[Neonatal alloimmune thrombocytopenia due to a rare anti-HPA-1b antibody].

Foetal and neonatal alloimmune thrombocytopenia is caused by transplacental transfer of antibodies directed against platelet antigens and affects approximately 1 in 1000-2500 neonates. Clinically relevant complications are the intracranial haemorrhages that occur in 10-20% of cases. 20 platelet antigen systems are currently known. However, immunisation is most frequently seen against two of these (HPA-1a and HPA-5b). Treatment options include transfusion of compatible or, if these are not available while urgently needed, random donor platelets, intravenous immunoglobulin, and steroids. We report on a case of neonatal alloimmune thrombocytopenia due to an anti-HPA-1b antibody in the third pregnancy of a 31-year-old Caucasoid woman. The infant was treated with repeated maternal and random donor platelet transfusions and with a single dose of intravenous immunoglobulin.