Recombinant human α-interferon is now under intensive investigation as therapy for chronic Type B hepatitis. Recent reports have suggested that prolonged α-interferon therapy may induce autoimmune reactions. We have evaluated the problem of autoimmunity related to α-interferon therapy by testing for 15 different antibodies in the sera of 31 patients treated with α-interferon. No patient had autoantibodies before treatment; 27 (87%) of 31 patients developed at least one autoantibody. Eleven patients had antinuclear antibodies and 21 had smooth muscle antibodies, both of which usually developed during α-interferon therapy. In contrast, antibodies to endocrine organs such as thyroid microsomal, thyroglobulin and parietal cell antibodies arose in 12 patients, but usually several months after α-interferon treatment. The appearance of these autoantibodies did not correlate with disease activity or response to α-interferon. No patient developed autoantibodies specifically associated with autoimmune liver diseases such as liver kidney microsomal antibodies, autoantibodies to soluble liver antigen and the primary billiary cirrhosis-specific subtypes of antimitochondrial antibodies.

These results suggest that prolonged α-interferon therapy can induce autoantibody production and, in susceptible patients, may lead to autoimmune disorders.