Human Leukocyte Antigen Mismatch Research Articles

Renal transplantation in older adults: retrospective cohort study to examine the impact of the new 2019 kidney offering scheme on older adult transplant recipients.

In 2019, a new kidney offering scheme was launched in the United Kingdom, aiming to better match estimated patient survival and graft life expectancy. The scheme's impact on older patients undergoing kidney transplantation (KT) is unknown. This study aims to compare the outcomes of older adult KT recipients before and after introduction of the 2019 scheme. A retrospective observational cohort study of older adults who underwent KT was undertaken. Group 1 were transplanted between 1 September 2017 and 31 August 2019 (2006 allocation scheme) and group 2 between 1 September 2019 and 31 August 2021 (2019 offering scheme). An older adult was any person ≥60 years old at the time of KT. Univariable binary logistic regression analysis was performed to determine odds ratios (OR) and 95% confidence intervals (CI). There were 107 older adult deceased donor KT recipients, 62 from group 1 and 45 from group 2. Median age at transplantation was 68 (interquartile range [IQR] 62-71) and 67 (IQR 64-73) years, respectively. Univariable analysis showed that re-intervention (OR 6.486, 95% CI 1.306-32.216, p = 0.022) and critical care admission (OR 5.619, 95% CI 1.448-21.812, p = 0.013) were significantly more likely in group 2. Group 2 recipients were significantly more likely to have a level 4 human leucocyte antigen (HLA) mismatch (OR 4.667, 95% CI 1.640-13.275, p = 0.004) and to have undergone previous KT (OR 4.691, 95% CI 1.385-15.893, p = 0.013). The introduction of the 2019 offering scheme was associated with re-intervention and critical care admission for older KT recipients. We also observed less-favourable HLA matches but more KT in difficult-to-match groups.

Differences in chronic lung allograft dysfunction between deceased-donor lung transplantation and living-donor lobar lung transplantation

This study explored the characteristics and prognostic impact of chronic lung allograft dysfunction (CLAD) after deceased-donor lung transplantation and living-donor lobar lung transplantation, wherein the lower lobes from two donors are usually transplanted into one recipient. The clinical data of 123 deceased-donor and 67 living-donor lung transplantations performed in adult patients at our institution between June 2008 and September 2019 were retrospectively reviewed. The cumulative incidence of CLAD was evaluated on a per-recipient and per-donor graft basis using the Kaplan-Meier method. The smaller number of human leukocyte antigen mismatches, shorter ischemic time, and lower incidence of grade 3 primary graft dysfunction were observed in living-donor transplantation than in deceased-donor transplantation (p<0.001). Restrictive allograft syndrome (RAS)-type CLAD occurred in 9 (20.9%) of 43 CLAD patients after deceased-donor transplantation and 9 (45.0%) of 20 CLAD patients after living-donor transplantation. CLAD occurred unilaterally in 15 patients (75.0%) after bilateral living-donor transplantation. Despite the higher incidence of RAS-type CLAD after living-donor transplantation, the overall survival rates after the transplantation and survival rates after the onset of CLAD were comparable between the deceased-donor transplant and living-donor transplant patients. The cumulative incidence of CLAD per recipient was similar between the deceased-donor and the living-donor transplant recipients (p=0.32). In the per-donor graft analysis, the cumulative incidence of CLAD was significantly lower in the living-donor grafts than in the deceased-donor grafts (p=0.003). The manifestation of CLAD after living-donor lobar lung transplantation is unique and differs from that after deceased-donor lung transplantation.

High-Risk HLA-DQ Mismatches Are Associated With Adverse Outcomes After Lung Transplantation.

