Kidneys at higher risk of discard: expanding the role of dual kidney transplantation.

Half of the recovered expanded criteria donor (ECD) kidneys are discarded in the United States. A new kidney allocation system offers kidneys at higher risk of discard, Kidney Donor Profile Index (KDPI)>85%, to a wider geographic area to promote broader sharing and expedite utilization. Dual kidney transplantation (DKT) based on the KDPI is a potential option to streamline allocation of kidneys which otherwise would have been discarded. To assess the clinical utility of the KDPI in kidneys at higher risk of discard, we analyzed the OPTN/UNOS Registry that included the deceased donor kidneys recovered between 2002 and 2012. The primary outcomes were allograft survival, patient survival and discard rate based on different KDPI categories (<80%, 80-90% and >90%). Kidneys with KDPI>90% were associated with increased odds of discard (OR=1.99, 95% CI 1.74-2.29) compared to ones with KDPI<80%. DKTs of KDPI>90% were associated with lower overall allograft failure (HR=0.74, 95% CI 0.62-0.89) and better patient survival (HR=0.79, 95% CI 0.64-0.98) compared to single ECD kidneys with KDPI>90%. Kidneys at higher risk of discard may be offered in the up-front allocation system as a DKT. Further modeling and simulation studies are required to determine a reasonable KDPI cutoff percentile.

Availability, utilization and outcomes of deceased diabetic donor kidneys; analysis based on the UNOS registry.

The number of kidneys obtained from deceased diabetic donors available for transplantation has increased >eightfold increase in the past 15 years. We assessed allograft outcomes associated with deceased diabetic donors and compared them with that of standard and extended criteria donors (ECD) in the UNOS data registry. We identified 1982 recipients of diabetic standard criteria donors over a 10-year period from 1995 through 2004. Both overall and death-censored survival of organs from diabetic standard criteria donors was significantly better than that of organs obtained from nondiabetic ECD while inferior to that from nondiabetic standard criteria donors. Compared with ECD donors, diabetic donors had lower serum creatinine, less cold ischemia and these kidneys were less likely to be pump-perfused. Recipients of diabetic kidneys were younger and less likely to experience delayed graft function compared with recipient of ECD kidneys. More recently, many diabetic donor kidneys have been given to diabetic recipients with early graft survival being similar to that among nondiabetic recipients. These findings demonstrate the potential to expand and to improve utilization of this resource without compromising outcomes for recipients. Improved, evidence-based evaluation and allocation of deceased diabetic donor kidneys is needed to optimize their use.

A case of human intramuscular adrenal gland transplantation as a cure for chronic adrenal insufficiency.

Intramuscular endocrine gland transplantation has been well described as it pertains to parathyroid autotransplantation; however, transplantation of the adrenal gland is less well characterized. While adrenal autotransplantation in the setting of Cushing's disease has been described, intramuscular adrenal allotransplantation as a cure for adrenal insufficiency to our knowledge has not been previously carried out. Current treatment for adrenal insufficiency leaves patients without diurnal variation in cortisol release and susceptible to the detrimental effects of chronic hypercortisolism. We describe here the case of a 5-year-old girl with renal failure who had adrenal insufficiency following fulminant meningococcemia that led to requirements for both stress-dose steroid and mineralocorticoid replacement. Ten months after the onset of her disease, she received a simultaneous renal and adrenal gland transplant from her mother. The adrenal gland allograft was morselized into 1 mm(3) segments and implanted into three 2 cm pockets created in her rectus abdominis muscle. Three years after surgery, her allograft remains fully functional, responding well to adrenocorticotropin hormone stimulation and the patient does not require any steroid or mineral-corticoid supplementation. We believe this case represents the first description of successful functional intramuscular adrenal allograft transplantation with long-term follow up as a cure for adrenal insufficiency.

Survival outcomes following liver transplantation (SOFT) score: a novel method to predict patient survival following liver transplantation.

It is critical to balance waitlist mortality against posttransplant mortality. Our objective was to devise a scoring system that predicts recipient survival at 3 months following liver transplantation to complement MELD-predicted waitlist mortality. Univariate and multivariate analysis on 21,673 liver transplant recipients identified independent recipient and donor risk factors for posttransplant mortality. A retrospective analysis conducted on 30,321 waitlisted candidates reevaluated the predictive ability of the Model for End-Stage Liver Disease (MELD) score. We identified 13 recipient factors, 4 donor factors and 2 operative factors (warm and cold ischemia) as significant predictors of recipient mortality following liver transplantation at 3 months. The Survival Outcomes Following Liver Transplant (SOFT) Score utilized 18 risk factors (excluding warm ischemia) to successfully predict 3-month recipient survival following liver transplantation. This analysis represents a study of waitlisted candidates and transplant recipients of liver allografts after the MELD score was implemented. Unlike MELD, the SOFT score can accurately predict 3-month survival following liver transplantation. The most significant risk factors were previous transplantation and life support pretransplant. The SOFT score can help clinicians determine in real time which candidates should be transplanted with which allografts. Combined with MELD, SOFT can better quantify survival benefit for individual transplant procedures.

