IMMUNE THROMBOCYTOPENIA AND ALPHA-INTERFERON THERAPY

Thrombocytopenia is often found in patients with liver diseases, espec ially due to congestive splenomegaly caused by portal hypertension. Im mune thrombocytopenia has been described rarely, and it seems to be es pecially associated with hepatitis C virus, which has been described a s having a particular interaction with the immune system contributing to the induction of autoimmunity. Interferons, on the other hand, beca use of their immunomodulatory properties, are able to induce or exacer bate autoimmune diseases. Mild thrombocytopenia is a common adverse ef fect of interferon therapy. Severe life-threatening thrombocytopenia i s extremely rare, We report two cases of severe immune thrombocytopeni a in patients with chronic hepatitis C, probably induced by alpha-inte rferon. Bone marrow aspirate and elevated platelet-associated IgG anti bodies, determined by indirect immunofluorescence, were suggestive of immune thrombocytopenia. None of the patients had any clinical sign of autoimmune syndrome, including arthritis, serositis. Sicca syndrome, vasculitis, thyroid abnormalities and others. Cryoglobulins and rheuma toid factor were tested and were undetectable. The patients' histories of exposure to alpha-interferon and the exclusion of other causes are most consistent with drug-induced immune thrombocytopenia. After alph a-interferon withdrawal, thrombocytopenia was treated successfully wit h prednisolone and immunoglobulins. Response to treatment was consiste nt with the diagnosis of alpha-interferon-induced immune thrombocytope nia and peripheral consumption of platelets.