Genetic predispositions for the immunological features of chronic active hepatitis.

To assess the frequency and genetic predispositions of concurrent immunological diseases and immunoserological markers in autoimmune hepatitis and chronic viral hepatitis, we assessed 185 patients prospectively, including 122 patients with autoimmune hepatitis and 63 patients with viral disease. Human leukocyte antigens were determined in all patients. Sixty patients (32%) had concurrent immunological diseases, and the majority of the diseases (68%) had known human leukocyte antigen associations. Although patients with autoimmune hepatitis had concurrent immunological diseases more commonly than those with viral disease (38% vs. 22%; p = 0.04), the nature of the diseases was similar in both groups, as were the frequencies of human leukocyte antigen-DR4 (42% vs. 39%; p = 0.7). The presence of human leukocyte antigen-DR4 was associated with the concurrence of immunological diseases in both autoimmune (62% vs. 33%; p = 0.01) and viral hepatitis (75% vs. 29%; p = 0.009). In autoimmune hepatitis, human leukocyte antigen-DR4 was also associated with the expression of smooth muscle antibodies and high-titer antinuclear antibodies. We conclude that concurrent immunological diseases and immunoserological markers are common in autoimmune and chronic viral hepatitis. Both conditions have a common genetic predisposition for concurrent immunological disease associated with human leukocyte antigen-DR4. The expression of smooth muscle antibodies and high-titer antinuclear antibodies is associated with human leukocyte antigen-DR4 in autoimmune hepatitis only, suggesting that this response is associated with triggering antigens and immune recognition systems that are different from those in viral disease.