Gene expression-based molecular scoring of pancreas transplant rejection for a quantitative assessment of rejection severity and resistance to treatment.

Pancreas transplantation improves glycemic control and mortality in patients with diabetes but requires aggressive immunosuppression to control the alloimmune and autoimmune response. Recent developments in "omics" methods have provided gene transcript-based biomarkers for organ transplant rejection. The tissue Common Response Module (tCRM) score is developed to identify the severity of rejection in kidney, heart, liver, and lung transplants. Still, it has not yet been validated in pancreas transplants (PT). We evaluated the tCRM score's relevance in PT and additional markers of acute cellular rejection (ACR) for PT. An analysis of 51 pancreas biopsies with ACR identified 37 genes and 56 genes significantly upregulated in the case of grade 3 and grade 2 ACR, respectively (P < .05). Significant differences were seen with higher grades of rejection among several transcripts. Of the 22 genes differentially expressed in grade 3 ACR, 18 were also differentially expressed in grade 2 ACR. The rejection signal was attributable to activated leukocytes' infiltration. Significantly higher tCRM scores were found in grade 3 ACR (P = .007) and grade 2 ACR (P = .004), compared to normal samples. The tCRM score was able to distinguish treatment-resistant cases from those successfully treated for rejection.

An Enhanced Role of Innate Immunity in the Immune Response After Kidney Transplant in People Living With HIV: A Transcriptomic Analysis.

BACKGROUND: Although kidney transplantation (KT) has become the standard of care for people living with HIV (PLWH) suffering from renal failure, early experiences revealed unanticipated higher rejection rates than those observed in HIV- recipients. The cause of increased acute rejection (AR) in PLWH was assessed by performing a transcriptomic analysis of biopsy specimens, comparing HIV+ to HIV- recipients. METHODS: An analysis of 68 (34 HIV+, 34 HIV-) formalin-fixed paraffin-embedded (FFPE) renal biopsies matched for degree of inflammation was performed from KT recipients with acute T cell-mediated rejection (aTCMR), borderline for aTCMR (BL), and normal findings. Gene expression was measured using the NanoString platform on a custom gene panel to assess differential gene expression (DE) and pathway analysis (PA). RESULTS: DE analysis revealed multiple genes with significantly increased expression in the HIV+ cohort in aTCMR and BL relative to the HIV- cohort. PA of these genes showed enrichment of various inflammatory pathways, particularly innate immune pathways associated with Toll-like receptors. CONCLUSIONS: Upregulation of the innate immune pathways in the biopsies of PLWH with aTCMR and BL is suggestive of a unique immune response that may stem from immune dysregulation related to HIV infection. These findings suggest that these unique HIV-driven pathways may in part be contributory to the increased incidence of allograft rejection after renal transplantation in PLWH.

OPTN/SRTR 2022 Annual Data Report: Pancreas.

The postpandemic recovery did not occur in pancreas transplantation as in other organs. The number of pancreas transplants in the United States decreased to 918 in 2022 from 963 in 2021. The number of simultaneous pancreas-kidney transplants decreased to 810 in 2022 from 820 in 2021, but the largest decrease was in pancreas transplant alone: 62 in 2022 compared with 92 in 2021. Pancreas-after-kidney transplants decreased to 46 in 2022 from 51 in 2021. The trend of increasing proportions of pancreas transplants in patients with type 2 diabetes seen over the past few years ended in 2022; there were 22.4% of such transplants in 2022 compared with 25.8% in 2021. The proportion of recipients older than 45 years decreased in 2022 as well. However, the proportions of candidates with type 2 diabetes and older candidates on the waiting list did not decrease. The number of pancreas donors decreased and the pancreas nonuse rate increased in 2022. Outcomes after pancreas transplant continued to improve, with an impressive 8.1% pancreas and 4.3% kidney graft failure rate for simultaneous pancreas-kidney transplant at 1 year in 2022. The proportion of pancreas transplants performed by medium-volume centers (11-24 transplants/year) returned to 37.2% in 2022 from a high of 48.3% in 2021, whereas the proportion of those done by large-volume centers (25 or more transplants/year) returned to 25.3% in 2022 from a low of 15.9% in 2021.

