Transplantation

Background: Antibody-mediated rejection (AMR) after heart transplant (HT) is associated with increased risk of mortality and graft loss. Contemporary studies delineating AMR presentation, management, and response to treatment are lacking, especially for patients who do not have typical immunohistological evidence of rejection (biopsy-negative, BN-AMR). In this study, we sought to describe the prevalence and clinical course of BN-AMR compared to biopsy-positive (BP-AMR) patients in a multicenter HT population. Methods: We conducted a retrospective analysis of all adult HT recipients at 2 academic medical centers. AMR was further divided into BP-AMR and BN-AMR, depending on their endomyocardial biopsy findings. The primary outcome was death and secondary outcome was a composite of death, retransplant, and new International Society of Heart and Lung Transplant grade 2 or 3 coronary artery vasculopathy. Results: A total of 742 patients were included in this study. We found that AMR occurred in 10% of HT recipients and was associated with worse overall survival compared to those with only cellular rejection or no rejection. BN-AMR accounted for 33% of AMR cases. Compared to BP-AMR, BN-AMR was diagnosed later, less aggressively treated, and associated with high morbidity and mortality. The long-term outcomes between BP-AMR and BN-AMR were similarly poor, with 5-year mortality approaching 50% after diagnosis. Conclusions: AMR after HT is associated with poor clinical outcomes and BN-AMR is common. Future studies should focus on incorporating novel tools for earlier detection of AMR and investigating AMR sub-phenotypes and optimal modes of treatment.

Heart transplantation (HT) is the durable therapy for end-stage heart failure (HF). Despite advances in immunosuppression, cardiac allograft vasculopathy (CAV) remains a leading cause of late graft failure and mortality in the modern era. Prior studies have established donor age and immunological phenomena, such as acute cellular rejection (ACR), antibody-mediated rejection (AMR), and development of donor-specific antibodies (DSAs) as risk factors for CAV. However, it remains unclear whether acute rejection (AR) that occurs early post-HT, when individuals experience the highest degree of immunosuppression, reflects higher baseline immune activity and confers a higher risk of future CAV compared to later AR, when immunosuppression is minimized. We therefore examined whether AR occurring during pre-specified early and intermediate intervals compared to those who did not experience AR in the first post-HT year was associated with future CAV among recipients without CAV at 1 year.

Background: Modern therapy for childhood and adolescent leukemia requires accurate risk classification of genomic subtype. Although short-read next-generation sequencing (NGS)- based approaches provide comprehensive clinical diagnostics in limited, highly resourced settings, they remain expensive, slow, and inaccessible to most children worldwide. Transformative approaches are needed to improve diagnostic classification for leukemia globally. Methods: We simultaneously continued to develop an analytical pipeline NASVar (Nanopore variant calling for adaptive sampling), and conducted a multicenter, type-two hybrid clinical validation study of an Oxford Nanopore Technologies (ONT) adaptive-sampling whole-genome sequencing (asWGS) assay across hospitals with varying diagnostic resources. In preparation for implementation, a global panel developed a leukemia-based standardized gene set and consensus laboratory-developed test (LDT) validation guidelines. Measures of assay effectiveness compared to both conventional and orthogonal NGS methods, where available, were simultaneously collected with data to measure the implementation outcomes of feasibility, fidelity, appropriateness, and cost. Results: All four centers successfully completed the LDT validation, with minimal adaptations required for regulatory compliance. A total of 457 specimens were sequenced (331 B-ALL, 83 AML, 43 T-ALL). For the 210 B-ALL cases with locally resolved genomic subtypes defined by DNA alterations, asWGS was 100% concordant (210/210). Cases locally defined as B-other were resolved via asWGS with disease-defining DNA alterations in 47% (49/105) of cases. An additional 41% (43/105) of locally defined B-other cases were classified by incorporation of DNA methylation, and all 16 B-ALL patient-derived xenograft controls were correct, for a total of 96% (318/331) of all B-ALL cases in the cohort resolved with single assay asWGS. For AML, 97% (56/58) of cases with locally resolved genomic subtypes were identified by automated asWGS analysis, while an additional two cases were identified after targeted manual review. At Indus Hospital in Pakistan, the B-ALL and AML diagnostic genomic subtype yield increased from 28% with local standard of care diagnostic testing, to 84% with asWGS. The cost of reagents and consumables in the United States, assuming pooled three-plexing, was $343/sample. Based on the combined hybrid validation results, all centers are independently preparing for clinical return of results. Conclusions: ONT asWGS was successfully validated as a clinical assay in four diverse hospital settings. As a single, multi-omic platform that delivers value across the continuum of high-resource to resource-limited contexts, the approach offers a disruptive solution to address the global equity gap in cancer diagnostics.

