Immunological features of patients with primary biliary cirrhosis (PBC) overlapping systemic sclerosis: a comparison with patients with PBC alone.

To characterize the immunological features of patients with primary biliary cirrhosis (PBC) overlapping systemic sclerosis (SSc), 26 patients with PBC were classified according to the presence of scleroderma-related features (Raynaud's phenomenon, sclerodactyly etc.). The patients were classified into 10 patients with PBC overlapping SSc (PBC-SSc), four patients with some scleroderma-related features although not meeting the criteria of SSc (PBC-SSc spectrum) and 12 patients with PBC alone. Sera from PBC-SSc showed a significantly higher positivity to anti-centromere antibody (P< 0.01) and to E1beta of pyruvate dehydrogenase complex (P< 0.005) than those from patients with PBC alone. The same tendency was observed in PBC-SSc spectrum patients. Patients with PBC exhibiting scleroderma-related features, in both the PBC-SSc and PBC-SSc spectrum, may comprise a subset in PBC, not only clinically, but also immunologically.