Journal of Experimental Medicine

RIG-I is a cytosolic immune receptor that provides the first line of defense by detecting viral RNA and triggering antiviral responses. Its physiological role in humans remains unclear, as no patients with complete RIG-I deficiency have yet been reported. We identified a critically ill COVID-19 patient with severe RIG-I deficiency caused by heterozygous RIG-I G731R, a novel dominant loss-of-function variant. The G731R mutation in helicase motif VI disrupts the arginine finger, impairing the ATPase activity of RIG-I, but not its RNA-binding ability. However, viral RNA binding fails to expose the signaling domains, thereby impairing the IFN-{beta} response of G731R. Instead, G731R competes with wild-type RIG-I, exerting a dominant negative effect. The loss-of-function is caused by bulky-charged substitutions at G731, as alanine or leucine substitution results in an unexpected gain-of-function phenotype. These findings highlight the importance of uncompromised RIG-I function for human antiviral immunity and the pleiotropic effects of single mutations.

Sjogrens disease (SjD) is a chronic autoimmune disorder characterized by inflammation of the exocrine glands, leading to dry mouth and dry eyes. This study investigates the role of interleukin-9 (IL-9) and T helper 9 (Th9) cells in the pathogenesis of SjD. We found that serum IL-9 levels were significantly elevated in SjD patients and correlated with clinical laboratory parameters, including autoantibody production. In a mouse model of SjD, IL-9 and Th9-associated cytokines were also elevated, and Th9 cells were enriched in the salivary glands. Our results suggest that IL-9 is produced by multiple cell types, including macrophages, CD4+ T cells, and NK cells, and that Th9 cells contribute to the development of SjD by promoting inflammation and autoantibody production. We also found that Th9 and Th17 polarization conditions increased Th2 and Th17 cells in SjD mice, indicating a shared epigenetic program that renders T cells permissive to multiple differentiation pathways. Anti-IL-9 treatment had a sex-dependent effect, reducing autoantibody production in male mice but worsening focal glandular infiltration in female mice. Our findings suggest that IL-9 plays a complex role in SjD pathobiology, contributing to both local immunoregulation and systemic autoantibody response. Overall, this study offers new insights into the role of IL-9 and Th9 cells in SjD, highlighting the potential for therapeutic targeting of the IL-9/Th9 axis in the treatment of this disease.

BackgroundGastroenteric tract requires robust tolerogenic mechanisms to tolerize foreign antigens like foods and microbiota. This is critical to establish the immune homeostasis, which upon disruption, might contribute to a plethora of atopic disorders, including food allergy and eosinophilic esophagitis (EOE). Recently, there was a new subset of tolerizing dendritic cells (tolDCs), PRDM16 tolDC, discovered in the gut of mice and humans, which confers protection against food allergy. Whether an analogous population of it exist in the esophagus is unknown, especially in the context of EOE, another atopic disease associated with dietary antigens. MethodsWe thoroughly analyzed the human esophagus cell atlas single cell RNA-seq dataset and the myeloid DC-VERSE dataset, in an attempt to identify and characterize the esophageal counterpart of the intestinal PRDM16 tolDC. ResultsWe identified the esophageal counterpart of intestinal PRDM16 tolDC as a conventional type II DC subtype expressing PRDM16, termed as cDC2C (PRDM16). We demonstrated the similarities between PRDM16 tolDC and cDC2C (PRDM16) regarding their transcriptomic and functional profiles. Importantly, we found that cDC2C (PRDM16) were expanded during EOE and exhibited an anti-inflammatory phenotype, suggesting their protective role in EOE. Notably, these tolerogenic DCs were not found in other atopic diseases beyond the gastroenteric tract. ConclusionsWe here defined a novel tolerogenic DC population in human esophagus and demonstrated their implications in the pathophysiology of EOE. These findings would provide novel insights towards the tolerogenic mechanisms along the gastroenteric tract and possess translational relevance for EOE diagnosis and interventions.

