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Background: Lymphoscintigraphy accurately maps lymphatic drainage from sites of cutaneous melanoma to the draining sentinel lymph nodes. The Sydney Melanoma Unit has accumulated lymphoscintigraphy data from over 5000 patients with cutaneous melanoma over more than 15 years, collectively revealing patterns of skin lymphatic drainage. We aimed to map these data onto a three-dimensional computer model to provide improved visualisation and analysis of lymphatic drainage from sites of cutaneous melanoma. Methods: Lymphoscintigraphy data from 5239 patients with cutaneous melanoma were collected between July 27, 1987 and Dec 16, 2005. 4302 of these patients had primary melanoma sites below the neck, and were included in this analysis. From these patients, two-dimensional lymphoscintigraphy data were mapped onto an anatomically based three-dimensional computer model of the skin and lymph nodes. Spatial analysis was done to visualise the relation between primary melanoma sites and the locations of sentinel lymph nodes. Findings: We created three-dimensional, colour-coded heat maps that showed the drainage patterns from melanoma sites below the neck to individual lymph-node fields and to many lymph-node fields. These maps highlight the inter-patient variability in skin lymphatic drainage, and show the skin regions in which highly variable drainage can occur. To enable interactive and dynamic analysis of these data, we also developed software to predict lymphatic drainage patterns from melanoma skin sites to sentinel lymph-node fields. Interpretation: The heat maps confirmed that the commonly used Sappey's lines are not effective in predicting lymphatic drainage. The heat maps and the interactive software could be a new resource for clinicians to use in preoperative discussions with patients with melanoma and other skin cancers that can metastasise to the lymph nodes, and could be used in the identification of sentinel lymph-node fields during follow-up of such patients. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study is to examine NCAA Division I volleyball players' return to play rates and performance statistics compared to pre-injury levels following ACL injury., Methods: Female volleyball players that sustained ACL injuries from 2008 to 2020 and competed in one of seven collegiate conferences ( n  = 99) were identified via an internet search algorithm. Players were categorized by position, academic year, and playing time pre- and post-injury. Post-injury performance statistics were gathered for a subset of outside hitters and middle blockers that played in ≥35 sets in a single season for up to 3 years following injury (mean 1.7 seasons). A control group ( n  = 512) was generated for demographic and statistical comparison. Mean pre-injury and post-injury statistics were compared for players that did not change positions and played ≥35 sets before and after injury., Results: Volleyball attackers were 54.7% of the control population but sustained 78.8% of identified injuries. Following ACL injury, 6.1% of players registered no in-game statistics, 16.2% played in <35 sets, 65.7% played in ≥35 sets, and 12.1% graduated. Mean performance statistics increased linearly the more years players were from ACL injury., Conclusions: Female collegiate volleyball players return to play following ACL injury at high rates (93.1%) and maintain pre-injury performance levels. Volleyball attackers sustain ACL injuries more commonly than setters and libero/defensive specialists.

HumanIslets.com supports diabetes research by offering easy access to islet phenotyping data, analysis tools, and data download. It includes molecular omics, islet and cellular function assays, tissue processing metadata, and phenotypes from 547 donors. As it expands, the resource aims to improve human islet data quality, usability, and accessibility., Competing Interests: Declaration of interests A.L.G.’s spouse is an employee of Genentech and holds stock options in Roche. A.R.P. serves on the Scientific Advisory Committee for Encellin Inc. J.X. is founder of XiaLab Analytics, which provides omics data science training and support., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Human islets from deceased organ donors have made important contributions to our understanding of pancreatic endocrine function and continue to be an important resource for research studies aimed at understanding, treating, and preventing diabetes. Understanding the impacts of isolation and culture upon the yield of human islets for research is important for planning research studies and islet distribution to distant laboratories. Here, we examine islet isolation and cell culture outcomes at the Alberta Diabetes Institute (ADI) IsletCore ( n  = 197). Research-focused isolations typically have a lower yield of islet equivalents (IEQ), with a median of 252,876 IEQ, but a higher purity (median 85%) than clinically focused isolations before culture. The median recovery of IEQs after culture was 75%, suggesting some loss. This was associated with a shift toward smaller islet particles, indicating possible islet fragmentation, and occurred within 24 h with no further loss after longer periods of culture (up to 136 h). No overall change in stimulation index as a measure of islet function was seen with culture time. These findings were replicated in a representative cohort of clinical islet preparations from the Clinical Islet Transplant Program at the University of Alberta. Thus, loss of islets occurs within 24 h of isolation, and there is no further impact of extended culture prior to islet distribution for research.

