Transplantation

BACKGROUND: Machine learning (ML) models have been used to evaluate one-year post-transplant mortality in donor-recipient pairs. Previous modeling utilizing noninterpretable ML methods (deep neural networks [DNN] and XGBoost) showed modest gains in area under the receiver operating curve (AUC) beyond logistic regression, but suffered a significant drop in predictive AUC applied to the subsequent years' data and lacked statistical significance in validating previously identified risk factors. METHODS: Using balanced SRTR datasets, we evaluated non-interpretable models against interpretable ML models (adaptive logistic regression with interaction terms [aLR], Classification and Regression tree [CART], and conditional inference tree [CIT]) for one-year mortality, including comprehensive clinician-supervised data curation and inclusion of variables describing pre- and post-2018 listing status changes. Models were trained/tested using rolling-window validation across years and further analyzed with repeated ten-fold crossvalidation. Interaction terms were obtained via Adaptive Best-Subset Selection (ABESS). RESULTS: Predictive validation before the listing policy change in 2018 showed similar AUCs between DNN (0.579), aLR (0.642), CART (0.579), and CIT (0.584), with XGBoost having a higher (0.763) AUC. However, in the post-2018 predictive analysis, aLR outperformed XGBoost (AUC 0.613 vs. 0.586). The interpretable ML models confirm the significance of previously reported risk factors (recipient bilirubin and creatinine) and identify risk factors not previously reported (donor pH, potential recipient distance, and recipient transfusion), as well as clinically relevant interaction terms. CONCLUSIONS: Carefully developed interpretable ML models of one-year transplant mortality have similar predictive performance to black-box models, while identifying novel risk factors, and showing improved performance after recent listing policy changes. With appropriate validation and additional data, interpretable ML modeling may allow real-time data-driven donor selection.

Kidney transplant recipients experience a higher burden of several malignancies, yet the factors associated with prostate cancer presentation after transplantation remain poorly understood. Unlike malignancies strongly associated with impaired immune surveillance, prostate cancer has not consistently demonstrated an increased incidence after transplantation, suggesting that different mechanisms may underlie disease presentation. This study evaluated recipient, donor, transplant, immunologic, and immunosuppressive factors associated with prostate cancer phenotype after kidney transplantation. A retrospective cohort study was conducted using national transplant registry data from adult kidney transplant recipients diagnosed with post-transplant prostate cancer between 2015 and 2024. Cases were classified as de novo (no pre-transplant history of prostate cancer) or recurrent (documented pre-transplant history). Multivariable Firth penalized logistic regression was used to evaluate factors associated with recurrent phenotype. Prespecified sensitivity analyses included deceased donor restricted models, incorporation of donor organ quality variables, and adjustment for time from transplantation to cancer diagnosis. Exploratory machine learning analyses included elastic net logistic regression, random forest, and extreme gradient boosting. The cohort included 660 recipients, of whom 623 (94.4%) had de novo disease and 37 (5.6%) had recurrent disease. Recipient age was the only variable consistently associated with recurrent phenotype across primary and sensitivity analyses (adjusted odds ratio per year 1.11, 95% CI 1.05-1.17; p<0.001). Immunosuppressive regimen, donor characteristics, immunologic variables, and time from transplantation to cancer diagnosis were not independently associated with phenotype in the primary cohort. In deceased donor restricted analyses, alemtuzumab induction showed an exploratory association with recurrent phenotype, although estimates were imprecise. Machine learning models demonstrated modest discrimination and calibration and did not outperform penalized regression approaches. These findings suggest that, among kidney transplant recipients with prostate cancer, differences between recurrent and de novo presentation are more closely associated with recipient age and underlying disease characteristics than with transplant exposures or specific immunosuppressive regimens.