The Endoplasmic Reticulum AminoPeptidase 2 (ERAP2) gene encodes an aminopeptidase involved in antigenic peptide processing for the MHC-I pathway. Genetic variants in the ERAP2 gene are associated with autoimmune conditions and infectious diseases. The linkage between genetic variants in the ERAP2 gene has given rise to the prevailing assumption that a single ERAP2 allotype with invariant amino acid sequence accounts for all immunological functions of ERAP2. Here, we show by analyzing exon-sequencing data from 160,000 individuals that 15 missense amino acid variants across the ERAP2 gene result in an array of different protein allotypes that are maintained in the European population. These allotypes can be divided into three haplotype groups, defined by the genotypes of two common splice-altering variants. We found novel associations between newly identified protein allotypes and immune-mediated diseases, suggesting that ERAP2 functional variation modifies disease susceptibility at the population level. An MHC class I antigen presentation assay revealed that disease-associated ERAP2 allotypes differ in their capacity to generate antigenic peptides for MHC-I presentation, resulting in differential activation of an antigen-specific T-cell receptor compared to non-disease-associated allotypes. These findings provide strong evidence that ERAP2 function is allotype-dependent and demonstrate that ERAP2 diversity shapes MHC-I antigen presentation and T-cell immunity. Significance statementThe ERAP2 enzyme modulates adaptive immunity and plays a role in autoimmunity, infection, and cancer. The authors discovered that a variety of protein allotypes of ERAP2 are maintained in the human population. Allotypes that increase disease risk for autoimmune and cardiovascular conditions are functionally distinct in their capacity to activate T-cells. The results of this study demonstrate that ERAP2 is a functionally diverse immune modulator that contributes to immune variation and influences susceptibility to immune-mediated diseases.

Antimicrobial peptides (AMPs) are essential components of the innate immune system, exhibiting diverse mechanisms of action. This study investigates the roles of cathelicidin (LL-37), alpha-defensins, and the S100 proteins S100A8 and S100A9 in systemic inflammation associated with sepsis, severe COVID-19, and acute pancreatitis using whole-blood bulk RNA-sequencing data. Gene co-expression network analysis revealed that during septic shock and severe COVID-19, cathelicidin and alpha-defensins act synergistically in innate immune responses, while S100A8 and S100A9 function through distinct pathways related to mitochondrial metabolism and ubiquitin ligase binding. In contrast, the acute pancreatitis network displayed a different pattern, with CAMP co-expressed alongside S100A8 and S100A9, whereas alpha-defensins were downregulated and associated with inhibited mucosal immune responses. These findings suggest that antimicrobial peptides contribute variably to systemic inflammation depending on the underlying insult, underscoring their complex, context-dependent roles in critical illness.

Immune checkpoint inhibitors (ICIs) have transformed cancer treatment but commonly cause immune-related adverse events (irAEs), whether administered as monotherapy or in combination with other oncological agents. We present the first reported case of ICI-induced granulomatous sialadenitis in a male patient in his mid-fifties with BRAF-V600E-mutated papillary thyroid carcinoma who received sequential treatment with BRAF/MEK inhibitors followed by pembrolizumab. The patient experienced acute-onset severe xerostomia and salivary hypofunction, prompting ICI cessation and salivary gland biopsy. Integrative analysis using histology, single-cell RNA sequencing, and spatial transcriptomics revealed macrophage- and T-cell-mediated epithelial damage driven by epithelial senescence and Th1-polarized inflammation. Corticosteroid therapy reduced granuloma burden and improved salivary flow rates and tissue architecture; however, extensive fibrosis persisted despite treatment. These findings underscore the critical importance of early irAE recognition and intervention to preserve glandular function and enable continuation of cancer therapy.

