HLA typing in an IFN-alpha-induced scar sarcoidosis: possible pathogenetic and clinical implications

Sarcoidosis is a multisystemic granulomatous disease of unknown aetiology, although genetic factors and environmental antigens are thought to be involved in its pathogenesis. Sarcoidosis as a complication of interferon (IFN) administration was first described in 1987 in a patient with renal cancer. Since then, more than 50 cases of pulmonary and/or extrapulmonary sarcoidosis, mainly occurring in middle-aged women, have been correlated to IFN-alpha therapy, either associated or not to ribavirin, in patients with chronic viral hepatitis C. Several lines of evidence suggest that HLA class I and class II alleles may be considered possible markers for susceptibility, clinical behaviour and prognosis of sarcoidosis. Herein we report a case of scar sarcoidosis which occurred one month after completion of a course of PEG-IFN-alpha therapy for chronic hepatitis C (HCV) infection. HLA typing was performed to evaluate the potential role of an immunogenetic predisposition factor.