Interstitial immunofluorescence in nephritis of Sjögren's syndrome.

A patient with Sjögren's syndrome (SS) developed mild renal insufficiency without significant proteinuria; the diagnosis of interstitial nephritis secondary to SS was made on the basis of history, serological data and renal biopsy. The renal biopsy revealed immunofluorescence of the interstital infiltrates and the importance of this finding in the differential diagnosis of interstitial nephritis is considered. In addition, further studies to detect anti-renal antibodies and circulating immune complexes are reported and the possible interpretation of the results is discussed in regard to pathogenesis.