Transplantation in the Context of Migration and Refugees: A Summary of the DICG and TTS Ethics Committee Workshop, Buenos Aires, Argentina, September 2022.

Global conflicts and humanitarian crises have resulted in an unprecedented number of refugees and migrants. This challenges the limited resources of health care systems and jeopardizes the availability of transplant care for these deserving migrants and refugees. This was the basis for a workshop held during the Congress of the Transplantation Society (Buenos Aires, 2022). We elaborate on the proceedings of the workshop entitled "Transplantation in the Context of Migration and Refugees," organized by the Ethics Committee of The Transplantation Society and Declaration of Istanbul Custodian Group. Transplant providers from around the world shared strategies of how each region has responded to providing access to care for refugees and migrants in need of transplant services. The potential exploitation of this vulnerable group leading to illicit organ removal was addressed for each region. The Transplantation Society, Declaration of Istanbul Custodian Group, and global transplant community should continue to focus on the status of refugees and migrants and collaborate on strategies to provide access to transplant care for this deserving population. Global cooperation will be essential to provide vigilant oversight to prevent exploitation of this vulnerable population.

Expanding Access to Organ Transplant for People Living With HIV: Can Policy Catch Up to Outcomes Data?

Advances in antiretroviral and immunosuppressive regimens have improved outcomes following solid organ transplantation in people living with HIV (PLWH). The HIV Organ Policy and Equity Act was conceived to reduce the discard of HIV-positive organs and improve access to transplant for PLWH. Nevertheless, PLWH continue to experience disproportionately low rates of transplant. This overview examines the hurdles to transplantation in PLWH with end-organ disease, the potential and realized impact of the HIV Organ Policy and Equity Act, and changes that could permit expanded access to organ transplant in this population.

A Multi-Modal Approach to Islet and Pancreas Transplantation With Calcineurin-Sparing Immunosuppression Maintains Long-Term Insulin Independence in Patients With Type I Diabetes.

Long-term success in beta-cell replacement remains limited by the toxic effects of calcineurin inhibitors (CNI) on beta-cells and renal function. We report a multi-modal approach including islet and pancreas-after-islet (PAI) transplant utilizing calcineurin-sparing immunosuppression. Ten consecutive non-uremic patients with Type 1 diabetes underwent islet transplant with immunosuppression based on belatacept (BELA; n = 5) or efalizumab (EFA; n = 5). Following islet failure, patients were considered for repeat islet infusion and/or PAI transplant. 70% of patients (four EFA, three BELA) maintained insulin independence at 10 years post-islet transplant, including four patients receiving a single islet infusion and three patients undergoing PAI transplant. 60% remain insulin independent at mean follow-up of 13.3 ± 1.1 years, including one patient 9 years after discontinuing all immunosuppression for adverse events, suggesting operational tolerance. All patients who underwent repeat islet transplant experienced graft failure. Overall, patients demonstrated preserved renal function, with a mild decrease in GFR from 76.5 ± 23.1 mL/min to 50.2 ± 27.1 mL/min (p = 0.192). Patients undergoing PAI showed the greatest degree of renal impairment following initiation of CNI (56% ± 18.7% decrease in GFR). In our series, repeat islet transplant is ineffective at maintaining long-term insulin independence. PAI results in durable insulin independence but is associated with impaired renal function secondary to CNI dependence.

OPTN/SRTR 2021 Annual Data Report: Pancreas.