Tacrolimus is an immunosuppressant drug commonly used in transplantation. Although multiple studies have demonstrated that polymorphisms in the CYP3A5 gene impact the metabolism of tacrolimus, routine pre-transplant testing for these markers is still not broadly implemented. TacroType - a new laboratory developed test implemented by One Lambda Laboratories - utilizes a qPCR-based six-plex assay for CYP3A5 genotyping and detects the three most common genetic variants (*3, *6 and *7) associated with loss of CYP3A5 protein function and reduced tacrolimus metabolism. TacroType was optimized to address known sources of protocol, technical or sample variability to achieve accurate and reproduceable genotyping results. An analytical performance study was completed following CLSI guidelines. Accuracy was confirmed for each possible CYP3A5 genotype involving 6 target alleles using 32 well-characterized reference samples. TacroType exhibited accurate performance within a broad range of DNA concentrations and quality. Precision studies indicated consistent genotyping results across 4 operators, 2 instrument types and 5 lots of reagents. Accurate and reproducible assay performance was demonstrated using whole blood from 100 and buccal swabs from 70 donors. The analytical performance of TacroType was evaluated in 4014 total qPCR reactions, with a report rate of 99.8% and genotyping accuracy of 100% (95% confidence interval of 99.9%).

Background: Multiple myeloma (MM) remains incurable despite therapeutic advances, reflecting limited understanding of the molecular mechanisms underlying disease initiation and progression. MM develops through asymptomatic precursor stages, monoclonal gammopathy of undetermined significance (MGUS) and smouldering multiple myeloma (SMM). This study aimed to investigate protein changes associated with disease progression and, through a further integrative approach, to highlight molecular changes of potential predictive and/or therapeutic value. Methods: We performed a comparative proteomic analysis of 94 bone marrow-derived CD138+-selected plasma cell samples (29 MGUS, 20 SMM, and 45 MM) using LC-MS/MS. Differential protein abundance was assessed using pairwise Mann-Whitney U tests between groups, with Benjamini-Hochberg correction. Pathway enrichment, protein-protein interaction, and co-expression network analyses were also conducted. Selected proteins were further evaluated using public transcriptomic datasets and experimentally validated in independent samples by flow cytometry and enzyme-linked immunosorbent assay (ELISA). Results: Following data processing, proteomic analysis identified 6,203 proteins. Pairwise comparisons revealed significant proteomic differences across disease stages, with 370 differentially abundant proteins exhibiting monotonic changes during disease progression. Pathway analysis showed that monotonically upregulated proteins were mainly associated with gene expression and cell proliferation, whereas downregulated proteins were linked to immune-related processes. Further co-expression network analysis, combined with criteria including detection frequency, biological relevance, and translational potential, highlighted a group of prioritised proteins. Representative examples include nucleolin (NCL) and U3 small nucleolar ribonucleoprotein IMP3 (IMP3), involved in nucleolar organisation, ribosome biogenesis and rRNA processing, as well as the immune-associated lactotransferrin (LTF) and serine protease cathepsin G (CTSG). Transcriptomic support and independent experimental validation by flow cytometry and ELISA confirmed the relevance of selected candidates. Conclusions: Taken together, our findings highlight coordinated changes in immune regulation, RNA processing and ribosome biogenesis during MM progression and identify candidate proteins and their networks, including the emerging pharmacologically tractable target NCL and the underexplored IMP3 of potential therapeutic relevance, opening new avenues for further investigation.