Immune checkpoint inhibitors are widely used anticancer therapies 1 that can cause morbid and potentially fatal immune-related adverse events such as immune-related myocarditis (irMyocarditis) 2-5 . The pathogenesis of irMyocarditis and its relationship to antitumour immunity remain poorly understood. Here we sought to define immune responses in heart, tumour and blood in patients with irMyocarditis by leveraging single-cell RNA sequencing coupled with T cell receptor (TCR) sequencing, microscopy and proteomics analyses of samples from 28 patients with irMyocarditis and 41 unaffected individuals. Analyses of 84,576 cardiac cells by single-cell RNA sequencing combined with multiplexed microscopy demonstrated increased frequencies and co-localization of cytotoxic T cells, conventional dendritic cells and inflammatory fibroblasts in irMyocarditis heart tissue. Analyses of 366,066 blood cells revealed decreased frequencies of plasmacytoid dendritic cells, conventional dendritic cells and B lineage cells but an increased frequency of other mononuclear phagocytes in irMyocarditis. Fifty-two heart-expanded TCR clones from eight patients did not recognize the putative cardiac autoantigens α-myosin, troponin I or troponin T. Additionally, TCRs enriched in heart tissue were largely nonoverlapping with those enriched in paired tumour tissue. The presence of heart-expanded TCRs in a cycling blood CD8 T cell population was associated with fatal irMyocarditis case status. Collectively, these findings highlight crucial biology driving irMyocarditis and identify putative biomarkers., Competing Interests: Competing interests: S.M.B.: consultant to Two River Consulting and Third Rock Ventures; and equity in Candid Therapeutics, Kronos Bio, 76Bio and Allogene Therapeutics. D.A.Z.: consultant to Bristol Myers Squibb, Freeline Therapeutics and Intrinsic Imaging; and research funding from Abbott Laboratories. N.P.S.: consultant to Hera Biotech. L.Z.: consultant to Bristol Myers Squibb and Merck. J.F.G.: consultant to Amgen, Arcus Biosciences, AI Proteins, AstraZeneca, Beigene, Blueprint Medicines, Bristol Myers Squibb, Genentech/Roche, EMD Serono, InterVenn Biosciences, Gilead Sciences, iTeos Therapeutics, Jounce Therapeutics, Karyopharm Therapeutics, Lilly, Loxo, Merus, Mirati Therapeutics, Pfizer, Sanofi, Silverback Therapeutics, Merck, Moderna Therapeutics, Mariana Oncology and Takeda; honorarium from Merck, Pfizer, Novartis, Pfizer and Takeda; research funding from Adaptimmune, Alexo Therapeutics, Array BioPharma, AstraZeneca, Blueprint Medicines, Bristol Myers Squibb, Genentech, Jounce Therapeutics, Merck, Moderna Therapeutics, Novartis and Tesaro; has an immediate family member who is an employee with stock and other ownership interests in Ironwood Pharmaceuticals; and equity in AI Proteins. C.J.W.: equity in BionTech; research funding from Pharmacyclics; and is on the scientific advisory board of Repertoire, Adventris and Aethon Therapeutics. D.J.: grants and personal fees from Novartis, Genentech, Syros and Eisai; personal fees from Vibliome, PIC Therapeutics, Mapkure and Relay Therapeutics; and grants from Pfizer, Amgen, InventisBio, Arvinas, Takeda, Blueprint Medicines, AstraZeneca, Ribon Therapeutics and Infinity that are outside the submitted work. M.M.-K.: consultant to AstraZeneca, Pfizer, Repare, Boehringer Ingelheim, Sanofi, AbbVie and Daiichi-Sankyo; and royalties from Elsevier. G.O.: consultant to Bicycle Therapeutics. R.J.S.: consultant to Bristol Myers Squibb, Merck, Pfizer, Marengo Therapeutics, Novartis, Eisai, Iovance, OncoSec and AstraZeneca; and research funding from Merck. G.M.B.: sponsored research agreements through her institution with Olink Proteomics, Teiko Bio, InterVenn Biosciences and Palleon Pharmaceuticals; is on advisory boards for Iovance, Merck, Nektar Therapeutics, Novartis and Ankyra Therapeutics; is a consultant for Merck, InterVenn Biosciences, Iovance and Ankyra Therapeutics; and has equity in Ankyra Therapeutics. T.G.N.: consultant to Bristol Myers Squibb, Genentech, CRC Oncology, Roche, Sanofi and Parexel Imaging Pharmaceuticals; and grant funding from Astra Zeneca, Bristol Myers Squibb related to the cardiac effects of ICIs. K.L.R.: on the advisory board to SAGA Diagnostics; speaker’s fees from CMEOutfitters and Medscape; and research funding from Bristol Myers Squibb. A.-C.V.: consultant to Bristol Myers Squibb; and financial interest in 10x Genomics. 10x Genomics designs and manufactures gene sequencing technology for use in research, and such technology is being used in this research; these interests were reviewed by the Massachusetts General Hospital and Mass General Brigham in accordance with their institutional policies. All other authors (I.J.K., S.R., J.C., N.S., S.M., M.W., A.T., Y.S., K.H.X., J.B., P.S., K.S., J.T., K.M., B.Y.A., M.N., C.J.P., D.M., M.J., P.C., A.L., W.A.M., T.S., L.T.N., J.R.S. and M.F.T.) declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Asthma is often accompanied by type 2 immunity rich in IL-4, IL-5, and IL-13 cytokines produced by T H 2 lymphocytes or type 2 innate lymphoid cells (ILC2s). IL-2 family cytokines play a key role in the differentiation, homeostasis, and effector function of innate and adaptive lymphocytes., Objective: IL-9 and IL-21 boost activation and proliferation of T H 2 and ILC2s, but the relative importance and potential synergism between these γ common chain cytokines are currently unknown., Methods: Using newly generated antibodies, we inhibited IL-9 and IL-21 alone or in combination in various murine models of asthma. In a translational approach using segmental allergen challenge, we recently described elevated IL-9 levels in human subjects with allergic asthma compared with nonasthmatic controls. Here, we also measured IL-21 in both groups., Results: IL-9 played a central role in controlling innate IL-33-induced lung inflammation by promoting proliferation and activation of ILC2s in an IL-21-independent manner. Conversely, chronic house dust mite-induced airway inflammation, mainly driven by adaptive immunity, was solely dependent on IL-21, which controlled T H 2 activation, eosinophilia, total serum IgE, and formation of tertiary lymphoid structures. In a model of innate on adaptive immunity driven by papain allergen, a clear synergy was found between both pathways, as combined anti-IL-9 or anti-IL-21 blockade was superior in reducing key asthma features. In human bronchoalveolar lavage samples we measured elevated IL-21 protein within the allergic asthmatic group compared with the allergic control group. We also found increased IL21R transcripts and predicted IL-21 ligand activity in various disease-associated cell subsets., Conclusions: IL-9 and IL-21 play important and nonredundant roles in allergic asthma by boosting ILC2s and T H 2 cells, revealing a dual IL-9 and IL-21 targeting strategy as a new and testable approach., Competing Interests: Disclosure statement This work was funded by a Baekeland Mandate of Flanders Innovation & Entrepreneurship (VLAIO) (HBC.2019.2598) to F.B. B.N.L. acknowledges support from a European Research Council (ERC) advanced grant (789384 ASTHMA CRYSTAL CLEAR), a concerted research initiative grant from Ghent University (GOA, 01G010C9), a Fonds Wetenschappelijk Onderzoek (FWO) Methusalem grant (01M01521) and an FWO Excellence of Science (EOS) Consortium research grant (3G0H1222), and the Flanders Institute of Biotechnology (VIB). H.H. is supported by a concerted research initiative grant from Ghent University (GOA, 01G010C9) and FWO EOS Consortium research grant (3G0H1222). M.J.S. acknowledges support from FWO Vlaanderen (12Y5322N), Fund Suzanne Duchesne (managed by the King Baudouin Foundation), and Fondation ACTERIA. Disclosure of potential conflict of interest: N. P. Smith is a consultant for Hera Biotech. A.-C. Villani has financial interest in 10X Genomics. B. D. Medoff serves on advisory boards for Sanofi, Verona Pharma, and Apogee Therapeutics and has sponsored research agreements from Sanofi and Regeneron. R. Bigirimana is an employee of argenx. C. Blanchetot is a consultant and shareholder of argenx. B. N. Lambrecht receives consultancy fees from GSK Biologics, Novartis, Sanofi, AstraZeneca, ALK, OncoArendi, and argenx and has research grants from ALK, argenx, AstraZeneca, GSK, GSK Biologics, and Johnson & Johnson. The rest of the authors declare that they have no relevant conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown., Objective: To identify novel pathways associated with tolerance in food allergy, we used metabolomic profiling to find pathways important for food allergy in multiethnic cohorts and responses to OIT., Methods: Untargeted plasma metabolomics data were generated from the VDAART healthy infant cohort (N = 384), a Costa Rican cohort of children with asthma (N = 1040), and a peanut OIT trial (N = 20) evaluating sustained unresponsiveness (SU, protection that lasts after therapy) versus transient desensitization (TD, protection that ends immediately afterward). Generalized linear regression modeling and pathway enrichment analysis identified metabolites associated with food allergy and OIT outcomes., Results: Compared with unaffected children, those with food allergy were more likely to have metabolomic profiles with altered histidines and increased bile acids. Eicosanoids (e.g., arachidonic acid derivatives) (q = 2.4 × 10 -20 ) and linoleic acid derivatives (q = 3.8 × 10 -5 ) pathways decreased over time on OIT. Comparing SU versus TD revealed differing concentrations of bile acids (q = 4.1 × 10 -8 ), eicosanoids (q = 7.9 × 10 -7 ), and histidine pathways (q = .015). In particular, the bile acid lithocholate (4.97 [1.93, 16.14], p = .0027), the eicosanoid leukotriene B4 (3.21 [1.38, 8.38], p = .01), and the histidine metabolite urocanic acid (22.13 [3.98, 194.67], p = .0015) were higher in SU., Conclusions: We observed distinct profiles of bile acids, histidines, and eicosanoids that vary among patients with food allergy, over time on OIT and between SU and TD. Participants with SU had higher levels of metabolites such as lithocholate and urocanic acid, which have immunomodulatory roles in key T-cell subsets, suggesting potential mechanisms of tolerance in immunotherapy., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