BackgroundAn adverse female sex-bias exists across many autoimmune disorders, yet its underlying mechanisms, particularly the role of sex hormones, remains poorly understood. Furthermore, the physiological influence of sex hormones in regulating T cell function remains undefined. We examined for the critical role of estrogen and progesterone, in regulating CD4+ T cell responses, specifically with respect to inflammation and their bone erosion potential in RA. MethodsInflammatory markers, circulating antibodies, sex hormone receptors, ER and PR levels were investigated in both RA patients and controls. Further, RA CD4+ T cells were stimulated in varying concentrations of estradiol and progesterone and assessed for modulation in cytokines, transcription factors, RANKL, and FasL expression. Subsequent ex-vivo studies were performed to examine the role of sex hormones in modulating T cell responses. ResultsRA patients displayed systemic inflammation and high circulating antibodies, with significantly higher expression in synovial fluid. Higher expression of ER and PR was evinced on RA CD4+ T cells. Upon hormone stimulation, two cohorts of patients namely responders and non-responders were observed with respect to modulation in cytokines, transcription factors, RANKL, and FasL expression. Our ex-vivo Th1 and Th17 cells demonstrated that sex hormones play a physiological role in modulating inflammation and have bone erosion potential. ConclusionOur findings demonstrate the pivotal significance of sex hormones in modulating TCR responses, thereby regulating inflammation and bone erosion in RA pathology. Further dissection of TCR signaling pathways with respect to sex hormone stimulation may provide promising targets for therapeutic implications. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/25342530v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@b74525org.highwire.dtl.DTLVardef@1cc01aorg.highwire.dtl.DTLVardef@1881e4forg.highwire.dtl.DTLVardef@17de2a8_HPS_FORMAT_FIGEXP M_FIG C_FIG

Epstein-Barr virus (EBV) is strongly implicated as an essential environmental trigger of multiple sclerosis (MS), yet the host genetic mechanisms governing EBV activity and how infection triggers the disease are not known. We developed a pipeline to quantify EBV DNA from whole-genome sequencing data and applied it to population-scale cohorts. Using this pipeline, we performed a cross-ancestry genome-wide association study (GWAS) of EBV DNA positivity in 617,186 individuals and identified 39 independent susceptibility risk loci, with the strongest associations in the HLA region. We validated this finding in our independent cohort (N=94) and found that quantitative PCR (qPCR)-confirmed EBV DNA positive individuals were enriched in the top decile of EBV polygenic risk scores (PRS) containing newly discovered loci. A significant overlap with genetic variants associated with MS risk was observed. PRS and Mendelian randomization analyses further supported a causal role of EBV activity on MS risk, which was also seen in other autoimmune diseases. A meta-analysis of qPCR based case-control studies showed elevated EBV DNA positivity in MS. By establishing a single-cell RNA-seq method optimized for EBV detection, we identified EBV-infected B cells, primarily in memory B cells, atypical B cells and antibody-secreting cells from MS and healthy individuals. Notably, EBV-infected memory B cells and atypical B cells showed strong upregulation of cytokines and costimulatory signals that influence T cell activation, IFNg secreting Tregs, and regulators of B cell differentiation and survival. EBV-infected memory B cells also upregulated risk genes from both the EBV and MS GWAS, suggesting that EBV-infected B cells constitute a critical hub that modulates T cell responses while simultaneously activating MS susceptibility pathways within the B cell compartment. Together, these findings define a genetic and cellular framework linking EBV infection to the initiation of MS.

