Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) has recently been described in cases with glomerular disease. Only a dozen 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. Paramesangial deposits were found on the 2-year post-transplant protocol biopsy and C1q deposition 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. This case demonstrates that paramesangial deposits and/or C1q deposition could be findings of subclinical PGNMID in the transplanted kidney.

Figure 1. Clinical course after kidney transplantation

Figure 2. Histological findings from protocol biopsies conducted 4 years after renal transplant

CITATION INFORMATION: Tsuji T, Miura M, Yanai M, Itami H, Ishii Y, Akimoto M, Fukasawa Y. De Novo Proliferative Glomerulonephritis with Monoclonal IgG Deposits of the IgG1κ Subtype in a Kidney Allograft: Protocol Biopsy Findings. Am J Transplant. 2016;16 (suppl 3).

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