Human leukocyte antigen (HLA) mismatches (MM) between donor and recipient lead to eplet MM (epMM) in lung transplantation (LTX), which can induce the development of de-novo donor-specific HLA-antibodies (dnDSA), particularly HLA-DQ-dnDSA. Aim of our study was to identify risk factors for HLA-DQ-dnDSA development. We included all patients undergoing LTX between 2012 and 2020. All recipients/donors were typed for HLA 11-loci. Development of dnDSA was monitored 1-year post-LTX. EpMM were calculated using HLAMatchmaker. Differences in proportions and means were compared using Chi2-test and Students' t-test. We used Kaplan-Meier curves with LogRank test and multivariate Cox regression to compare acute cellular rejection (ACR), chronic lung allograft dysfunction (CLAD) and survival. Out of 183 patients, 22.9% patients developed HLA-DQ-dnDSA. HLA-DQ-homozygous patients were more likely to develop HLA-DQ-dnDSA than HLA-DQ-heterozygous patients (p = 0.03). Patients homozygous for HLA-DQ1 appeared to have a higher risk of developing HLA-DQ-dnDSA if they received a donor with HLA-DQB1*03:01. Several DQ-eplets were significantly associated with HLA-DQ-dnDSA development. In the multivariate analysis HLA-DQ-dnDSA was significantly associated with ACR (p = 0.03) and CLAD (p = 0.01). HLA-DQ-homozygosity, several high-risk DQ combinations and high-risk epMM result in a higher risk for HLA-DQ-dnDSA development which negatively impact clinical outcomes. Implementation in clinical practice could improve immunological compatibility and graft outcomes.

Basiliximab induction alone vs a dual ATG-basiliximab approach in first live-donor non-sensitized kidney transplant recipients with low HLA matching.

Individualizing induction therapy based on immunological risk is crucial for optimizing outcomes in kidney transplantation. A retrospective analysis included 157 first live-donor non-sensitized kidney transplant recipients (KTRs). Within this cohort, 96 individuals exhibited low human leukocyte antigen (HLA) matching (5-6 HLA mismatches). The low HLA match subgroup was categorized into 52 KTRs receiving basiliximab alone and 44 recipients treated with a combined single ATG dose of 1.5mg/kg and basiliximab. The primary endpoint was early acute cellular rejection (ACR) within 6months post-transplant while secondary outcomes encompassed infection rates, renal allograft function, length of stay (LOS) and readmissions post-transplant. The incidence of early ACR was decreased for low HLA match KTRs, who received ATG-basiliximab, when compared with low HLA-matched KTRs who received basiliximab alone (9.1% vs 23.9%, P=.067). Age was a predictor for rejection, and subgroup analysis showed consistent rejection reduction across age groups. No significant differences were observed in admission for transplant LOS or in peri-operative complications, nor in infections rate including BK and cytomegalovirus viremia, allograft function and number of readmissions post-transplant up to 6months post-transplant. In non-sensitized first live-donor KTRs with low HLA matching, a dual ATG-basiliximab induction approach significantly reduced early ACR without compromising safety.

Human leukocyte antigen compatibility and incidence of donor-specific antibodies in pediatric liver transplant recipients.

Antibody-mediated rejection following liver transplantation (LT) has been increasingly recognized, particularly with respect to the emergence of de novo donor-specific antibodies (DSAs) and their impact on graft longevity. While substantial evidence for adult populations exists, research focusing on pediatric LT outcomes remains limited. To investigate the prevalence of human leukocyte antigen (HLA) mismatches and DSA and evaluate their association with rejection episodes after pediatric LT. A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre, Brazil, between December 2013 and December 2023. Only patients who survived for > 30 days after LT with at least one DSA analysis were included. DSA classes I and II and cross-matches were analyzed. The presence of de novo DSA (dnDSA) was evaluated at least 3 months after LT using the Luminex® single antigen bead method, with a positive reaction threshold set at 1000 MFI. Rejection episodes were confirmed by liver biopsy. Overall, 67 transplanted children were analyzed; 61 received grafts from living donors, 85% of whom were related to recipients. Pre-transplant DSA (class I or II) was detected in 28.3% of patients, and dnDSA was detected in 48.4%. The median time to DSA detection after LT was 19.7 [interquartile range (IQR): 4.3-35.6] months. Biopsy-proven rejection occurred in 13 patients at follow-up, with C4d positivity observed in 5/13 Liver biopsies. The median time to rejection was 7.8 (IQR: 5.7-12.8) months. The presence of dnDSA was significantly associated with rejection (36% vs 3%, P < 0.001). The rejection-free survival rates at 12 and 24 months were 76% vs 100% and 58% vs 95% for patients with dnDSA anti-DQ vs those without, respectively. Our findings highlight the importance of incorporating DSA assessment into pre- and post-transplantation protocols for pediatric LT recipients. Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.

HLA class I expression on human platelets is highly variable and correlates with distinct allele group frequencies.