Microscopic intrarenal particles after pulsatile machine preservation do not adversely affect outcomes after renal transplantation.

INTRODUCTION: Our center has recently observed foreign carbohydrate-appearing particles (FP) on transplant postreperfusion biopsy specimens: (PRBx). METHODS: To further characterize FPs, we reviewed all renal transplant RBx (30-45 minutes) performed between September 1, 2004 and December 3, 2005. Donor, preservation, and outcome variables were collected among patients with FP. RESULTS: A total of 135 PRBx were performed (45 deceased donors [DD] and 90 live donors [LD]). Fifteen PRBx demonstrated FP. All 15 cases were DD kidneys that underwent machine perfusion (MP) on the Waters RM3 (Waters Medical Systems, Rochester, Minn, United States) with Belzer MP solution (Trans Med, Elk River, Minn, United States). Donor age was 39.8 +/- 15.7 years. Terminal creatinine level was 1.45 +/- 0.8 mg/dL. Two of 15 were flushed in situ with HTK solution (no starch). Cold ischemia time was 28.8 +/- 9.1 hours with 14.3 +/- 5.1 hours of MP. In 13 of 15 patients, perfusion parameters were excellent (flow > 100 mL; resistance < .35). CHARACTERISTICS OF FP: Particles were 10-30 mu and globular in shape. FP were not visible on hematoxylin and eosin stain, but stained strongly periodic acid-Schiff-(PAS) positive and were refractile under polarized light. FP were seen segmentally within glomerular capillaries in all cases and in peritubular capillaries in 3. In 11 of the 15 cases with FP, focal glomerular fibrin thrombi or intracapillary neutrophil margination was seen. Ten of 15 patients with FP had a biopsy within the first week with no identifiable FP. OUTCOMES: Recipient age was 45.3 +/- 11.6 years. Eight patients (53.3%) had delayed graft function. Biopsy-proven rejection occurred in 3 patients (20%). Three-month creatinine level was 1.59 +/- 0.35 mg/dL. One graft was lost to early thrombosis in a patient with a hypercoagulable state and 1 patient died of sepsis at 2 months. All remaining 13 patients are alive with excellent graft function at a median follow-up of 6.7 months (range, 3-17 months). CONCLUSIONS: Microscopic intrarenal particles may be seen on DD kidney PRBx after MP. These FPs likely originate from surgical gloves. FPs are too small to be captured by standard filters but clear spontaneously and do not have deleterious effects on renal function or outcomes.

Validation of the scoring system for standardization of the pancreatic donor for islet isolation as used in a new islet isolation center.

BACKGROUND: The aim of this study was to evaluate the effectiveness of the Edmonton Donor Scoring System for use in our much less active islet center. Because the ability to recognize an appropriate donor may help to achieve consistent and predictable success of pancreatic islet isolation, it should lead to increased effectiveness and lower cost. MATERIAL AND METHODS: Charts of 36 consecutive pancreas donors were reviewed to assess the donor points (DP). DP ranged from 0 to 100 based on donor age, body mass index, cause of death, social and medical history, hospital stay, vasopressor dosages, laboratory tests, cold ischemia time and procurement team, as well as pancreas size, consistency, fat content, damage, and quality of procurement and packing. RESULTS: Successful isolation was achieved in 39% of donors (14 of 36), a value similar to that achieved in Edmonton (40%). We used the optimal cutoff value (DP = 79) proposed by the Edmonton group. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66%, 75%, 57%, 82% and 72%, respectively. Successful islet isolation from poor or marginal donors (DP < 49.5 and 50 to 59.5) was 0% and 28.6% respectively; it was 63% and 100% in optimal donors (DP = 80 to 89.5 and 90 to 100). We concluded that islet isolation success correlated with the previously proposed donor scoring system. CONCLUSIONS: The Donor Scoring System can be successfully implemented regardless of the level of activity of an experienced isolation center. This system permits identification of a suitable donor prior to organ processing. It may guide a center's donor selection strategy based on its goals and its budget.

Two-layer method in short-term pancreas preservation for successful islet isolation.

