SP167
RECURRENCE OF MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS AFTER KIDNEY TRANSPLANTATION

INTRODUCTION AND AIMS: Recurrence of membranoproliferative glomerulonephritis (MPGN) is not infrequent after kidney transplantation (KT). Because of the pathogenetic heterogeneity of this disease, there are numerous aspects incompletely understood that deserve further investigation.This study aims to analyze the main clinical and histologic characteristics of recurrence MPGN, and its influence on KT survival.

METHODS: Retrospective, observational study in a cohort of adult patients diagnosed with MPGN in their native kidneys, and who received a KT at our hospital between 1983 and 2015. MPGN were classified according to both the location of immune deposits ('old classification') and the immunofluorescence staining ('new classification'). When information about immunofluorescence or electron microscopy was unavailable, patients were categorized as having 'unknown origin' (UO). Clinical, biochemical and histologic parameters of prognostic interest were recorded and used to analyze the main differences between recurrent and non-recurrent MPGN.

RESULTS: We included 88 patients (mean age 45±15 years, 52% males). According to the old classification, patients were categorized as having MPGN type I 54 patients (62%), type II 3 patients (3%), type III 24 patients (27%), and UO 7 patients (8%); and according to the new classification: immune complex-mediated (IC) 66 patients (75%), complement-mediated (CM) 14 patients (16%), and UO 8 (9%).During a median follow-up time of 94 months, recurrence was diagnosed in 21 patients (24%): 22% of IC vs. 43% of CM MPGN, whereas no recurrence was found among the patients with MPGN of UO. No significant differences were found in age, sex, co-morbid conditions or immediate post-transplant complications between recurrent and non-recurrent MPGN. Of note, the only two patients with monoclonal gammopathy had a post-transplant recurrence.By Cox regression analysis, the best determinants associated with the composite endpoint of death or graft loss were donor age (HR=1.028; 95% CI: 1.08-1.05, p=0.006), and recurrence of MPGN (HR=3.48; 95% CI: 1.8-6.7; p<0.0001).

CONCLUSIONS: Nearly one-quarter of patients with MPGN who underwent KT have recurrence of the disease, whose pathogenic mechanisms could influence on the risk of developing this complication. Recurrence of MPGN is associated with a significant worse KT outcome.