Antibody responses to tetanus toxoid in patients with primary biliary cirrhosis.

The primary and secondary antibody responses to tetanus toxoid were measured in 18 patients with primary biliary cirrhosis and compared with those in age and sex matched controls. Although the primary antibody response in the two groups was similar, the secondary IgM antibody response in primary biliary cirrhosis was significantly higher than that in control subjects. There seems to be a correlation between secondary IgM antibody titre and total serum IgM concentration, although this fails to reach significance (p = 0.069). These results show that in primary biliary cirrhosis there is a failure to switch from IgM to IgG antibody synthesis in response to foreign antigens, and this may account for the increased serum IgM concentrations that are usually found in this disease.