For more than 60 years, humans have travelled into space. Until now, the majority of astronauts have been professional, government agency astronauts selected, in part, for their superlative physical fitness and the absence of disease. Commercial spaceflight is now becoming accessible to members of the public, many of whom would previously have been excluded owing to unsatisfactory fitness or the presence of cardiorespiratory diseases. While data exist on the effects of gravitational and acceleration (G) forces on human physiology, data on the effects of the aerospace environment in unselected members of the public, and particularly in those with clinically significant pathology, are limited. Although short in duration, these high acceleration forces can potentially either impair the experience or, more seriously, pose a risk to health in some individuals. Rather than expose individuals with existing pathology to G forces to collect data, computational modelling might be useful to predict the nature and severity of cardiovascular diseases that are of sufficient risk to restrict access, require modification, or suggest further investigation or training before flight. In this Review, we explore state-of-the-art, zero-dimensional, compartmentalized models of human cardiovascular pathophysiology that can be used to simulate the effects of acceleration forces, homeostatic regulation and ventilation-perfusion matching, using data generated by long-arm centrifuge facilities of the US National Aeronautics and Space Administration and the European Space Agency to risk stratify individuals and help to improve safety in commercial suborbital spaceflight., (© 2024. Springer Nature Limited.)

In naive individuals, sensory neurons directly detect and respond to allergens, leading to both the sensation of itch and the activation of local innate immune cells, which initiate the allergic immune response 1,2 . In the setting of chronic allergic inflammation, immune factors prime sensory neurons, causing pathologic itch 3-7 . Although these bidirectional neuroimmune circuits drive responses to allergens, whether immune cells regulate the set-point for neuronal activation by allergens in the naive state is unknown. Here we describe a γδ T cell-IL-3 signalling axis that controls the allergen responsiveness of cutaneous sensory neurons. We define a poorly characterized epidermal γδ T cell subset 8 , termed GD3 cells, that produces its hallmark cytokine IL-3 to promote allergic itch and the initiation of the allergic immune response. Mechanistically, IL-3 acts on Il3ra-expressing sensory neurons in a JAK2-dependent manner to lower their threshold for allergen activation without independently eliciting itch. This γδ T cell-IL-3 signalling axis further acts by means of STAT5 to promote neuropeptide production and the initiation of allergic immunity. These results reveal an endogenous immune rheostat that sits upstream of and governs sensory neuronal responses to allergens on first exposure. This pathway may explain individual differences in allergic susceptibility and opens new therapeutic avenues for treating allergic diseases., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Breastfeeding is a parenting practice that combines close intimate contact with the opportunity to be sensitive and responsive to the infant, and may have direct and indirect relations with infant attachment. However, researchers have produced inconsistent findings, suggesting there may be other mechanisms involved. Coparenting may play a significant role, as it has been consistently associated with mother-infant relationships., Research Aims: The aims of this study were to examine: (1) whether breastfeeding would be directly associated with infant-mother attachment; (2) whether this association was also indirect, through mothers' quality of caregiving; and (3) whether partners' coparenting support moderates breastfeeding's indirect association with attachment., Methods: This was a prospective, longitudinal study that drew data from a larger NIH-funded study on sleep and family relationships (R01HD052809). Mothers reported on their feeding practices and coparenting relationships. Independent observations were used to assess mothers' emotional availability toward infants. A separate team of observers assessed infant-mother attachment., Results: Exclusive breastfeeding during the first 6 months, and longer duration of any breastfeeding across the 1st year, were directly associated with more secure infant-mother attachment. These associations were also indirect, through maternal emotional availability. Coparenting was a significant moderator, such that the influence of longer breastfeeding duration on improved emotional availability, and, in turn, on more secure attachment, was significant only for mothers who perceived coparenting quality to be low., Conclusion: Findings highlighted the importance of breastfeeding on both the quality of mothering and infant attachment, but also emphasized that coparenting support may be particularly important for mothers who are unable to breastfeed., Competing Interests: Disclosures and Conflicts of InterestThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Christine Youngwon Kim is a PhD student, Nicole P. Smith was an undergraduate student, and Douglas M. Teti was the advisor to both at the time this article was written.