Background and hypothesis: Sodium-glucose cotransporter-2 inhibitors (SGLT2-inhibitors) slow chronic kidney disease progression, but evidence in non-diabetic kidney transplant recipients is limited. We evaluated associations between SGLT2-inhibitor use and major adverse kidney events (MAKE), major adverse cardiovascular events (MACE), and all-cause mortality. Methods: In this retrospective cohort study using the TriNetX federated research network, adult non-diabetic kidney transplant recipients transplanted between January 2015 and January 2022 were identified. SGLT2-inhibitor users initiating therapy [≥]1000 days post-transplant were compared with non-users after 1:1 propensity score matching. The primary outcome was MAKE, defined as dialysis initiation or death. Secondary outcomes included all-cause mortality and MACE. Results: Propensity score matching yielded 867 pairs of SGLT2-inhibitor users and non-users. SGLT2-inhibitor use was associated with lower risks of MAKE (adjusted hazard ratio [aHR] 0.64, 95% CI 0.45-0.91) and all-cause mortality (aHR 0.55, 95% CI 0.36-0.85). No significant association was observed for MACE (aHR 0.86, 95% CI 0.64-1.17). No increased risk of urinary tract infections was observed among SGLT2-inhibitor users. Conclusion: SGLT2-inhibitor use was associated with lower risks of MAKE and all-cause mortality in non-diabetic kidney transplant recipients.

Non-HLA donor-recipient (D-R) genetic mismatches contribute to kidney allograft injury and long-term graft loss, but their clinical use is limited by the unavailability of donor DNA after transplantation. We tested whether non-invasively obtained, recipient-derived samples could be used to infer donor genotype and D-R mismatches. Genomic DNA (g-DNA) of 11 unselected kidney transplant recipients and donors underwent whole-exome sequencing (100x). Additional customized probes were added for intronic coverage (300x) of 55 targeted non-HLA genes of reported clinical relevance. Variants identified from sequencing results were compared with plasma cell-free DNA (cfDNA), urine cell-pellet DNA (U-DNA) obtained from the same recipients. Genome-wide-, exonic-, or non-synonymous exonic- mismatches in transmembrane or secreted proteins, and mismatches within target genes were benchmarked using donor g-DNA to generate mismatch scores for each D-R pair. Within each of these genomic scales of mismatch, U-DNA identified D-R mismatches significantly better than the corresponding cfDNA (P<0.001 for each comparison). U-DNA also identified gene-level mismatches in the LIMS1 gene, and correctly inferred established donor-origin risk alleles, including SHROOM3 and APOL1. Our findings demonstrate proof-of-concept that U-DNA in tandem with recipient genome, can non-invasively infer relevant non-HLA loci/mismatches circumventing the need for the donor genomic DNA.

Introduction: To investigate the epidemiological characteristics of chronic kidney diseases (CKD) in China in 2021 and its trends between 1990 and 2021, in the context of significant population growth and lifestyle changes over the past 30 years that have likely influenced the CKD spectrum. Methods: Data on CKD prevalence, mortality, disability-adjusted life-years (DALY), and risk factors were obtained from the Global Burden of Disease Study 2021. The estimated decadal percentage changes were calculated to evaluate changes in trends in prevalence, mortality and disease burden. Results: In 2021, an estimated 118.4 (95% UI 109.4 to 127.5) million people in China were affected by CKD, contributing to 204 230 (95% UI 164 736 to 246 372) deaths and 6.13 (95% UI 5.18 to 7.21) million DALY. Although CKD due to diabetes mellitus and hypertension accounted for less than a quarter of all cases, they were responsible for over 90% of CKD-related deaths. Over the past three decades, CKD mortality and DALY rates have steadily increased, although the prevalence has stabilized in the last decade. Diabetes mellitus type 2 and hypertension have emerged as key drivers of CKD burden in China. Conclusions: The CKD burden in China shows a dual pattern of rising incidence and high mortality from diabetes and hypertension-related chronic kidney disease, alongside persistently high years lived with disability from glomerulonephritis and other causes.