Human leukocyte antigen (HLA) class I molecules are expressed on platelets and can represent a source of alloimmunization in recipients of platelet transfusions. HLA mismatch between donors and recipients may be associated with the induction of anti-HLA antibodies, which can culminate in refractoriness to platelet transfusions. In the present study we analyzed HLA allele group frequencies and HLA expression levels on human platelets from blood donors. Platelet-rich plasma was collected from 139 donors to monitor platelet HLA class I expression by flow cytometry. DNA from donors with high and low platelet HLA expression was used in the genotype studies. Frequencies of large and normal-sized platelet subpopulations were determined and HLA class I expression was studied. Mean platelet volume (MPV) and platelet large-cell ratio (P-LCR) were analyzed in both groups of donors. The analysis showed variable platelet HLA class I expression with significant differences among donors. HLA class I allele group frequencies in donors with high and low platelet HLA expression showed distinctive genotypic features strictly related to expression level. The main allele groups found in samples with high platelet HLA class I expression were HLA-A*02, -A*68, -B*15, -B*49, and -C*03. Platelet HLA class I expression did not change over time or during freezing-thawing cycles. The analysis of platelet subpopulations showed a statistically significant higher expression of HLA class I molecules on large platelets than on normal-sized platelets. Moreover, donors with high HLA class I expression showed a higher frequency of large platelets (p<0.0001). The analysis of P-LCR in both groups of donors showed a statistically significant difference (p<0.05) within high HLA-expressing donors. Our data suggest an allele-dependent expression of HLA class I molecules on human platelets with distinct HLA allele group frequencies and different platelet subpopulation frequencies among blood donors.

Management of Refractory/Resistant Herpes Simplex Virus Infections in Haematopoietic Stem Cell Transplantation Recipients: A Literature Review.

Herpes simplex virus (HSV) infections in allogeneic haematopoietic stem cell transplantation (HSCT) recipients pose significant challenges, with higher incidence, severity, and risk of emergence of resistance to antivirals due to impaired T-cell mediated immunity. This literature review focuses on acyclovir-refractory/resistant HSV infections in HSCT recipients. The review addresses the efficacy of antiviral prophylaxis, the incidence of acyclovir-refractory/resistant HSV infections, and the identification of risk factors and potential prognostic impact associated with those infections. Additionally, alternative therapeutic options are discussed. While acyclovir prophylaxis demonstrates a significant benefit in reducing HSV infections in HSCT recipients and, in some cases, overall mortality, concerns arise about the emergence of drug-resistant HSV strains. Our systematic review reports a median incidence of acyclovir-resistant HSV infections of 16.1%, with an increasing trend in recent years. Despite limitations in available studies, potential risk factors of emergence of HSV resistance to acyclovir include human leucocyte antigen (HLA) mismatches, myeloid neoplasms and acute leukaemias, and graft-versus-host disease (GVHD). Limited evidences suggest a potentially poorer prognosis for allogeneic HSCT recipients with acyclovir-refractory/resistant HSV infection. Alternative therapeutic approaches, such as foscarnet, cidofovir, topical cidofovir, optimised acyclovir dosing, and helicase-primase inhibitors offer promising options but require further investigations. Overall, larger studies are needed to refine preventive and therapeutic strategies for acyclovir-refractory/resistant HSV infections in allogeneic HSCT recipients and to identify those at higher risk.

Human Leukocyte Antigen Mismatching and Survival in Contemporary Hematopoietic Cell Transplantation for Hematologic Malignancies.

PURPOSEHuman leukocyte antigen (HLA) mismatching can reduce survival of patients with blood cancer after hematopoietic cell transplantation (HCT). How recent advances in HCT practice, in particular graft-versus-host disease (GVHD) prophylaxis by post-transplantation cyclophosphamide (PTCy), influence HLA risk associations is unknown.PATIENTS AND METHODSThe study included 17,292 unrelated HCTs with 6-locus high-resolution HLA typing, performed mainly for acute leukemia or related myeloid neoplasms between 2016 and 2020, including 1,523 transplants with PTCy. HLA risk associations were evaluated by multivariable Cox regression models, with overall survival (OS) as primary end point.RESULTSOS was lower in HLA mismatched compared with fully matched transplants (hazard ratio [HR], 1.23 [99% CI, 1.14 to 1.33]; P < .001). This was driven by class I HLA-A, HLA-B, HLA-C (HR, 1.29 [99% CI, 1.19 to 1.41]; P < .001) but not class II HLA-DRB1 and HLA-DQB1 (HR, 1.07 [99% CI, 0.93 to 1.23]; P = .19). Class I antigen-level mismatches were associated with worse OS than allele-level mismatches (HR, 1.36 [99% CI, 1.24 to 1.49]; P < .001), as were class I graft-versus-host peptide-binding motif (PBM) mismatches compared with matches (HR, 1.42 [99% CI, 1.28 to 1.59]; P < .001). The use of PTCy improved GVHD, relapse-free survival compared with conventional prophylaxis in HLA-matched transplants (HR, 0.77 [0.66 to 0.9]; P < .001). HLA mismatching increased mortality in PTCy transplants (HR, 1.32 [1.04 to 1.68]; P = .003) similarly as in non-PTCy transplants (interaction P = .43).CONCLUSIONClass I but not class II HLA mismatches, especially at the antigen and PBM level, are associated with inferior survival in contemporary unrelated HCT. These effects are not significantly different between non-PTCy compared with PTCy transplants. Optimized HLA matching should still be considered in modern HCT.

