Proliferative Glomerulonephritis with Monoclonal IgG Deposits Without Detectable Clonality: A Case Series with Infection-Associated Features

Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) is categorized under monoclonal gammopathy of renal significance; however, a circulating clone is often absent. We report seven patients with biopsy-proven PGNMID with no detectable clonality despite extensive evaluation. Mean age was 51.7 years; 57% were male. Clinical presentations included dialysis-requiring acute kidney injury (AKI) (n = 3), nephrotic syndrome (n = 3), and non–dialysis AKI on CKD with nephrotic range proteinuria (n = 1). Antecedent or concurrent infection was present in 6 patients. Kidney biopsy demonstrated a membranoproliferative pattern, with subepithelial hump-like deposits identified in 3 cases. Management included supportive therapy (n = 4), corticosteroids (n = 2), and limited clone-directed therapy (n = 1). All patients with dialysis-requiring AKI became dialysis-independent, and those with nephrotic syndrome achieved remission with supportive therapy/steroids alone. These findings are consistent with emerging evidence that a subset of clone-negative PGNMID may be infection-associated.