Secondary hyperparathyroidism persists in the majority of kidney transplant recipients and is associated with adverse graft and cardiovascular outcomes. The immunosuppressive drug class used post-transplant may modulate parathyroid hormone (PTH) levels through distinct mechanisms: calcineurin inhibitors (CNI) stabilize PTH mRNA, while mTOR inhibitors (mTORi) suppress parathyroid cell proliferation in experimental models. We report supporting evidence from two independent analyses. In a multinational real-world database analysis (TriNetX Global Collaborative Network), kidney transplant recipients with documented mTORi use and eGFR in the target range had lower PTH than those on CNI across eGFR strata examined (15-30, 30-45, 45-60, 60-75, >75 mL/min/1.73 m2), with risk ratios for PTH >130 pg/mL ranging from 0.47 to 0.67 in propensity-matched analyses (all p < 0.05). The known confounders - calcium (higher in CNI) and phosphate (higher in mTORi) - both act to oppose this pattern, strengthening the possibility of a drug effect. In a longitudinal single-center cohort (n = 118; 796 PTH measurements), a linear mixed-effects model with time-varying mTORi exposure confirmed a 42% lower PTH during on-mTORi periods after adjustment for eGFR, transplant vintage, diabetes, age, and sex (fold-change 0.58 [95% CI 0.50-0.68]; p < 0.0001). These findings suggest a direct PTH-lowering effect of mTORi. Immunosuppression choice may be considered in the management of post-transplant hyperparathyroidism in selected patients.

Background Thalassemia is one of the most common monogenic disorders worldwide, current screening strategies combining hematological testing with molecular assays still carry a risk of missed diagnoses and undesirable efficiency, particularly for complex structural variants and rare mutations. Methods In this prospective double-blind, multicenter cohort study of 3,842 participants (3,362 pregnant women and 480 male partners), we conducted a head-to-head comparison to systematically evaluate the incremental clinical value and detection performance of single-molecule nanopore sequencing in thalassemia (SMITH) against conventional hematological testing and next-generation sequencing (NGS). Findings The overall concordance rate between NGS and SMITH was 98.6% (3789/3842). The discrepant cases (n=53) were directly attributed to the superior detection capabilities of SMITH, which successfully identified complex structural rearrangements-including 45 -globin gene triplications and four HK alleles-that were missed by NGS. Furthermore, SMITH accurately detected four rare variants (c.134_135insT/, c.-22(C>T)/, {beta}N/{beta}c.316-290delinsAGGGCAATAATTT and {beta}3.5 kb deletion/{beta}N ) and resolved ten trans and three cis configurations within the globin gene allele. Clinically, these technical advantages translated to a 9.3% (5/54) increase in the detection rate of high-risk prenatal couples, effectively preventing one birth affected by moderate-to-severe thalassemia. Additionally, SMITH corrected a diagnostic discrepancy in one case (HK vs. -3.7), sparing the couple from an unnecessary invasive procedure. Interpretation Our findings demonstrate that SMITH provides a powerful platform for resolving globin gene rearrangements, detecting rare variants, and enabling direct haplotype phasing. By effectively eliminating diagnostic blind spots, SMITH is expected to become an optimal method for thalassemia prevention programs. Funding This study was supported by Chinese National Natural Science Foundation Projects 81760037 and 82271894.

