Renal involvement in primary Sjögren's syndrome: a clinicopathologic study.

Background & Objectives: Renal pathology and clinical outcomes in patients with primary Sjögren's syndrome (pSS) who underwent kidney biopsy (KB) because of renal impairment are reported.

Design, Setting, Participants, & Measurements: Twenty-four of 7276 patients with pSS underwent KB over 40 years. Patient cases were reviewed by a renal pathologist, nephrologist, and rheumatologist. Presentation, laboratory findings, renal pathology, initial treatment, and therapeutic response were noted.

Results: Seventeen patients (17 of 24; 71%) had acute or chronic tubulointerstitial nephritis (TIN) as the primary lesion, with chronic TIN (11 of 17; 65%) the most common presentation. Two had cryoglobulinemic GN. Two had focal segmental glomerulosclerosis. Twenty patients (83%) were initially treated with corticosteroids. In addition, three received rituximab during follow-up. Sixteen were followed after biopsy for more than 12 mo (median 76 mo; range 17 to 192), and 14 of 16 maintained or improved renal function through follow-up. Of the seven patients presenting in stage IV chronic kidney disease, none progressed to stage V with treatment.

Conclusions: This case series supports chronic TIN as the predominant KB finding in patients with renal involvement from pSS and illustrates diverse glomerular lesions. KB should be considered in the clinical evaluation of kidney dysfunction in pSS. Treatment with glucocorticoids or other immunosuppressive agents appears to slow progression of renal disease. Screening for renal involvement in pSS should include urinalysis, serum creatinine, and KB where indicated. KB with characteristic findings (TIN) should be considered as an additional supportive criterion to the classification criteria for pSS because it may affect management and renal outcome.