We recently came across a case of neonatal alloimmune thrombocytopenic purpura (NAITP) in a set of triplets.
The serum obtained from the mother of the child with NAITP contained platelet-specific alloantibody, anti HPA-4b. The antibody was of IgG class detected by anti-IgG indicator cells. The serum of the mother strongly reacted with the platelets of her husband (1:1, 024), but not with her own.
After delivery, the platelet count of the triplet with NAITP was 1.2×104/μl. The platelet count of the other two infants were 29.5×104/μl, 29.7×104/μl each.
