Detection of anti-gp210 antibodies in primary biliary cirrhosis by enzyme-linked immunosorbent assay with a synthesized polypeptide

Autoantibodies against the nuclear envelope protein are detectable in patients with primary biliary cirrhosis (PBC). The major target antigen of antinuclear envelope antibodies is a transmembrane 210-kDa glycoprotein of the nuclear pore complex (gp210). An immunoblot assay has been used for detecting anti-gp210. We developed a simple enzyme-linked immunosorbent assay (ELISA) to detect anti-gp210 antibodies using a synthesized polypeptide containing 19-amino-acid residues in the carboxyl-terminal domain of gp210 and evaluated its clinical usefulness. Anti-gp210 antibodies were detected by ELISA in 22/80 (27.5%) patients with PBC, in 4/80 (5.0%) patients with connective tissue diseases, in none of chronic hepatitis (0/40) and normal individuals (0/30). The diagnostic performance of ELISA was equivalent to the immunoblot assay (sensitivity and specificity, 27.5% and 97.3% for ELISA, 30% and 99.3% for immunoblot assay respectively). We concluded that anti-gp210 antibodies can be reliably determined by ELISA with a synthesized polypeptide and that these autoantibodies recognize an epitope in the carboxyl-terminal domain of gp210.