Antiphospholipid syndrome (APS) and systemic sclerosis (SSc) are immune-mediated multisystem autoimmune diseases with distinct clinical phenotypes but overlapping pathogenic themes, including immune dysregulation, chronic inflammation, and endothelial injury. Using peripheral blood transcriptome datasets from the Gene Expression Omnibus (GSE102215: 9 APS/9 controls; GSE231691: 49 SSc/18 controls), we performed differential expression analysis within each cohort (limma; |log2FC|>1, P<0.05) and identified 281 genes dysregulated in the same direction in both diseases (100 upregulated and 181 downregulated). Enrichment analyses highlighted interferon-related and cytokine/inflammatory signaling programs in APS and SSc. To derive a compact diagnostic signature, we combined random forest feature ranking with a single-hidden-layer artificial neural network, prioritizing five shared candidate biomarkers (S100A8, IER5L-AS1, LTK, PRR5-ARHGAP8, and PCDH1). Each gene showed consistent case-control differences in both cohorts (P<0.001) and achieved good discrimination (AUC>0.75), with S100A8 performing most consistently (AUC=0.98 in APS; AUC=0.88 in SSc). CIBERSORT deconvolution indicated a myeloid-skewed blood profile in both diseases, characterized by higher neutrophil and monocyte/macrophage signals; SSc additionally showed stronger inferred CD4+ T cell and NK cell signals. S100A8 expression correlated with inferred neutrophil abundance in both cohorts (APS r=0.62; SSc r=0.58; P<0.05). Finally, miRNA-target prediction and DSigDB drug-signature enrichment generated regulatory and pharmacologic hypotheses, including immune-regulatory miRNAs (e.g., miR-155 and miR-146a) and candidate compounds (celecoxib, tamibarotene, HMN-176, and XMD14-99). Overall, these results nominate shared blood transcriptional markers and immune correlates across APS and SSc for follow-up validation.

BackgroundCervical cancer is one of the most common malignant tumors of the female reproductive system. Existing treatments provide limited benefit for patients with advanced, recurrent or metastatic disease, and reliable prognostic markers are lacking. In this study we integrated multi-omic data from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database. Protein-coding genes meeting the criteria of an adjusted P value < 0.05 and |log2 fold-change| > 5 were screened; 693 genes were identified. We further focused on three genes related to the tumor microenvironment--interleukin 21 (IL21), C-X-C motif chemokine ligand 9 (CXCL9) and cluster of differentiation 1A (CD1A)--and performed differential expression analysis, survival analysis, clinical stage analysis and immune infiltration correlation analysis to clarify their prognostic value and potential mechanisms in cervical cancer. Results(1) CXCL9 and CD1A were highly expressed in cervical cancer tissues, and all three genes showed high expression across different pathological stages without stage-dependent differences; (2) high expression of IL21, CXCL9 and CD1A improved patient prognosis and was positively associated with overall survival (OS), disease-specific survival (DSS) and progression-free interval (PFI); (3) expression of IL21, CXCL9 and CD1A was closely correlated with infiltration of multiple immune cells: IL21 correlated with total T cells, helper T cells and B cells, CXCL9 correlated with T cells and activated dendritic cells, and CD1A correlated with immature dendritic cells. ConclusionIL21, CXCL9 and CD1A are potential prognostic biomarkers and key immunomodulatory factors in cervical cancer. This study provides a new direction for immunotherapy and individualized precision treatment of cervical cancer.

