Proliferative glomerulonephritis with monoclonal IgG deposits in an adolescent successfully treated with daratumumab

There is no specific treatment for proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID), a disease that is very rare in the pediatric population. We report the case of a 15-year-old boy who presented with mildly reduced kidney function and nephrotic syndrome. Kidney biopsy revealed PGNMID with monoclonal deposits of IgG3 with kappa light chain restriction. Flow cytometry showed a significant CD38 plasma cell population in the peripheral blood in the absence of other signs of hematological malignancy. The patient was treated with a 6-month course of daratumumab, a monoclonal antibody targeting CD38. There was a significant reduction in proteinuria and normalization of kidney function. Based on positive experience with adults, daratumumab should also be studied in children with PGNMID.