BACKGROUND: We sought to determine whether the two-layer method (TLM) offers advantages over UW storage solution for locally procured pancreata with cold ischemia time of <8 hours for successful islet isolation. METHODS: From October 2003 through February 2005, 22 human pancreata were procured locally from cadaveric donors and preserved using UW solution (n = 11) or TLM (n = 11). RESULTS: Donor characteristics were similar in the two groups, with no statistical difference. Cold ischemia time was 4.5 +/- 0.6 (2.5 to 8) hours in the UW and 5.1 +/- 0.5 (3 to 8) hours in TLM group (P > .05). Organs preserved with TLM were exposed to PFC for 4 +/- 0.5 (2 to 7.5) hours. After TLM preservation, 8 of 11 (72%) pancreata yielded >300,000 IEQ pancreatic islets, which met all criteria for clinical transplantation; after UW cold storage, only 3 of 11 isolations were equally successful (27%) (P < .05). Mean IEQ was higher in the TLM than in the UW group: 349,000 +/- 37,000 vs 277,800 +/- 34,000; IEQ/g was also higher at 5100 +/- 760 vs 3000 +/- 570, respectively (P < .05). Islet quality, characterized by purity, viability, and insulin SI, did not differ statistically in the two groups: 67 +/- 4 vs 74 +/- 4%, 87 +/- 2 vs 83 +/- 4%, and 4 +/- 0.7 vs 4.8 +/- 1, respectively (P > .05). CONCLUSIONS: The Two Layer Method for locally procured human pancreata with cold ischemia time lower than 8 hours offers significant advantage over UW cold storage increasing the pancreatic islet isolation yield and the isolation success rate.

Infectious tolerance mediated by CD8+ T-suppresor cells after UV-B-irradiated donor-specific transfusion and rat heart transplantation.

AIMS: CD8+CD28- human T-suppressor cells (Ts), which can be generated in vitro, act directly on APC rendering them tolerogenic to unprimed and primed CD4+ T cells. The aim of this study was to investigate the possibility that CD8+ T cells mediate the induction of tolerance in a heart transplantation model in rodents. MATERIALS AND METHODS: Blood from Lewis rats was UV-B-irradiated and transfused into ACI recipients on days -21, -14, and -7 before heart allograft transplantation on day 0. CD4(+) and CD8(+) T cells were positively selected from ACI rats, which had tolerated Lewis heart allografts for more than 100 days and were adoptively transferred to naive ACI rats pretreated (day -1) with gamma irradiation. These ACI rats underwent transplantation with Lewis hearts 24 hours after adoptive transfer of putative T-suppressor cells. RESULTS: Adoptive transfer of CD8(+) T cells from tolerant ACI to naive ACI rats significantly prolonged Lewis heart mean allograft survival time (MST +/- SD) to 69 +/- 13 days as compared with 15 +/- 1 and 14 +/- 1 days in animals adoptively transferred with CD4+ T cells or untreated controls, respectively (P < .001). Similarly, adoptive transfer of CD8(+) T cells from secondary ACI recipients to naive syngeneic animals also significantly prolonged survival of heart allografts to MST +/- SD of 72 +/- 4 for CD8(+) and 15 +/- 4 days for CD4(+) T cells (P < .001). CONCLUSIONS: These data demonstrate that allogeneic tolerance induced in ACI recipients by treatment with UV-B-irradiated blood from Lewis donors is mediated by CD8+ T-suppressor cells.

Effect of streptavidin on cardiac allograft prolongation is due to host T-Cell suppression.

AIM: The aim of this study was to evaluate the effectiveness of streptavidin immunomodulation in the high-responder WF-to-Lewis combination. METHODS/RESULTS: We examined the effects of streptavidin on the proliferative response of T cells in coculture studies. Two to 200 microg/mL streptavidin significantly (P < .001) suppressed the proliferation of Lewis T cells to WF by 76%-83% compared with untreated responders. Next, we studied the survival of WF cardiac allografts in Lewis recipients pretreated with streptavidin. A 5-day course of peritransplantation recipient treatment with streptavidin doses of 8, 12, 20, 40, and 60 mg/kg combined with single dose of 0.5 mL antilymphocyte serum (ALS) significantly (P < .001) prolonged cardiac allograft survival from MST of 7 +/- 0.5 and 8 +/- 0.5 days in naive and ALS-treated controls to 15 +/- 1, 20 +/- 3, 16 +/- 3, 17 +/- 3, and 23 +/- 2 days, respectively. In contrast, posttransplantation administration of 80 mg/kg streptavidin resulted in animal death, suggesting toxicity of this dose. Additionally, 10 mg/kg or 20 mg/kg streptavidin administration for 10 consecutive days resulted in significant graft prolongation (MST of 18 +/- 1 and 21 +/- 1 days, respectively; P < .001). CONCLUSION: Although peritransplantation streptavidin treatment is effective in prolonging rat cardiac allografts in the high-responder WF-to-Lewis combination, it does not induce permanent graft survival as observed in the low-responder combination of Lewis-to-ACI. Our finding of in vitro immunomodulatory effect of streptavidin on T-cell proliferation suggests that its in vivo effect is partly due to prevention of T-cell activation following antigen exposure.

