Immunosuppression withdrawal in living-donor renal transplant recipients following induction with antithymocyte globulin and rituximab: Results of a prospective clinical trial

Durable tolerance in kidney transplant recipients remains an important but elusive goal. We hypothesized that adding B cell depletion to T cell depletion would generate an immune milieu postreconstitution dominated by immature transitional B cells, favoring tolerance. The Immune Tolerance Network ITN039ST Research Study of ATG and Rituximab in Renal Transplantation was a prospective multicenter pilot study of live donor kidney transplant recipients who received induction with rabbit antithymocyte globulin and rituximab and initiated immunosuppression (IS) withdrawal (ISW) at 26 weeks. The primary endpoint was freedom from rejection at 52 weeks post-ISW. Six of the 10 subjects successfully completed ISW. Of these 6 subjects, 4 restarted immunosuppressive medications due to acute rejection or recurrent disease, 1 remains IS-free for over 9 years, and 1 was lost to follow-up after being IS-free for 42 weeks. There were no cases of patient or graft loss. CD19+ B cell frequencies returned to predepletion levels by 26 weeks posttransplant; immunoglobulin D+CD27--naïve B cells predominated. In contrast, memory cells dominated the repopulation of the T cell compartment. A regimen of combined B and T cell depletion did not generate the tolerogenic B cell profile observed in preclinical studies and did not lead to durable tolerance in the majority of kidney transplant recipients.

Early allogeneic immune modulation after establishment of donor hematopoietic cell-induced mixed chimerism in a nonhuman primate kidney transplant model

Background

Mixed lymphohematopoietic chimerism is a proven strategy for achieving operational transplant tolerance, though the underlying immunologic mechanisms are incompletely understood.

Methods

A post-transplant, non-myeloablative, tomotherapy-based total lymphoid (TLI) irradiation protocol combined with anti-thymocyte globulin and T cell co-stimulatory blockade (belatacept) induction was applied to a 3-5 MHC antigen mismatched rhesus macaque kidney and hematopoietic cell transplant model. Mechanistic investigations of early (60 days post-transplant) allogeneic immune modulation induced by mixed chimerism were conducted.

Results

Chimeric animals demonstrated expansion of circulating and graft-infiltrating CD4+CD25+Foxp3+ regulatory T cells (Tregs), as well as increased differentiation of allo-protective CD8+ T cell phenotypes compared to naïve and non-chimeric animals. In vitro mixed lymphocyte reaction (MLR) responses and donor-specific antibody production were suppressed in animals with mixed chimerism. PD-1 upregulation was observed among CD8+ T effector memory (CD28-CD95+) subsets in chimeric hosts only. PD-1 blockade in donor-specific functional assays augmented MLR and cytotoxic responses and was associated with increased intracellular granzyme B and extracellular IFN-γ production.

Conclusions

These studies demonstrated that donor immune cell engraftment was associated with early immunomodulation via mechanisms of homeostatic expansion of Tregs and early PD-1 upregulation among CD8+ T effector memory cells. These responses may contribute to TLI-based mixed chimerism-induced allogenic tolerance.

Design and testing of a humanized porcine donor for xenotransplantation

Recent human decedent model studies1,2 and compassionate xenograft use3 have explored the promise of porcine organs for human transplantation. To proceed to human studies, a clinically ready porcine donor must be engineered and its xenograft successfully tested in nonhuman primates. Here we describe the design, creation and long-term life-supporting function of kidney grafts from a genetically engineered porcine donor transplanted into a cynomolgus monkey model. The porcine donor was engineered to carry 69 genomic edits, eliminating glycan antigens, overexpressing human transgenes and inactivating porcine endogenous retroviruses. In vitro functional analyses showed that the edited kidney endothelial cells modulated inflammation to an extent that was indistinguishable from that of human endothelial cells, suggesting that these edited cells acquired a high level of human immune compatibility. When transplanted into cynomolgus monkeys, the kidneys with three glycan antigen knockouts alone experienced poor graft survival, whereas those with glycan antigen knockouts and human transgene expression demonstrated significantly longer survival time, suggesting the benefit of human transgene expression in vivo. These results show that preclinical studies of renal xenotransplantation could be successfully conducted in nonhuman primates and bring us closer to clinical trials of genetically engineered porcine renal grafts.

Helical TomoTherapy Total Lymphoid Irradiation and Hematopoietic Cell Transplantation for Kidney Transplant Tolerance in Rhesus Macaques

Development of a post-transplant kidney transplant tolerance induction protocol involving a novel total lymphoid irradiation (TLI) conditioning method in a rhesus macaque model is described. We examined the feasibility of acheiving tolerance to MHC 1-haplotype matched kidney transplants by establishing a mixed chimeric state with infusion of donor hematopoietic cells (HC) using TomoTherapy TLI. The chimeric state was hypothesized to permit the elimination of all immunosuppressive (IS) medications while preserving allograft function long-term without development of graft-versus-host-disease (GVHD) or rejection. An experimental group of 11 renal transplant recipients received the tolerance induction protocol and outcomes were compared to a control group (n = 7) that received the same conditioning but without donor HC infusion. Development of mixed chimerism and operational tolerance was accomplished in two recipients in the experimental group. Both recipients were withdrawn from all IS and continued to maintain normal renal allograft function for 4 years without rejection or GVHD. None of the animals in the control group achieved tolerance when IS was eliminated. This novel experimental model demonstrated the feasibility for inducing of long-term operational tolerance when mixed chimerism is achieved using a TLI post-transplant conditioning protocol in 1-haplotype matched non-human primate recipients of combined kidney and HC transplantation.

Master protocol to assess the long-term safety in kidney transplant recipients who previously received Medeor's cellular immunotherapy products: the MDR-105-SAE

BACKGROUND

Immunosuppression in transplantation continues to be associated with a multitude of adverse effects. Induction of immune tolerance may be a viable strategy to reduce dependence on immunosuppression. Various trials are currently underway to assess the efficacy of this strategy. However, long-term safety data for these immune tolerance regimes has yet to be established.

