Autoantibodies by line immunoassay in patients with primary biliary cirrhosis

We attempted to measure multiple autoantibodies simultaneously using line immunoassay (LIA) in patients with primary biliary cirrhosis (PBC) with or without anti-mitochondrial antibody (AMA) and patients with PBC-autoimmune hepatitis (AIH) overlap, and we examined the clinical significance of measuring these autoantibodies.

The study population consisted of 80 patients with PBC (including 12 AMA-negative patients), 16 patients with PBC-AIH overlap and 40 patients with AIH as controls. Nine antibodies (AMA-M2, M2-3E, Sp100, PML, gp210, Ro-52, LKM-1, LC-1 and SLA/LP) were detected by LIA, and AMA-M2 and anti-centromere antibody (ACA) were detected by ELISA. We examined the relationship between these autoantibodies and clinical findings.

The positive prevalence of each autoantibody and ACA in the PBC group, as determined by LIA, was as follows: 13.8% for anti-Sp100, 8.7% for anti-PML, 40% for anti-gp210 and 27.5% for anti-Ro-52 antibodies and 32.5% for ACA. In the PBC-AIH overlap group, the prevalence of anti-gp210 antibody (68.7%) and that of anti-Ro-52 antibody (81.2%) were significantly higher than those in the PBC and AIH groups. Only a few patients were positive for 2 or more autoantibodies. Nine patients were determined to be negative for all autoantibodies by LIA, of whom 7 were positive for ACA. Patients positive for anti-gp210 antibody included more patients classified as stage 4 on histology than did the negative group. Those positive for ACA included more patents with varices than did the negative group.

LIA can measure multiple autoantibodies simultaneously and thus is considered useful in diagnosing PBC and PBC-AIH overlap. In addition, ACA is a useful marker for identifying AMA-negative PBC.