Familial clustering and immune response in family contacts of patients with HBsAg-positive liver cirrhosis.

Families of 11 patients with hepatitis B surface antigen (HBsAg)-positive cirrhosis were studied to evaluate the immunologic correlates and extent of intrafamilial HBsAg clustering. Of 76 family contacts, 12 were identified to be asymptomatic carriers of HBsAg and two were diagnosed to have HSsAg-positive cirrhosis. The over-all HBsAg prevalence for the 76 contacts was 18% and that for all 87 members studied 29.0%. Serologic evidence of hepatitis B virus (HBV) infection (either HBsAg, anti-HBs, or both) was detected in 59% of all family members. HBsAg was more prevalent in males (47%) compared with females (16%), and anti-HBs was more prevalent in females (42%) compared with males (18%). Evidence of an immunologic response in clinically unaffected HBsAg-negative family contacts consisted of elevated serum IgG levels (mean 1660 mg/100 ml) and increased prevalence of anti-smooth muscle and antimitochondrial antibodies (16% and 6%, respectively). The prevalence of one or more autoantibodies in all HBsAg-negative family contacts was 20%, and it was higher in females (25%) than in males (13%). The present study demonstrates that HBsAg clustering occurs in families of patients with cirrhosis in the Jerusalem area and indicates that HBsAg-negative family contacts may have increased B-cell activity.