Background: Cardiac surgery using cardiopulmonary bypass uses controlled hypoperfusion which leads to relative organ damage. Acute kidney injury is the most frequent and most important organ failure, in particular in patients with chronic kidney disease. To date, there are no approved drug treatments that could effectively prevent acute kidney injury. SP16, an agonist of the low-density lipoprotein receptor-related protein 1, has been shown to exert both reno- and cardioprotective effects in preclinical trials. Early clinical use of SP16 in phase I trials was safe. Administration of SP16 had beneficial trends on inflammatory response and infarct size in patients with ST-segment elevation myocardial infarction. The primary objective of this phase IIa trial is to demonstrate that injection of SP16 is safe and superior to placebo in preventing cardiac surgery-associated acute kidney injury within 7 days after surgery. Methods: This randomised, double-blinded, placebo-controlled, single centre study evaluates the efficacy and safety of SP16 in 120 high-risk chronic kidney disease patients with disease stadium G2-G3b undergoing cardiac surgery who are randomised into one of two treatment groups in a 1:1 ratio: SP16 (12 mg) or placebo. The study medication is administered via two subcutaneous injections, with the first dose given before surgery, followed by an additional dose after 9 h. Primary endpoints are the incidence of acute kidney injury during 7 days post-surgery and the frequency of adverse events within 72 h after index surgery. Important secondary endpoints include the incidence of major adverse kidney events at day 90 and impact on cardiac function. Safety assessments encompass adverse events, vital signs, electrocardiograms and routine safety laboratory tests. Additional evaluations include pharmacokinetics and immunological biomarkers. Discussion: This single-centre phase IIa trial will assess the incidence of cardiac surgery-associated acute kidney injury, describing the renoprotective potential of SP16 and its safety profile in patients undergoing cardiac surgery.

Tricuspid regurgitation and pulmonary artery systolic pressure may contribute to post-operative morbidity and mortality in liver transplantation. Previous studies suggest that a high Model for End-Stage Liver Disease score may influence the relationship between tricuspid regurgitation and post-operative mortality. Adult patients undergoing liver transplantation workup between 2010 and 2023 were included in this retrospective observational cohort study. Patients with significant portopulmonary hypertension were excluded. Transthoracic echocardiograms were completed pre-transplant and patients were followed up for one year post-operatively. 1031 patients (median MELD score 17, IQR 12-23) underwent transthoracic echocardiography for liver transplantation workup, of whom 708 underwent successful transplantation. Mild or greater tricuspid regurgitation did not predict 1-year mortality in the overall population (HR 1.79 (95% CI 0.78-4.11), p=0.19). Among patients with MELD scores [&ge;]20, mild or greater tricuspid regurgitation was a significant predictor of 1-year mortality (7 (12.7%) vs 9 (3.8%), p=0.01) (HR 3.46 (1.30-10.32), p=0.02). Tricuspid regurgitation in patients with high MELD scores was associated with a trend towards an increased risk of 30-day major adverse cardiovascular events (9 (16.4)% vs 46 (8.1%), p=0.06), driven predominantly by rates of post-operative heart failure (12.7% vs 3.8%, HR 3.66 (95%CI 1.30-10.32), p=0.01). Elevated pulmonary artery systolic pressure was associated with prolonged hospital stay (30 days (14-46) vs 15 days (11-29), p=0.01). Our study confirms that mild or greater tricuspid regurgitation is a significant predictor of 1-year mortality in patients with high MELD scores undergoing liver transplantation. Tricuspid regurgitation severity should be considered during pre-liver transplantation risk stratification.

Kidney injury is a frequent and serious complication of allogeneic hematopoietic cell transplantation (HCT), yet its pathophysiology remains poorly understood and effective treatments are lacking. Through analysis of kidney tissue from HCT recipients, we identified substantial acute tubular injury and T cell infiltration that correlated with extra-renal graft-versus-host disease (GVHD) severity, linking systemic alloreactivity and post-transplant renal pathology. In murine models, GVHD was similarly associated with acute kidney injury, renal Th1-type T cell infiltration, and hyperactivation of NF-{kappa}B and JAK-STAT signalling. Notably, galectin-3, a damage-associated lectin, was upregulated in both patient biopsies and experimental GVHD target organs. Leveraging this pathological feature, we engineered galectin-3-targeted lipid nanoparticles for tissue-specific delivery of ruxolitinib, an approved GVHD therapy. Galectin-3 upregulation was also identified in canonical acute GVHD target organs including the liver and intestinal tract, and nanoparticle-delivered ruxolitinib substantially enhanced renal function, reduced systemic GVHD, and minimized hematologic toxicity compared to conventional drug administration. Our findings demonstrate renal involvement in acute GVHD and establish a nanoparticle-based strategy for precision delivery of immunomodulatory therapies to affected tissues.