Unplanned readmissions after liver transplantation occur in over 30% of recipients, yet no validated prediction models exist, and prior observational studies suffer from immortal time bias. The optimal readmission window for outcome prediction and the feasibility of early risk stratification remain undefined. This study is a retrospective analysis of 922 adult liver transplant recipients (August 2018-August 2025) at a single center. Time-varying Cox regression evaluated 14-, 30-, and 90-day readmission windows as predictors of 1-year mortality, correcting for immortal time bias. Gradient-boosted machine learning models leveraging 528,400 laboratory measurements (28 analytes) predicted 90-day readmission using either complete hospitalization data or data restricted to postoperative day 7. Feature importance was quantified by gain, and clinical utility was assessed through risk stratification. Among 902 hospital survivors, 342 (37.9%) experienced an unplanned readmission within 90 days of initial discharge. Only the 90-day readmission window predicted 1-year mortality in time-varying analysis (HR 1.73, 95% CI 1.17-2.57, p=0.006). The model for readmission using complete data achieved AUC 0.614 (95% CI 0.576-0.652); the postoperative day 7 restricted model achieved AUC 0.615 (95% CI 0.577-0.652), with no meaningful performance difference. The tacrolimus coefficient of variation x peak creatinine interaction was the dominant predictor in both the complete model (17.3% importance, rank 1) and the day 7 restricted model (20.4% importance, rank 2). This interaction stratified patients into high-risk (tacrolimus CV >0.3 and creatinine >2.0 mg/dL; 49.8% readmission) versus low-risk (24.8% readmission) groups (risk ratio 2.01, p<0.001). These results identify a modifiable biological determinant of readmission and establish a framework for targeted interventions to reduce unplanned readmission and improve post-transplant outcomes.

Background Donation after circulatory death (DCD) is an increasingly accepted strategy to expand the adult heart donor pool, but its use in children remains limited and incompletely characterized. We compared national characteristics and post-transplant outcomes of pediatric DCD versus donation after brain death (DBD) heart transplantation. Methods We performed a retrospective cohort study of the Organ Procurement and Transplantation Network (OPTN) registry, including patients younger than 18 years who underwent primary isolated heart transplantation between January 1993 and March 2025. Recipients were stratified by donor type (DCD vs DBD). Continuous variables were compared with the Mann Whitney U test and categorical variables with the Fisher exact test. Survival was estimated by the Kaplan Meier method and compared using the log-rank test and Cox proportional hazards regression. Results Of 10,671 pediatric heart transplant recipients, 33 (approximately 0.3%) received DCD allografts. The first DCD transplant was recorded in 2004, with a marked increase in 2023 to 2024. Compared with DBD recipients, DCD recipients were more frequently infants (<1 year, 51.5% vs 28.4%) and more often had congenital heart disease (69.7% vs 47.6%; P=0.033); DCD donors were younger (median 0 vs 6 years; P=0.038) and more frequently died of anoxia (72.7% vs 37.0%; P<0.001). Donor and recipient left ventricular mass were lower in the DCD group (P<0.05), but predicted left ventricular mass matching was similar. DCD recipients had longer hospital stays (median 31.5 vs 19 days; P=0.023); rates of treated rejection, dialysis, stroke, and pacemaker implantation were comparable. Early survival did not differ (30-day, 90-day, and 1-year), and Kaplan Meier survival through 5 years was not significantly different (hazard ratio 1.17; 95% CI 0.49 to 2.81; log-rank P=0.73). More than 90% of DCD transplants were performed in four UNOS regions (11, 4, 5, and 8). Conclusions In this national analysis, pediatric DCD heart transplantation was uncommon but expanding rapidly, concentrated in a few regions, and used preferentially in infants and children with congenital heart disease. Early post-transplant outcomes were not significantly different from DBD, supporting cautious expansion of DCD as a means of enlarging the pediatric donor pool. The small number of DCD recipients and limited followup warrant confirmation in larger, longer-term studies. Keywords: pediatric heart transplantation; donation after circulatory death; donor pool; congenital heart disease; OPTN registry; organ allocation.

