NEONATAL THROMBOCYTOPENIA - INCIDENCE AND CHARACTERIZATION OF MATERNAL ANTIPLATELET ANTIBODIES BY MAIPA ASSAY

Neonatal thrombocytopenia (NNT) which is frequent in distressed newbor ns was uncommon in a nonselected population of neonates, The aim of th is prospective study was to determine the frequency of NNT and, in con firmed NNT, to search for maternal antiplatelet antibodies with a mono clonal antibody-specific immobilization of platelet antigens (MAIPA) a ssay, Among the 8388 newborns studied, 40 (0.5%, 95% CI 0.3-0.6) had c onfirmed NNT, which was severe (platelet count < 50 x 10(9)/l) in 10 c ases (0.12%, 95% CL 0.05-0.20). Antiplatelet antibodies were detected in 10/31 studied mothers of thrombocytopenic newborns (32.3%): they we re alloantibodies in five cases and autoantibodies in five other cases , Among these 10 newborns, seven had severe thrombocytopenia and four had bleeding complications. As controls, antiplatelet antibodies were also searched for in mothers of non-thrombocytopenic newborns: antipla telet antibodies were present in 8.5% (95% CI 5.9-11.7) of thrombocyto penic mothers (n = 400) and 3.2% (95% CI 0.7-9.0) of non-thrombocytope nic mothers (n = 95). The difference was significant between the contr ol groups and the group of mothers of thrombocytopenic newborns. In co nclusion, our data indicate that an immune origin is frequent in NNT a nd should be looked for, particularly when the platelet count is < 50 x 10(9)/l.