Perinatal intracranial hemorrhage due to severe neonatal alloimmune thrombocytopenic purpura (NAITP) associated with anti-Yukb (HPA-4a) antibodies

Neonatal alloimmune thrombocytopenic purpura (NAITP) is one of the causes of thrombocytopenia in the newborn period. The thrombocytopenia is caused by maternal transplacental antiplatelet alloantibodies. We report a case of NAITP in a newborn infant having subarachnoid hemorrhage. Examination of platelet antibodies revealed anti-Yuk b , that is, human platelet antigen (HPA)-4a incompatibility. Cranial ultrasound and brain magnetic resonance imaging revealed subarachnoid hemorrhage in the temporal region inferior to the cephalohematoma. The lesion seemed to have been sustained during delivery. The patient was treated with high-dose γ-globulin and several transfusions of random donor platelets and showed a good clinical course. This is the second reported case of NAITP associated with the Yuk antigen system having intracranial hemorrhage.