Predicting prognostic factors in kidney transplantation using a machine learning approach to enhance outcome predictions: a retrospective cohort study.

Accurate forecasting of clinical outcomes after kidney transplantation is essential for improving patient care and increasing the success rates of transplants. Our study employs advanced machine learning (ML) algorithms to identify crucial prognostic indicators for kidney transplantation. By analyzing complex datasets with ML models, we aim to enhance prediction accuracy and provide valuable insights to support clinical decision-making. Analyzing data from 4077 KT patients (June 1990 - May 2015) at a single center, this research included 27 features encompassing recipient/donor traits and peri-transplant data. The dataset was divided into training (80%) and testing (20%) sets. Four ML models-eXtreme Gradient Boosting (XGBoost), Feedforward Neural Network, Logistic Regression, and Support Vector Machine-were trained on carefully selected features to predict the success of graft survival. Performance was assessed by precision, sensitivity, F1 score, Area Under the Receiver Operating Characteristic (AUROC), and Area Under the Precision-Recall Curve. XGBoost emerged as the best model, with an AUROC of 0.828, identifying key survival predictors like T-cell flow crossmatch positivity, creatinine levels two years post-transplant and human leukocyte antigen mismatch. The study also examined the prognostic importance of histological features identified by the Banff criteria for renal biopsy, emphasizing the significance of intimal arteritis, interstitial inflammation, and chronic glomerulopathy. The study developed ML models that pinpoint clinical factors crucial for KT graft survival, aiding clinicians in making informed post-transplant care decisions. Incorporating these findings with the Banff classification could improve renal pathology diagnosis and treatment, offering a data-driven approach to prioritizing pathology scores.

Diagnostic Methods in the Determination of Immunological Risk in a Patient before Kidney Transplantation

Abstract Kidney transplantation is the treatment of choice in patients with an end-stage kidney disease (ESKD). Before kidney transplantation, it is important to assess the patient's immunological risk, which has an impact on graft survival after kidney transplantation. Human leukocyte antigens (HLA), also known as major histocompatibility complex (MHC) are responsible for the rejection of genetically different tissue by recognizing and distinguishing foreign proteins from self-proteins. HLA-typing and anti-HLA antibody screening are crucial to determine the donor/recipient mismatching. Diagnostic methods used for anti-HLA antibody detection and immunological risk assessment are complement-dependent cytotoxicity (CDC), flow cytometry crossmatch (FCXM), bead-based assays (Luminex technology), calculated panel-reactive antibody (cPRA), and algorithm “predicted Indirectly Recognizable HLA Epitopes“ (PIRCHE). The aim of these diagnostic tests is to minimize HLA mismatch between the donor and the recipient and prevent an early graft failure by the presence of HLA donor-specific antibodies (DSA).

Orchestrating the Impact of KIR/HLA Interactions on Kidney Transplant.

