: C3 glomerulonephritis associated with monoclonal gammopathy of renal significance

Abstract

Introduction: Monoclonal gammopathy of renal significance (MGRS) is described as a hematologic condition characterized by nephrotoxic monoclonal proteins produced by a non-malignant B-cell or plasma cell clone. Nevertheless, MGRS can cause serious renal and systemic lesions, leading to high morbidity. In C3 Glomerulonephritis (C3GN), a monoclonal protein can cause renal damage not by deposition, but indirectly through continuous activation of the alternative pathway of complement. Methods: This non-systematic review was based on a comprehensive search in databases and scientific journals, such as PubMed, Nature Reviews Nephrology and Kidney International, including the terms 'C3 Glomerulonephritis' and 'Monoclonal gammopathy of renal significance'. We present a review of the pathophysiology, presentation, diagnosis, differential diagnosis and treatment of C3GN associated with MGRS. Discussion/Conclusion: With the increasing understanding of the complex interaction between monoclonal complement and renal damage, such as C3GN, it becomes clear that an early recognition is crucial, as clone-directed therapy might improve outcome. In this context, in order to maximize the chance of a correct diagnosis, a renal biopsy is mandatory to determinate the exact nature of the lesion, and the severity of renal disease. This review emphasizes the importance of early diagnosis of MGRS-associated C3GN in medical practice in order to prevent not only the progression to a hematological malignancy, but also end-stage renal disease (ESRD).