Proliferative glomerulonephritis with monoclonal IgG deposits in renal allografts: clinicopathologic features and prognosis

Abstract

Objective To characterize the clinicopathologic features, treatment efficacy and prognoses of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) in renal allografts. Methods Electronic medical records of Jinling Hospital were searched for PGNMID that was diagnosed during January 2008 to April 2017. Clinicopathologic features, treatment regimens and prognoses information were retrieved and analyzed. Results We identified 5 cases of PGNMID with clinical symptoms of proteinuria (5/5), serum creatinine elevation (4/5) or hematuria (4/5) 5 to 19 months after kidney transplantation. Various light microscopic features were observed, with predominantly membranoprolifeative pattern. Mild mesangial proliferation pattern could be observed in early stages of disease progression. Immunofluorescence revealed monoclonal IgG3κ in 3 patients and IgG3λ in another 2 cases. One case of PGNMID with normal light microscopy but monoclonal IgG deposits was verified by IgG and light-chain subtyping. In the 4 patients treated with rituximab or bortezomib, decreased proteinuria was achieved in all treated patients while the decreases in serum creatinine decrease were only observed in 2 patients. At last follow-up, one patient was in dialysis and serum creatinine levels of other 2 patients were >265.2 μmol/L. Conclusion Membranoprolifeative pattern is the most frequently observed microscopic findings and IgG3 is the most frequent IgG subtype in PGNMID. PGNMID recurs shortly after kidney transplantation. Rituximab and/or bortezomib is conducive to decrease proteinuria while their efficacy to decrease serum creatinine is dubious. The most effective treatment protocol for PGNMID remains to be determined in larger samples. Key words: Kidney transplantation; Proliferative glomerulonephritis with monoclonal IgG deposits; Bortezomib; Rituximab