Corticosteroid therapy alone for the treatment of C3 glomerulonephritis in association with monoclonal gammopathy

Introduction: C3 glomerulonephritis (C3GN) is a form of proliferative glomerulonephritis characterized by dominant glomerular C3 deposition. There is currently no consensus guideline on therapy for this disease. Experience with corticosteroids alone is scant in C3GN. We report the experience of treating patients with C3GN in association with monoclonal gammopathy with corticosteroid at a single center. Materials and methods: Corticosteroid therapy alone was used to treat 6 patients with C3GN who were also found to have monoclonal gammopathy at the time of presentation. Results: Median age of this cohort was 65 years. Median estimated glomerular filtration rate (eGFR) by MDRD equation was 31.6 mL/min/1.73m² at presentation. After a median duration of follow-up of 23.5 months, all patients showed improvement in proteinuria: median proteinuria reduced from 2.3 to 0.5 g/d. Four of 6 patients showed improvement in kidney function. One patient who had required renal replacement therapy recovered renal function. Median eGFR at follow-up was 38.7 mL/min/1.73m². Discussion: In patients with C3GN in association with monoclonal gammopathy, corticosteroid therapy alone may be a viable treatment option. Work-up should be done to exclude a hematologic neoplasm and inherited complement abnormalities before proceeding to corticosteroid therapy.