Pulmonary sarcoidosis during interferon therapy: a rare or underestimated event?

Interferon (IFN)-alpha with or without ribavirin is the treatment of choice for patients with chronic HCV-related hepatitis. Cough and dyspnea during IFN therapy are often regarded as a side effect and not as a possible sign of the onset of a pulmonary interstitial disease. It may therefore be claimed that the likelihood that patients treated with IFN develop sarcoidosis is being underestimated. Although they are not conventionally classified as etiopathologic agents of sarcoidosis, the IFNs have been proven to be capable of triggering macrophages and of promoting the expression of class II HLA antigens. It is therefore possible that IFN-alpha treatment could trigger macrophages and promote the polarization of the immune response towards Th1 in the presence of particular susceptibility conditions, thus starting the series of events that lead to the onset of sarcoidosis. We describe a case of pulmonary sarcoidosis in a 33-year-old patient treated with IFN-alpha2b and ribavirin for chronic HCV-related hepatitis after 6 months of therapy. The case we report here brings forth the issue of a possible underestimation of the real incidence of sarcoidosis during IFN therapy and highlights the need for more attention to and a more careful evaluation of respiratory symptoms manifesting in treated patients.