Autoimmunity induced by interferon-alpha therapy for chronic viral hepatitis

Type I interferons, which are mostly a-interferons (either as single agents or in combination with antiviral drugs), are currently the standard therap y for chronic viral hepatitis B, B/D, and C. Side-effects are not uncommon and include exacerbation of preexisting autoimmune disorders or the de novo induction of autoimmunity. These adverse effects are attributed to the imm unomodulatory properties of type I interferons, and should be distinguished from autoimmunity associated with chronic viral hepatitis in which interfe ron treatment may indeed be beneficial. The major autoimmune side-effects o f interferon therapy for chronic viral hepatitis are thyroid or liver disea se. Therefore, screening for thyroid antibodies and auto-antibodies indicat ive of autoimmune hepatitis both before, during, and after interferon thera py is strongly recommended. The presence of high concentrations of thyroid auto-antibodies or antibodies associated with autoimmune hepatitis can be c ontraindicative to interferon therapy. However, treatment is not contraindi cated in viral hepatitis (in particular chronic hepatitis C) associated wit h autoimmune phenomena - including low-titer thyroid antibodies or other no n-organ specific autoantibodies. If interferon-induced autoimmunity occurs, the necessity of therapy has to be balanced carefully against the risks of autoimmune disease. Further research is needed to identify the factors whi ch determine susceptibility to interferon-associated autoimmunity in indivi dual patients. (C) 1999 Elsevier, Paris.