The Frequency of Platelet Alloantibodies in Pregnant Women and the Occurrence and Management of Neonatal Alloimmune Thrombocytopenic Purpura

Abstract

Neonatal alloimmune thrombocytopenic purpura (NAITP) is induced by maternal antibodies to fetal platelet alloantigens. The disease is rare, but is often responsible for intracranial hemorrhages leaving severe neurological damage. Although this occurrence is rare, its frequency may be underestimated. In order to determine the frequency of alloimmunization to platelet antigens, serum from pregnant women were investigated in platelet-ELISA and lymphocytotoxic test (LCT). Seventy-eight out of 556 pregnant women (14%) were found to have antibodies to platelet antigens in ELISA and/or LCT. In one case (0.18%) a platelet specific antibody, anti-Zwa(-PIA1), was found in the platelet-ELISA. In all of the other cases only HLA-antibodies were detected. The only mother who was delivered of a child with clinical NAITP was the woman with anti-Zwa(PIA1) in serum. Furthermore, in a review from the currently available literature the following items will be discussed: 1) human platelet antigens involved in NAITP, 2) clinical aspects and prognosis of NAITP, 3) immunological diagnosis of NAITP, and 4) prevention and treatment of the disease.