Adult stem cells play a crucial role in tissue homeostasis and repair through multiple mechanisms. In addition to being able to replace aged or damaged cells, stem cells provide signals that contribute to the maintenance and function of neighboring cells. In the lung, airway basal stem cells also produce cytokines and chemokines in response to inhaled irritants, allergens, and pathogens, which affect specific immune cell populations and shape the nature of the immune response. However, direct cell-to-cell signaling through contact between airway basal stem cells and immune cells has not been demonstrated. Recently, a unique population of intraepithelial airway macrophages (IAMs) has been identified in the murine trachea. Here, we demonstrate that IAMs require Notch signaling from airway basal stem cells for maintenance of their differentiated state and function. Furthermore, we demonstrate that Notch signaling between airway basal stem cells and IAMs is required for antigen-induced allergic inflammation only in the trachea where the basal stem cells are located whereas allergic responses in distal lung tissues are preserved consistent with a local circuit linking stem cells to proximate immune cells. Finally, we demonstrate that IAM-like cells are present in human conducting airways and that these cells display Notch activation, mirroring their murine counterparts. Since diverse lung stem cells have recently been identified and localized to specific anatomic niches along the proximodistal axis of the respiratory tree, we hypothesize that the direct functional coupling of local stem cell-mediated regeneration and immune responses permits a compartmentalized inflammatory response.

Comprehensive molecular and cellular phenotyping of human islets can enable deep mechanistic insights for diabetes research. We established the Human Islet Data Analysis and Sharing (HI-DAS) consortium to advance goals in accessibility, usability, and integration of data from human islets isolated from donors with and without diabetes at the Alberta Diabetes Institute (ADI) IsletCore. Here we introduce HumanIslets.com, an open resource for the research community. This platform, which presently includes data on 547 human islet donors, allows users to access linked datasets describing molecular profiles, islet function and donor phenotypes, and to perform various statistical and functional analyses at the donor, islet and single-cell levels. As an example of the analytic capacity of this resource we show a dissociation between cell culture effects on transcript and protein expression, and an approach to correct for exocrine contamination found in hand-picked islets. Finally, we provide an example workflow and visualization that highlights links between type 2 diabetes status, SERCA3b Ca 2+ -ATPase levels at the transcript and protein level, insulin secretion and islet cell phenotypes. HumanIslets.com provides a growing and adaptable set of resources and tools to support the metabolism and diabetes research community., Competing Interests: Declaration of Interests ALG’s spouse is an employee of Genentech and holds stock options in Roche AP serves on the Scientific Advisory Committee for Encellin Inc. JX is founder of XiaLab Analytics, which provides omics data science training and support. All other authors confirm no relevant interests to declare.

Background: The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown., Objective: To identify novel pathways associated with tolerance in food allergy, we used metabolomic profiling to find pathways important for food allergy in multi-ethnic cohorts and responses to OIT., Methods: Untargeted plasma metabolomics data were generated from the VDAART healthy infant cohort (N=384), a Costa Rican cohort of children with asthma (N=1040), and a peanut OIT trial (N=20) evaluating sustained unresponsiveness (SU, protection that lasts after therapy) versus transient desensitization (TD, protection that ends immediately afterwards). Generalized linear regression modeling and pathway enrichment analysis identified metabolites associated with food allergy and OIT outcomes., Results: Compared with unaffected children, those with food allergy were more likely to have metabolomic profiles with altered histidines and increased bile acids. Eicosanoids (e.g., arachidonic acid derivatives) (q=2.4×10 -20 ) and linoleic acid derivatives (q=3.8×10 -5 ) pathways decreased over time on OIT. Comparing SU versus TD revealed differing concentrations of bile acids (q=4.1×10 -8 ), eicosanoids (q=7.9×10 -7 ), and histidine pathways (q=0.015). In particular, the bile acid lithocholate (4.97[1.93,16.14], p=0.0027), the eicosanoid leukotriene B4 (3.21[1.38,8.38], p=0.01), and the histidine metabolite urocanic acid (22.13[3.98,194.67], p=0.0015) were higher in SU., Conclusions: We observed distinct profiles of bile acids, histidines, and eicosanoids that vary among patients with food allergy, over time on OIT and between SU and TD. Participants with SU had higher levels of metabolites such as lithocholate and urocanic acid, which have immunomodulatory roles in key T-cell subsets, suggesting potential mechanisms of tolerance in immunotherapy., Key Messages: - Compared with unaffected controls, children with food allergy demonstrated higher levels of bile acids and distinct histidine/urocanic acid profiles, suggesting a potential role of these metabolites in food allergy. - In participants receiving oral immunotherapy for food allergy, those who were able to maintain tolerance-even after stopping therapyhad lower overall levels of bile acid and histidine metabolites, with the exception of lithocholic acid and urocanic acid, two metabolites that have roles in T cell differentiation that may increase the likelihood of remission in immunotherapy., Capsule Summary: This is the first study of plasma metabolomic profiles of responses to OIT in individuals with IgE-mediated food allergy. Identification of immunomodulatory metabolites in allergic tolerance may help identify mechanisms of tolerance and guide future therapeutic development.

