A Review on the Diagnosis and Treatment of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a new entity of monoclonal gammopathy of renal significance (MGRS) due to monoclonal immunoglobulin (mIg) deposits in the glomerulus leading to kidney injury. Patients with PGNMID typically present with proteinuria, haematuria, and abnormal renal function. Only ~30% of patients have a detectable clone in the blood, urine or bone marrow. Histologically, the membranoproliferative glomerulonephritis (MPGN) pattern of injury is the most common, with approximately 50% of patients demonstrating IgG3κ monoclonal deposition in the glomerulus. Approximately 20% of PGNMID patients progress to end-stage kidney disease (ESΚD), and recurrence with renal allograft is frequent. Treatment of PGNMID relies on targeting identifiable B-cell or plasma cell clones. Due to the relatively short history of research on this disease and incomplete understanding, it is easy to misdiagnose and miss diagnosis, and there are also objections on how to treat it. Therefore, we review the development of PGNMID understanding in the past 20 years and discuss this new entity from a holistic and progressive perspective.