METHODS/DESIGN

At the completion of primary follow-up of various Medeor kidney transplant studies, subjects receiving cellular immunotherapy products will be followed annually as per protocolized schedule for up to an additional 84 months (7 years) to evaluate long-term safety. Long-term safety will be assessed by summarizing incidence of serious adverse events, adverse events leading to study withdrawal and hospitalization rates.

DISCUSSION

This extension study will be an important step in evaluating safety issues pertaining to immune tolerance regimens, long-term effects of which are largely unknown. These data are essential for furthering an unrealized goal of kidney transplantation- graft longevity without the adverse effects from long-term immunosuppression. The study design utilizes the methodology of a master protocol, wherein multiple therapies can be assessed simultaneously with accompanied gathering of long-term safety data.

Early Increases in Posttransplant Pancreatic Enzymes Are Associated With Surgical Complications But Not Graft Failure Among Pancreas Transplant Recipients

OBJECTIVES

This study aimed to find the association between immediate postoperative increases in pancreatic enzymes and posttransplant complications among pancreas transplant recipients (PTRs).

METHODS

We analyzed all PTRs transplanted at the University of Wisconsin between June 2009 and September 2018. Enzyme levels were presented as a ratio of absolute numbers to the upper limit of normal value, with value >1 considered as abnormal. We specifically evaluated bleeding, fluid collections, and thrombosis complications based on the amylase or lipase ratios on day 1 (Amylase1, Lipase1) and maximum ratios within 5 days of transplant (Amylasemax, Lipasemax). For early complications, we focused on technical complications that occurred within 90 days of transplant. For long-term outcomes, we assessed patient and graft survival, and rejections.

RESULTS

There were a total of 443 PTRs, 287 were simultaneous pancreas and kidney recipients, and 156 were solitary pancreas recipients. Higher Amylase1, Liplase1, Amylasemax, and Lipasemax were associated with an increase in early complications, mainly need for pancreatectomy, fluid collections, bleeding complications, or graft thrombosis, particularly in the solitary pancreas group.

CONCLUSIONS

Our finding suggests that cases of early perioperative enzyme increase merit consideration for early imaging investigation to mitigate detrimental outcomes.

Post-pancreatic transplant enteric leaks: The role of the salvage operation

Enteric drainage in pancreas transplantation is complicated by an enteric leak in 5%-8%, frequently necessitating pancreatectomy. Pancreatic salvage outcomes are not well studied. Risk factors for enteric leak were examined and outcomes of attempted graft salvage were compared to immediate pancreatectomy. Pancreas transplants performed between 1995 and 2018 were reviewed. Donor, recipient, and organ variables including demographics, donor type, ischemic time, kidney donor profile index, and pancreas donor risk index were analyzed. Among 1153 patients, 33 experienced enteric leaks (2.9%). Donors of allografts that developed leak were older (37.9y vs. 29.0y, p = .001), had higher KDPI (37% vs. 24%, p < .001), higher pancreas donor risk index (1.83 vs. 1.32, p < .001), and longer cold ischemic time (16.5 vs. 14.8 h, p = .03). Intra-abdominal abscess and higher blood loss decreased the chance of successful salvage. Enteric leak increased 6-month graft loss risk (HR 13.9[CI 8.5-22.9], p < .001). However, 50% (n = 12) of allografts undergoing attempted salvage survived long-term. After 6 months of pancreas graft survival, salvage and non-leak groups had similar 5-year graft survival (82.5% vs. 81.5%) and mortality (90.9% vs. 93.5%). Enteric leaks remain a challenging complication. Pancreatic allograft salvage can be attempted in suitable patients and accomplished in 50% of cases without significantly increased graft failure or mortality risk.

Association of human leukocyte antigen mismatches between donor-recipient and donor-donor in pancreas after kidney transplant recipients

The effects of HLA mismatching on pancreas outcomes among pancreas after kidney (PAK) recipients are undefined. Outcomes might potentially differ depending on whether there is a mismatch between pancreas donor and recipient (PD-R) or pancreas donor and kidney donor(PD-KD). All primary PAK at our centre were included in this study. Patients were divided into two groups based on the degree of HLA mismatching: low (L-MM) as 0-4 and high (H-MM) as 5-6. We analysed all (N = 73) PAK for PD-R mismatch and the subset of PAK for PD-KD mismatch (N = 71). Comparing PD-R L-MM (n = 39) and H-MM (n = 34) PAKs, we observed no difference in the rate of pancreas graft failure. There was also no difference in the rate of rejection (L-MM 33% vs. H-MM 41%) or the severity of rejection. However, we observed a significantly (P < 0.01) shorter time to acute pancreas rejection in the H-MM group (6.8 ± 8.7 mo) versus the L-MM cohort (29.0 ± 36.2 mo) (P < 0.001). Similar to the PD-R mismatched cohort, we did not observe a detrimental effect of HLA mismatching on graft outcomes in the PD-KD cohort; time to rejection was again shorter in the H-MM subset. In this study, we found no impact of HLA mismatch on either pancreas graft survival or rejection rates, though rejection occurred earlier in high mismatched PAK transplants.

Tomotherapy Applied Total Lymphoid Irradiation and Allogeneic Hematopoietic Cell Transplantation Generates Mixed Chimerism in the Rhesus Macaque Model

Development of a new methodology to induce immunological chimerism after allogeneic hematopoietic cell (HC) transplantation in a rhesus macaque model is described. The chimeric state was achieved using a non-myeloablative, helical tomotherapy-based total lymphoid irradiation (TomoTLI) conditioning regimen followed by donor HC infusions between 1-haplotype matched donor/recipient pairs. The technique was tested as a feasibility study in an experimental group of seven rhesus macaques that received the novel TomoTLI tolerance protocol and HC allo-transplants. Two tomotherapy protocols were compared: TomoTLI (n = 5) and TomoTLI/total-body irradiation (TBI) (n = 2). Five of seven animals developed mixed chimerism. Three of five animals given the TomoTLI protocol generated transient mixed chimerism with no graft-versus-host disease (GVHD) with survival of 33, 152 and >180 days. However, the inclusion of belatacept in addition to a single fraction of TBI resulted in total chimerism and fatal GVHD in both animals, indicating an unacceptable conditioning regimen.

