To study the specific autoantibodies against nuclear antigens in patients with primary biliary cirrhosis (PBC).
Sera from 21 patients with PBC were tested for antinuclear antibody (ANA) by indirect immunofluorescence on human epithelial (HEp)-2 cells, and for antibodies to various nuclear antigens by enzyme linked immunosorbent assay (ELISA) using different purified proteins or recombinant proteins as antigens.
ANA detected in 10 of 21 patients (48%) with PBC included five anti-centromere antibody (ACA), two speckled, two homogeneous and one nuclear dot staining. ACA were present in 24% of PBC patients. By ELISA, anti-histone antibodies were detected in 81% of PBC patients, anti-ssDNA antibodies in 71% and anti-dsDNA in 10%, anti-topoisomerase-1 antibodies in 24%, anti-Sm/RNP antibodies in 24%, anti-La-48(SS-A) antibodies in 21%, and anti-Ro-60(SS-A) and anti-Ro-52(SS-A) antibodies in 30% and 25%, respectively.
The high frequencies of various antibodies directed against intracellular proteins and nucleic acids in patients with PBC suggests that PBC is a multisystem autoimmune disease which is similar to other systemic autoimmune diseases.