Background Graft versus host disease (GVHD) remains a major determinant of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (allo HSCT). Existing GVHD prediction models demonstrate modest discrimination and limited generalizability, and calibration drift across external populations is rarely characterized despite its essential role in the clinical interpretability of predicted probabilities. Objectives To develop and externally validate an explainable machine learning framework for predicting acute and chronic GVHD and associated overall survival in patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndromes (MDS) undergoing allo HSCT, and to systematically characterize calibration across heterogeneous external validation cohorts to inform deployment requirements. Study Design The model was developed on three publicly available registry-derived datasets (N = 2,509) and externally validated across six independent cohorts (N = 14,788) comprising adult and pediatric allo HSCT recipients, including a regional Middle Eastern cohort (UAE and Jordan). A standardized preprocessing pipeline harmonized heterogeneous datasets. Gradient boosting models (CatBoost) were used for binary GVHD prediction; exploratory overall survival analysis used a Cox proportional hazards model with predicted acute GVHD risk as a covariate. Discrimination (AUROC with bootstrap 95% CI), calibration (logistic recalibration intercept and slope with analytical 95% CI), and feature importance (SHapley Additive exPlanations, SHAP) were assessed in training out-of-fold and all external cohorts. Results In internal validation, AUROC was 0.63 (95% CI 0.61-0.65) for acute GVHD and 0.72 (95% CI 0.70-0.74) for chronic GVHD. External validation demonstrated AUROC ranges of 0.51-0.57 (acute) and 0.54-0.64 (chronic), with consistent performance across disease subgroups despite substantial heterogeneity in transplant practices and feature availability. In exploratory survival analysis, the acute-GVHD-informed Cox model achieved a training-cohort C-index of 0.679 (95% CI 0.658-0.697); external C-indices ranged from 0.47-0.53. Calibration analysis identified systematic external risk overestimation (negative calibration intercept in 10 of 11 evaluable external cohort-target combinations) with heterogeneous slope drift requiring cohort-specific recalibration. Key predictors included recipient age, graft source, conditioning intensity, GVHD prophylaxis, and HLA match ratio. Conclusions An explainable, externally validated GVHD prediction framework was developed using heterogeneous registry-derived datasets, with systematic characterization of calibration drift across multiple external cohorts, an analysis rarely reported in prior GVHD prediction literature. Predictive performance was modest for acute GVHD and moderate for chronic GVHD, constrained by missing immunobiological variables and incomplete HLA characterization. Per-cohort recalibration is required before clinical deployment, with prospective validation and benchmarking against established GVHD risk scores identified as priority next steps.

BACKGROUND: Increased left ventricular mass (LVM) at a single time point after heart transplantation (HT) predicts future adverse outcomes. However, dynamic changes in LVM could have better biological relevance and reflect adverse graft remodeling (AGR). The prognostic significance of such serial changes has not been studied. METHODS: Using an automated, electronic health record-based institutional data infrastructure, we studied 439 HT recipients with 5,563 LVM measurements. Separate Bayesian joint models estimated the simultaneous associations of current LVM and its instantaneous rate of change with graft dysfunction (GD) and mortality. A joint-model-derived remodeling score combining patient-specific deviations in LVM and slope was dichotomized to define AGR and non-AGR groups. A mixed-effects analysis of all clinical variables was performed to assess associations with LVM both between and within patients. An independent cohort of 35 patients with 79 surveillance-biopsy RNA-sequencing samples was used to examine early stress-responsive pathways associated with the remodeling score. RESULTS: LVM declined by approximately 7 g/year after transplantation, with regression attenuating over time. Sixty patients (13.7%) had GD, and 75 (17.1%) died. Higher LVM was associated with subsequent GD (hazard ratio [HR] per 10 g, 1.14; 95% credible interval [CrI], 1.02-1.28) and mortality (HR, 1.10; 95% CrI, 1.02-1.19). A more positive LVM slope was associated with GD (HR per 1 g/year, 1.21; 95% CrI, 1.06-1.42) and with cardiac allograft vasculopathy (CAV) grade 2 or 3 (HR, 1.39; 95% Crl, 1.02-1.96). LVM regressed more slowly in the AGR group (-5.8 vs -8.4 g/year), with higher GD (21.0% vs 6.4%) and mortality (24.2% vs 10.0%). Time-updated GD was associated with subsequent death (HR, 8.12; 95% Confidence Interval [CI], 4.67-14.14). Transcriptomic analysis showed enrichment of interferon-mediated signaling and vascular endothelial activation with higher remodeling scores, whereas lower scores were associated with mitochondrial and metabolic processes, ribosome biogenesis, and pathways related to tissue repair and stress responses. CONCLUSIONS: AGR is an easily accessible imaging biomarker that reflects the changes in the allograft in response to various stressors and predicts future adverse outcomes. Discovery of molecular mechanisms of AGR could lead to novel therapies to protect the allograft from chronic rejection.