Background: ADTKD-MUC1 is one of the major entities of ADTKD caused by frameshift variants in the MUC1 VNTR that standard short-read sequencing fails to detect. Existing 59dupC-targeted probe-extension assays do not allow for broad screening and cannot detect atypical non-dupC variants. Recently, VNtyper, a Kestrel-based genotyping pipeline with optional code-adVNTR cross-validation for MUC1 VNTR genotyping from short-read sequencing data allowed to circumvent this diagnostic limitation, but needed further development for easy access and rapid sample processing. Methods: We developed VNtyper 2, by refactoring VNtyper into a modular, production-grade tool with a companion web platform, VNtyper-Online (https://vntyper.org), for freely available browser-based analysis with short turnaround time and without local bioinformatics infrastructure. We validated VNtyper 2 on 400 simulated samples generated with MucOneUp and 142 clinical exomes with independently confirmed genotypes. Results: In simulation, VNtyper 2 detected the canonical 59dupC variant with 96% sensitivity and 100% specificity. Reference-standard validation on 142 samples yielded 90.6% sensitivity and 98.2% specificity overall, with cohort-dependent performance across the Twist Exome v2 French-German cohort (98% sensitivity, 87.5% specificity) and the KAPA HyperExome V2 (Roche) Czech-US cohort (79.4% sensitivity, 100% specificity). Screening of 3582 exomes and targeted panels from international CKD referral programmes identified 51 positive individuals, including 9 with atypical non-dupC frameshift variants that would have been missed by 59dupC-targeted probe-extension assays. In unselected CKD cohorts, a descriptive random-effects summary estimated a detection rate of 1.4% (95% CI 0.6 to 3.1%). Conclusions: VNtyper 2 and VNtyper-Online are open-source tools for MUC1 VNTR genotyping from short-read data and can support locally validated workflows when VNTR coverage is adequate. By improving accessibility and turnaround time, these tools democratize MUC1 diagnostics at global scale. For its integration into routine diagnostics, we propose an expert-informed two-pathway workflow developed through European ADTKD-Net consortium consensus.

Xenotransplantation using genetically engineered pig organs offers a promising solution to the shortage of donor organs for life-saving transplants. However, human preformed antibodies against unknown pig xenoantigens remain a significant barrier to successful xenotransplantation. Current methods for characterizing these antibodies or xenoantigens are limited to cellular-level crossmatch assays. In this study, we developed a novel approach to identify pig xenoantigens, including peptide and glycopeptide epitopes that react with human preformed antibodies. First, human preformed antibodies against xenoantigens were enriched from plasma using immobilized pig kidney proteins. The enriched antibodies were then immobilized and used to isolate pig kidney proteins, peptides, and intact glycopeptides, followed by liquid chromatography-tandem mass spectrometry analysis. This dual-level approach identified 221 peptides corresponding to 153 proteins, with a significant enrichment of plasma membrane and extracellular proteins. Notably, 11 peptides were unique to pig sequences, suggesting their potential role in driving xenogeneic immune responses. Glycoproteomic analysis identified 122 intact glycopeptides, predominantly complex/hybrid glycoforms and Neu5Gc-containing glycans. Our method effectively identifies peptides and intact glycopeptides reactive to human preformed antibodies, providing critical insights for discovering xenoantigens. These findings could guide genetic engineering strategies and enhance recipient candidate screening for xenotransplantation, ultimately increasing the feasibility and success of xenogeneic organ transplantation.

Long-term ex situ machine perfusion of donor organs is an emerging clinical strategy that creates a window for advanced therapeutic interventions. Replacing donor endothelial cells during machine perfusion with recipient endothelium could conceal the allogeneic epithelium from the recipients (humoral) immune response. We postulated that brief exposure to low concentrations of decellularizing agents could selectively remove vascular endothelium. Porcine kidneys were partially decellularized with five 2-minute infusions of either 0.01%, 0.1% or 1.0% SDS during acellular perfusion. As proof-of-concept, fluorescently-labelled porcine endothelial colony forming cells (ECFCs) were infused into the renal vein and artery of a partially decellularized kidney. Tissue analysis identified 0.1% SDS effectively removed endothelial cells from glomerular and peritubular capillaries. Infused ECFCs could be found back within the glomeruli. However, partial decellularization significantly impaired renal flow and increased vascular resistance. While partial decellularization successfully removed donor endothelium, the loss of vascular patency limits its clinical potential. Future research should prioritize modifying rather than removing donor endothelial cells.

