GENETIC PREDISPOSITIONS FOR THE IMMUNOLOGICAL FEATURES OF CHRONIC ACTIVE HEPATITIS

To assess the frequency and genetic predispositions of concurrent immu nological diseases and immunoserological markers in autoimmune hepatit is and chronic viral hepatitis, we assessed 185 patients prospectively , including 122 patients with autoimmune hepatitis and 63 patients wit h viral disease. Human leukocyte antigens were determined in all patie nts. Sixty patients (32%) had concurrent immunological diseases, and t he majority of the diseases (68%) had known human leukocyte antigen as sociations. Although patients with autoimmune hepatitis had concurrent immunological diseases more commonly than those with viral disease (3 8% 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 assoc iated with the concurrence of immunological diseases in both autoimmun e (62% vs. 33%; p = 0.0 1) and viral hepatitis (75% vs. 29%; p = 0.009 ). In autoimmune hepatitis, human leukocyte antigen-DR4 was also assoc iated with the expression of smooth muscle antibodies and high-titer a ntinuclear antibodies. We conclude that concurrent immunological disea ses 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 associ ated with triggering antigens and immune recognition systems that are different from those in viral disease.