Expansion of polymorphonuclear myeloid-derived suppressor cells in patients with end-stage renal disease may lead to infectious complications.

Myeloid-derived suppressor cells (MDSCs) are recently identified immune suppressive cells in multiple chronic inflammations. Here, we investigated MDSCs in patients with end-stage renal disease (ESRD) and their clinical significance in these patients and healthy individuals (49 each). Polymorphonuclear and mononuclear MDSCs were investigated by flow cytometry. Patients with ESRD before hemodialysis presented a significantly higher level of polymorphonuclear MDSCs. Depletion of polymorphonuclear-MDSCs resolved T cell IFN-γ responses. By co-culture, T cell proliferation and the production of IFN-γ were abrogated by the addition of polymorphonuclear MDSCs in a dose-dependent manner. Both of these effects were reversed by a reactive oxygen species inhibitor. The levels of reactive oxygen species were higher in polymorphonuclear MDSCs derived from patients with ESRD than from normal individuals. The mRNA level of NOX2, the key protein complex responsible for reactive oxygen species production, was higher in ESRD-related polymorphonuclear MDSCs. The phospho-STAT3 level, a key activator of MDSCs, was higher in ESRD-related polymorphonuclear MDSCs. Finally, the polymorphonuclear MDSC level before and after hemodialysis was positively related to infectious diseases. Patients with ESRD were dichotomized into 2 groups by the amount of polymorphonuclear MDSCs. Patients with high levels of polymorphonuclear MDSCs presented with a higher incidence of infectious events. Thus, polymorphonuclear MDSCs were elevated in ESRD patients with strong immune-suppressive capability through a phospho-STAT3/reactive oxygen species pathway. Hence, polymorphonuclear MDSCs might increase the risk of infectious complications.

Delayed graft function is correlated with graft loss in recipients of expanded-criteria rather than standard-criteria donor kidneys: a retrospective, multicenter, observation cohort study.

BACKGROUND: Although the use of expanded-criteria donors (ECDs) alleviates the problem of organ shortage, it significantly increases the incidence of delayed graft function (DGF). DGF is a common complication after kidney transplantation; however, the effect of DGF on graft loss is uncertain based on the published literature. Hence, the aim of this study was to determine the relationship between DGF and allograft survival. METHODS: We conducted a retrospective, multicenter, observation cohort study. A total of 284 deceased donors and 541 recipients between February 2012 and March 2017 were included. We used logistic regression analysis to verify the association between clinical parameters and DGF, and Cox proportional hazards models were applied to quantify the hazard ratios of DGF for kidney graft loss. RESULTS: Among the 284 deceased donors, 65 (22.8%) donors were ECD. Of the 541 recipients, 107 (19.8%) recipients developed DGF, and this rate was higher with ECD kidneys than with standard-criteria donor (SCD) kidneys (29.2% vs. 17.1%; P = 0.003). The 5-year graft survival rate was not significantly different between SCD kidney recipients with and without DGF (95.8% vs. 95.4%; P = 0.580). However, there was a significant difference between ECD kidney recipients with and without DGF (71.4% vs. 97.6%; P = 0.001), and the adjusted hazard ratio (HR) for graft loss for recipients with DGF was 1.885 (95% confidence interval [CI] = 1.305-7.630; P = 0.024). Results showed that induction therapy with anti-thymocyte globulin was protective against DGF (odds ratio = 0.359; 95% CI = 0.197-0.652; P = 0.001) with all donor kidneys and a protective factor for graft survival (HR = 0.308; 95% CI = 0.130-0.728; P = 0.007) with ECD kidneys. CONCLUSION: DGF is an independent risk factor for graft survival in recipients with ECD kidneys, but not SCD kidneys.