Renal fibrosis is the common final pathway of chronic kidney disease (CKD), driven in part by myofibroblast-mediated extracellular matrix deposition. M2 macrophages, hereafter referred to as MAC-M2, have been implicated in renal fibrosis, yet whether M2 macrophages are pro- or anti-fibrotic remains controversial, and the spatial context in which MAC-M2-fibrosis coupling occurs is unknown. Here, we applied geographically weighted regression (GWR), a spatial statistical method, to Visium spatial transcriptomics data from diabetic kidney disease (DKD) to characterize spatially resolved high-coupling spots where MAC-M2-fibrosis coupling is significantly positive. In a small DKD cohort (n=6), GWR identified high-coupling spots enriched for B cell and tertiary lymphoid structure (TLS)-like immune signatures, suggesting that the GWR-defined regions captured biologically meaningful immune microenvironments. To gain statistical power for differential gene expression (DEG) analysis, we then applied the same pipeline to the larger Kidney Precision Medicine Project (KPMP) DKD cohort (n=30), in which high-coupling spots showed upregulation of IgE-related immune genes (IGHE, FCER1A) together with the mast cell tryptase TPSB2. These findings suggest that IgE-related immune responses may be present within DKD fibrotic microenvironments characterized by local MAC-M2-fibrosis coupling. As a disease comparison, we further applied the pipeline to a KPMP hypertensive kidney disease (HKD) cohort (n = 27), where high-coupling spot signatures were distinct from DKD and did not show enrichment of IgE-related genes. Together, this study provides the first application of GWR to kidney spatial transcriptomics and suggests that IgE-related immune responses may be a feature of DKD fibrotic microenvironments in which M2 macrophages are locally associated with fibrosis. HighlightsO_LIGeographically weighted regression (GWR) maps spatially variable M2 macrophage-fibrosis coupling in diabetic kidney disease (DKD). C_LIO_LIGWR-defined high-coupling spots show immune activation and loss of kidney-specific programs. C_LIO_LIThe GWR-based analysis was replicated across two independent DKD cohorts. C_LIO_LIIGHE, FCER1A, and the mast cell marker TPSB2 are enriched in high-coupling spots in the KPMP DKD cohort. C_LI

Background: Chronic low-grade inflammation drives cardiovascular-kidney-metabolic (CKM) syndrome. Clonal hematopoiesis of indeterminate potential (CHIP), an age-related driver of systemic inflammation, is linked to several cardiometabolic disorders. However, whether CHIP modifies CKM progression and contributes to heterogeneity in cardiovascular disease (CVD) risk within the CKM framework remains uninvestigated. Methods: This cohort study included 307,025 UK Biobank participants at CKM stages 0-3 free of baseline CVD. CHIP status was identified via whole-exome sequencing (WES). The association between CHIP and baseline CKM severity was examined, along with the independent and joint effects of CHIP and CKM stages on incident CVD risk. The joint effects of CHIP and polygenic risk scores (PRS) were further assessed, and the incremental predictive value of incorporating CHIP into the AHA PREVENT equations was evaluated. Results: CHIP carriers were more likely to present with advanced CKM stages [OR 1.14 (1.09-1.20), P < 0.001] and exhibited higher incident CVD risk during follow-up [HR 1.13 (1.08-1.18), P < 0.001]. Significant joint effects between CHIP and CKM stages were observed, with the highest risk among CHIP carriers at CKM stage 3 [HR 1.63 (1.50-1.78), P < 0.001]. Large or multiple CHIP mutations conferred greater hazards, with distinct gene-specific effects observed. Moreover, CHIP and high genetic risk also jointly amplified CVD susceptibility. Most importantly, incorporating CHIP into AHA PREVENT significantly improved risk discrimination. Conclusions: CHIP is a significant risk factor associated with more advanced CKM stages and amplifies incident CVD risk. Integrating CHIP into existing prevention strategies may refine CVD risk stratification.

