Abstract: TH-PO648

De Novo Proliferative Glomerulonephritis with Monoclonal IgG in Renal Allograft

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Long, Brad, University of Utah Hospital, Salt lake, Utah, United States
  • Marji, Catreena, University of Utah Hospital, Salt lake, Utah, United States
  • Ahmed, Faris, University of Utah Hospital, Salt lake, Utah, United States
  • Khalighi, Mazdak A., University of Utah Hospital, Salt lake, Utah, United States
  • Shihab, Fuad S., University of Utah Hospital, Salt lake, Utah, United States
  • Al-Rabadi, Laith, University of Utah Hospital, Salt lake, Utah, United States
Background

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) has recently been recognized as a unique type of glomerular injury with a wide spectrum of pathologic and clinical manifestations. It is characterized by deposition of monotypic IgG in glomeruli and is often accompanied by C3 and C1q deposition. We have previously reported a series of three cases of recurrent PGNMID in renal allografts, all of which were associated with IgG3-Kappa deposition. De novo PGNMID in renal allografts has only been reported in three cases.

Results

Herein, we present a fourth case of de novo disease that occurred in the renal allograft of a 32 year old man with primary disease of renal dysplasia since birth and prior allograft failure due to chonic antibody-mediated rejection. The patient presented to the hospital with 10 day history of dark urine. He was found to have acute kidney injury with Cr up to 2.5 mg/dl from 1.4 mg/dl. Urine microscopy showed many RBCs and several WBCs. Urine protein to Creatinine ratio was 1.5 g/g. Serum protein electrophoresis and immunofixation were normal. Serum kappa lambda ratio was 1.3. Cryoglobulins were negative. Biopsy showed mild mesangial hypercellularity without evidence of allograft rejection. Immunofluorescence microscopy revealed mesangial deposits staining for IgG, C3, C1q and kappa light chain without staining for lambda light chain. IgG subtype staining revealed IgG1-restriction. Electron microscopy showed mesangial electron dense deposits without substructural organisation.

Conclusion

Similar to native cases of PGNMID, recurrent disease in the allograft is most often related to deposition of IgG3-kappa. However, of the four reported cases of de novo PGNMID, three were IgG1-Kappa and only one was IgG3-kappa. IgG1-kappa in renal allografts has so far been described only in de novo cases, not in recurrent cases. Ours is the fourth de novo case but is the only one that occured in the second allograft. Patients with renal transplants are on immunosuppressive therapy that may alter the disease course. Deposition of IgG1-kappa in renal allografts may represent a distinict entity which is more resistant to IS therapy. More studies are needed to investigate the impact of different immunoglobulin subclasses on disease phenotype.