Immune checkpoint inhibitor (ICI) therapy has revolutionized oncology, but treatments are limited by immune-related adverse events, including checkpoint inhibitor colitis (irColitis). Little is understood about the pathogenic mechanisms driving irColitis, which does not readily occur in model organisms, such as mice. To define molecular drivers of irColitis, we used single-cell multi-omics to profile approximately 300,000 cells from the colon mucosa and blood of 13 patients with cancer who developed irColitis (nine on anti-PD-1 or anti-CTLA-4 monotherapy and four on dual ICI therapy; most patients had skin or lung cancer), eight controls on ICI therapy and eight healthy controls. Patients with irColitis showed expanded mucosal Tregs, ITGAE Hi CD8 tissue-resident memory T cells expressing CXCL13 and Th17 gene programs and recirculating ITGB2 Hi CD8 T cells. Cytotoxic GNLY Hi CD4 T cells, recirculating ITGB2 Hi CD8 T cells and endothelial cells expressing hypoxia gene programs were further expanded in colitis associated with anti-PD-1/CTLA-4 therapy compared to anti-PD-1 therapy. Luminal epithelial cells in patients with irColitis expressed PCSK9, PD-L1 and interferon-induced signatures associated with apoptosis, increased cell turnover and malabsorption. Together, these data suggest roles for circulating T cells and epithelial-immune crosstalk critical to PD-1/CTLA-4-dependent tolerance and barrier function and identify potential therapeutic targets for irColitis., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Background: Most genetic studies of asthma and allergy have focused on common variation in individuals primarily of European ancestry. Studying the role of rare variation in quantitative phenotypes and in asthma phenotypes in populations of diverse ancestries can provide additional, important insights into the development of these traits., Objective: We sought to examine the contribution of rare variants to different asthma- or allergy-associated quantitative traits in children with diverse ancestries and explore their role in asthma phenotypes., Methods: We examined whole-genome sequencing data from children participants in longitudinal studies of asthma (n = 1035; parent-identified as 67% Black and 25% Hispanic) to identify rare variants (minor allele frequency < 0.01). We assigned variants to genes and tested for associations using an omnibus variant-set test between each of 24,902 genes and 8 asthma-associated quantitative traits. On combining our results with external data on predicted gene expression in humans and mouse knockout studies, we identified 3 candidate genes. A burden of rare variants in each gene and in a combined 3-gene score was tested for its associations with clinical phenotypes of asthma. Finally, published single-cell gene expression data in lower airway mucosal cells after allergen challenge were used to assess transcriptional responses to allergen., Results: Rare variants in USF1 were significantly associated with blood neutrophil count (P = 2.18 × 10 -7 ); rare variants in TNFRSF21 with total IgE (P = 6.47 × 10 -6 ) and PIK3R6 with eosinophil count (P = 4.10 × 10 -5 ) reached suggestive significance. These 3 findings were supported by independent data from human and mouse studies. A burden of rare variants in TNFRSF21 and in a 3-gene score was associated with allergy-related phenotypes in cohorts of children with mild and severe asthma. Furthermore, TNFRSF21 was significantly upregulated in bronchial basal epithelial cells from adults with allergic asthma but not in adults with allergies (but not asthma) after allergen challenge., Conclusions: We report novel associations between rare variants in genes and allergic and inflammatory phenotypes in children with diverse ancestries, highlighting TNFRSF21 as contributing to the development of allergic asthma., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Immune checkpoint inhibitors (ICIs) are widely used anti-cancer therapies that can cause morbid and potentially fatal immune-related adverse events (irAEs). ICI-related myocarditis (irMyocarditis) is uncommon but has the highest mortality of any irAE. The pathogenesis of irMyocarditis and its relationship to anti-tumor immunity remain poorly understood. We sought to define immune responses in heart, tumor, and blood during irMyocarditis and identify biomarkers of clinical severity by leveraging single-cell (sc)RNA-seq coupled with T cell receptor (TCR) sequencing, microscopy, and proteomics analysis of 28 irMyocarditis patients and 23 controls. Our analysis of 284,360 cells from heart and blood specimens identified cytotoxic T cells, inflammatory macrophages, conventional dendritic cells (cDCs), and fibroblasts enriched in irMyocarditis heart tissue. Additionally, potentially targetable, pro-inflammatory transcriptional programs were upregulated across multiple cell types. TCR clones enriched in heart and paired tumor tissue were largely non-overlapping, suggesting distinct T cell responses within these tissues. We also identify the presence of cardiac-expanded TCRs in a circulating, cycling CD8 T cell population as a novel peripheral biomarker of fatality. Collectively, these findings highlight critical biology driving irMyocarditis and putative biomarkers for therapeutic intervention., Competing Interests: Conflict of Interest S.M.B has been a paid consultant to Two River Consulting and Third Rock Ventures. He has equity positions in Kronos Bio, 76Bio, and Allogene Therapeutics. D.A.Z. has been a paid consultant to Bristol Myers Squibb, Freeline Therapeutics, and Intrinsic Imaging. L.Z. has received consulting fees from Bristol Myers Squibb and Merck. R.J.S has been a paid consultant to Bristol Myers Squibb, Merck, Pfizer, Marengo Therapeutics, Novartis, Eisai, Iovance, OncoSec, and AstraZeneca and has received research funding from Merck. T.G.N has been a paid consultant to Bristol Myers Squibb, Genentech, CRC Oncology, Roche, Sanofi and Parexel Imaging Pharmaceuticals and has received grant funding from Astra Zeneca and Bristol Myers Squibb related to the cardiac effects of immune checkpoint inhibitors. K.L.R has served as an advisory board to SAGA Diagnostics and received speaker’s fees from CMEOutfitters and Medscape as well as research funding from Bristol Myers Squibb. A.C.V. has been a paid consultant to Bristol Myers Squibb.

Lyme disease is caused by the bacterial pathogen Borrelia burgdorferi , which can be readily modeled in laboratory mice. In order to understand the cellular and transcriptional changes that occur during B. burgdorferi infection, we conducted single-cell RNA sequencing (scRNA-seq) of ankle joints of infected C57BL/6 mice over time. We found that macrophages/monocytes, T cells, synoviocytes and fibroblasts all showed significant differences in gene expression of both inflammatory and non-inflammatory genes that peaked early and returned to baseline before the typical resolution of arthritis. Predictions of cellular interactions showed that macrophages appear to communicate extensively between different clusters of macrophages as well as with fibroblasts and synoviocytes. Our data give unique insights into the interactions between B. burgdorferi and the murine immune system over time and allow for a better understanding of mechanisms by which the dysregulation of the immune response may lead to prolonged symptoms in some patients., Competing Interests: L.T.H. receives support for contract research services through Tufts University from companies including Moderna, Sanofi, Tarsus, and Massbiologics for vaccine and drug development unrelated to the content of this article., (© 2023 The Author(s).)

Tissue-resident memory T (T RM ) cells play a central role in immune responses to pathogens across all barrier tissues after infection. However, the underlying mechanisms that drive T RM differentiation and priming for their recall effector function remains unclear. In this study, we leveraged both newly generated and publicly available single-cell RNA-sequencing (scRNAseq) data generated across 10 developmental time points to define features of CD8 T RM across both skin and small-intestine intraepithelial lymphocytes (siIEL). We employed linear modeling to capture temporally-associated gene programs that increase their expression levels in T cell subsets transitioning from an effector to a memory T cell state. In addition to capturing tissue-specific gene programs, we defined a consensus T RM signature of 60 genes across skin and siIEL that can effectively distinguish T RM from circulating T cell populations, providing a more specific T RM signature than what was previously generated by comparing bulk T RM to naïve or non-tissue resident memory populations. This updated T RM signature included the AP-1 transcription factor family members Fos, Fosb and Fosl2 . Moreover, ATACseq analysis detected an enrichment of AP-1-specific motifs at open chromatin sites in mature T RM . CyCIF tissue imaging detected nuclear co-localization of AP-1 members Fosb and Junb in resting CD8 T RM >100 days post-infection. Taken together, these results reveal a critical role of AP-1 transcription factor members in T RM biology and suggests a novel mechanism for rapid reactivation of resting T RM in tissue upon antigen encounter.

