Clinical evaluation of primary biliary cirrhosis in Chinese patients without serum anti-mitochondrial antibody.

Background: Primary biliary cirrhosis (PBC), a chronic, progressive, cholestatic liver disease characterized by frequent presence of the anti-mitochondrial antibody (AMA), is rarely seen in the Asian population. Whether or not the presence of AMA alters the clinical, serological and histological features of the disease remains unclear.

Methods: During the 25-year period from 1972 to 1996, 71 Chinese patients with PBC who were diagnosed clinically and/or histologically were reviewed. Seventeen (24%) of them repeatedly tested negative for serum AMA. Clinical, biochemical, immunological, histological data and treatment response to ursodeoxycholic acid were compared between PBC patients with positive and negative serum AMA.

Results: Mean serum immunoglobulin M (IgM) level was significantly lower in AMA-negative PBC patients when compared with AMA-positive PBC patients (422 +/- 163 vs. 651 +/- 412 mg/dL, p = 0.042). Serum anti-nuclear antibodies (ANA) were positive in 93% of the AMA-negative PBC patients, a significantly higher percentage when compared with the 66% of AMA-positive patients (p = 0.048). There were no significant differences with regard to age, sex, clinical manifestations, liver biochemistries, histological findings, survival and response to 1-year ursodeoxycholic acid treatment between the AMA-negative and AMA-positive patients. Univariate logistic regression analysis showed relatively lower serum IgM levels, positive serum ANA and anti-centromere type ANA were significant predictive factors to negative serum AMA in PBC patients (p = 0.035, 0.044 and 0.029, respectively). Multi-variate analysis revealed relatively lower serum IgM levels were the only independent significant predictor to negative serum AMA in PBC patients (p = 0.015).

Conclusions: Twenty-four percent of Chinese patients with PBC were negative for serum AMA. AMA-negative PBC patients were characterized by relatively lower serum IgM levels and a higher rate of positive serum ANA.