This study examines the interplay between human leukocyte antigen (HLA) compatibility and killer-cell immunoglobulin-like receptor (KIR) genotypes in influencing kidney transplantation outcomes. Understanding these interactions is crucial for improving graft survival and minimizing rejection risks. We evaluated 84 kidney transplant recipients, dividing them into two groups based on post-transplant outcomes: there were 68 with stable graft function (SGF) and 16 who experienced chronic rejection (CR). Patients were selected based on specific inclusion criteria. HLA mismatches (Class I: HLA-A, -B; Class II: HLA-DR) and KIR genotypes were determined using standard genotyping techniques. Statistical analyses, including logistic regression, were performed to correlate these factors with transplant outcomes. Significant age differences were observed, with younger patients more likely to experience graft rejection, while no significant gender-based differences were noted. A significant correlation was found between Class II mismatches and increased rejection rates, highlighting the importance of HLA-DR compatibility. Further analysis revealed that certain inhibitory KIRs, such as KIR3DL1, were associated with favorable outcomes, suggesting a protective role against graft rejection. These findings were corroborated by evaluating serum creatinine levels over multiple years, serving as a biomarker for renal function post transplant. This study underscores the critical need for meticulous HLA matching and the consideration of KIR genotypes in pre-transplant evaluations to enhance graft survival and minimize rejection risks. Integrating these genetic factors into routine clinical assessments could significantly improve personalized transplant medicine strategies, ultimately enhancing patient outcomes. Further research is needed to explore the underlying mechanisms and validate these findings in larger, diverse populations.

Effect of donor and recipient HLA mismatched locus on the prognosis of childhood with leukemia after umbilical cord blood transplantation

Objective: The aim of the study was to investigate the impact of the sites of high-resolution human leukocyte antigen (HLA) mismatch on the prognosis of children with leukemia undergoing umbilical cord blood transplantation (UCBT). Methods: Clinical data and high-resolution HLA-A, HLA-B, HLA-C, HLA-DRB1 and HLA-DQB1 locus gene information were collected in the children who underwent the UCBT for the first time at Children's Hospital of Soochow University between January 2016 and June 2023. In each locus, according to whether the two genes were compatible, they were divided into a compatible group (two genes were perfectly matched) and a non-compatible group (one gene was not matched). In different loci, the differences in occurrence, recurrence, non-recurrence death and survival of acute graft versus host disease (aGVHD) were compared between the two groups. Multivariate Cox regression was employed to analyzed the influencing factors for overall survival rate, and Fine-Gray proportional hazards model was employed to analyze the influencing factors of other outcome events. Results: A total of 100 patients were enrolled (55 males and 45 females), whose age [M (Q1, Q3)] at the time of transplantation was 3.9 (2.0, 6.5) years. There were 55 cases in the HLA-A matched group and 45 cases in the mismatched group. The 5-year non-recurrence mortality (NRM) in the HLA-A matched group was lower than that in the mismatched group (P=0.024). The cumulative incidence of aGVHD within 100 days after transplantation in the HLA-A matched group was lower than that in the mismatched group (P=0.017), and there were no statistically significant differences in other outcome events between the groups (all P>0.05). There were 70 cases in the HLA-B matched group and 30 cases in the mismatched group. The 5-year cumulative recurrence rate in the HLA-B matched group was higher than that in the mismatched group (P=0.027). There were 79 cases in the HLA-C matched group and 21 cases in the mismatched group, and there were no statistically difference in the outcome events between the groups (P>0.05). There were 73 cases in HLA-DRB1 matched group and 27 cases in mismatched group. The 5-year overall survival rate in HLA-DRB1 matched group was higher than that in mismatched group (P=0.036), the 5-year cumulative recurrence rate in HLA-DRB1 matched group was higher than that in mismatched group (P=0.028), and the 5-year NRM in HLA-DRB1 matched group was lower than that in mismatched group (P=0.008). The cumulative incidence of aGVHD within 100 days after transplantation in the matched group was lower than that in the mismatched group (P=0.010), and and there were no statistically significant difference in other outcome events between the groups (P>0.05). There were 68 cases in HLA-DQB1 matched group and 32 cases in mismatched group. There was no statistical difference in outcome events between the two groups (all P>0.05). The risk of aGVHD in HLA-A mismatched group was higher than that in HLA-A matched group (HR=1.25, 95%CI: 1.12-1.38). The risk of recurrence in HLA-B mismatched group was lower than that in HLA-B matched group (HR=0.77, 95%CI: 0.63-0.91). Mismatched group at HLA-DRB1 compared with matched group at HLA-DRB1, had a higher risk of aGVHD (HR=1.37, 95%CI: 1.26-1.48), a higher risk of non-recurrence death (HR=1.39, 95%CI: 1.28-1.50), and a higher risk of death (HR=1.27, 95%CI: 1.18-1.36). No association was found between HLA-C and HLA-DQB1 locus with the risk of aGVHD, recurrence, non-recurrence death, and survival (all P>0.05). Conclusions: In UCBT, the risk of aGVHD in children with matching HLA-A sites of donor and recipient is lower than that in children with incompatible HLA-A sites. Compared with children with incompatible HLA-DRB1 sites, children with HLA-DRB1 matched sites has a lower risk of acute GVHD, a lower 5-year NRM, and a higher risk of death. The recurrence rate of children with matching HLA-B loci is higher than that of children without matching HLA-B loci.