Background: Adult congenital heart disease (ACHD) patients are prone to HLA-antibody formation from multiple surgeries, transfusions, and prosthetic surgical material. Females with ACHD may accrue additional, non-surgical alloantigen exposure. Whether sex modifies the impact of allosensitization on heart transplant (HT) access and outcomes in ACHD remains unknown. Methods: We retrospectively analyzed the OPTN/UNOS registry of adults with ACHD listed for first-time HT (2018-2025). Sensitization was defined by calculated panel reactive antibodies (cPRA) at listing. We tested the sex x sensitization (highly sensitized, cPRA >50%) interaction on transplant access using Fine-Gray competing-risks regression, treating transplantation as the event of interest and death or removal from the waitlist as competing events, and on post-transplant survival using multivariable Cox proportional-hazards regression, both adjusted for age at listing, mechanical support at listing, and the number of distinct prior cardiac surgery categories. Results: Among 856 candidates (38% female), females were more often highly sensitized than males (23% vs 14%; age-adjusted OR 1.81, 95% CI 1.26-2.61), even after adjusting for surgical burden. Sensitization reduced transplant access in females (84% to 71%; median wait 60 to 110 days, p < 0.001) but not males (79% vs 79%, median wait 88 vs 98 days). In adjusted Fine-Gray models, the subdistribution hazard for transplant was reduced in sensitized females (sHR 0.54, 95% CI 0.41-0.72) with no effect in males (sHR 0.96, 95% CI 0.73-1.26), and the sex x sensitization interaction was significant (interaction sHR 0.64, 95% CI 0.44-0.94, p = 0.02). Post-transplant mortality was numerically higher in sensitized than non-sensitized candidates in both sexes and the sex x sensitization interaction on 1-year mortality was not significant. The sex-asymmetric effect persisted and was more pronounced in the multiorgan candidates. Conclusions: Allosensitization is not a sex-neutral barrier to transplant in HT candidates with ACHD. Females are more sensitized and have reduced transplant access without differences in 1-year mortality. The female excess in sensitization is not accounted for by surgical burden, and the exposures responsible remain to be defined. These findings warrant a sex-aware listing strategy and further studies.

Viral infections remain a cause of substantial morbidity and mortality in allogeneic hematopoietic cell transplant (aHCT) recipients. While antiviral prophylaxis has dramatically reduced the risk of herpes simplex virus (HSV) disease, the relationship between HSV serostatus and major post-transplant complications in the context of HSV prophylaxis is unknown. We evaluated the association between HSV serostatus and survival among adults who received a first aHCT at the Fred Hutchinson Cancer Center between 2002 and 2022. Patients were screened for HSV-1 and HSV-2 by Western blot (WB) prior to transplant. We fit Cox proportional hazards models for mortality up to one year post-transplant, comparing HSV seropositive to seronegative patients. Models were adjusted for age, sex, cytomegalovirus (CMV) serostatus, conditioning regimen, disease risk, graft type and HLA matching, year of transplant and acute graft-versus host disease. A total of 4,016 aHCT recipients were included in this analysis. The cumulative all-cause 1-year mortality was 29.8%. For HSV-1, the adjusted hazard ratio (aHR) for all-cause mortality comparing seropositive to seronegative individuals was 1.20 (95% CI: 1.06-1.36). The aHRs for relapse, non-relapse mortality (NRM) and relapse-related mortality (RRM) were 1.46 (1.24-1.71), 1.04 (0.89-1.21), and 1.75 (1.40-2.19), respectively. For HSV-2, the aHRs for all-cause mortality, relapse, NRM, and RRM were 1.03 (0.93-1.14), 1.16 (1.03-1.31), 0.99 (0.87-1.13), and 1.13 (0.97-1.33), respectively. Despite universal antiviral prophylaxis, HSV-1 seropositivity was associated with higher mortality in the year after transplant, driven by RRM. Further studies are needed to confirm the association and understand the potential mechanisms underlying this relationship.

Haplo-identical hematopoietic cell transplantation (haploHCT) is an integral treatment paradigm for patients with leukemia. While overall survival (OS) post-haploHCT has steadily improved, relapse-free survival (RFS) remains relatively stagnant. Upon the discovery of killer immunoglobulin-like receptors (KIRs) on natural killer (NK) cells and their cognate human leukocyte antigen (HLA) ligands, algorithms have been developed to enhance graft versus leukemia effects. However, these algorithms fail to yield consistent predictions in patient outcomes. We utilized a combination of in silico protein folding and interactions to determine KIR:HLA reactivity in conjunction with in vitro acoustic force microscopy to measure cell avidity (CA) as a readout for KIR signal strength. CA was determined using monoallelic HLA expressing K562 cell lines, monoallelic KIR Jurkat cells, and peripheral blood NK cells. We extended the CA results and performed standard cytotoxicity assays as well. We discovered that HLA-B*35 interacts with KIR2DS4. We applied the newly discovered interaction to predict outcomes for HCT patients. Stratifying patients based on their HLA-B*35 positivity and donor KIR2DS4 status, we delineated a correlation to survival (P=0.061) when donors only had full-length KIR2DS4. Patients who received a haploHCT and NK cell addback from donors with only full-length KIR2DS4 had a significantly improved RFS (P=0.001) and OS (P=0.016) compared to truncated (KIR1D) and full-length KIR2DS4 donors. This was independently validated in a diverse 10/10 HLA matched European cohort with RFS (P=0.0255) and OS (P=0.0388). Thus, the identified novel KIR2DS4:HLA-B*35 interaction axis predicts patient survival, in both haplo-identical and fully matched, HCT and highlights that our current understanding of the KIR:HLA interactome is incomplete and requires remapping for enhanced therapeutic applications.

