Impact of graft nephrectomy on outcomes of second kidney transplantation.

OBJECTIVES: To determine the impact of renal graft nephrectomy on second kidney transplantation survival. METHODS: We carried out a retrospective single-center study by analyzing cases performed from January 2000 to December 2011. Retransplanted patients who underwent previous allograft nephrectomy more than 3 months post-transplantation (group 1) were compared with those who did not (group 2) in terms of graft survival, incidences of acute rejection and delayed graft function. Multivariate Cox proportional hazard models were used to assess risk factors of graft loss after retransplantation. RESULTS: Overall, 146 patients were analyzed, including 52 (35.6%) in group 1 and 94 (64.4%) in group 2. Group 1 patients presented a significantly shorter first graft survival (0.8 vs 8.6 years, P < 0.001) and more anti-class I antibodies (90.5% vs 74.2%, P = 0.03). A total of 10 patients (19%) in group 1 and 16 patients (17%) in group 2 had at least one acute rejection episode (P = 0.74). Delayed graft function was observed in 13 patients (25%) in group 1 and 17 patients (18%) in group 2 (P = 0.32). Graft survival at 1, 5 and 10 years was, respectively, 94%, 81% and 58% in group 1, and 99%, 93% and 66% in group 2 (P = 0.10). Graft survival was decreased by increased donor age and serum creatinine, and tended to be associated with post-transplantation presence of anti-class I and II antibodies. Graft nephrectomy was not associated with graft survival in multivariate analysis. CONCLUSIONS: Graft nephrectomy, probably a marker of high immunological risk patients, is not a risk factor of increased retransplant failure.

C5b9 Deposition in Glomerular Capillaries Is Associated With Poor Kidney Allograft Survival in Antibody-Mediated Rejection.

C4d deposition in peritubular capillaries (PTC) reflects complement activation in antibody-mediated rejection (ABMR) of kidney allograft. However, its association with allograft survival is controversial. We hypothesized that capillary deposition of C5b9-indicative of complement-mediated injury-is a severity marker of ABMR. This pilot study aimed to determine the frequency, location and prognostic impact of these deposits in ABMR. We retrospectively selected patients diagnosed with ABMR in two French transplantation centers from January 2005 to December 2014 and performed C4d and C5b9 staining by immunohistochemistry. Fifty-four patients were included. Median follow-up was 52.5 (34.25-73.5) months. Thirteen patients (24%) had C5b9 deposits along glomerular capillaries (GC). Among these, seven (54%) had a global and diffuse staining pattern. Twelve of the C5b9+ patients also had deposition of C4d in GC and PTC. C4d deposits along GC and PTC were not associated with death-censored allograft survival (p = 0.42 and 0.69, respectively). However, death-censored allograft survival was significantly lower in patients with global and diffuse deposition of C5b9 in GC than those with a segmental pattern or no deposition (median survival after ABMR diagnosis, 6 months, 40.5 months and 44 months, respectively; p = 0.015). Double contour of glomerular basement membrane was diagnosed earlier after transplantation in C5b9+ ABMR than in C5b9- ABMR (median time after transplantation, 28 vs. 85 months; p = 0.058). In conclusion, we identified a new pattern of C5b9+ ABMR, associated with early onset of glomerular basement membrane duplication and poor allograft survival. Complement inhibitors might be a therapeutic option for this subgroup of patients.