Kidney transplantation in children and adolescents with C3 glomerulopathy or immune complex membranoproliferative glomerulonephritis: a real-world study within the CERTAIN research network.

Background: Complement 3 glomerulopathy (C3G) and immune complex membranoproliferative glomerulonephritis (IC-MPGN) are ultra-rare chronic kidney diseases with an overall poor prognosis, with approximately 40-50% of patients progressing to kidney failure within 10 years of diagnosis. C3G is characterized by a high rate of disease recurrence in the transplanted kidney. However, there is a lack of published data on clinical outcomes in the pediatric population following transplantation.

Methods: In this multicenter longitudinal cohort study of the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) registry, we compared the post-transplant outcomes of pediatric patients with C3G (n = 17) or IC-MPGN (n = 3) with a matched case-control group (n = 20).

Results: Eleven of 20 children (55%) with C3G or IC-MPGN experienced a recurrence within 5 years post-transplant. Patients with C3G or IC-MPGN had a 5-year graft survival of 61.4%, which was significantly (P = 0.029) lower than the 5-year graft survival of 90% in controls; five patients with C3G or IC-MPGN lost their graft due to recurrence during this observation period. Both the 1-year (20%) and the 5-year (42%) rates of biopsy-proven acute rejection episodes were comparable between patients and controls. Complement-targeted therapy with eculizumab, either as prophylaxis or treatment, did not appear to be effective.

Conclusions: These data in pediatric patients with C3G or IC-MPGN show a high risk of post-transplant disease recurrence (55%) and a significantly lower 5-year graft survival compared to matched controls with other primary kidney diseases. These data underscore the need for post-transplant patients for effective and specific therapies that target the underlying disease mechanism.