Objective: Recent advances in tissue clearing and high-throughput imaging have enabled the acquisition of extended-volume microvasculature images at a submicron resolution. The objective of this study was to extract information from this type of images by integrating a sequence of 3D image processing steps on Terabyte scale datasets., Methods: We acquired coronary microvasculature images throughout an entire short-axis slice of a 3-month-old Wistar-Kyoto rat heart. This dataset covered 13 × 10 × 0.6 mm at a resolution of 0.933 × 0.933 × 1.866 μm and occupied 700 Gigabytes of disk space. We used chunk-based image segmentation, combined with an efficient graph generation technique, to quantify the microvasculature in the large-scale images. Specifically, we focused on the microvasculature with a vessel diameter up to 15 μm., Results: Morphological data for the complete short-axis ring were extracted within 16 h using this pipeline. From the analyses, we identified that microvessel lengths in the rat coronary microvasculature varied from 6 to 300 μm. However, their distribution was heavily skewed toward shorter lengths, with a mode of 16.5 μm. In contrast, vessel diameters ranged from 3 to 15 μm and had an approximately normal distribution of 6.5 ± 2 μm., Conclusion: The tools and techniques from this study will serve other investigations into the microcirculation, and the wealth of data from this study will enable the analysis of biophysical mechanisms using computer models., (© 2023 The Authors. Microcirculation published by John Wiley & Sons Ltd.)

Asthma is a chronic disease most commonly associated with allergy and type 2 inflammation. However, the mechanisms that link airway inflammation to the structural changes that define asthma are incompletely understood. Using a human model of allergen-induced asthma exacerbation, we compared the lower airway mucosa in allergic asthmatics and allergic non-asthmatic controls using single-cell RNA sequencing. In response to allergen, the asthmatic airway epithelium was highly dynamic and up-regulated genes involved in matrix degradation, mucus metaplasia, and glycolysis while failing to induce injury-repair and antioxidant pathways observed in controls. IL9 -expressing pathogenic T H 2 cells were specific to asthmatic airways and were only observed after allergen challenge. Additionally, conventional type 2 dendritic cells (DC2 that express CD1C ) and CCR2 -expressing monocyte-derived cells (MCs) were uniquely enriched in asthmatics after allergen, with up-regulation of genes that sustain type 2 inflammation and promote pathologic airway remodeling. In contrast, allergic controls were enriched for macrophage-like MCs that up-regulated tissue repair programs after allergen challenge, suggesting that these populations may protect against asthmatic airway remodeling. Cellular interaction analyses revealed a T H 2-mononuclear phagocyte-basal cell interactome unique to asthmatics. These pathogenic cellular circuits were characterized by type 2 programming of immune and structural cells and additional pathways that may sustain and amplify type 2 signals, including TNF family signaling, altered cellular metabolism, failure to engage antioxidant responses, and loss of growth factor signaling. Our findings therefore suggest that pathogenic effector circuits and the absence of proresolution programs drive structural airway disease in response to type 2 inflammation.

Introduction: The importance of sociodemographic factors such as race, education, and income on spine surgery outcomes has been well established, yet the representation of sociodemographic data within randomized controlled trials (RCTs) in spine literature remains undefined in the United States (U.S)., Methods: Medical literature was reviewed within PubMed for RCTs with "spine" in the title or abstract published within the last 8 years (2014 to 2021) in seven major spine journals. This yielded 128 results, and after application of inclusion criteria (RCTs concerning adult spine pathologies conducted in the U.S), 54 RCTs remained for analysis. Each article's journal of publication, year of publication, and spinal pathology was recorded. Pathologies included cervical degeneration, thoracolumbar degeneration, adult deformity, cervical trauma, and thoracolumbar trauma. Sociodemographic variables collected were race, ethnicity, insurance status, income, work status, and education. The Fisher's exact test was used to compare inclusion of sociodemographic data by journal, year, and spinal pathology., Results: Sociodemographic data were included in the results and in any section of 57.4% (31/54) of RCTs. RCTs reported work status in 25.9% (14/54) of results and 38.9% (21/54) of RCTs included work status in any section. Income was included in the results and mentioned in any section in 13.0% (7/54) of RCTs. Insurance status was in the results or any section of 9.3% (5/54) and 18.5% (10/54) of RCTs, respectively. There was no association with inclusion of sociodemographic data within the results of RCTs as a factor of journal ( P = 0.337), year of publication ( P = 0.286), or spinal pathology ( P = 0.199)., Discussion: Despite evidence of the importance of sociodemographic factors on the natural history and treatment outcomes of myriad spine pathologies, this study identifies a surprising absence of sociodemographic data within contemporary RCTs in spine surgery. Failure to include sociodemographic factors in RCTs potentially bias the generalizability of outcome data., (Copyright © 2023 by the American Academy of Orthopaedic Surgeons.)

