Clinicopathological study of glomerular diseases associated with sarcoidosis: a multicenter study.

Background: The association between sarcoidosis and glomerular diseases has not been extensively investigated in a large series and the potential features of this uncommon association remain to be determined.

Methods: We retrospectively identified 26 patients with biopsy-proven glomerular lesions that occurred in a sarcoidosis context. Potential remission of glomerular disease and sarcoidosis under specific treatment (steroid and/or immunosuppressive agents) was recorded for all patients. Demographic, clinical and biological characteristics were assessed at the time of kidney biopsy for each patient. Therapeutic data were analyzed for all patients.

Results: Glomerular disease occurred after the diagnosis of sarcoidosis in 11 of 26 cases (42%) (mean delay of 9.7 years). In six patients (23%), the glomerulopathy preceded the sarcoidosis diagnosis (mean delay 8 years). In the last nine patients (35%), both conditions occurred simultaneously. The most frequent glomerular disease occurring in sarcoidosis patients was membranous nephropathy in eleven cases. Other glomerular lesions included IgA nephropathy in six cases, focal segmental glomerulosclerosis in four patients, minimal change nephrotic syndrome for three patients and proliferative lupus nephritis in two patients. Granulomatous interstitial nephritis was associated with glomerular disease in six patients and was exclusively found in patients in whom the both disease occurred simultaneously. In nine patients with simultaneous glomerular and sarcoidosis diseases, we observed a strong dissociation between glomerular disease and sarcoidosis in terms of steroid responsiveness. At the end of the follow-up (mean of 8.4 years), six patients had reached end-stage renal disease and three patients had died.

Conclusions: A wide spectrum of glomerular lesions is associated with sarcoidosis. The close temporal relationship observed in some patients suggests common causative molecular mechanisms of glomerular injury but complete remission of both diseases in response to exclusive steroid therapy is infrequent.