Rituximab therapy for factor II inhibitor in a patient with antiphospholipid antibody syndrome

Factor II inhibitors have been associated with an increased risk of bleeding. The management of patients with factor II inhibitors has not been adequately described. We describe a patient with an increased bleeding tendency due to factor II inhibitor who was unable to undergo surgery due to her bleeding tendency. The patient was successfully treated with a course of rituximab, which markedly reduced her factor II inhibitor: the factor II level rose from 12 to 61%; prothrombin time decreased from 20 to 14.7s; and partial thromboplastin time (PTT) decreased from 148 to 38.8s. She was able to undergo abdominal surgery without any hemorrhagic complications. This case exemplifies the possibility of treating patients with factor II inhibitors with rituximab therapy.