Multiple sclerosis (MS) therapies primarily rely on lymphocyte depletion or trafficking blockade, carrying risks of systemic immunosuppression; however, such treatments have limited efficacy in secondary progressive multiple sclerosis (SPMS). Thus, drugs that target stage-specific inflammation without broad immunosuppression are an unmet clinical need. In this double-blind, placebo-controlled phase II trial, 30 patients with relapsing MS received weekly oral OCH or placebo for 24 weeks. In the pre-specified SPMS subgroup (n=12), OCH achieved complete relapse prevention (p=0.0003), prolonged relapse-free survival (p=0.0079), no new lesions (0/6), with no evidence of disease activity (NEDA-3) in 5/6 patients. In comparison, for the placebo-treated group, 5/6 patients suffered relapses, 2/6 patients developed new lesions, and no placebo-treated SPMS achieved NEDA-3. Invariant natural killer T (iNKT) cells, a regulatory lymphocyte population that is numerically and functionally impaired in MS, are a potential target for MS therapy. Glycolipid OCH is a selective iNKT cell stimulator, skewing the cytokine environment towards Th2. OCH treatment resulted in increased IL-4-producing Th cells in patient peripheral blood while decreasing pathogenic GM-CSF-producing Th cells. Parallel studies in mouse models of MS (EAE) corroborated this mechanism and further revealed that OCH activated gut iNKT cells. Disease amelioration by OCH depended on IL-4 and its efficacy was further enhanced by depletion of B cells. These data revealed the gut-brain axis mediation of progressive-stage pathology distinct from relapsing-remitting MS. Findings from this bidirectional translational study uncover mechanistic differences between SPMS and other types of MS and highlight divergent roles for B cells and Th cells. Furthermore, OCH exerts its therapeutic benefit via targeting mechanisms that are distinct from currently available drugs; exploiting iNKT cell regulatory potential to reprogram pathogenic T helper responses without lymphocyte depletion. The unique yet effective nature of OCH treatment positions it as an attractive future oral therapy for SPMS. One Sentence SummaryThe iNKT cell activating ligand OCH suppresses disease activity selectively in secondary progressive MS in a phase II clinical trial, revealing stage-specific IL-4-mediated immune cell interactions in MS pathology.

AimsGestational diabetes mellitus (GDM) is the most common pregnancy-related medical complication. GDM is linked to aberrant immune responses in both mothers and offsprings, specifically, the subsequent development of inflammatory diseases. Whereas prior research has focused on specific immune cell subsets, a comprehensive overview of the impacts of GDM on maternal and fetal immune landscape is lacking. Here, we aim to comprehensively decipher how GDM modulates various immune cell populations in mothers and offsprings. MethodsA prospective, longitudinal case-control study was carried out. Maternal blood from GDM-affected (GDM, n=18) and non-GDM-affected (Ctrl, n=21) mothers were collected at ante-(36-38 weeks of gestation) and post-partum (6-8 weeks post-partum) timepoints. Cord blood from GDM (n=7) and Ctrl (n=11) pregnancies were collected upon C-section. They were analyzed with the state-of-the-art cytometry by time of flight (CyTOF) with a 40-marker panel. Additionally, a publicly available RNA-seq dataset for cord blood mononuclear cells was re-analyzed to confirm results from CyTOF experiments. ResultsCompared to Ctrl, GDM was associated with more activated maternal T cell subsets ante-partum, including increased CD45RO+ and Ki67+ CD4+ T cell populations, which reverted post-partum. GDM-affected maternal innate lymphoid cell (ILC) also exhibited increased granzyme B production ante-partum. On the other hand, in GDM-impacted cord blood, fetal T and B cells were more activated, displaying less naive and more effector phenotypes, further supported by RNA-seq analyses. ConclusionsOur comprehensive analyses revealed that GDM is linked to profound changes in the immune landscapes of the mothers (ante-/post-partum) and foetuses (at birth), casting novel insights towards GDM pathophysiology. Longitudinal immune profiling might be warranted for early detection and stratification of risk, and development of targeted interventions to prevent inflammatory disorders in GDM mothers and their offspring. Research in contextO_LIWhat is already known about this subject? O_LIThe maternal and intrauterine environments are important contributors to long-term health outcomes of mothers and offsprings. C_LIO_LISome maternal and fetal immunity changes have been observed in gestational diabetes mellitus (GDM)-affected pregnancies. C_LIO_LIGDM is associated with increased risk of later-life metabolic and inflammatory diseases in mothers as well as offsprings. C_LI C_LIO_LIWhat is the key question? O_LIWhat are the longitudinal alterations in maternal and fetal immune landscapes in GDM-affected pregnancies? C_LI C_LIO_LIWhat are the new findings? O_LIHigh-dimensional immune profiling provided the most comprehensive overview of alterations in maternal and fetal immune landscapes associated with GDM. C_LIO_LIGDM is associated with skewing of maternal CD4+ T cell and ILC towards activated phenotypes ante-partum. C_LIO_LIGDM is linked to more activated fetal T and B cell profiles. C_LI C_LIO_LIHow might this impact on clinical practice in the foreseeable future? O_LIUnderstanding the complex alterations in the maternal and fetal immune landscape in GDM-affected pregnancy provides insights into the long-term impacts of GDM on the mother and offspring. C_LI C_LI