The number of pancreas transplants in the United States was largely unchanged in 2021 at 963 transplants compared with 962 in 2020, showing that recovery from the COVID-19 pandemic was not as pronounced in pancreas transplantation as in other organs. The number of simultaneous pancreas-kidney transplants (SPKs) decreased from 827 to 820, whereas the number of pancreas-after-kidney transplants and pancreas transplants alone increased marginally to compensate. The proportion of patients with type 2 diabetes on the waiting list increased to 22.9% in 2021, compared with 20.1% in 2020. Consequently, the proportion of transplants in patients with type 2 diabetes increased from 21.3% in 2020 to 25.9% in 2021. The proportion of transplants in older recipients (aged 55 years or older) also increased to 13.5% in 2021 from 11.7% in 2020. Outcomes after SPK continue to be the best of the three categories of pancreas transplants: 1-year graft failure for kidney at 5.7% and pancreas at 10.5% for transplants performed in 2020. The proportion of pancreas transplants performed by medium-volume centers (11-24 transplants per year) increased sharply to 48.3% in 2021 from 35.1% in 2020, with a corresponding decrease in transplants in large-volume centers (25 or more transplants per year) to 15.9% in 2021 from 25.7% in 2020.

COVID-19 infection and vaccination rarely impact HLA antibody profile in waitlisted renal transplant candidates- a multicenter cohort.

Although rare, infection and vaccination can result in antibodies to human leukocyte antigens (HLA). We analyzed the effect of SARS-CoV-2 infection or vaccination on HLA antibodies in waitlisted renal transplant candidates. Specificities were collected and adjudicated if the calculated panel reactive antibodies (cPRA) changed after exposure. Of 409 patients, 285 (69.7 %) had an initial cPRA of 0 %, and 56 (13.7 %) had an initial cPRA > 80 %. The cPRA changed in 26 patients (6.4 %), 16 (3.9 %) increased, and 10 (2.4 %) decreased. Based on cPRA adjudication, cPRA differences generally resulted from a small number of specificities with subtle fluctuations around the borderline of the participating centers' cutoff for unacceptable antigen listing. All five COVID recovered patients with an increased cPRA were female (p = 0.02). In summary, exposure to this virus or vaccine does not increase HLA antibody specificities and their MFI in approximately 99 % of cases and 97 % of sensitized patients. These results have implications for virtual crossmatching at the time of organ offer after SARS-CoV-2 infection or vaccination, and these events of unclear clinical significance should not influence vaccination programs.

Impact of Donor Liver Macrovesicular Steatosis on Deceased Donor Yield and Posttransplant Outcome.

BACKGROUND: The Scientific Registry of Transplant Recipients (SRTR) had not traditionally considered biopsy results in risk-adjustment models, yet biopsy results may influence outcomes and thus decisions regarding organ acceptance. METHODS: Using SRTR data, which includes data on all donors, waitlisted candidates, and transplant recipients in the United States, we assessed (1) the impact of macrovesicular steatosis on deceased donor yield (defined as number of livers transplanted per donor) and 1-y posttransplant graft failure and (2) the effect of incorporating this variable into existing SRTR risk-adjustment models. RESULTS: There were 21 559 donors with any recovered organ and 17 801 liver transplant recipients included for analysis. Increasing levels of macrovesicular steatosis on donor liver biopsy predicted lower organ yield: ≥31% macrovesicular steatosis on liver biopsy was associated with 87% to 95% lower odds of utilization, with 55% of these livers being discarded. The hazard ratio for graft failure with these livers was 1.53, compared with those with no pretransplant liver biopsy and 0% to 10% steatosis. There was minimal change on organ procurement organization-specific deceased donor yield or program-specific posttransplant outcome assessments when macrovesicular steatosis was added to the risk-adjustment models. CONCLUSIONS: Donor livers with macrovesicular steatosis are disproportionately not transplanted relative to their risk for graft failure. To avoid undue risk aversion, SRTR now accounts for macrovesicular steatosis in the SRTR risk-adjustment models to help facilitate use of these higher-risk organs. Increased recognition of this variable may also encourage further efforts to standardize the reporting of liver biopsy results.

A Worldwide Survey of Activities and Practices in Clinical Islet of Langerhans Transplantation.