Islet transplantation can restore glycemic control in type 1 diabetes, yet the heterogeneity of patient immune responses and transplant outcomes motivates the need for technologies to monitor the graft. Since transplanted islets are not readily accessible for biopsy due to their diffuse engraftment within the liver, clinical monitoring relies on measurements such as islet mass, blood glucose, and C-peptide levels, which are lagging indicators that change only after substantial graft injury. Here, we developed a minimally invasive synthetic immunological niche (IN) that captures graft-associated immune responses through serial subcutaneous biopsy. We evaluated the IN across murine syngeneic, allogeneic, and autoimmune islet transplant models, including CD40/CD154 costimulatory blockade with anti-CD40L. In syngeneic versus allogeneic recipients, IN identified immune populations and transcriptomic signatures that mirrored the graft and distinguished healthy from rejecting grafts. In anti-CD40L treated allografts, IN revealed innate macrophage- and dendritic cell-associated programs linked to graft acceptance versus rejection, whereas IN from untreated allografts showed stronger adaptive immune signatures. Longitudinal IN profiling further detected progressive inflammatory activation in accepted allografts, indicating persistent subclinical risk. Finally, in an autoimmune allograft model treated with anti-CD40L plus rapamycin, IN identified a 13-gene signature that separated early from late rejection trajectories and distinguished autoimmune-from alloimmune-associated rejection programs. Overall, these findings establish IN as a surrogate tissue for minimally invasive monitoring of islet graft and early detection of rejection-associated immune dysregulation. One Sentence SummaryAn engineered immunological niche captures distinct immune signatures of allo- and auto-mediated islet transplant rejection

Most cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by mutations in PKD1, which reduce polycystin-1 (PC1) levels below a critical functional threshold. Normalizing PC1 dosage mitigates disease progression; therefore, we sought to develop a CRISPR activation (CRISPRa) strategy to transcriptionally upregulate endogenous PKD1. We systematically screened multiple single-guide RNAs using an EGFP-reporter platform and identified potent candidates targeting the proximal PKD1 promoter in mouse and human cell models. Our results demonstrate that CRISPRa effectively increased endogenous Pkd1 mRNA in the mouse collecting duct-derived Pkd1RC/-cell model and in the primary renal epithelial cells from PKD mice. In Pkd1RC/- cells, CRISPRa of Pkd1 increased PC1 protein levels and significantly reduced cell proliferation and in vitro cyst formation in 3D cultures. Mechanistically, Pkd1 activation improved mitochondrial membrane potential, reduced dependency on aerobic glycolysis, and corrected signaling pathways involved in cystogenesis, specifically reducing intracellular cAMP, cMyc, pCreb, and pErk levels, while increasing pYap1 levels. We confirmed the translational potential of this platform by successfully activating PKD1 in primary renal epithelial cells from human kidneys. We observed a heterogeneous response across both normal and ADPKD patient-derived donor lines, with significant upregulation achieved in two of the tested cell preparations. These findings provide a compelling proof-of-concept that CRISPRa-mediated gene augmentation can increase PC1 levels, establishing a foundation for promising gene therapies aimed at successfully suppressing the pathogenic features of ADPKD. New and noteworthyThis study provides proof-of-concept for a CRISPR activation (CRISPRa)-based approach to ADPKD. CRISPRa targeting the PKD1 promoter, increased polycystin-1 levels in mouse and human cells. Upregulation of a hypomorphic Pkd1 allele increased functional polycystin-1, corrected dysregulated signaling pathways, suppressed cell proliferation and in vitro cyst formation. These results establish CRISPRa as a promising therapeutic approach to restore polycystin levels above a critical threshold and suppress cystogenesis in ADPKD.