Recurrence of C3 Glomerulopathy and Immune Complex–Mediated Membranoproliferative Glomerulonephritis After Kidney Transplantation: Challenges and Opportunities

Recurrent C3 glomerulopathy (C3G) and primary immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) remain major causes of kidney allograft dysfunction and loss. Their pathogenesis involves genetic susceptibility, acquired complement dysregulation, and transplant-related triggers, yet no clear validated predictors of recurrence exist. Recurrence rates after kidney transplantation frequently exceed 60% and are associated with progression to graft failure. Early detection, often achievable through protocol biopsies, offers an opportunity for timely intervention, although histologic recognition of early recurrence can be challenging. Comprehensive pretransplant evaluation, including genetic and molecular complement testing and screening for monoclonal gammopathies, may refine risk stratification. Conventional treatments, including intensified immunosuppression, rituximab, and plasma exchange, have shown limited and inconsistent efficacy. Conversely, complement-targeted therapies have yielded promising outcomes. Although eculizumab remains the most extensively studied agent, emerging proximal complement inhibitors such as iptacopan and pegcetacoplan have shown encouraging efficacy in both native and recurrent disease. However, optimal timing, prophylactic use, and long-term safety in transplant recipients remain uncertain. In this review, we outline the clinical spectrum, key diagnostic and therapeutic challenges, and emerging treatment strategies for recurrent C3G and IC-MPGN, highlighting advances that may ultimately improve graft survival and patient outcomes.