A global online survey was administered to 69 islet transplantation programs, covering 84 centers and 5 networks. The survey addressed questions on program organization and activity in the 2000-2020 period, including impact on activity of national health care coverage policies. We obtained full data from 55 institutions or networks worldwide and basic activity data from 6 centers. Additional data were obtained from alternative sources. A total of 94 institutions and 5 networks was identified as having performed islet allotransplantation. 4,365 islet allotransplants (2,608 in Europe, 1,475 in North America, 135 in Asia, 119 in Oceania, 28 in South America) were reported in 2,170 patients in the survey period. From 15 centers active at the start of the study period, the number of simultaneously active islet centers peaked at 54, to progressively decrease to 26 having performed islet allotransplants in 2020. Notably, only 16 centers/networks have done >100 islet allotransplants in the survey period. Types of transplants performed differed notably between North America and the rest of the world, in particular with respect to the near-absence of simultaneous islet-kidney transplantation. Absence of heath care coverage has significantly hampered transplant activity in the past years and the COVID-19 pandemic in 2020.

Pancreas Transplantation for Type 2 Diabetes: A Systematic Review, Critical Gaps in the Literature, and a Path Forward.

Pancreas transplantation in patients with type 2 diabetes (T2D) remains relatively uncommon compared with pancreas transplantation in patients with type 1 diabetes (T1D); however, several studies have suggested similar outcomes between T2D and T1D, and the practice has become increasingly common. Despite this growing interest in pancreas transplantation in T2D, no study has systematically summarized the data to date. We systematically reviewed the literature on pancreas transplantation in T2D patients including patient and graft survival, glycemic control outcomes, and comparisons with outcomes in T2D kidney transplant alone and T1D pancreas transplant recipients. We searched biomedical databases from January 1, 2000, to January 14, 2021, and screened 3314 records, of which 22 full texts and 17 published abstracts met inclusion criteria. Full-text studies were predominantly single center (73%), whereas the remaining most often studied the Organ Procurement and Transplantation Network database. Methodological quality was mixed with frequent concern for selection bias and concern for inconsistent definitions of both T2D and pancreas graft survival across studies. Overall, studies generally reported favorable patient survival, graft survival, and glycemic control outcomes for pancreas transplantation in T2D and expressed a need to better characterize the T2D patients who would benefit most from pancreas transplantation. We suggest guidance for future studies, with the aim of supporting the safe and evidence-based treatment of end-stage T2D and judicious use of scarce resources.

Effects of Multi-stage Procurement on the Viability and Function of Human Donor Parathyroid Glands.

INTRODUCTION: Parathyroid allotransplantation is an emerging treatment for severe hypoparathyroidism. Ensuring the viability and functional integrity of donor parathyroid glands following procurement is essential for optimal transplantation outcomes. METHODS: Cellular viability, calcium-responsive hormone secretion, and gland xenograft survival were assessed in a series of deceased donor parathyroid glands following a two-stage procurement procedure recently developed by our group (en bloc cadaveric dissection with subsequent gland isolation after transport to the laboratory). RESULTS: Parathyroid glands resected in this manner and stored up to 48 h in 4°C University of Wisconsin (UW) media retained in vitro viability with no induction of hypoxic stress (HIF-1α) or apoptotic (caspase-3) markers. Ex vivo storage did not significantly affect parathyroid gland calcium sensing capacity, with comparable calcium EC50 values and suppression of parathyroid hormone secretion at high ambient calcium concentrations. The isolated glands engrafted readily, vascularizing rapidly in vivo following transplantation into mice. CONCLUSIONS: Parathyroid tissue retains viability, calcium-sensing capacity, and in vivo engraftment capability after en bloc cadaveric resection, ex vivo dissection, and extended cold storage.

Procurement of Deceased Donor Parathyroid Glands With the Aid of Near-infrared Autofluorescence Imaging.