Characterization of recurrent cytomegalovirus reactivations post allogenic stem cell transplantation in a population with high seropositivity

ObjectivesThis study aimed to characterize incidences of CMV reactivations within one year post-allo-SCT and identify risk factors for CMV second reactivation episode in population with high seropositivity where first CMV reactivation episode deemed to be high.MethodsThis retrospective cohort study analyzed data from 359 allo-SCT patients aged 14 and older admitted to a tertiary academic hospital. Data on demographic and clinical factors, CMV serostatus, conditioning regimens, graft-versus-host disease prophylaxis, engraftment time, and CMV reactivations were collected.ResultsFirst and second CMV reactivations occurred in 88.9% and 18.4% of post-allo-SCT patients respectively. Patients were stratified into two groups based on primary disease necessitating allo-SCT, patients with malignant (Group 1) and non-malignant (Group 2) hematological disease. Factors associated with the second reactivation included cord blood as a stem cell source, human leukocyte antigen mismatch, acute graft-versus-host disease, and hematological malignancies. Patients with non-malignant hematological disease displayed better outcomes, including a higher rate of spontaneous clearance of first CMV reactivation (70% versus 49.4%) and lower rates of second CMV reactivation (9.6% versus 31%) than those with malignant hematological disease. The one-year overall survival rate was 87.7% (95.5% in non-malignant hematological disease and 78.13% in malignant hematological disease).ConclusionOur findings are concordant with previous local study in regard to high rate of first CMV reactivation post-allo-SCT. It appears that patients with nonmalignant hematological disease had better outcomes, such as lower second CMV reactivation and higher survival rates compared to patients with malignant hematological disease. Further investigation is needed to identify other factors affecting recurrent CMV reactivations in allo-SCT in patients with malignant hematological disease.

Development of the DONOR prediction model on the risk of hypertensive complications in oocyte donation pregnancy: study protocol for a multicentre cohort study in the Netherlands

IntroductionOocyte donation (OD) pregnancy is accompanied by a high incidence of hypertensive complications, with serious consequences for mother and child. Optimal care management, involving early recognition, optimisation of suitable treatment...

Induction Therapies Determine the Distribution of Perforin and Granzyme B Transcripts in Kidney Transplant Recipients.

Peripheral blood mononuclear cells contain secretory granules with Perforin and Granzyme B for defense against pathogens. The objective of the present study was to compare the effects of immunosuppressive induction therapies on Perforin and Granzyme B transcripts in kidney transplant recipients. Transcripts were determined in 408 incident kidney transplant recipients eight days posttransplant using quantitative real-time PCR. Compared to 90 healthy subjects, the median Perforin transcripts were lower in kidney transplant recipients with blood-group ABO-incompatible donors (N = 52), compatible living donors (N = 130), and deceased donors (N = 226) (25.7%; IQR, 6.5% to 46.0%; 31.5%; IQR, 10.9% to 57.7%; and 35.6%; IQR, 20.6% to 60.2%; respectively; p = 0.015 by the Kruskal-Wallis test). Kidney transplant recipients who were treated with thymoglobulin (N = 64) had significantly lower Perforin as well as Granzyme B compared to all other induction therapies (N = 344) (each p < 0.001). Receiver operator characteristics analysis showed that both Perforin (area under curve, 0.919) and Granzyme B (area under curve, 0.915) indicated thyroglobulin-containing induction therapies. Regression analysis showed that both reduction in plasma creatinine and human leukocyte antigen mismatches were positively associated with elevated Perforin/Granzyme B transcript ratio posttransplant. We conclude clinical parameters and therapies affect Perforin and Granzyme B transcripts posttransplant.

Pancreas after kidney transplantation, is it the time to overcome the stigma?

