[1653] Membranous Glomerulonephritis Secondary to IgG4-Related Disease

Mariam P Alexander, Ian W Gibson, Yassaman Raissian, Suresh Chari, Naoki Takahashi, Samih H Nasr, Sanjeev Sethi, Thomas C Smyrk, Lynn D Cornell. Mayo Clinic, Rochester, MN; University of Manitoba, Winnipeg, MB, Canada

Background: IgG4-related disease (IgG4-RD) is a multiorgan inflammatory disease. Renal involvement is usually recognized in the form of IgG4-related tubulointerstitial nephritis (IgG4-TIN). There are case reports of glomerular disease associated with IgG4-RD, usually membranous glomerulonephritis (MGN). This is the first series of MGN associated with IgG4-RD.
Design: Patients(pts) were identified from a biopsy database based on the combination of MGN and clinical or histopathologic evidence of IgG4-TIN or other organ involvement by IgG4-RD. Presenting clinical data and treatment and follow-up data were obtained. Pathology material was reviewed.
Results: Eight IgG4-RD pts with MGN were identified. All pts had nephrotic-range proteinuria (ave 9.6 g/day;range 3.5-16). The mean serum creatinine (SCr) was 2.5 mg/dl(range 0.8-6.6); one pt had acute renal failure due to IgG4-TIN. 6 pts (75%) had other organ involvement by IgG4 disease. All 4 pts with available data had an increased serum IgG4 level. On biopsy, 4 pts (50%) had concurrent IgG4-TIN with increased IgG4+ plasma cells. Two pts had other glomerular disease in addition to MGN: one had diabetic glomerulosclerosis and the other had IgA nephropathy. One pt had a segmental endocapillary proliferative pattern with MGN. By immunofluorescence, glomeruli showed granular glomerular capillary loop staining for IgG, C3, kappa and lambda. One biopsy showed tubular basement membrane deposits. Electron microscopy revealed stage I-II MGN.
Follow-up data were available for all pts, at a mean of 37 mos(range 1-184). 6 of 8 pts were treated for MGN. Two pts received prednisone monotherapy, 2 prednisone followed by mycophenolate mofetil (MMF), one rituximab and MMF, and one prednisone and cyclophosphamide. The 2 untreated pts developed end-stage renal disease within 1 mo and 3 yrs; one of these pts was transplanted, without clinical evidence of recurrent disease and with stable SCr 11 years post-transplant. The mean SCr at follow-up of the other 6 pts was 1.4 mg/dl(range 0.8-2.5) and proteinuria was 1.4 g/day range 0.17-3.1). 2/6 pts showed a complete response of proteinuria to treatment and 3 showed a partial response; the other had heavy proteinuria at 1 mo follow-up. The pt with acute renal failure and TIN showed marked improvement in SCr with prednisone monotherapy.
Conclusions: MGN should be included in the spectrum of IgG4-RD and should be suspected in pts with nephrotic-range proteinuria. MGN can occur concomitantly with IgG4-TIN. Treatment with immunosuppressive drugs may improve proteinuria and may improve renal function in pts with decreased renal function.
Category: Kidney (does not include tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 268, Wednesday Afternoon

 

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