Neonatal thrombocytopenia caused by passive transfer of anti-PLA1 antibody by blood transfusion.

A premature male infant with hyaline membrane disease received a 34 ml transfusion of packed erythrocytes from a CPDA1 blood unit on day 2 with no adverse consequences. On day 34 he was given a transfusion, and the platelet count decreased. Intravenous immune globulin therapy was initiated and the platelet count steadily increased. Human leukocyte (HLA) antigen and platelet antibody testing showed that the thrombocytopenia was due to passive transfer of platelet-specific antibody from the blood donor.