Pancreas transplantation is the most effective treatment to improve quality of life and overcome complications in patients with end-stage renal disease and diabetes mellitus. One of the main approaches for concurrent renal disease and diabetes mellitus which has been underutilized during the past decade is a pancreas transplant after kidney transplantation. Our study aimed to quantify outcomes following pancreas after kidney transplants (PAKs) in the United States from 2001 to 2020 with an emphasis on graft and patient survival. A retrospective registry analysis was performed by accessing the OPTN/UNOS database for PAKs that were performed in the United States from January 2001 to April 2020. The study population was divided into two subgroups: patients receiving a pancreas transplant between 2001 and 2010 and those receiving a pancreas transplant between 2011 and 2020. The study examined a total number of 3706 PAK recipients; patients who received a PAK from January 2001 through December 2010 (n=2892) and those who received a PAK from January 2011 to April 2020 (n=814). The selection process of transplant recipients did not drastically change throughout the 2001-2010 and 2011-2020 periods. Length of stay at the hospital after the transplantation improved significantly in the 2011-2020 group relative to the 2001-2010 group (8.48 vs. 10.08days, mean, p<0.01). Additionally, more transplantation with 4-6 human leukocyte antigen mismatch occurred in the 2011-2020 group than in the 2001-2010 group (80.6% vs. 71.4%, p<0.01). The pancreas preservation time of 13.35h in the 2001-2010 group decreased significantly to 11.17h in the 2011-2020 group (p<0.001). The mean donor's amylase and lipase also decreased significantly in the 2011-2020 cohort. Significant graft survival improvement was observed in the 2011-2020 group compared to the 2001-2010 group after a long-term follow-up (p<0.001). The mean Calculated Pancreas Donor Risk Index was 1.08 for the 2001-2010 group and 0.99 for the 2011-2020 group with a significant difference (p<0.001). The beneficial results and improved outcomes observed in PAK patients demonstrate the effectiveness of the operation for individuals in need of a pancreas transplant. PAKs can prove to be a meaningful solution to overcome long waiting times, decrease the donor-recipient imbalance, expand the donor pool, and overcome the current underutilization in order to improve the short- and long-term quality of life in the groups of interest.

Better kidney allograft survival despite higher-risk donor and recipient characteristics between 1995 and 2014.

Advances in organ procurement, surgical techniques, immunosuppression regimens, and prophylactic antibiotic therapies have dramatically improved kidney transplant graft failure. It is unclear how these interventions have affected longer-term graft failure. It is hypothesized that graft failure has improved over the last 20 years. Data on all first kidney transplants from 1995 to 2014 were extracted from the Australia and New Zealand Dialysis and Transplant Registry with follow-up as of 31 December 2021. Primary exposure was transplant era, classified into 5-year intervals. Primary outcome was all-cause 5-year graft failure. Secondary outcomes included all-cause 10-year graft failure and cause-specific graft failure. Kaplan-Meier curves and multivariable Cox proportional hazards regression models were used to assess trends in all-cause graft failure. Fine-Gray subdistribution hazard models verified that changes in death rates were not biasing the Cox proportional hazards regression models. Cumulative incidence functions were used to assess temporal trends in cause-specific graft failure. Across 10871 kidney transplants, there was a shift towards transplanting more recipients aged >45 years old, with more comorbidities, longer dialysis vintage, body mass index >30kg/m2, and greater human leukocyte antigen mismatches. Donor age has increased but no clear shift in donor source was observed. Compared to 1995-99 (reference), the adjusted hazard ratio for 5-year graft failure was 0.78 (95% CI 0.67-0.91), 0.70 (95% CI 0.59-0.83), and 0.60 (95% CI 0.50-0.73) for 2000-04, 2005-09, and 2010-14, respectively. Ten-year graft failure similarly reduced from 0.83 (95% CI 0.74-0.93) for 2000-04 to 0.78 (95% CI 0.68-0.89) for 2010-14, compared to 1995-99. Medium- and long-term all-cause graft failure has improved steadily since 1995-99. Significant reductions in graft failure due to rejection and vascular causes were observed at 5 years, and due to rejection, vascular causes, death, and glomerular disease at 10 years.

