Antimitochondrial Antibody Negative Primary Biliary Cirrhosis in Japan: Utilization of Clinical Data When Patients Applied to Receive Public Financial Aid

BACKGROUND: We examined patients who showed laboratory and histological evidence of primary biliary cirrhosis (PBC) in the absence of antimitochondrial antibody (AMA) to elucidate the characteristics of AMA negative PBC. METHODS: From a total of 5,805 patients with symptomatic PBC, 2,419 cases (41.7%) were selected in the present study, who were diagnosed using the following criterion; chronic non-suppurative destructive cholangitis was histologically observed and laboratory data did not contradict PBC. The information collected from records included sex, age, symptoms, physical findings, and complicated autoimmune diseases. We then evaluated these data according to the positivity of AMA. RESULTS: Of the total subjects, 470 cases (19.4%) were found to be negative for AMA. The proportion of female patients was higher among the AMA negative group than among the AMA positive one. Pruritus was found less frequently among patients with AMA negative PBC than among those with AMA positive PBC. Levels of alkaline phosphatase, γ-glutamyl transpeptidase, and IgM were significantly lower among patients with AMA negative PBC than among those with AMA positive PBC. Complications such as Sjögren’s syndrome, rheumatoid arthritis, and scleroderma, including CREST syndrome, were found with significantly higher frequency among patients with AMA negative PBC than among those with AMA positive PBC. CONCLUSION: Considering serum level of IgM and frequencies of complicated autoimmune diseases, it is possible that Japanese patients with AMA negative PBC are consistent with the disease entity of autoimmune cholangitis reported in western countries.