Using toxin receptor-mediated cell ablation, a diabetes mouse model was generated that supports engraftment of human hematopoietic stem/progenitor cells (HSPCs) without the need for irradiation. The NBSGW immunodeficient strain was crossed with the NSG RIP-DTR which carries the diphtheria toxin receptor (hDTR) under the control of the rat insulin promoter to generate the NBSGW RIP-DTR mouse. This model enables controlled {beta}-cell ablation, robust human immune system reconstitution without myeloablative conditioning, and evaluation of human immune-mediated graft rejection within a single platform. NBSGW RIP-DTR mice exhibited reproducible and titratable diabetes induction, supported durable human islet engraftment and glycemic correction, and retained efficient human hematopoietic reconstitution comparable to the parental NBSGW strain. In humanized mice, diphtheria toxin-mediated diabetes induction was well tolerated and enabled assessment of human immune responses to allogeneic islet grafts. Collectively, these findings establish the NBSGW RIP-DTR mouse as an integrated and clinically relevant platform for studying {beta}-cell replacement therapies and human immune-mediated graft rejection. Article HighlightsO_LICurrent preclinical models do not simultaneously support controlled diabetes induction, human islet transplantation, and durable human immune reconstitution without irradiation. C_LIO_LIThis study asked whether the NBSGW RIP-DTR mouse could integrate diphtheria toxin-mediated {beta}-cell ablation with irradiation-free humanization in a single platform. C_LIO_LINBSGW RIP-DTR mice demonstrated reproducible diabetes induction, supported functional human islet engraftment, and retained robust human hematopoietic reconstitution comparable to parental strains. C_LIO_LIThese findings establish the NBSGW RIP-DTR model as a clinically relevant platform for studying {beta}-cell replacement and human immune response to islet allografts, xenografts and stem cell-derived islets. C_LI

Purpose: Adults with high- or very high-risk acute leukemia (AL) or myelodysplastic syndrome (MDS) face substantial relapse risk after allogeneic hematopoietic stem-cell transplantation. We evaluated single-unit cord blood (CB) transplantation after ex vivo expansion with UM171 in this population. Patients and Methods: Two prospective, single-arm phase II trials at four centers enrolled 64 adults with high- or very high-risk AL or MDS; 60 received a UM171-expanded CB transplant and comprised the analysis population. CB units were preferentially selected at a 5/8 HLA match to maximize the graft versus leukemia effect. Patients received intermediate- or high-intensity conditioning with tacrolimus/mycophenolate mofetil graft-versus-host-disease (GVHD) prophylaxis. Endpoints included safety, feasibility, non-relapse mortality (NRM), relapse-free survival (RFS), overall survival (OS), GVHD, GVHD-free relapse-free survival (GRFS), chronic GVHD-free relapse free survival (CRFS). Results: Thirty-two percent of patients had undergone previous transplantation, 17% of patients with AL were not in remission and 24% of those with AML/MDS had TP53 mutations. Of 62 patients who remained eligible for transplantation, 60 had a graft successfully manufactured and infused. Median times to neutrophil and platelet engraftment were 17 and 38 days, respectively. NRM was 5.1% at day 100 and 15.2% at 1 year. Two-year cumulative incidence of relapse was 22.3%. Two-year OS and RFS were 63.9% and 60.4%, respectively. Grade III-IV acute GVHD incidence was 20.3% at 1 year and moderate-to-severe chronic GVHD incidence was 6.8% at 2 years. Conclusion: UM171-expanded CB transplantation was feasible and provided prompt engraftment, durable disease control, and infrequent clinically significant chronic GVHD in adults with high- and very high-risk AL/MDS. Comparative studies are warranted to define its role relative to contemporary donor platforms.