Phase 3 trial of human islet-after-kidney transplantation in type 1 diabetes

Allogeneic islet transplant offers a minimally invasive option for β cell replacement in the treatment of type 1 diabetes (T1D). The CIT consortium trial of purified human pancreatic islets (PHPI) in patients with T1D after kidney transplant (CIT06), a National Institutes of Health-sponsored phase 3, prospective, open-label, single-arm pivotal trial of PHPI, was conducted in 24 patients with impaired awareness of hypoglycemia while receiving intensive insulin therapy. PHPI were manufactured using standardized processes. PHPI transplantation was effective with 62.5% of patients achieving the primary endpoint of freedom from severe hypoglycemic events and HbA_1c  ≤ 6.5% or reduced by ≥ 1 percentage point at 1 year posttransplant. Median HbA_1c declined from 8.1% before to 6.0% at 1 year and 6.3% at 2 and 3 years following transplant (P < .001 for all vs baseline), with related improvements in hypoglycemia awareness and glucose variability. The improved metabolic control was associated with better health-related and diabetes-related quality of life. The procedure was safe and kidney allograft function remained stable after 3 years. These results add to evidence establishing allogeneic islet transplant as a safe and effective treatment for patients with T1D and unstable glucose control despite intensive insulin treatment, supporting the indication for PHPI in the post-renal transplant setting.

The demise of islet allotransplantation in the United States: A call for an urgent regulatory update

Islet allotransplantation in the United States (US) is facing an imminent demise. Despite nearly three decades of progress in the field, an archaic regulatory framework has stymied US clinical practice. Current regulations do not reflect the state-of-the-art in clinical or technical practices. In the US, islets are considered biologic drugs and "more than minimally manipulated" human cell and tissue products (HCT/Ps). In contrast, across the world, human islets are appropriately defined as "minimally manipulated tissue" and not regulated as a drug, which has led to islet allotransplantation (allo-ITx) becoming a standard-of-care procedure for selected patients with type 1 diabetes mellitus. This regulatory distinction impedes patient access to islets for transplantation in the US. As a result only 11 patients underwent allo-ITx in the US between 2016 and 2019, and all as investigational procedures in the settings of a clinical trials. Herein, we describe the current regulations pertaining to islet transplantation in the United States. We explore the progress which has been made in the field and demonstrate why the regulatory framework must be updated to both better reflect our current clinical practice and to deal with upcoming challenges. We propose specific updates to current regulations which are required for the renaissance of ethical, safe, effective, and affordable allo-ITx in the United States.

Complex Ureteral Reconstruction in Kidney Transplantation

OBJECTIVES

Despite advances in surgical techniques and organ preservation, transplant ureteric strictures remain a common complication in kidney transplantation. A variety of endourological and surgical techniques have been utilized; however, there is a lack of consensus on the optimal modality in dealing with these complex cases.

MATERIALS AND METHODS

We present challenging ureteral reconstruction cases after failed attempts at ureteral dilatation, failed conventional open repairs, and/or with bladder dysfunction.

RESULTS

All renal allografts were salvaged by successful use of bladder Boari flap and intestinal segment interpositions/diversions.

CONCLUSIONS

Operative repair remains the most durable and successful approach, and minimally invasive options should be reserved for nonsurgical candidates, with consideration of a single attempt in patients with early, distal, short (<2 cm), nonischemic strictures.

The Fourth International Workshop on Clinical Transplant Tolerance

The International Workshop on Clinical Transplant Tolerance is a biennial meeting that aims to provide an update on the progress of studies of immunosuppression minimization or withdrawal in solid organ transplantation. The Fourth International Workshop on Clinical Tolerance was held in Pittsburgh, Pennsylvania, September 5-6, 2019. This report is a summary of presentations on the status of clinical trials designed to minimize or withdraw immunosuppressive drugs in kidney, liver, and lung transplantation without subsequent evidence of rejection. All protocols had in common the use of donor or recipient cell therapy combined with organ transplantation. The workshop also included presentations of mechanistic studies designed to improve understanding of the cellular and molecular basis of tolerance and to identify potential predictors/biomarkers of tolerance. Strategies to enhance the safety of hematopoietic cell transplantation and to improve patient selection/risk stratification for clinical trials were also discussed.

Induction and Donor Specific Antibodies in Low Immunologic Risk Kidney Transplant Recipients

Background

Optimal induction for patients without pretransplant donor-specific antibodies (DSAs) is poorly defined. The goal of this study was to compare the incidence of de novo DSA (dnDSA) and graft outcomes between induction therapies in patients with a negative virtual crossmatch (VXM).

Methods

A retrospective chart review was performed, identifying 782 patients with a negative VXM who underwent kidney transplantation at a single, high-volume institution between January 2013 and May 2017. Kaplan-Meier analysis was used to assess the incidence of dnDSA and allograft survival between induction therapies in this group. dnDSA is defined as the development of new post-transplant DSA, at any MFI level.

Results

Induction therapy included alemtuzumab (N=87, 11%), basiliximab (N=522, 67%), and anti-thymocyte globulin (ATG; N=173, 22%). One-year graft survival was similar between groups (alemtuzumab, 100%; basiliximab, 98%; ATG, 99%). Incidence of acute rejection at 1 year was <2% and not different between the three groups. Alemtuzumab was associated with the highest incidence of dnDSA at 14%, compared with 5% and 8% in basiliximab and ATG groups, respectively, at 1 year (P=0.009). In multivariate regression analyses, alemtuzumab retained its significant association with a dnDSA HR of 2.5 (95% CI, 1.51 to 4.25; P=0.0004).

Conclusions

In summary, alemtuzumab was associated with a higher rate of dnDSA development in patients with a negative VXM; however, this finding was not associated with rejection or graft failure.