Vaccination frequently elicits suboptimal immunogenicity in organ transplant recipients, particularly those on long-term immunosuppressive therapy, highlighting the need for improved understanding of immunosuppression mechanisms and optimized vaccination strategies. This study enrolled a cohort of 132 individuals and observed significantly lower antibody levels in kidney transplant recipients (KTRs) compared to non-transplant controls (non-KTRs). Antibody levels were inversely associated with both the dosage and duration of immunosuppressive therapy. Complementary small animal studies demonstrated that immunosuppressive treatment dosage-dependently and reversibly impaired antibody production, primarily by depleting immune cells, notably B cells. A single shot of adenoviral vector-based vaccines demonstrated enhanced immunogenicity relative to two shots of alum-adjuvanted protein vaccines, inducing potent neutralizing antibodies (NAbs) and a Th1-biased T-cell response even under continuous immunosuppression. The enhanced response was driven by reduced interference from pre-existing antibodies, sustained transgene expression, and the reprogramming of lipid metabolism to activate T and B cells. Our findings advocate for tailored vaccination strategies, positioning adenoviral vectors as a candidate modality for this vulnerable population.

In this study, we provide a comprehensive characterization of the alveolar immune landscape in patients suffering from severe acute respiratory failure, predominantly caused by pneumonia or acute respiratory distress syndrome, conditions defined by intense pulmonary inflammation and immune dysregulation. Despite diverse underlying causes, the overall composition of alveolar immune cells was largely consistent, with neutrophils and macrophages comprising the majority of cells. However, the maturation and activation states of immune cell subsets varied significantly, not only between patients with and without pneumonia, but also among pneumonia cases stratified by pathogen type. We also observed dynamic shifts in immune cell subsets over the disease course and found that an increased proportion of CD123bright immature neutrophils and a reduction in alveolar resident macrophages were associated with increased 28-day mortality. Integration with alveolar cytokine profiles revealed strong correlations between immune cell populations and the local cytokine milieu. These findings highlight the importance of assessing immune cell function, not merely abundance, through broad and longitudinal investigation to better understand the pathophysiology of acute respiratory failure and to guide precision immunomodulatory therapy.

PurposeSepsis-associated immunothrombosis significantly contributes to high mortality, yet the role of N-glycosylation in this process remains poorly understood. This study aimed to comprehensively profile the plasma N-glycosylation landscape in sepsis and elucidate how its specific reprogramming in the complement and coagulation cascades influences immunothrombotic balance and patient outcomes. MethodsWe performed in-depth 4D-DIA proteomic and N-glycomic analyses on plasma from 43 sepsis patients and 9 healthy controls. Differential expression, weighted gene co-expression network analysis (WGCNA), and protein-glycosylation correlation analyses were used to characterize molecular features. Clinical relevance was assessed via correlation and survival analyses. ResultsExtensive N-glycosylation reprogramming was observed in sepsis plasma,with marked enrichment in complement and coagulation pathways(KEGG p=7.76x10- {superscript 2}{superscript 1}).Pro-coagulant proteins(eg,vWF,fibrinogen)showed increased abundance together with enhanced site-specific glycosylation,potentially amplifying their activity.In contrast,key anticoagulant proteins(eg,SERPINC1)displayed unchanged glycosylation at critical sites despite abundance changes,which may impair function.Survival analysis revealed distinct prognostic values of glycoproteins and specific glycosylation sites.For instance,high vWF protein levels predicted mortality(HR=2.83),whereas elevated glycosylation at vWF N211 was associated with improved survival(HR=0.135),suggesting a negative regulatory role.These glycosylation markers correlated closely with disease severity and prognosis,representing potential early-warning biomarkers independent of current clinical coagulation indicators. ConclusionOur study demonstrates widespread reprogramming of the plasma proteome and N-glycome in sepsis.We propose that decoupling of protein function from abundance through N-glycosylation in the complement-coagulation network contributes to immunothrombotic imbalance.Specific N-glycosylation sites may serve as novel prognostic biomarkers,offering new perspectives for early risk stratification and glycosylation-targeted therapies in sepsis. Key PointsO_LISepsis plasma exhibits specific N-glycosylation reprogramming overwhelmingly focused on the complement and coagulation cascade. C_LIO_LIA dominant "glycosylation-dominated co-upregulation" mode in procoagulant factors, coupled with a "silent" glycosylation state in key anticoagulants, drives prothrombotic imbalance. C_LIO_LISite-specific N-glycosylation levels provide prognostic information distinct from, and often superior to, their carrier protein abundance, offering novel early-risk biomarkers. C_LI

