Occurrence of autoantibody to protein disulfide isomerase in patients with hepatic disorder.

The occurrence of autoantibody to protein disulfide isomerase (PDI) was examined in sera from patients with alcoholic liver disease, liver cirrhosis, systemic lupus erythmatosus (SLE) and cancer. Judging by results of Western blotting using a purified preparation of PDI, the anti-PDI antibody was hardly seen in most sera from healthy controls but was raised in patients with alcoholic liver disease, liver cirrhosis, SLE and liver cancer. When the antibody titer to PDI was measured by radioactivity in a radioimmunoassay, positive values (cut off value; mean + 2SD = 256 cpm) were seen in 46% (11/24) of the patients with moderate alcoholic liver disease (mean radioactivity, 339 cpm) and in 54% (7/13) of those with severe alcoholic liver disease (mean radioactivity, 664 cpm). Only 8% (4/48) of the healthy controls were positive (mean radioactivity, 50 cpm). Four of six patients with hepatoma were positive, while none of the seven patients with non-hepatic cancer were positive. The positive proportions in the patients with liver cirrhosis and SLE were 64% (9/14) and 40% (4/10), respectively. These results suggest that the occurrence of anti-PDI antibody would play an immunological role in the progression of hepatic disorders.