Third-party vessel allografts in kidney and pancreas transplantation: Utilization, de novo DSAs, and outcomes

Third-party vascular allografts (VAs) are an invaluable resource in kidney and pancreas transplantation when vascular reconstruction is needed and additional vessels from the organ donor are not available. We report the largest single-center experience to date on VA use, at a high-volume U.S. transplant center. Over a 7-year period, VAs were used for vascular reconstruction of 65 kidneys and 5 pancreases, in 69 recipients. The renal vein required reconstruction more often with right kidney transplantation (72.5% vs 27.5%, P < .001), and the renal artery required reconstruction more often with left kidney transplantation (67.6% vs 32.4%, P = .003). Eleven patients (15.9%) developed anti-VA de novo HLA donor-specific antibodies (dnDSAs) at a median time after transplantation of 19.0 months. Higher number of HLA mismatches between the VA donor and the recipient, and development of anti-organ allograft dnDSAs were significant predictors of anti-VA dnDSA development. Those with anti-VA dnDSAs had a higher rate of organ allograft rejection (45.4% vs 13.8%, P = .03) compared to those without, but there was no significant difference in incidence of vascular complications or graft outcomes. VAs can help circumvent challenging surgical situations. Anti-VA dnDSAs do not adversely affect organ allograft outcomes; however, they can contribute to HLA sensitization in the recipients.

Delayed kidney graft function in simultaneous pancreas-kidney transplant recipients is associated with early pancreas allograft failure

Delayed graft function (DGF) is a common complication associated with significant untoward effects in kidney-alone transplantation. The incidence and outcomes following kidney delayed graft function (K-DGF) among patients undergoing simultaneous pancreas-kidney (SPK) transplantation are less certain. We analyzed SPK recipients transplanted at our center between January 1994 and December 2017. A total of 632 recipients fulfilled the selection criteria, including 69 (11%) with K-DGF and 563 without. The incidence of K-DGF was significantly higher in recipients of organs from older donors and donation after circulatory death (DCD). The presence of K-DGF was significantly associated with an increased risk of pancreas graft failure during the first 90 days (n = 9, incidence rate [IR] 2.45/100 person-months), but not with late pancreas failure (n = 32, IR 0.84/100 person-months), kidney graft failure, or patient death. Although DCD was associated with K-DGF, it was not associated with either pancreas (hazard ratio [HR] 0.91, 95% CI 0.58-1.44, P = .69) or kidney (HR 1.09, 95% CI 0.66-1.82, P = .74) graft failure after adjustment for potential confounders. We found K-DGF to be a significant risk factor for pancreas graft failure but not kidney graft failure, with the major risk period being early (<90 days) posttransplant, and the major donor risk factor being older donor age.

Pancreas transplants from small donors: are the outcomes acceptable? A retrospective study

Despite good organ quality, pancreata from extremely small pediatric donors (<30 kg) are generally avoided by many centers because of concerns of reduced islet cell mass and early technical failure. Therefore, we sought to compare the outcomes of small pancreas grafts (<30 kg) to those from higher weight donors from transplants performed between 1994 and 2015 (n = 1183). A total of 33 pancreata were from donors' ≤30 kg (3%), with a mean weight of 23.8 kg and mean age of 7.8 years. Patient survival was similar at 1, 5, and 10 years between recipients of ≤30 and >30 kg donors (≤30 kg: 96.8%, 86.8%, and 78.1% vs. >30 kg: 96.8%, 89.5%, and 79.1%, P = 0.5). Pancreas graft survival at 1, 5, and 10 years was also similar, ≤30 kg: 93.9%, 73.2%, and 61.0% vs. >30 kg: 87%, 73.3%, and 58.3% (P = 0.7). This graft survival pattern was also seen when comparing pancreata from ≤20 kg donors to those from >20 to 30 kg. Cause of graft loss, and metabolic and physiologic outcomes did not differ between the groups. After assessing the impact of donor weight as a continuous variable and calculating recipient-to-donor weight ratio (RDWR), we observed no effect of donor weight on patient and graft outcomes.

Belatacept-based immunosuppression with simultaneous calcineurin inhibitor avoidance and early corticosteroid withdrawal: A prospective, randomized multicenter trial

Simultaneous calcineurin inhibitor avoidance (CNIA) and early corticosteroid withdrawal (ESW) have not been achieved primarily due to excessive acute rejection. This trial compared 2 belatacept-based CNIA/ESW regimens with a tacrolimus-based ESW regimen. Kidney transplant recipients were randomized to receive alemtuzumab/belatacept, rabbit anti-thymocyte globulin (rATG)/belatacept, or rATG/tacrolimus. The combinatorial primary endpoint consisted of patient death, renal allograft loss, or a Modification of Diet in Renal Disease-calculated eGFR of <45 mL/min/1.73 m² at 12 months. Results are reported by treatment group (alemtuzumab/belatacept, rATG/belatacept, and rATG/tacrolimus). Superiority was not observed at 1 year for the primary endpoint (9/107 [8.4%], 15/104 [14.4%], and 14/105 [13.3%], respectively; P = NS) for either belatacept-based regimen. Differences were not observed for secondary endpoints (death, death-censored graft loss, or estimated glomerular filtration rates < 45 mL/min/1.73 m² ). Differences were observed in biopsy-proved acute cellular rejection (10.3%, 18.3%, and 1.9%, respectively) (P < .001), but not in antibody-mediated rejection, mixed acute rejection, or de novo donor-specific anti-HLA antibodies. Neurologic and electrolyte abnormality adverse events were less frequent under belatacept. Belatacept-based CNIA/ESW regimens did not prove to be superior for the primary or secondary endpoints. Belatacept-treated patients demonstrated an increase in biopsy-proved acute cellular rejection and reduced neurologic and metabolic adverse events. These results demonstrate that simultaneous CNIA/ESW is feasible without excessive acute rejection.

Isolated pancreas transplantation: Is rank list position related to outcomes of imported grafts?

Transplant centers may decline an import pancreas offer based on demographics and laboratory test results, without information on actual gland quality. The relationship between position on the match run, indicative of the number of centers that chose not to use a pancreas, and patient and death-censored graft survival, is not known. We studied all 199 isolated pancreas grafts transplanted at the University of Wisconsin since July 2000 and compared overall patient and death-censored graft survival based on import vs local status. Of the 199 isolated pancreas transplants, 184 (92.5%) were imported from another donor service area with a median match rank of 49 (interquartile range 14-129). Median cold ischemia time was longer for imported pancreata (16.6 vs 13.4 hours, P = .02). In multivariate Cox modeling, there was no association with position on the rank list and patient (P = .44) or death-censored graft survival (P = .99). There was an overall rate of 6.5% of graft failure within 30 days; however, there was no association with position on the rank list and graft failure at 30 days (P = .33). Although the logistics may be challenging, sound judgment to accept offers independent of prior centers' decisions can result in quality utilization of imported pancreata.

