Background: There is little published information on the natural history and the treatment of immune complex membrano-proliferative glomerulonephritis (IC-MPGN) of unknown cause in the transplanted kidney.
Materials and methods: From 01/2004 to 12/2018, 41 patients had the diagnosis of post-transplant idiopathic IC-MPGN and were included in the study.
Results: The mean age of the cohort at the time of transplant was 50 ± 13 years. The most common presentation was increased proteinuria, followed by kidney dysfunction. Fewer than 50% of patients had hematuria at presentation. 25 patients (61%) had no change in their baseline immunosuppression after the diagnosis of idiopathic IC-MPGN. Eight patients (19.5%) received steroids alone, and 8 patients (19.5%) received rituximab with (7) or without (1) steroids. The patients who received rituximab had better uncensored graft survival than the patients who received no treatment (p = 0.02), but the benefit of steroids compared to no treatment did not reach statistical significance (p = 0.05). The multivariate analysis retained eGFR < 30 mL/min/1.73m2 at time of diagnosis (HR = 3.30, p = 0.02; 95% Cl 1.15 - 9.46) as a significant predictor of graft loss. In this analysis, treatment of idiopathic IC-MPGN was associated with lower graft loss (HR = 0.22, p = 0.02; 95% Cl 0.06 - 0.78).
Conclusion: To the best of our knowledge, this is the largest clinic-pathological series of post-transplant idiopathic IC-MPGN. Treatment of idiopathic IC-MPGN may be associated with better graft outcomes.