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

Abstract

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.

Figure 1.

Representative microphotographs of the diverse glomerular pathology seen in pSS. (A) Healed proliferative GN and focal global and segmental glomerulosclerosis (not shown). Healed proliferative glomerular lesions consistent with prior proliferative process (silver stain). (B) Minimal-change GN (hematoxylin and eosin). (C) Membranous nephropathy with localized subepithelial deposits confirmed on electron microscopy (not shown) (silver). (D) MPGN (hematoxylin and eosin). (E) Large subendothelial deposits characteristic of cryoglobulinemic GN (trichrome stain). Magnifications: ×100.

Figure 2.

Representative microphotographs of the various tubulointersitital infiltrates in pSS. (A) Acute or chronic TIN with proteinaceous casts and atrophic tubules. (B) Granulomatous TIN. (C) Chronic TIN. (D) Chronic TIN. Magnifications: ×200 in A and B through D; ×100 (hematoxylin and eosin).

Figure 3.

Longitudinal changes in renal function (estimated GFR) seen in patients with pSS receiving immunosuppressive therapy. Patients who received no treatment and those with insufficient follow-up of <3 mo were excluded (n = 7). *Paired t test. HC, hydroxychloroquine; C, cyclophosphamide; R, rituximab.

Figure 4.

Longitudinal changes in proteinuria seen in patients with pSS receiving immunosuppressive therapy. Only patients that had protein excretion of >0.3 g/24 h at the time of biopsy and who received immunosuppressive treatment were included in this analysis. Patients who received no treatment, those with insufficient follow-up of <3 mo, and those lacking follow-up urine collections for protein measurement were excluded (n = 7 of 16). *Paired t test.

Figure 5.

Pie chart showing distribution of renal pathologic findings in the 24 patients included in this case series.