Parathyroid allotransplantation is a burgeoning treatment for severe hypoparathyroidism. Deceased donor parathyroid gland (PTG) procurement can be technically challenging due to lack of normal intraoperative landmarks and exposure constraints in the neck of organ donors. In this study, we assessed standard 4-gland exposure in situ and en bloc surgical techniques for PTG procurement and ex vivo near-infrared autofluorescence (NIRAF) imaging for identification of PTGs during organ recovery. Methods: Research tissue consent was obtained from organ donors or donor families for PTG procurement. All donors were normocalcemic, brain-dead, solid organ donors between 18 and 65 y of age. PTGs were procured initially using a standard 4-gland exposure technique in situ and subsequently using a novel en bloc resection technique after systemic organ preservation flushing. Parathyroid tissue was stored at 4 °C in the University of Wisconsin solution up to 48 h post-procurement. Fluoptics Fluobeam NIRAF camera and Image J software were utilized for quantification of NIRAF signal. Results: Thirty-one brain-dead deceased donor PTG procurements were performed by abdominal transplant surgeons. In the initial 8 deceased donors, a mean of 1.75 glands (±1.48 glands SD) per donor were recovered using the 4-gland in situ technique. Implementation of combined en bloc resection with ex vivo NIRAF imaging in 23 consecutive donors yielded a mean of 3.60 glands (±0.4 SD) recovered per donor (P < 0.0001). Quantification of NIRAF integrated density signal demonstrated >1-fold log difference in PTG (2.13 × 105 pixels) versus surrounding anterior neck structures (1.9 × 104 pixels; P < 0.0001). PTGs maintain distinct NIRAF signal from the time of recovery (1.88 × 105 pixels) up to 48 h post-procurement (1.55 × 105 pixels) in organ preservation cold storage (P = 0.34). Conclusions: The use of an en bloc surgical technique with ex vivo NIRAF imaging significantly enhances the identification and recovery of PTG from deceased donors.

International Survey of Clinical Monitoring Practices in Pancreas and Islet Transplantation.

BACKGROUND: The long-term outcomes of both pancreas and islet allotransplantation have been compromised by difficulties in the detection of early graft dysfunction at a time when a clinical intervention can prevent further deterioration and preserve allograft function. The lack of standardized strategies for monitoring pancreas and islet allograft function prompted an international survey established by an International Pancreas and Islet Transplant Association/European Pancreas and Islet Transplant Association working group. METHODS: A global survey was administered to 24 pancreas and 18 islet programs using Redcap. The survey addressed protocolized and for-cause immunologic and metabolic monitoring strategies following pancreas and islet allotransplantation. All invited programs completed the survey. RESULTS: The survey identified that in both pancreas and islet allograft programs, protocolized clinical monitoring practices included assessing body weight, fasting glucose/C-peptide, hemoglobin A1c, and donor-specific antibody. Protocolized monitoring in islet transplant programs relied on the addition of mixed meal tolerance test, continuous glucose monitoring, and autoantibody titers. In the setting of either suspicion for rejection or serially increasing hemoglobin A1c/fasting glucose levels postpancreas transplant, Doppler ultrasound, computed tomography, autoantibody titers, and pancreas graft biopsy were identified as adjunctive strategies to protocolized monitoring studies. No additional assays were identified in the setting of serially increasing hemoglobin A1c levels postislet transplantation. CONCLUSIONS: This international survey identifies common immunologic and metabolic monitoring strategies utilized for protocol and for cause following pancreas and islet transplantation. In the absence of any formal studies to assess the efficacy of immunologic and metabolic testing to detect early allograft dysfunction, it can serve as a guidance document for developing monitoring algorithms following beta-cell replacement.

International Travel for Liver Transplantation: A Comprehensive Assessment of the Impact on the United States Transplant System.

