A case of recurrent proliferative glomerulonephritis with monoclonal IgG deposits or de novo C3 glomerulonephritis after kidney transplantation.

Proliferative glomerulonephritis with monoclonal immunoglobulin (Ig)G deposits (PGNMID) is a rare disease with a treatment that is not well established. Several cases of recurrent PGNMID after kidney transplantation have been documented, but almost all cases reported symptoms such as elevated serum creatinine and/or urinary protein levels; subsequently, episode biopsies were performed and a diagnosis was made. This is the case of a 27-year-old man who underwent living-donor kidney transplantation. The aetiology of renal failure was membranoproliferative glomerulonephritis type III, which had been diagnosed at the age of 9 years. Protocol biopsy performed on postoperative day 62 revealed isolated granular C3 deposits in the glomerular capillaries and mesangium. We reviewed the native kidney biopsy and confirmed IgG3 deposition alone, with strong glomerular staining for lambda light chains and negative staining for kappa light chains. Accordingly, we re-diagnosed the aetiology of his renal failure as PGNMID and suspected recurrent PGNMID in the early stage; therefore, we administered plasma exchange therapy. Thereafter, protocol biopsies were performed twice, which revealed persistent isolated C3 deposition; therefore, we made a diagnosis of recurrent PGNMID or C3 glomerulonephritis. Currently, the patient has normal renal function, with negative urine findings for >1 year. Here, we present the histological findings of consecutive allograft biopsies performed in this patient.

Tamura T ，Unagami K ，Okumi M ，Kakuta Y ，Horita S ，Ishida H ，Koike J ，Honda K ，Tanabe K ，Nitta K ... -  《-》

Proliferative glomerulonephritis with monoclonal immunoglobulin G deposits complicated by immunoglobulin A nephropathy in the renal allograft.

Immunoglobulin (Ig) A nephropathy (IgAN) is a known autoimmune disease due to abnormal glycosylation of IgA1, and occasionally, IgG co-deposition occurs. The prognosis of IgG co-deposition with IgAN is adverse, as shown in the previous studies. However, in the clinical setting, monoclonality of IgG co-deposition with IgAN has not been observed. We describe a case of proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) combined with IgAN in a renal allograft. A-21-year-old man developed end-stage renal failure with unknown aetiology and underwent living-donor kidney transplantation from his mother 2 years after being diagnosed. One year after kidney transplantation, proteinuria 2+ and haematuria 2+ were detected; allograft biopsy revealed mesangial IgA and C3 deposits, indicating a diagnosis of IgAN. After tonsillectomy and steroid pulse therapy, proteinuria and haematuria resolved. However, 4 years after transplantation, pedal oedema, proteinuria (6.89 g/day) and allograft dysfunction (serum creatinine (sCr) 203.3 µmol/L) appeared. A second allograft biopsy showed mesangial expansion and focal segmental proliferative endocapillary lesions with IgA1λ and monoclonal IgG1κ depositions. Electron microscopic analysis revealed a massive amount of deposits, located in the mesangial and subendothelial lesions. A diagnosis of PGNMID complicated with IgAN was made, and rituximab and plasmapheresis were added to steroid pulse therapy. With this treatment, proteinuria was alleviated to 0.5 g/day, and the allograft dysfunction recovered to sCr 132.6 µmol/L. This case suggests a necessity for investigation of PGNMID and IgA nephropathy in renal allografts to detect monoclonal Ig deposition disease.

Sawada A ，Kawanishi K ，Horita S ，Koike J ，Honda K ，Ochi A ，Komoda M ，Tanaka Y ，Unagami K ，Okumi M ，Shimizu T ，Ishida H ，Tanabe K ，Nagashima Y ，Nitta K ... -  《-》

De novo proliferative glomerulonephritis with monoclonal IgG deposits of the IgG1κ subtype in a kidney allograft.

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) has recently been described in cases with glomerular disease. Only 16 cases of recurrent or de novo PGNMID have been reported in the transplanted kidney. Here we report a case of de novo PGNMID in a renal allograft diagnosed in the early stage by protocol biopsy. A 41-year-old male with end-stage kidney disease caused by focal glomerular sclerosis received a living-related kidney transplant. The post-transplantation course was stable, except for an early episode of acute T cell-mediated rejection. Mesangial C1q deposition was found on the 3-year protocol biopsy. On the 4-year protocol biopsy, mild mesangioproliferative changes and deposition of IgG, C1q, C3, IgG1, and κ light chain were evident, confirming the diagnosis of PGNMID of the IgG1κ subtype. Furthermore, mild proteinuria was detected at that time. Because a subsequent haematological examination revealed high copy number Epstein-Barr virus (EBV) DNA and free κ light chain in blood, the post-transplant lymphoproliferative disorder (PTLD) was suspected. Mycophenolate mofetil (MMF) was discontinued and rituximab was administered for the treatment of PTLD; subsequently, the improvement in proteinuria and serum creatinine was found 2 months after rituximab administration.

Tsuji T ，Miura M ，Yanai M ，Itami H ，Ishii Y ，Akimoto M ，Fukasawa Y ... -  《-》

Complete biopsy-proven resolution of deposits in recurrent proliferative glomerulonephritis with monoclonal IgG deposits (PGNMIGD) following rituximab treatment in renal allograft.

Von Visger J ，Cassol C ，Nori U ，Franco-Ahumada G ，Nadasdy T ，Satoskar AA ... -  《BMC Nephrology》

Recurrence of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin G Deposits with a Striated Ultrastructure.

A 64-year-old man with nephrotic syndrome was admitted to another hospital where his renal biopsy revealed membranoproliferative glomerulonephritis (MPGN) with monoclonal immunoglobulin (Ig) G, subclass 1, κ light chain (IgG1κ) deposition on immunofluorescence (IF). Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) was suspected due to monoclonal IgG1κ deposits and the absence of hematological abnormalities. However, the typical PGNMID phenotype was not observed by electron microscopy. Instead, an organized and striated muscle-like structure was observed in the subendothelial space. Since a 2-year treatment with immunosuppressants did not improve his proteinuria, a second biopsy was performed at our hospital. It showed an MPGN-like phenotype; however, monoclonal Ig deposits on IF were no longer observed. One year after the second biopsy, he developed ESRD. Thus, he underwent living kidney transplantation from his wife. Allograft biopsy was performed as proteinuria was observed 3 months after transplantation, which again showed an MPGN-like phenotype with monoclonal IgG1κ deposits. The observed electron-dense deposits were similar to those in the native biopsies. Accordingly, the patient was diagnosed with recurrent MPGN. Adding methylprednisolone pulse therapy to conventional immunosuppressants did not improve the patient's renal function or proteinuria. He died of Legionella pneumonia 8 months after transplantation. Considering the patient's histological findings of MPGN with monoclonal IgG1κ deposits and early recurrence of glomerulonephritis after transplantation, he was diagnosed with PGNMID with novel electron-dense deposits.

Namba-Hamano T ，Hamano T ，Imamura R ，Yamaguchi Y ，Kyo M ，Yonishi H ，Takahashi A ，Kawamura M ，Nakazawa S ，Kato T ，Abe T ，Kyakuno M ，Takabatake Y ，Nonomura N ，Isaka Y ... -  《-》