Inhibitor against coagulation factor v after liver transplantation - Possible role of the FK506 immunosuppressive drug

A new case of anti-factor V inhibitor is described in a 46-year-old man, wh o received a liver transplantation for hepatocellular carcinoma, without ex posure to bovine thrombin or fibrin glue during the operative course. The i nhibition occurred on the 14th postoperative day, while the patient was bei ng treated with oxacillin, azathioprine, and a new immunosuppressive drug, FK506. The inhibition was of short duration (3 days), and no bleeding compl ication occurred despite a very low plasmatic level of factor V activity an d antigen (<5%). Plasma samples drawn after cessation of FK506 disclosed a dose-dependent inhibitory activity when alcoholic solutions of FK506 were e xogeneously added; this suggests a possible role of the FK506 drug in the o ccurrence of this anti-factor V inhibitor.