Enteric conversion after bladder-drained pancreas transplantation is not associated with worse allograft survival

In the early experience of pancreas transplantation, bladder drainage was favored, but it often caused urologic, metabolic, and infectious complications that necessitated conversion to enteric drainage. Long-term graft survival after enteric conversion and the impact of time interval from transplantation to enteric conversion on graft survival is poorly understood. We studied all bladder-drained first-time pancreas transplantations performed at the University of Wisconsin from 1985 to 2000. Time to conversion was estimated with the Kaplan-Meier technique, whereas risk factors associated with conversion were estimated via a time-varying Cox proportional hazards model. Of 386 bladder-drained pancreata, 162 (41.9%) eventually required enteric conversion, 29 (17.9%) within the first year. Median time to conversion varied by indication: 0.68 years for surgical, 3.1 years for urologic, and 2.7 years for metabolic disorders. In a time-varying Cox model adjusting for donor and recipient factors, enteric conversion did not affect the risk of pancreas graft loss (hazard ratio [HR] 0.86, P = .26). Kidney survival was not associated with enteric conversion. When necessary due to symptoms or complications, enteric conversion of bladder-drained pancreata is safe and does not affect overall graft survival. This relationship appears to be true no matter when the conversion is performed.

The impact of kidney donor profile index on delayed graft function and transplant outcomes: A single-center analysis

INTRODUCTION

Renal transplant outcomes result from a combination of factors. Traditionally, donor factors were summarized by classifying kidneys as extended criteria or standard criteria. In 2014, the nomenclature changed to describe donor factors with the kidney donor profile index (KDPI). We aim to evaluate the relationship between KDPI and delayed graft function (DGF), and the impact KDPI on transplant outcomes for both donor after cardiac death (DCD) and donor after brain death (DBD).

METHODS

An IRB-approved single-center retrospective chart review was performed from January 1999 to July 2013. The patients were divided into six groups: DBD KDPI ≤60, DBD KPDI 61-84, DBD KDPI ≥85, DCD KDPI ≤60, DCD KPDI 61-84, and DCD KDPI ≥85. Rates of DGF, patient survival, and graft survival were examined among groups.

RESULTS

A total of 2161 kidney transplants were included. DGF rates increased, and graft and patient survival decreased with increasing KDPI (P < .001). DCD kidneys had higher DGF rates than their DBD counterparts (P < .001). In DCD kidneys, a higher KDPI score did not significantly affect the DGF rates (P > .302). There was no significant difference in graft or patient survival in all-comers when comparing DCD and DBD kidneys with equivalent KDPIs (P > .317). Patients with DGF across all categories demonstrated worse graft half-lives.

CONCLUSION

The KDPI system is an accurate predictor of donor contributions to transplant outcomes. Recipients of DBD kidneys experience an increase in the rate of DGF as their KDPI increases. DCD kidneys have higher DGF rates than their DBD counterparts with similar KDPIs. Patients with documented post-transplant DGF had between 3- and 5-year shorter graft half-lives when compared to recipients that did not experience DGF. Initiatives to reduce the rate of DGF could provide a significant impact on graft survival and result in a reduction in the number of patients requiring retransplant.

Prevalence and Prognosis of Unrecognized Myocardial Infarction in Asymptomatic Patients With Diabetes: A Two-Center Study With Up to 5 Years of Follow-up

OBJECTIVE

To determine the prevalence and prognostic significance of unrecognized myocardial infarction (MI) by delayed-enhancement MRI (DE-MRI) in asymptomatic patients with diabetes.

RESEARCH DESIGN AND METHODS

In this prospective, two-center study of asymptomatic patients without known cardiac disease (n = 120), two prespecified cohorts underwent a research MRI: 1) a high-risk group with type 1 diabetes and chronic renal insufficiency (n = 50) and 2) an average-risk group with type 2 diabetes (n = 70). The primary end point was a composite of all-cause mortality and clinical MI.

RESULTS

Overall, the prevalence of unrecognized MI was 19% by DE-MRI (28% high-risk group and 13% average-risk group) and 5% by electrocardiography. During up to 5 years of follow-up with a total of 460 patient-years of follow-up, the rate of death/MI was markedly higher in patients with diabetes with (vs. without) unrecognized MI (all 44% vs. 7%, high-risk group 43% vs. 6%, and average-risk group 44% vs. 8%; all P < 0.01). After adjustment for Framingham risk score, left ventricular ejection fraction, and diabetes type, the presence of unrecognized MI by DE-MRI conferred an eightfold increase in risk of death/MI (95% CI 3.0-21.1, P < 0.0001). Addition of unrecognized MI to clinical indices significantly improved model discrimination for adverse events (integrated discrimination improvement = 0.156, P = 0.001).

CONCLUSIONS

Unrecognized MI is prevalent in asymptomatic patients with diabetes without a history of cardiac disease and confers a markedly increased risk of death and clinical MI.

Impact of ureteral stricture and treatment choice on long-term graft survival in kidney transplantation

We aimed to evaluate the influence of urological complications occurring within the first year after kidney transplantation on long-term patient and graft outcomes, and sought to examine the impact of the management approach of ureteral strictures on long-term graft function. We collected data on urological complications occurring within the first year posttransplant. Graft survivals, patient survival, and rejection rates were compared between recipients with and without urological complications. Male gender of the recipient, delayed graft function, and donor age were found to be significant risk factors for urological complications after kidney transplantation (P < .05). Death censored graft survival analysis showed that only ureteral strictures had a negative impact on long-term graft survival (P = .0009) compared to other complications. Death censored graft survival was significantly shorter in kidney recipients managed initially with minimally invasive approach when compared to the recipients with no stricture (P = .001). However, graft survival was not statistically different in patients managed initially with open surgery (P = .47). Ureteral strictures following kidney transplantation appear to be strongly negatively correlated with long-term graft survival. Our analysis suggests that kidney recipients with ureteral stricture should be managed initially with open surgery, with better long-term graft survival.