The emergence of donor-specific antibodies (DSA) against HLA-DQ reduces graft survival and limits future transplant options. Current practice predicts DSA development from HLA antigen mismatches or unique eplet counts (HLAMatchmaker), but predictive accuracy remains limited. Improving the prediction accuracy is crucial for solid organ transplants. We analysed a retrospective cohort of 240 kidney transplants (480 donor-DQ samples) in which the donor DQ allele targeted by each post-transplant DSA was identified. We compared the predictive accuracy of unique eplets (HLAMatchmaker), total eplets, amino acid mismatches, PAM genetic distance, and electrostatic mismatch score (EMS), individually and in combination. DSA emerge through the response of two donor and two patient DQ heterodimers. We evaluate the appropriate combination method of patient and donor alleles. Total eplet or amino acid mismatch counts outperformed unique eplets as used in HLAMatchmaker (AUC 0.79 vs. 0.73). Combining eplets with PAM and EMS distances in an XGBoost classifier achieved AUC 0.84, with a hazard ratio above 7. The most informative features were PAM distance and a subset of eplets distributed across the HLA-DQ alpha and beta chains. When extending prediction from a single donor DQ allele to the donor as a whole, the maximum of the two per-allele scores outperformed a probabilistic combination. The unique-eplet approach is suboptimal for predicting anti-DQ DSA in this cohort; combining total eplets with genetic and biochemical distance metrics yields substantially better prediction, essential for the reduction of DSA emergence. External validation in independent cohorts is the necessary next step.

Antibody-mediated rejection (AMR) is a major cause of kidney allograft failure, with donor HLA-specific antibodies (DSA) recognized as primary drivers of AMR pathology. However, a significant proportion of AMR diagnoses lack detectable DSA, thus implicating DSA-independent mechanisms. In support, we previously reported on the accumulation of autoreactive B cells in rejecting renal biopsies, which raised the possibility that autoreactive IgG produced within the allograft contributes to graft pathology. In this study, we used mouse models to show that rejecting kidney allografts preferentially promoted a breach in autoreactive B cell tolerance, leading to the local production of autoreactive antibodies. Notably, autoreactive IgG responses were uncoupled from DSA production, indicative of distinct regulation. Organoid cultures confirmed that autoantibody production was observed in the rejecting kidney, whereas DSAs were produced in both the lymph node and graft. Intrarenal B cells expressing Nur77 were enriched for autoreactivity, consistent with in situ antigen recognition. Finally, autoreactive antibodies are pathogenic, since inhibiting autoantibody production with transient anti-IL-15 and CTLA-4Ig led to preserved kidney allografts. These unique features of in situ autoantibody responses may be relevant to diverse diseases with chronic tissue inflammation beyond transplantation.

The human kidney contains highly specialized cell populations. Despite numerous single-cell and single-nucleus transcriptomics studies, differences in cohorts, technologies, analytical pipelines, and annotation frameworks have limited the ability to define consensus kidney cell states, identify disease-associated populations and interpret kidney disease genetic susceptibility. Here, we assembled 18 human kidney single-cell and single-nucleus RNA-sequencing datasets spanning 232 donors and five major disease contexts into a uniformly processed and computationally integrated Human Kidney Cell Atlas (HKCA), comprising over one million high-quality cells (816,895) and nuclei (215,308). The HKCA resolves 63 cell types and 120 harmonized cell states, including rare epithelial and stromal populations associated with kidney diseases. Integration with spatial transcriptomics, intercellular communication networks, and human genetic association data further defined the anatomical context and disease relevance of these populations. The HKCA also provides a framework for automated annotation of independent kidney human and mouse datasets. Together, the HKCA establishes a comprehensive reference for human kidney biology, enabling disease interpretation and genetic risk localization at cellular resolution.

