Association between polymyositis and hepatitis C virus infection: treatment-related difficulties.

Introduction. - Chronic hepatitis C virus infection is often associated wit h various auto-immune disorders. We report four cases of an association bet ween polymyositis and hepatitis C virus infection. The course and the diffi culties of therapy are discussed. Exegesis. - Among 510 consecutive patients infected by viral hepatitis C, w e report four cases of polymyositis. Corticosteroids increased serum alanin e aminotransferase levels in two cases, leading to severe liver injury in o ne patient. Worsening of polymyositis under interferon-a therapy was observ ed in one case. Clinical and biological stability were reported in another case. Aggravation of polymyositis with severe muscle weakness and dyspnea o ccurred in two patients after disruption of interferon-alpha. treatment. In travenous gamma globulins subsequently improved their condition, without bi ological worsening of viral hepatitis. Conclusion. - These observations suggest an association between hepatitis C virus infection and polymyositis. Because corticosteroids can induce adver se effects in the liver, intravenous gamma globulins could be used for the treatment of this particular form of polymyositis. (C) 2000 Editions scient ifiques ef medicales Elsevier SAS.