[Acquired hemophilia A with high-titer factor VIII inhibitor developing subsequent to clopidogrel administration]

An 80-year-old male was referred to our department for prolonged APTT (activated partial thromboplastin time) and subcutaneous hemorrhage. His medical history comprised alcoholic liver cirrhosis, hepatocellular carcinoma (HCC), and peripheral artery disease (PAD). For refractory HCC, he had received transcatheter arterial chemoembolization and was followed up regularly at our hospital. He underwent percutaneous transluminal angioplasty for PAD 10 months ago, and dual antiplatelet therapy with clopidogrel and cilostazol was initiated. Cilostazol was discontinued owing to subcutaneous hemorrhage 6 months ago. The prolonged APTT level, inhibitor pattern by cross-mixing test, and the presence of the inhibitor against factor VIII (449 Bethesda unit/ml) corroborated acquired hemophilia A (AHA). Thus, clopidogrel was discontinued for possible drug-induced AHA. After 4-week oral corticosteroid therapy, the APTT level recovered to normal. This case highlights two distinct features as follows: (1) possible relation to clopidogrel; and (2) despite extremely high titer of factor VIII inhibitor, his bleeding episodes were managed without antihemorrhagic agents. Here we present a case of clopidogrel-related AHA. Further accumulation of such cases is warranted to determine the potential correlation with clopidogrel and AHA.