Objectives: Flow competition between coronary artery bypass grafts (CABG) and native coronary arteries is a significant problem affecting arterial graft patency. The objectives of this study were to compare the predictive hemodynamic flow resulting from various total arterial grafting configurations and to evaluate whether the use of computational fluid dynamics (CFD) models capable of predicting flow can assist surgeons to make better decisions for individual patients by avoiding poorly functioning grafts., Methods: Sixteen cardiac surgeons declared their preferred CABG configuration using bilateral internal mammary and radial arteries for each of 5 patients who had differing degrees of severe triple vessel coronary disease. Surgeons selected both a preferred 'aortic' strategy, with at least one graft arising from the ascending aorta, and a preferred "anaortic" strategy which could be performed as a "no-aortic touch" operation. CT coronary angiograms of the 5 patients were coupled to CFD models using a novel flow solver "COMCAB." Twelve different CABG configurations were compared for each patient of which 4 were "aortic" and 8 were "anaortic." Surgeons then selected their preferred grafting configurations after being shown predictive hemodynamic metrics including functional assessment of stenoses (instantaneous wave-free ratio; fractional flow reserve), transit time flowmetry graft parameters (mean graft flow; pulsatility index) and myocardial perfusion., Results: A total of 87.5% (7/8) of "anaortic" configurations compared to 25% (1/4) of "aortic" configurations led to unsatisfactory grafts in at least 1 of the 5 patients ( P = 0.038). The use of the computational models led to a significant decrease in the selection of unsatisfactory grafting configurations when surgeons employed "anaortic" (21.25% (17/80) vs. 1.25% (1/80), P < 0.001) but not "aortic" techniques (5% (4/80) vs. 0% (0/80), P = 0.64). Similarly, there was an increase in the selection of ideal configurations for "anaortic" (6.25% (5/80) vs. 28.75% (23/80), P < 0.001) but not "aortic" techniques (65% (52/80) vs. 61.25% (49/80), P = 0.74). Furthermore, surgeons who planned to use more than one unique "anaortic" configuration across all 5 patients increased (12.5% (2/16) vs. 87.5% (14/16), P <0.001)., Conclusions: "COMCAB" is a promising tool to improve personalized surgical planning particularly for CABG configurations involving composite or sequential grafts which are used more frequently in anaortic operations., Competing Interests: AP was employed by New Zealand eScience Infrastructure (NeSI). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Chaudhuri, Pletzer, Waqanivavalagi, Milsom and Smith.)

A discoid meniscus is a congenital abnormality that usually affects the lateral meniscus, leading to instability and increased risk of tearing. A discoid medial meniscus is an extremely rare pathology that is seldom described in literature. In this report, we present the technique of operative treatment of a symptomatic, torn discoid medial meniscus. The meniscus is saucerized to 6-8 mm of stable rim, and the inside-out technique is used as the modality of meniscal fixation. Although a discoid medial meniscus is an uncommon finding, all treating surgeons should be aware of the possibility during surgical intervention., (© 2022 The Authors.)

Cardiac surgeons face a significant degree of uncertainty when deciding upon coronary artery bypass graft configurations for patients with coronary artery disease. This leads to significant variation in preferred configuration between different surgeons for a particular patient. Additionally, for the majority of cases, there is no consensus regarding the optimal grafting strategy. This situation results in the tendency for individual surgeons to opt for a "one size fits all" approach and use the same grafting configuration for the majority of their patients neglecting the patient-specific nature of the diseased coronary circulation. Quantitative metrics to assess the adequacy of coronary bypass graft flows have recently been advocated for routine intraoperative use by cardiac surgeons. In this work, a novel patient-specific 1D-0D computational model called "COMCAB" is developed to provide the predictive haemodynamic parameters of functional graft performance that can aid surgeons to avoid configurations with grafts that have poor flow and thus poor patency. This model has significant potential for future expanded applications., Competing Interests: Author AP is employed by New Zealand eScience Infrastructure (NeSI). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Chaudhuri, Pletzer and Smith.)

Background: Component positioning in total hip arthroplasty (THA) may be improved with utilization of intraoperative imaging. The purpose of this study is to determine if intraoperative imaging during THA is cost-effective., Methods: A break-even analysis was used as a model for cost-effectiveness, which incorporates cost of imaging (including direct charges and the additional time required for imaging), rate of revision surgery, and cost of revision surgery, yielding a final revision rate that needs to be achieved with use of intraoperative imaging in order for its use to be cost-effective. Absolute risk reduction (ARR) is determined by the difference between the initial revision rate and final revision rate., Results: At an anticipated institutional cost of $120 and requiring 4 additional minutes, intraoperative fluoroscopy would be cost-effective if the baseline rate of revision due to component mispositioning (0.62%) is reduced to 0.46%. Intraoperative flat plate radiographs ($127) are cost-effective at an ARR of 0.16%. Cost-effectiveness is achieved with lower ARR in the setting of lower imaging costs ($15, ARR 0.02%), and higher ARR with higher imaging costs ($225, ARR 0.29%). ARR for cost-effectiveness is independent of baseline revision rate, but varies with the cost of revision procedures., Conclusion: At current revision rates for component malpositioning, only 1 revision among 400 THAs needs to be prevented for the utilization of fluoroscopy (or 1 in 385 THAs with flat plate imaging), to achieve cost-effectiveness., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose of Review: The standard of care in meniscal tear management is constantly evolving, especially for athletes and high-demand patients. Meniscus repairs, meniscus transplants, and partial meniscectomies are commonly performed, and rehabilitation methods following these operations are becoming more sophisticated. The ultimate goal of these procedures is returning patients to full activity with minimal risks. Return to play should be systematic, pathology dependent, and individualized to an athlete's needs, expectations, and level of play. This article provides a review of the current treatment modalities of meniscus tears, the rehabilitation protocols following each modality, and the return to play criteria that must be met before releasing the player to competition. In addition, it overviews articles that describe performance outcomes of patients that have undergone meniscus surgery., Recent Findings: Current research shows high return to play rates for athletes that undergo meniscus surgery and describes effective rehabilitation protocols to facilitate recovery. There is an increased emphasis on meniscus preservation in recent literature. In addition, meniscus allograft transplantation has demonstrated its efficacy as a salvage procedure and has become a stronger consideration in the athlete with meniscus pathology. No standardized return to play protocol can be applied uniformly to all kinds of meniscal surgeries, and two athletes with the same pathology cannot be expected to follow identical paths towards full recovery. A multidisciplinary approach to care should be provided to the patients, and in the case of patients with high levels of athleticism, the road to recovery starts even before the injury itself., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: During the COVID-19 pandemic, thousands of pregnant women have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The implications of maternal SARS-CoV-2 infection on fetal and childhood well-being need to be characterized. We aimed to characterize the fetal immune response to maternal SARS-CoV-2 infection., Methods: We performed single-cell RNA-sequencing and T cell receptor sequencing on cord blood mononuclear cells (CBMCs) from newborns of mothers infected with SARS-CoV-2 in the third trimester (cases) or without SARS-CoV-2 infection (controls)., Results: We identified widespread gene expression changes in CBMCs from cases, including upregulation of interferon-stimulated genes and major histocompatibility complex genes in CD14 + monocytes, transcriptional changes suggestive of activation of plasmacytoid dendritic cells, and activation and exhaustion of natural killer cells. Lastly, we observed fetal T cell clonal expansion in cases compared to controls., Conclusions: As none of the infants were infected with SARS-CoV-2, our results suggest that maternal SARS-CoV-2 infection might modulate the fetal immune system in the absence of vertical transmission., Impact: The implications of maternal SARS-CoV-2 infection in the absence of vertical transmission on fetal and childhood well-being are poorly understood. Maternal SARS-CoV-2 infection might modulate the fetal immune system in the absence of vertical transmission. This study raises important questions about the untoward effects of maternal SARS-CoV-2 on the fetus, even in the absence of vertical transmission., (© 2021. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)