BACKGROUND: International travel for transplantation remains a global issue as countries continue to struggle in establishing self-sufficiency. In the United States, the United Network for Organ Sharing (UNOS) requires citizenship classification at time of waitlisting to remain transparent and understand to whom our organs are allocated. This study provides an assessment of patients who travel internationally for liver transplantation and their outcomes using the current citizenship classification used by UNOS. METHODS: Adult liver UNOS data from 2003 to 2019 were used. Patients were identified as citizens, noncitizen, nonresidents (NCNR), or noncitizen residents (NC-R) according to citizenship status. Descriptive statistics compared demographics among the waitlisted patients and demographics and donor characteristics among transplant recipients. A competing risks model was used to examine waitlist outcomes. The Kaplan-Meier method and Cox proportional hazards were used for posttransplant outcomes. RESULTS: There were significant demographic differences according to citizenship group among waitlisted (n = 125 652) and transplanted (n = 71 536) patients. Compared with US citizens, NCNR was associated with a 9% increase in transplant (subdistribution hazard ratio [SHR], 1.09; 95% confidence interval [CI], 1.00-1.18; P = 0.04), and NC-R was associated with a 24% decrease in transplant (SHR, 0.76; 95% CI, 0.72-0.79; P < 0.0001) and a 23% increase in death or removal for being too sick (SHR, 1.23; 95% CI, 1.14-1.33; P < 0.0001). US citizens had significantly inferior graft and patient survival (P < 0.001). CONCLUSIONS: Though the purpose of the citizenship classification system is transparency, the results of this study highlight significant disparities in the access to and outcomes following liver transplantation according to citizenship status.

Ethical review of COVID-19 vaccination requirements for transplant center staff and patients.

Transplant centers seeking to increase coronavirus disease 2019 (COVID-19) vaccine coverage may consider requiring vaccination for healthcare workers or for candidates. The authors summarize current data to inform an ethical analysis of the harms, benefits, and individual and societal impact of mandatory vaccination, concluding that vaccine requirements for healthcare workers and transplant candidates are ethically justified by beneficence, net utility, and fiduciary duty to patients and public health. Implementation strategies should mitigate concerns about respect for autonomy and transparency for both groups. We clarify how the same arguments might be applied to related questions of caregiver vaccination, allocation of other healthcare resources, and mandates for non-COVID-19 vaccines. Finally, we call for effort to achieve global equity in vaccination as soon as possible.

National Landscape of Human Immunodeficiency Virus-Positive Deceased Organ Donors in the United States.

BACKGROUND: Organ transplantation from donors with human immunodeficiency virus (HIV) to recipients with HIV (HIV D+/R+) presents risks of donor-derived infections. Understanding clinical, immunologic, and virologic characteristics of HIV-positive donors is critical for safety. METHODS: We performed a prospective study of donors with HIV-positive and HIV false-positive (FP) test results within the HIV Organ Policy Equity (HOPE) Act in Action studies of HIV D+/R+ transplantation (ClinicalTrials.gov NCT02602262, NCT03500315, and NCT03734393). We compared clinical characteristics in HIV-positive versus FP donors. We measured CD4 T cells, HIV viral load (VL), drug resistance mutations (DRMs), coreceptor tropism, and serum antiretroviral therapy (ART) detection, using mass spectrometry in HIV-positive donors. RESULTS: Between March 2016 and March 2020, 92 donors (58 HIV positive, 34 FP), representing 98.9% of all US HOPE donors during this period, donated 177 organs (131 kidneys and 46 livers). Each year the number of donors increased. The prevalence of hepatitis B (16% vs 0%), syphilis (16% vs 0%), and cytomegalovirus (CMV; 91% vs 58%) was higher in HIV-positive versus FP donors; the prevalences of hepatitis C viremia were similar (2% vs 6%). Most HIV-positive donors (71%) had a known HIV diagnosis, of whom 90% were prescribed ART and 68% had a VL <400 copies/mL. The median CD4 T-cell count (interquartile range) was 194/µL (77-331/µL), and the median CD4 T-cell percentage was 27.0% (16.8%-36.1%). Major HIV DRMs were detected in 42%, including nonnucleoside reverse-transcriptase inhibitors (33%), integrase strand transfer inhibitors (4%), and multiclass (13%). Serum ART was detected in 46% and matched ART by history. CONCLUSION: The use of HIV-positive donor organs is increasing. HIV DRMs are common, yet resistance that would compromise integrase strand transfer inhibitor-based regimens is rare, which is reassuring regarding safety.