Ipsilateral versus contralateral placement of the pancreas allograft in pancreas after kidney transplant recipients

BACKGROUND

In a diabetic, uremic kidney transplant recipient that may receive a future pancreas after kidney (PAK) transplant, the kidney is typically implanted on the left side in anticipation of the subsequent pancreas transplant on the right side. In this study, we sought to determine if ipsilateral PAK (iPAK) is as safe as contralateral PAK (cPAK).

METHODS

The 115 PAK transplants (iPAK n = 57, cPAK n = 58) were performed from 1997-2010 and results were compared between the groups.

RESULTS

Kidney graft survival and pancreas graft survival was similar between the two groups. Kidney graft function according to serum creatinine and eGFR was not different between the cPAK and the iPAK groups and there were no episodes of kidney graft thrombosis in either group. Subgroup analyses focusing on donor source also did not show worse outcomes for graft survivals in iPAK group when compared to cPAK group.

CONCLUSIONS

Pancreas and kidney graft survival in PAK transplants is unaffected by the surgical procedure and iPAK is safe.

Prevalence and outcomes of cystic lesions of the transplant pancreas: The University of Wisconsin Experience

Literature on the behavior of cystic lesions in pancreas transplants is scarce, and hence a better understanding is warranted. Data on recipients and their respective donors that underwent simultaneous kidney and pancreas, pancreas transplant alone, and pancreas after kidney between 1994 and 2015 were reviewed (n = 1185). Cystic lesions of the transplant pancreas developed in 22 patients (1.8%): 12 pseudocysts, 2 cysts/remnants, 4 intraductal papillary mucinous neoplasms (IPMN), 2 adenocarcinomas, 1 low-grade intraepithelial pancreatic neoplasia, and 1 case of polycystic kidney disease. The median size was 3.6 cm (1.6-5.5 cm), and occurred at a median time of 65.5 months (2-183 months) posttransplant. The median age of the graft at time of diagnosis was 42 years (25.7-54.5), with 17 of 22 grafts (77%) functioning at time of diagnosis. Triggers for investigation were elevations in pancreatic enzymes, re-admissions for abdominal pain, and incidentalomas. High-resolution imaging and diagnostic biopsy/aspiration with ancillary tests were the main diagnostic tests. Most pseudocysts were managed by percutaneous drainage, and although no firm inference can be made from such a small series, we have observed that the behavior and management of IPMN and adenocarcinoma in the pancreas graft appears congruent to that of the native pancreas.

Pancreas-After-Islet Transplantation in Nonuremic Type 1 Diabetes: A Strategy for Restoring Durable Insulin Independence

Islet transplantation offers a minimally invasive approach for β cell replacement in diabetic patients with hypoglycemic unawareness. Attempts at insulin independence may require multiple islet reinfusions from distinct donors, increasing the risk of allogeneic sensitization. Currently, solid organ pancreas transplant is the only remaining surgical option following failed islet transplantation in the United States; however, the immunologic impact of repeated exposure to donor antigens on subsequent pancreas transplantation is unclear. We describe a case series of seven patients undergoing solid organ pancreas transplant following islet graft failure with long-term follow-up of pancreatic graft survival and renal function. Despite highly variable panel reactive antibody levels prior to pancreas transplant (mean 27 ± 35%), all seven patients achieved stable and durable insulin independence with a mean follow-up of 6.7 years. Mean hemoglobin A1c values improved significantly from postislet, prepancreas levels (mean 8.1 ± 1.5%) to postpancreas levels (mean 5.3 ± 0.1%; p = 0.0022). Three patients experienced acute rejection episodes that were successfully managed with thymoglobulin and methylprednisolone, and none of these preuremic type 1 diabetic recipients developed stage 4 or 5 chronic kidney disease postoperatively. These results support pancreas-after-islet transplantation with aggressive immunosuppression and protocol biopsies as a viable strategy to restore insulin independence after islet graft failure.

Pancreas transplantation in older patients is safe, but patient selection is paramount

Pancreas transplant outcomes have progressively improved. Despite this, some centers have continued to employ historical age limits for pancreas transplant candidates. We sought to determine the importance of chronological age in determining patient and graft survival rates after pancreas transplantation. A single-center, retrospective study of adult, deceased donor simultaneous pancreas and kidney (SPK) and solitary pancreas transplants (SP, including pancreas transplant alone and pancreas after kidney transplants) in recipients ≥ 55 years (55 + ), occurring between July 1, 1999, and June 30, 2012, was performed. Seven-hundred and forty patients underwent pancreas transplantation, of which 28 patients were 55 + . Patient survival was comparable for younger and older pancreas transplant recipients. Both non-death-censored and death-censored pancreatic graft survival rates were similar in younger and in older patients. Patients aged 45-54 and those aged 55 +  had more frequent cardiovascular events than younger pancreas transplant recipients. There was no difference in renal graft survival for SPK patients when compared with diabetic kidney transplant alone recipients aged 55 years and older. Older pancreas transplant recipients had acceptable long-term patient and graft survival rates, although complications may occur. Chronological age alone should not exclude a patient for pancreas transplant candidacy.

Th17 Responses to Collagen Type V, kα1-Tubulin, and Vimentin Are Present Early in Human Development and Persist Throughout Life

T helper 17 (Th17)-dependent autoimmune responses can develop after heart or lung transplantation and are associated with fibro-obliterative forms of chronic rejection; however, the specific self-antigens involved are typically different from those associated with autoimmune disease. To investigate the basis of these responses, we investigated whether removal of regulatory T cells or blockade of function reveals a similar autoantigen bias. We found that Th17 cells specific for collagen type V (Col V), kα1-tubulin, and vimentin were present in healthy adult peripheral blood mononuclear cells, cord blood, and fetal thymus. Using synthetic peptides and recombinant fragments of the Col V triple helical region (α1[V]), we compared Th17 cells from healthy donors with Th17 cells from Col V-reactive heart and lung patients. Although the latter responded well to α1(V) fragments and peptides in an HLA-DR-restricted fashion, Th17 cells from healthy persons responded in an HLA-DR-restricted fashion to fragments but not to peptides. Col V, kα1-tubulin, and vimentin are preferred targets of a highly conserved, hitherto unknown, preexisting Th17 response that is MHC class II restricted. These data suggest that autoimmunity after heart and lung transplantation may result from dysregulation of an intrinsic mechanism controlling airway and vascular homeostasis.