Ethical issues in living renal donation.

The widespread success of living renal transplantation has given the medical community both the opportunity and the responsibility of establishing social and ethical guidelines for the protection of donors and the treatment of recipients. While the prospects of treating more patients with organ transplant is exciting, the demand still far outpaces the supply. It is the responsibility of the transplant community and individual transplant centers to maintain a high level of integrity and ethical practice so that living renal transplantation can continue to be a viable and effective treatment for renal failure.

Role of reentry of in vivo alloMHC peptide-activated T cells into the adult thymus in acquired systemic tolerance.

BACKGROUND: T cell recognition of alloMHC peptide presented by self dendritic cells via the indirect pathway of allorecognition in the thymus induces T cell tolerance. Most recently we have shown that the i.v. administration of immunodominant Wistar Furth MHC class I (RT1.Au) peptide 5- (P5) pulsed myeloid or lymphoid dendritic cells induces operational tolerance to a fully MHC-mismatched cardiac allograft. This finding led us to hypothesize that circulation of peripheral P5-activated T cells to the thymus plays an important role in the induction of acquired tolerance. METHODS: We used the adoptive transfer of 111Indium-oxine- (111In-oxine) labeled P5-pulsed syngeneic dendritic cells and in vivo P5-activated syngeneic T cells to study the role of their circulation to the thymus in the induction of transplantation tolerance. RESULTS: Intravenously administered 111In-oxine-labeled naïve DC actively migrated to and localized in the liver and spleen but did not enter the lymph nodes, bone marrow, and thymus. In vitro peptide-pulsed dendritic cells had a similar pattern of tissue localization except for a modest number of myeloid but not lymphoid DC entering the thymus. The demonstration that adoptive transfer of in vivo peptide-primed T cells induces permanent graft survival in antilymphocyte serum transiently immunosuppressed syngeneic secondary hosts led us to examine the traffic of in vivo activated T cells. Whereas naïve syngeneic T cells preferentially homed to the peripheral lymphoid organs, they did not reenter the thymus. In contrast, in vivo peptide-activated peripheral T cells migrated to and accumulated in the thymus, thus confirming that reentry of T cells to the thymus is restricted to in vivo activated T cells. Although antilymphocyte serum immunosuppression significantly reduced circulation of primed T cells to the thymus, it did not completely abolish it, as seen with gamma-irradiated primed T cells. CONCLUSION: These findings provide the first formal evidence directly linking reentry of in vivo alloMHC peptide-activated T cells to the thymus with the induction and possibly maintenance of acquired antigen-specific tolerance. Our results suggest that the thymus is open to a two-way traffic with the periphery and may function as a repository of immunological memory.

Mechanisms of acquired thymic tolerance: induction of transplant tolerance by adoptive transfer of in vivo allomhc peptide activated syngeneic T cells.