Background: Reactivation of herpes simplex viruses (HSV) can occur in the early post-allogeneic hematopoietic cell transplant (aHCT) period despite antiviral prophylaxis. Few studies have assessed HSV infection in the modern era, in which acyclovir/valacyclovir is recommended for up to 1 year post aHCT. We evaluated the incidence and management of breakthrough HSV during the first 100 days post-aHCT over two decades. Methods: Patients who received their first aHCT at Fred Hutchinson Cancer Center between 2002-2022 were reviewed for breakthrough HSV infection within the first 100 days on prophylaxis (acyclovir 800 mg or valacyclovir 500 mg twice daily). Cases were identified via culture, polymerase chain reaction, and/or direct fluorescent antibody testing; clinical records were reviewed for symptoms, outcomes, and prophylaxis/treatment regimens. Refractory/resistant (R/R) infections were defined according to consensus guidelines. Results: We reviewed data from 4,357 aHCT recipients aged [&ge;]18 years, among whom 3,749 (86%) were HSV seropositive and 23 developed breakthrough HSV infection (observed probability = 0.6%). Among those who had an infection, the median time from transplant to first positive test was 46 days (IQR: 24.0-69.5). Oral and genital mucosa were the most common sites of infection. In total, 11 of 23 (47.8%) patients with breakthrough HSV developed R/R infection. Conclusions: Breakthrough HSV infections are rare in the first 100 days after aHCT among patients receiving antiviral prophylaxis. Refractory/resistant infections were uncommon but represented almost half of breakthrough cases. Our findings highlight the sustained effectiveness of universal prophylaxis in the early post-transplant period.

Background Cardiac magnetic resonance imaging (CMR) T1 and T2 mapping accurately detect acute heart transplant rejection, but the diagnostic value of CMR-derived strain imaging remains uncertain, particularly for right ventricular strain. Data incorporating donor-derived cell-free DNA (dd-cfDNA) into a composite reference standard are limited. We evaluated the diagnostic accuracy of CMR-derived left and right ventricular strain and ejection fraction for detecting acute rejection in pediatric and adult heart transplant recipients. Methods Blinded analysis of 1.5T CMR studies was performed in pediatric and adult heart transplant recipients 1-24 months post-transplant, as well as during five additional episodes of acute rejection occurring 3-14 years post-transplant. Left and right ventricular strain and ejection fraction were quantified using semi-automated post-processing. Acute rejection was defined using a composite reference standard comprising endomyocardial biopsy (EMB), clinical assessment, and dd-cfDNA. Diagnostic performance was assessed using cut-off values derived from receiver operator characteristic (ROC) analysis. Results Among 214 CMR studies in 58 patients, 13 cases of acute rejection were identified. Diagnostic performance for detecting acute rejection was moderate for pediatric right ventricular longitudinal strain (AUC 0.782, 95% CI 0.565-0.999), whereas all other cardiac functional parameters demonstrated limited discrimination in both pediatric and adult patients (AUC 0.536-0.739). Models based on individual rejection indicators (EMB, clinical assessment, and dd-cfDNA) also showed poor diagnostic accuracy. Conclusion CMR-derived left and right ventricular strain and ejection fraction demonstrated limited ability to independently detect acute rejection. However, strain abnormalities, particularly RVLS in pediatric patients, may reflect downstream functional effects in more advanced rejection and may complement T1 and T2 mapping in assessing rejection severity.

Background: The efficacy and safety of avacopan in ANCA-associated vasculitis (AAV) has been established in randomized trials of of avacopan as a glucocorticoid (GC) sparing therapy. However, real world evidence (RWE) has an important role in confirming effectiveness and evaluating safety in more generalizable settings. This study aimed to synthesize RWE on the effectiveness and safety of avacopan in adults with AAV. Methods: A systematic literature review and meta analysis of non interventional real world studies was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Eligible studies included adults with AAV treated with avacopan in routine clinical practice. Pooled estimates of effectiveness and safety outcomes were calculated using random effects meta-analyses. Primary outcomes included remission at 6 and 12 months and sustained remission at 12 months. Secondary outcomes included relapse, GC use and dosing, hepatotoxicity, infections, and treatment discontinuation. Exploratory outcomes included changes in estimated glomerular filtration rate (eGFR) and dialysis related endpoints. Results: A total of 71 studies were included and contributed to quantitative analyses. Pooled remission for patients on avacopan was 87% (95% CI: 75%-94%) at 6 months and 93% (95% CI: 86%-97%) at 12 months, and sustained remission was 86% (95% CI: 74%-93%) at 12 months. Relapse at 12 months was low (7%; 95% CI: 4%-11%). GC use was 36% at both 6 and 12 months. Improvements in eGFR were observed at 6 months (18 mL/min/1.73 m2) and 12 months (18 mL/min/1.73 m2), and dialysis liberation was 66% in a limited subset. Among avacopan patients, 11% experienced any hepatotoxicity, including 7% with serious (defined as directly reported or requiring hospitalization) hepatotoxicity, while 7% experienced serious (defined as directly reported or requiring hospitalization) infection. Conclusions: In real world clinical practice, avacopan is associated with high remission rates, low relapse rates, and a consistent GC sparing effect, with effectiveness comparable to standard of care regimens. Findings support its clinical use with appropriate safety monitoring; however, the observed heterogeneity in hepatotoxicity and the limited comparative effectiveness evidence highlight areas requiring further investigation.

