Multifocal phaeohyphomycosis caused by Exophiala xenobiotica in a kidney transplant recipient.

In recent years, black fungi have been increasingly reported as causing opportunistic infections after solid organ transplantation. Here, we report a case of insidious, relentless, and multifocal Exophiala xenobiotica infection in a kidney transplant recipient that eventually required multiple surgical excisions along with oral and intravenous antifungal combination therapy using liposomal amphotericin B and posaconazole. We compare the present case with all previously reported cases of Exophiala infection after kidney transplantation.

The Kidney Donor Profile Index (KDPI) of marginal donors allocated by standardized pretransplant donor biopsy assessment: distribution and association with graft outcomes.

Pretransplant donor biopsy (PTDB)-based marginal donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the United States. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score<4 [median KDPI: 87; interquartile range (IQR): 78-94] and 62 with a score=4 [median KDPI: 87; IQR: 76-93]; 102 dual transplants [median KDPI: 93; IQR: 86-96]) and 248 single standard transplant controls (median KDPI: 36; IQR: 18-51). PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year estimated GFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9 and -18.8 mL/min, for dual transplants, single kidneys with PTDB score<4 and =4, respectively; p<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80-1.79; p=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded.

Guiding postablative lymphocyte reconstitution as a route toward transplantation tolerance.

Anti-lymphocyte-depleting antibodies have increasingly been utilized in the clinic as induction therapy aiming to improve transplantation outcomes by reducing the need for long-term immunosuppression. However, maintenance immunosuppression is still required as lymphocyte reconstitution through homeostatic proliferation, partially driven by IL-7, continues to replenish tolerance-refractory immune cells capable of rejection. In murine models of MHC mismatched skin grafting, we investigated whether it is feasible to control the lymphocyte reconstitution process to delay rejection and favor tolerance processes. We found that a short course of anti-IL-7 receptor blocking antibody following T cell depletion, combined with the mammalian target of rapamycin inhibitor Rapamycin, could significantly delay graft rejection in one mouse strain, and achieve transplantation tolerance in another. The combination treatment was found to delay T cell reconstitution and, in the short term, enriched for Foxp3+ regulatory T cells (Tregs), at the expense of effector cells. Extended graft survival and tolerance were dependent on TGF-ß, indicating a role for induced Tregs. These findings point to the feasibility of building on lympholytic induction by guiding early lymphocyte reconstitution to favor endogenous regulatory mechanisms.

Mesenchymal stem cells infusion prevents acute cellular rejection in rat kidney transplantation.

Mesenchymal stem cells (MSC) are multipotent cells that differentiate into various mature cell lineages. MSC show immunomodulatory effects by inhibiting T-cell proliferation. We evaluated the effect of the infusion of MSC in rats experimental kidney transplantation. Sprague-Dawley transgenic rats (SD) able to express the green fluorescent protein (EGFP) were used as MSC donors. Syngeneic (Lewis to Lewis, n = 10) and allogeneic (Fischer to Lewis, n = 10) kidney transplantations were performed after bilateral nephrectomy. Five transplanted rats who received syngeneic grafts, were treated with 3 x 10(6) MSC (Gr B), while the other 5 did not received MSC (Gr A). Five rats with allogenic grafts received 3 x 10(6) MSC (Gr C) and another 5 did not receive MSC (Gr D). The MSC were infused directly into the renal artery of the graft. No immunosuppressive therapy was provided. The animals were killed after 7 days. Biochemical analysis for renal function, histological (Banff criteria) and immunohistological analysis (ED1+ and CD8+) were performed on treated animals. MSC improved kidney function in Gr B and D vs Gr A and C. The tubular damage appeared to be less severe among Gr B and Gr D with respect to Gr A and C (P < .01). Vasculitis was more accentuated in Gr A and C (P < .01). MSCs reduced the inflammatory infiltrate; in Gr B and D, the number of ED1+ cells was lower than in Gr A and C (P < .005), which was also observed for CD8+ cells (P < .05). Our study demonstrated that the infusion of MSC attenuated histological damage from acute rejection by reducing the cellular infiltration.

Which is the most suitable and effective route of administration for mesenchymal stem cell-based immunomodulation therapy in experimental kidney transplantation: endovenous or arterial?

Immunomodulating cell therapy represents a new perspective for the control of cellular immune responses that determine the occurrence of acute rejection (ACR) in allo-transplantation. Mesenchymal stem cells (MSC) demonstrate immunoregulatory effects by inactivating T-cell components that regulate tissue damage in transplantation models. The presumed mechanism of action is recruitment of cells by a cytokine network. The purpose of this study was to test which route of administration (intra-arterial vs intravenous) was the most effective route to achieve immunomodulating effects in experimental rat kidney transplantation. Transgenic Sprague-Dawley rats (SD) expressing the enhanced green fluorescent protein (EGFP) at the somatic level were used as MSC donors: Allogeneic Fischer to Lewis grafts (n = 4 per group) were performed in rats after bilateral nephrectomy. In Gr B, 3 x 10(6) MSCs were infused into the renal graft artery, whereas in Gr C, they were infused into the tail vein. The untreated Gr A were a control group. No immunosuppressive therapy was administered. The animals were sacrificed at day 7 postoperatively. Biochemical analysis for renal function, histological (Banff criteria) and immunohistological (anti-EGFP-Immunoglobulin) analysis were performed on the transplanted animals. In Gr B, functional recovery was more rapid (creatinine: Gr B vs Gr C, P < .05). The inflammatory infiltrate in the graft was less in Gr B vs Gr C, with preservation of tubules, arteries, and glomeruli (P < .01). Intra-arterial infusion of MSCs was more effective to control ACR.