Does DCD Donor Time-to-Death Affect Recipient Outcomes? Implications of Time-to-Death at a High-Volume Center in the United States

For donation after circulatory death (DCD), many centers allow 1 h after treatment withdrawal to donor death for kidneys. Our center has consistently allowed 2 h. We hypothesized that waiting longer would be associated with worse outcome. A single-center, retrospective analysis of DCD kidneys transplanted between 2008 and 2013 as well as a nationwide survey of organ procurement organization DCD practices were conducted. We identified 296 DCD kidneys, of which 247 (83.4%) were transplanted and 49 (16.6%) were discarded. Of the 247 recipients, 225 (group 1; 91.1%) received kidneys with a time to death (TTD) of 0-1 h; 22 (group 2; 8.9%) received grafts with a TTD of 1-2 h. Five-year patient survival was 88.8% for group 1, and 83.9% for group 2 (p = 0.667); Graft survival was also similar, with 5-year survival of 74.1% for group 1, and 83.9% for group 2 (p = 0.507). The delayed graft function rate was the same in both groups (50.2% vs. 50.0%, p = 0.984). TTD was not predictive of graft failure. Nationally, the average maximum wait-time for DCD kidneys was 77.2 min. By waiting 2 h for DCD kidneys, we performed 9.8% more transplants without worse outcomes. Nationally, this practice would allow for hundreds of additional kidney transplants, annually.

National Institutes of Health-Sponsored Clinical Islet Transplantation Consortium Phase 3 Trial: Manufacture of a Complex Cellular Product at Eight Processing Facilities

Eight manufacturing facilities participating in the National Institutes of Health-sponsored Clinical Islet Transplantation (CIT) Consortium jointly developed and implemented a harmonized process for the manufacture of allogeneic purified human pancreatic islet (PHPI) product evaluated in a phase 3 trial in subjects with type 1 diabetes. Manufacturing was controlled by a common master production batch record, standard operating procedures that included acceptance criteria for deceased donor organ pancreata and critical raw materials, PHPI product specifications, certificate of analysis, and test methods. The process was compliant with Current Good Manufacturing Practices and Current Good Tissue Practices. This report describes the manufacturing process for 75 PHPI clinical lots and summarizes the results, including lot release. The results demonstrate the feasibility of implementing a harmonized process at multiple facilities for the manufacture of a complex cellular product. The quality systems and regulatory and operational strategies developed by the CIT Consortium yielded product lots that met the prespecified characteristics of safety, purity, potency, and identity and were successfully transplanted into 48 subjects. No adverse events attributable to the product and no cases of primary nonfunction were observed.

Collection of hematopoietic CD34 stem cells in rhesus macaques using Spectra Optia

BACKGROUND

Nonhuman primates, particularly rhesus macaques, are ideal preclinical large animal models to investigate organ tolerance induction protocols using donor hematopoietic stem cells (HSCs) to induce chimerism. Their relatively small size poses some challenges for the safe and effective collection of peripheral blood HSCs through apheresis procedures. We describe our experiences using the Spectra Optia apheresis unit to successfully obtain HSCs from mobilized peripheral blood of rhesus macaques.

METHOD

Mobilization of peripheral blood HSCs was induced using granulocyte stimulating factor (G-CSF) and Mozobil. The Spectra Optia unit was used in 18 apheresis procedures in 13 animals (4.9-10 kg). Animal health was carefully monitored during and after the procedure. Changes in peripheral blood cells before, during and after procedure were determined by complete blood count and flow cytometry.

RESULTS

The automatic settings of the Spectra Optia unit were applied successfully to the procedures on the rhesus macaque. All animals tolerated the procedure well with no mortality. Mobilization of HSCs were most consistently achieved using 50 μg/kg of G-CSF for 5 days and a single dose of Mozobil on the 5th day, followed by collection of cells 3 h after Mozobil injection. The final apheresis product contained an average of 23 billion total nucleated cells with 47% granulocytes, 3,871 million total CD3 cells and 77 million CD34 cells which resulted in an average of 10 million CD34+ cells/kg of donor weight.

CONCLUSION

Apheresis of peripheral blood mobilized HSCs in rhesus macaques using Spectra Optia is a safe and effective procedure.

Phase 3 Trial of Transplantation of Human Islets in Type 1 Diabetes Complicated by Severe Hypoglycemia

OBJECTIVE

Impaired awareness of hypoglycemia (IAH) and severe hypoglycemic events (SHEs) cause substantial morbidity and mortality in patients with type 1 diabetes (T1D). Current therapies are effective in preventing SHEs in 50-80% of patients with IAH and SHEs, leaving a substantial number of patients at risk. We evaluated the effectiveness and safety of a standardized human pancreatic islet product in subjects in whom IAH and SHEs persisted despite medical treatment.

RESEARCH DESIGN AND METHODS

This multicenter, single-arm, phase 3 study of the investigational product purified human pancreatic islets (PHPI) was conducted at eight centers in North America. Forty-eight adults with T1D for >5 years, absent stimulated C-peptide, and documented IAH and SHEs despite expert care were enrolled. Each received immunosuppression and one or more transplants of PHPI, manufactured on-site under good manufacturing practice conditions using a common batch record and standardized lot release criteria and test methods. The primary end point was the achievement of HbA1c <7.0% (53 mmol/mol) at day 365 and freedom from SHEs from day 28 to day 365 after the first transplant.

RESULTS

The primary end point was successfully met by 87.5% of subjects at 1 year and by 71% at 2 years. The median HbA1c level was 5.6% (38 mmol/mol) at both 1 and 2 years. Hypoglycemia awareness was restored, with highly significant improvements in Clarke and HYPO scores (P > 0.0001). No study-related deaths or disabilities occurred. Five of the enrollees (10.4%) experienced bleeds requiring transfusions (corresponding to 5 of 75 procedures), and two enrollees (4.1%) had infections attributed to immunosuppression. Glomerular filtration rate decreased significantly on immunosuppression, and donor-specific antibodies developed in two patients.

