specific antibodies were found but 29 of the women had granulocyte-specific antibodies and the corresponding infants had granulocyte counts which were significantly lower than those of infants without antibodies. HLA antibodies were found in the sera of 57 women but were not associated with diminished platelet or granulocyte counts in the corresponding infants. Maternal granulocyte antibodies may be an underestimated contributory factor in the pathogenesis of neonatal neutropenia.