Clinical and immunological features of Sjögren's syndrome in patients with primary biliary cirrhosis with emphasis on focal sialadenitis.

Serological and pathological findings in 21 patients with primary Sjögren's syndrome (primary SS) were compared with those in 32 patients with primary biliary cirrhosis (PBC). In ELISA, anti-SS-B/La antibodies were detected in sera from 14 (67%) of the patients with primary SS, but only from 12 (38%) of those with PBC. With the Ouchterlony test, anti-SS-A/Ro antibodies were found in sera from 15 (71%) of the primary SS patients, but in no PBC patient. Of those PBC patients investigated prospectively with objective tests, four of 11 (36%) had keratoconjunctivitis sicca, and five of 15 (33%) had pathological sialometry results. In contrast, all PBC patients but one (i.e., 14 of 15 or 93%) showed evidence of focal sialadenitis. In immunochemical study of PBC patients, IgM immunoreactivity was found in the stroma, particularly adjacent to excretory ducts and acini in salivary glands (5 of 5), whereas no such IgM deposits were observed in patients with primary SS (3 of 3), nor in healthy controls (n = 20). We conclude that the frequency of anti-SS-A/Ro and anti-SS-B/La antibodies in serum is lower in PBC patients than in patients with primary SS. The incidence of focal sialadenitis is high in PBC, though only one third of the PBC patients studied here showed clinical evidence of glandular dysfunction. With immunochemical techniques, sialadenitis associated with PBC is distinguishable by its significant IgM reaction from sialadenitis in primary SS.