OBJECTIVETo study the clinical significance of the immunological characteristics in patients with primary biliary cirrhosis (PBC).

METHODS3000 patients with abnormal liver functions were examined for anti-nuclear antibodies (ANA), anti-mitochondrial antibodies (AMA), anti-smooth muscle antibodies (SMA) and anti-liver kidney microsomal antibody (LKM) using immunofluorescent assays (IFA). LKM-1, liver cytosolic-1 (LC-1), soluble liver antigen (SLA)/liver- pancreas antigen (LP) and subtype of AMA (M2, M4, M9) as well as ANA profile were detected by an immune blotting assay and an enzyme-linked immune absorbent assay (ELISA), respectively. Cytokines were tested by flow cytometry.

RESULTSOf the 3000 patients with liver diseases, 52 (1.7%) were diagnosed with PBC. All the PBC cases were positive for AMA and M2. 94% of them showed high titer of AMA (> or = 1:320), and in 79% of them M2 was >200 RU/L, and 78% of them were ANA positive. Three main fluorescent patterns of ANA seen were nuclear membrane, nuclear dots and centromere patterns. Sjogren's Syndrome A/B (SS-A/B), homogenous, nucleolar or nuclear granular patterns were seen in only a few patients. IgM, ALP and GGT in PBC patients were significantly higher than those in hepatitis B related liver cirrhosis patients. The levels of IL-6, IL-10, TNF-alpha and IFN-gamma in PBC patients were higher than in the normal controls. Among the 52 PBC patients, 5 had autoimmune liver disease overlap syndromes. Two of them were SLA/LP positive, indicated as AIH type III and PBC overlapping, and 1 was LKM-1 positive showing AIH type II overlapping PBC, and 2 had ANA positive and were identified as AIH and PBC by liver biopsy.

CONCLUSIONThe percentage of PBC in Chinese liver disease patients is about 1% to 2%. Most of the PBC patients have high levels of AMA and AMA-M2, IgM, ALP, GGT and several cytokines, indicating that abnormality of humeral and cellular immunity may be associated with the pathogenesis of PBC.