Pre-infusion cerebrospinal fluid (CSF) proteomics may enable risk stratification for immune effector cell-associated neurotoxicity syndrome (ICANS) after chimeric antigen receptor T-cell therapy, but disease-specific baseline variation may influence biomarker interpretation. We compared pre-infusion CSF proteomic profiles from 28 patients with diffuse large B-cell lymphoma (DLBCL) and 9 with multiple myeloma (MM). Although principal component analysis showed substantial overlap, orthoPLS-DA identified significant disease-associated discrimination supported by permutation testing. Proteins contributing to this separation were enriched for plasma cell-related, extracellular, and metabolic signatures. ICANS occurred in 7 of 28 DLBCL patients but in none of the 9 MM patients. MM cases aligned with the ICANS-negative group in binary analysis while remaining distinct from both DLBCL subgroups in three-group analysis. These findings indicate that pre-infusion CSF proteomics captures disease-specific molecular structure that should be considered when developing and interpreting biomarkers of CAR-T-associated neurotoxicity.

Gastric insulin-secreting organoids (GINS) represent a promising source of {beta}-like cells for type 1 diabetes (T1D) therapy. In same-donor comparisons with induced pluripotent stem cell-derived islets (iPSC-islets), GINS displayed robust glucose responsiveness and reduced expression of key T1D autoantigens. Importantly, GINS exhibited decreased susceptibility to cytotoxicity mediated by engineered HLA-matched preproinsulin-specific effector T cells (Avatar Teffs) and a distinct transcriptional profile enriched for immune-modulatory and stress-adaptive gene programs. To enhance immune evasion, we engineered gastric stem cells to overexpress Programmed Death Ligand 1 (PD-L1) in an inducible manner. PD-L1+ GINS maintained normal functionality, while exhibiting improved survival under allogeneic Avatar Teff challenge in a MHC class I-independent fashion. We evaluated PD-L1-mediated protection against autologous Avatar Teff attack using an endothelialized microfluidic platform recapitulating physiologic immune interactions. T cells show reduced infiltration into PD-L1 GINS, resulting in significantly higher organoid viability compared to control GINS. Together, these findings identify GINS as a functional and engineerable {beta}-like cell platform with intrinsic hypoimmunogenic features, and support PD-L1 engineering as a strategy to enhance immune protection for both allogeneic and autologous transplantation in T1D.

BACKGROUND: The transport and storage conditions of thawed plasma are not strictly regulated by the FDA and applying red blood cell transport standard of 1-10 degrees Celcius to recently thawed plasma often results in high discard rates. This study evaluated the extended 120-hour (5-day) coagulation factor stability and sterility of thawed plasma frozen within 24 hours (PF24) following a 6-hour transport cooler simulation. STUDY DESIGN AND METHODS: Fourteen PF24 units (8 group O, 6 group B) were thawed at 30-37 degrees Celcius and assigned as control (n=7, direct 1-6 degrees Celcius refrigeration) or experiment (n=7) units. Experiment units were held at room temperature for 30 minutes, stored in validated transport coolers for 6 hours, and then transferred to 1-6 degrees Celcius refrigeration. Measurements of temperature, prothrombin time (PT), Factor V (FV) activity, and Factor VIII (FVIII) activity were conducted at 0-, 6-, 24-, and 120-hour post-thaw. Sterility testing was performed at 0-hour and 120-hour using automated aerobic and anaerobic blood cultures. RESULTS: No statistically significant differences were observed between control and experiment units at 120-hour for mean PT (15.09 vs. 15.16 seconds, p = .44), FV activity (81.14 vs. 74.57%, p = .23), or FVIII activity (61.86 vs. 53.00%, p = .22). Delta analysis (120h-0h) confirmed equivalent factor decay rates between groups. All bacterial cultures showed no growth at 120-hour. CONCLUSION: A 6-hour cooler time of thawed PF24 does not accelerate coagulation factor degradation or compromise sterility over an extended 5-day shelf life. These findings validate flexible inventory return policies, allowing blood banks to reduce product waste.