CONCLUSIONS

Transplanted PHPI provided glycemic control, restoration of hypoglycemia awareness, and protection from SHEs in subjects with intractable IAH and SHEs. Safety events occurred related to the infusion procedure and immunosuppression, including bleeding and decreased renal function. Islet transplantation should be considered for patients with T1D and IAH in whom other, less invasive current treatments have been ineffective in preventing SHEs.

Outpatient Management of Delayed Graft Function Is Associated With Reduced Length of Stay Without an Increase in Adverse Events

Delayed graft function (DGF) is a common and costly complication of kidney transplantation. In July 2011, we established a multidisciplinary DGF clinic managed by nurse practitioners to facilitate early discharge and intensive management of DGF in the outpatient setting. We compared length of stay, 30-day readmission, acute rejection, and patient/graft survival in 697 consecutive deceased donor kidney transplantations performed between July 2009 and July 2014. Patients were divided into three groups: no DGF (n = 487), DGF before implementation of the DGF clinic (n = 118), and DGF clinic (n = 92). Baseline characteristics including age, gender, panel reactive antibody, retransplantation rates, HLA mismatches, induction, and maintenance immunosuppression were not significantly different between pre- and post-DGF clinic groups. Length of stay was significantly longer in pre-DGF clinic (10.9 ± 6.2 vs. 6.1 ± 2.1 days, p < 0.001). Thirty-day readmission (21% vs. 16%), graft loss (7% vs. 20%), and patient death (2% vs. 11%) did not differ significantly between pre- and post-DGF clinic. Patients in the DGF clinic were less likely to develop acute rejection (21% vs. 40%, p = 0.006). Outpatient management of DGF in a specialized clinic is associated with substantially shorter hospitalization and lower incidence of acute rejection without significant difference in 30-day readmission or patient and graft survival.

Digital Image Analysis to Assess Quantity and Morphological Quality of Isolated Pancreatic Islets

Quantity and quality assessment of human pancreatic islets are essential processes to define a safe and potent quality product used for clinical transplantation. The conventional method of manual assessment has been used in the field for longer than two decades. The high degree of variability in product quantity and lack of archival imaging records of the product for verification are two major disadvantages of using the manual method for quantity and quality assessment of human pancreatic islets. Investigators have developed promising new methods for technical improvement. In this study, we briefly review the published methods and highlight the advantages of digital imaging analysis (DIA) when compared to the manual method. The application of DIA reduces measurement variability and increases the precision of islet equivalent (IEQ) determination for batch analysis. It produces images that can be archived for retrospective analysis and validation, and the data can be transmitted electronically for off-site analysis. These features are important for quality pancreatic islet assessment and are consistent with FDA requirements of current good manufacturing practice for clinical islet transplantation.

Diagnosis and Treatment of Pancreas Rejection

Despite significant improvement in pancreas allograft survival, rejection of the pancreas remains a major clinical problem. In addition to cellular rejection of the pancreas, antibody-mediated rejection of the pancreas is now a well-described entity. The 2011 Banff update established comprehensive guidelines for the diagnosis of acute and chronic AMR. The pancreas biopsy is critical in order to accurately diagnose and treat pancreas rejection. Other modes of monitoring pancreas rejection we feel are neither sensitive nor specific enough. In this review, we examine recent advances in the diagnosis and treatment of pancreas rejection as well as describe practical diagnostic and treatment algorithms.

Conversion from calcineurin inhibitor-based immunosuppression to mammalian target of rapamycin inhibitors or belatacept in renal transplant recipients

The calcineurin inhibitors (CNIs) remain the standard of care for maintenance immunosuppression following renal transplantation. CNIs have demonstrated their effectiveness in reducing acute cellular rejection; however, some evidence suggests that these compounds negatively affect native renal function and are associated with allograft injury in renal transplant recipients. CNIs have also been linked with hypertension, new-onset diabetes after transplantation, tremor, and thrombotic microangiopathy, which have significant consequences for long-term allograft function and patient health overall. Thus, converting patients to a non-CNI-based regimen may improve renal function and also provide extrarenal benefits. A number of studies have been conducted that explore CNI conversion strategies in renal transplant recipients in an effort to improve long-term allograft function and survival. These include converting to alternative, non-nephrotoxic, maintenance immunosuppressants, such as the mammalian target of rapamycin inhibitors (sirolimus and everolimus) and the costimulation blocker belatacept. In this review of literature, evidence for the potential renal and extrarenal benefits of conversion to these non-CNI-based regimens is evaluated. Clinical challenges, including the adverse event profiles of non-CNI-based regimens and the selection of candidates for conversion, are also examined.

Application of Digital Image Analysis to Determine Pancreatic Islet Mass and Purity in Clinical Islet Isolation and Transplantation

Pancreatic islet mass, represented by islet equivalent (IEQ), is the most important parameter in decision making for clinical islet transplantation. To obtain IEQ, the sample of islets is routinely counted under a microscope and discarded thereafter. Islet purity, another parameter in islet processing, is routinely assessed by estimation only. In this study, we validated our digital image analysis (DIA) system by using the software of Image Pro Plus and a custom-designed Excel template to assess islet mass and purity to better comply with current good manufacturing practice (cGMP) standards. Human islet samples (60 collected from a single isolation and 24 collected from 12 isolations) were captured as calibrated digital images for the permanent record. Seven trained technicians participated in determination of IEQ and purity by the manual counting method (manual image counting, Manual I) and DIA. IEQ count showed statistically significant correlations between the Manual I and DIA in all sample comparisons (r > 0.819 and p < 0.0001). A statistically significant difference in IEQ between Manual I and DIA was not found in all sample groups (p > 0.05). In terms of purity determination, statistically significant differences between assessment and DIA measurement were found in high-purity 100-µl samples (p < 0.005) and low-purity 100-µl samples (p < 0.001) of the single isolation. In addition, islet particle number (IPN) and the IEQ/IPN ratio did not differ statistically between Manual I and DIA. In conclusion, the DIA used in this study is a reliable technique to determine IEQ and purity. Islet sample preserved as a digital image and results produced by DIA can be permanently stored for verification, technical training, and information exchange among islet centers. Therefore, DIA complies better with cGMP requirements than the manual counting method. We propose DIA as a quality control tool to supplement the established standard manual method for islet counting and purity estimation.