[A case positive for the inhibitor for coagulation factor V]

We report a 71-year-old man who exhibited hepatocellular carcinoma and the inhibitor for coagulation factor V (FV). The inhibitor was found when his coagulation screening tests revealed an abnormally prolonged prothrombin time (71.1 sec) and activated partial thromboplastin time (more than 120 sec) but normal values of fibrinogen (241 mg/dl), the thrombo test (84%) and hepaplastin test (71%). In addition, FV-coagulation activity of the patient's plasma showed less than 1% of the pooled normal plasma and inhibitory activity for FV of his plasma was 32 Bethesda units. This inhibitory activity was neutralized by the addition of anti-human immunoglobulin-gamma-chain serum. The patient was treated with a fibrin sealant including human thrombin when he underwent an partial hepatectomy (32 months before onset) and received 2 doses of thrombin orally (5 months and 2 weeks before onset) to stop bleeding from phlebeurysm. Several studies have reported that the inhibitor for FV was produced after treatment with bovine thrombin containing FV as a contaminant. These findings suggest that our patient may produce an immunoglobulin specific for FV after similar stimulation of human thrombin containing FV.