BACKGROUND: Our most recent observation that i.v. injection of Wistar-Furth (WF) major histocompatibility complex Class I peptide 5 (P5)-pulsed self-myeloid or lymphoid dendritic cells (DC) induces transplantation tolerance suggests that adoptive transfer of in vivo allopeptide-primed host T cells might induce acquired tolerance through their interaction with thymic DC. METHODS: To examine this hypothesis, host myeloid DC cultured in rat granulocyte/macrophage colony stimulating factor and interleukin 4 were pulsed in vitro with P5 and injected intravenously into syngeneic ACI rats. The T cells primed to P5 via the indirect pathway of allorecognition were harvested 7 days later and administered by either intravenously or intrathymically into syngeneic ACI recipients of WF cardiac allografts. RESULTS: Syngeneic T cells obtained from the spleen of P5-primed rats had a high mixed lymphocyte reaction proliferative response to P5 presented by self-DC. I.v. administration of 2x107 P5-primed alloreactive purified host splenic T cells alone on day -7 significantly (P<0.001) prolonged cardiac allograft survival from 10.5+/-1.0 days to 18.6+/-1.8 days in the WF-to-ACI rat combination. I.v. injection of P5-activated host T cells combined with 0.5 ml antilymphocyte serum (ALS)-transient immunosuppression on day -7 led to 100% donor-specific permanent graft survival (>200 days). Thymectomy before i.v. injection of P5-activated syngeneic T cells led to acute graft rejection, suggesting that the homing of in vivo activated T cells to the host thymus might play a role in the induction of tolerance. To further define the role of the recipient thymus in this model, we examined the effects of intrathymic (i.t.) injection of P5-primed alloreactive T cells on graft survival and found that i.t. administration of the P5-primed T cells on day -7 alone significantly prolonged graft survival (15.0+/-0.7 days) and when combined with 0.5 ml ALS led to donor-specific permanent graft survival. The long-term unresponsive recipients permanently (>100 days) accepted second-set donor-specific cardiac allografts but not third-party (Lewis) grafts. CONCLUSIONS: These findings demonstrate that the adoptive transfer of splenic T cells primed to an indirectly presented donor peptide induces transplantation tolerance in a transiently immunosuppressed secondary syngeneic recipient. Our data suggest that the interaction of thymic DC with activated peripheral T cells induces alloantigen (Ag)-specific T-cell tolerance by either inactivation or deletion of alloreactive T cells in the thymus. This observation provides the first formal evidence that the interaction between thymic DC and activated peripheral T cells that continuously circulate through the thymus plays an important role in the induction and maintenance of Ag-specific tolerance.

Indirect allorecognition in acquired thymic tolerance: induction of donor-specific permanent acceptance of rat islets by adoptive transfer of allopeptide-pulsed host myeloid and thymic dendritic cells.

Pancreatic islet transplantation remains a promising approach to the treatment of type 1 diabetes. Unfortunately, graft failure continues to occur because of immunologic rejection, despite the use of potent immunosuppressive agents. It is therefore reasoned that induction of peripheral tolerance by the use of self-dendritic cells (DCs) as a vehicle to deliver specific target antigens to self-T-cells without ex vivo manipulation of the recipient is an attractive strategy in the treatment of type 1 diabetes. The finding that intrathymic inoculation of an immunodominant WF major histocompatibility complex (MHC) Class I (RT1.A(u)) peptide five (P5) or P5-pulsed host myeloid DCs induces acquired thymic tolerance raises the possibility that adoptive transfer of allopeptide-primed host myeloid or lymphoid DCs might induce transplant tolerance. To address this hypothesis, we studied the effects of intravenous transfer of in vitro P5-pulsed syngeneic myeloid DCs or in vivo P5-primed syngeneic lymphoid (thymic) DCs on islet survival in the WF-to-ACI rat combination. In vivo primed thymic DCs isolated from ACI rats given intrathymic inoculation of P5 for 2 days were capable of in vitro restimulation of in vivo P5-primed T-cells (memory cells). In the first series of studies, we showed that intravenous-like intrathymic-inoculation of in vitro P5-pulsed host myeloid DCs induced donor-specific permanent acceptance of islets in recipients transiently immunosuppressed with antilymphocyte serum (ALS). We next examined whether thymic DCs isolated from animals that had been previously intrathymically inoculated with P5 could induce T-cell tolerance. The results showed that intravenous adoptive transfer of in vivo P5-primed thymic DCs led to donor-specific permanent acceptance of islets in recipients transiently immunosuppressed with ALS. This finding suggested that the thymic DCs take up and present P5 to developing T-cells to induce T-cell tolerance, thus providing evidence of a direct link between indirect allorecognition and acquired thymic tolerance. The second series of studies examined the mechanisms involved in this model by exploring whether in vivo generation of peptide-specific alloreactive peripheral T-cells by intravenous inoculation of P5-pulsed self-DCs was responsible for the induction of T-cell tolerance. Intrathymic inoculation of splenic T-cells obtained from syngeneic ACI rats primed with intravenous injection of P5-pulsed DCs with a high in vitro proliferative response to P5 in the context of self-MHC induced donor-specific permanent acceptance of islets from WF donors. In addition, the clinically relevant model of intravenous injection of P5-activated T-cells combined with transient ALS immunosuppression similarly induced transplant tolerance, which was then abrogated by thymectomy of the recipient before intravenous injection of the activated T-cells. These data raise the possibility that circulation of peptide-activated T-cells to the host thymus plays a role in the induction and possibly the maintenance of T-cell tolerance in this model. Our findings suggest that intravenous administration of genetically engineered host DCs expressing alloMHC peptides might have therapeutic potential in clinical islet transplantation for the treatment of autoimmune diabetes.