Food allergy affects an estimated 8% of children in the United States. Oral immunotherapy (OIT) is a recently approved treatment, with outcomes ranging from sustained tolerance to food allergens to no apparent benefit. The immunological underpinnings that influence clinical outcomes of OIT remain largely unresolved. Using single-cell RNA-Seq and paired T cell receptor α/β (TCRα/β) sequencing, we assessed the transcriptomes of CD154+ and CD137+ peanut-reactive T helper (Th) cells from 12 patients with peanut allergy longitudinally throughout OIT. We observed expanded populations of cells expressing Th1, Th2, and Th17 signatures that further separated into 6 clonally distinct subsets. Four of these subsets demonstrated a convergence of TCR sequences, suggesting antigen-driven T cell fates. Over the course of OIT, we observed suppression of Th2 and Th1 gene signatures in effector clonotypes but not T follicular helper-like (Tfh-like) clonotypes. Positive outcomes were associated with stronger suppression of Th2 signatures in Th2A-like cells, while treatment failure was associated with the expression of baseline inflammatory gene signatures that were present in Th1 and Th17 cell populations and unmodulated by OIT. These results demonstrate that differential clinical responses to OIT are associated with both preexisting characteristics of peanut-reactive CD4+ T cells and suppression of a subset of Th2 cells.

Recent developments in clearing and microscopy enable 3D imaging with cellular resolution up to the whole organ level. These methods have been used extensively in neurobiology, but their uptake in other fields has been much more limited. Application of this approach to the human heart and effective use of the data acquired present challenges of scale and complexity. Four interlinked issues need to be addressed: 1) efficient clearing and labelling of heart tissue, 2) fast microscopic imaging of human-scale samples, 3) handling and processing of multi-terabyte 3D images, and 4) extraction of structural information in computationally tractable structure-based models of cardiac function. Preliminary studies show that each of these requirements can be achieved with the appropriate application and development of existing technologies., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objectives: There is increasing interest regarding the risks and benefits of intrawound antibiotics applied directly to surgical wounds for the prevention of infection following orthopaedic trauma surgery. The purpose of this study was to investigate the economic justifiability of vancomycin and tobramycin powders for infection prophylaxis in orthopaedic trauma surgery., Methods: The cost of vancomycin and tobramycin powders, infection rates and costs of treating surgical site infections were obtained from our institution's records and existing literature. A break-even analysis was then performed using vancomycin powder only, tobramycin powder only and combined vancomycin and tobramycin powders to determine the respective absolute risk reduction (ARR) in infection rate needed to make the prophylactic application of each therapy type break-even., Results: At our institutional pricing of $20.64 and $75.80 for 1g vancomycin and 1.2g tobramycin, respectively, use of each individually would be economically justified if it reduced an average infection rate of 4.3% by an ARR of 0.02% and 0.07%, respectively. Used in combination for $90.66, the ARR was 0.09%. Varying cost of treating infection from $5,000-$200,000 while maintaining cost of antibiotic powder at $90.66 demonstrated a range in ARR from 1.93% to 0.05%, respectively. At the same cost of $90.66 but varying infection rate from 1% to 25% did not affect ARR, which was constant at 0.09%., Conclusions: Considering the cost of vancomycin and tobramycin powder at our institution, the application of these powders, whether independently or in combination, appear to be economically justifiable for infection prevention in orthopaedic trauma surgery., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Eosinophilic esophagitis (EoE) is an allergic disorder characterized by the recruitment of eosinophils to the esophagus, resulting in chronic inflammation. We sought to understand the cellular populations present in tissue biopsies of patients with EoE and to determine how these populations are altered between active disease and remission. To this end, we analyzed cells obtained from esophageal biopsies, duodenal biopsies, and peripheral blood of patients with EoE diagnosed with active disease or remission with single-cell RNA and T cell receptor (TCR) sequencing. Pathogenic effector T H 2 (peT H 2) cells present in the esophageal biopsies of patients with active disease expressed distinct gene signatures associated with the synthesis of eicosanoids. The esophageal tissue-resident peT H 2 population also exhibited clonal expansion, suggesting antigen-specific activation. Peripheral CRTH2 + CD161 - and CRTH2 + CD161 + memory CD4 + T cells were enriched for either a conventional T H 2 phenotype or a peT H 2 phenotype, respectively. These cells also exhibited substantial clonal expansion and convergence of TCR sequences, suggesting that they are expanded in response to a defined set of antigens. The esophagus-homing receptor GPR15 was up-regulated by peripheral peT H 2 clonotypes that were also detected in the esophagus. Finally, GPR15 + peT H 2 cells were enriched among milk-reactive CD4 + T cells in patients with milk-triggered disease, suggesting that these cells are an expanded, food antigen-specific population with enhanced esophagus homing potential., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Recent advances in high-throughput T cell receptor (TCR) sequencing have allowed for new insights into the human TCR repertoire. However, methods for capturing antigen-specific repertoires remain an area of development. Here, we describe a potentially novel approach that utilizes both a biological and statistical enrichment to define putatively antigen-specific complementarity-determining region 3 (CDR3) repertoires in unselected individuals. The biological enrichment entailed FACS of in vitro antigen-activated memory CD4+ T cells, followed by TCRβ sequencing. The resulting TCRβ sequences were then filtered by selecting those that are statistically enriched when compared with their frequency in the autologous resting T cell compartment. Applying this method to define putatively peanut protein-specific repertoires in 27 peanut-allergic individuals resulted in a library of 7345 unique CDR3β amino acid sequences that had similar characteristics to other validated antigen-specific repertoires in terms of homology and diversity. In-depth analysis of these CDR3βs revealed 36 public sequences that demonstrated high levels of convergent recombination. In a network analysis, the public CDR3βs were shown to be core sequences with more edges than their private counterparts. This method has the potential to be applied to a wide range of T cell-mediated disorders and to yield new biomarkers and biological insights.