O204: The influence of HLA matching on graft survival in lung transplant recipients is indication specific: An UNOS database analysis

Abstract Background and aims The importance of human leukocyte antigen (HLA) matching in lung transplantation remains unclear, and the influence of indication in HLA compatibility is unknown. This study aimed to determine the relationship between HLA matching and lung graft survival using a large-scale multi-center database (UNOS/OPTN) and multivariate logistic analysis. The secondary aim was to determine whether this relationship was influenced by transplant indication. Methods This retrospective observational analysis was performed using 26,312 lung transplant recipients from the UNOS/OPTN database. Patients were divided into two groups based on number of HLA mismatches (0-3 mismatches vs 4-6 mismatches) and then subcategorized by indication. Risk-adjusted outcomes were assessed by multivariate Cox analysis adjusting for donor and recipient characteristics and visualized using Kaplan-Meier survival curves. Results Increased HLA mismatch was associated with reduced allograft survival. Adjusted models found that the total HLA mismatch &amp;gt;3 increased the mortality hazard at 15 years (HR 1·05, p &amp;lt;0·05) and 20 years (HR 1·05, p&amp;lt;0·01). Pulmonary hypertension was the only indication with a statistically significant association between HLA mismatch and graft survival. Allografts in patients with 0-3 mismatches survived for 401 days longer than those with 4-6 mismatches (p=0·02). Conclusion Increased HLA mismatch reduced graft survival. When stratified by indication, this association was preserved exclusively in pulmonary hypertension. This finding is of potential clinical relevance to the management of this subsection of lung transplant recipients, impacting organ allocation, transplant surveillance and use of desensitisation and immunosuppression protocols.

O203: HLA Matching Between Donors and Recipients Improves Clinical Liver Transplant Graft Survival

Abstract Background and Aims The importance of human leukocyte antigen (HLA) matching between liver transplant donors and recipients on graft survival remains unclear and is not a clinical consideration in liver transplantation. This study aimed to determine the relationship between HLA matching and liver graft survival using a large-scale multi-center database (UNOS/OPTN) and multivariate logistic analysis. The secondary aim was to determine whether this relationship was influenced by transplant indication and donor status. Methods This retrospective observational analysis was performed using 22,702 liver transplant recipients from the UNOS/OPTN database. Patients were divided into two groups based on number of HLA mismatches (0-3 mismatches vs 4-6 mismatches), and then subcategorized by indication and donor status. Risk-adjusted outcomes were assessed by multivariate Cox analysis adjusting for donor and recipient characteristics and visualized using Kaplan-Meier survival curves. Results Allograft survival and risk of acute rejection were associated with degree of HLA mismatch. This association between HLA mismatch and graft survival persisted in individuals who underwent transplant for hepatitis, metabolic, drug toxicity and congenital indications. Donor status influenced the relationship between HLA mismatch and graft survival. Graft survival in DBD recipients was longer than in DCD in the 4-6 HLA mismatch group, whereas no significant difference was found in the 0-3 HLA mismatch group. Conclusion HLA mismatch significantly reduced graft survival and increased risk of acute rejection. This association was noted only in specific indications. These findings are of potential clinical relevance to organ allocation, allograft matching algorithms, immunosuppression protocols and transplant surveillance.

O236: The Impact of HLA Matching on Pancreas and Simultaneous Pancreas-Kidney (SPK) Transplantation Outcomes

Abstract Background This study evaluates the controversial impact of human leukocyte antigen (HLA) matching on pancreas graft survival and acute rejection. Methods Utilizing a large-scale multi-center database (UNOS/OPTN), we identified 8,005 pancreas and 7,850 simultaneous pancreas-kidney (SPK) transplant patients. Patients were classified into HLA matched (0-3 mismatches) and mismatched (4-6 mismatches) groups. Subsequently, utilizing multivariate Cox analysis, we evaluated risk-adjusted outcomes, represented through Kaplan-Meier survival curves. We also examined differences in graft survival and acute rejection based on transplant type (SPK or pancreas alone) within the same HLA mismatch group. Findings There were no significant differences in pancreas graft survival or acute rejection observed between HLA matched and mismatched groups for both pancreas and SPK transplant recipients (P &amp;gt; 0.05). However, among HLA mismatched patients, pancreas patients exhibited a 629-day lower pancreas graft survival than SPK patients (3774 vs. 4403 days, P &amp;lt; 0.001) and had a higher likelihood of experiencing acute rejection post-transplant (P &amp;lt; 0.001). Similarly, within the HLA matched groups, pancreas patients showed lower graft survival compared to SPK patients (3774 vs. 4403 days, P &amp;lt; 0.001); however, their acute rejection rates did not significantly differ (P &amp;gt; 0.05). Interpretation Although HLA matching was not associated with improved pancreas graft survival or a reduction in acute rejection, the results suggest a potential protective effect of the kidney in SPK transplants against the consequences of HLA mismatching. This underscores the clinical significance of considering the kidney component in donor-recipient matching for pancreas transplantation.