BackgroundAtopic dermatitis (AD) is a chronic skin disease that typically occurs in early childhood. In this cross-sectional case-control study, our objective was to employ machine learning approaches to identify novel clusters of protective or susceptibility features associated with AD. Methods and FindingsWe utilised an integrated dataset comprising previously established environmental, cytokine, antibody, and gene expression data from AmaXhosa children, both healthy and with AD, living in either rural or urban settings of South Africa, aged 12-36 months. The applied machine learning methods included the GeneSelectR workflow to identify a subset of relevant genes, the calculation of SHAP values to explain the machine learning output, and the use of DIABLO to integrate the datasets for a comprehensive analysis. Key findings included the identification of a protective cluster of environmental features primarily found in the rural setting, which were correlated with plasma cytokine levels and with expression of autophagy-related genes. Additionally, we identified AD susceptibility clusters where levels of allergen-specific and total IgE antibodies correlated with the cytokines MCP-4 and TARC. Lastly, we identified an RNA-Seq feature signature specific to the disease endotype. ConclusionsThe application of various machine learning methods enabled the identification of significant factors associated with AD in a complex, multi-modular dataset, making the output explainable and potentially informing targeted interventions and improved diagnostic criteria.

Haemorrhage is the leading preventable cause of trauma death, primarily through ischaemic consequences that current treatments cannot adequately address. We combined human transcriptomic data (n=458) with a controlled porcine model of haemorrhagic shock to identify treatment-responsive molecular mechanisms. Using latent factorisation, we prioritised distinct molecular signatures of the human shock response, including stress signalling, neutrophil activation, and cytotoxic lymphocyte programmes. We assessed the behaviour of these pathways in the experimental porcine system, revealing that shock-initiated immune trajectories are not immutable: blood resuscitation normalised maladaptive transcriptomic changes whilst noradrenaline exacerbated them. While resuscitation modulated neutrophil, heat-shock, and barrier defence programmes, interferon and coagulation pathways were neither mortality-predictive nor treatment-responsive. A factor representing p38-MAPK/AP-1 stress signalling emerged as the dominant mortality-predictive pathway. An in silico small molecule screen identified p38 inhibitors as leading candidates for reversing shock-induced transcriptomic signatures. Our framework identifies modifiable pathways in trauma shock, prioritising p38-MAPK inhibition for therapeutic development and providing a systematic approach for trauma drug repurposing. One sentence summary: Human-porcine cross-analysis reveals treatment-modifiable molecular signatures of trauma shock, identifying potential therapeutic strategies.

A role for substance P in promoting neurogenic inflammation and pain has been described in sickle cell disease (SCD). However its origin and contribution to SCD pathophysiology remain unclear. We measured substance P level in plasma from 225 patients with SCD and observed the highest concentrations during acute chest syndrome (ACS). Therefore, we tested the hypothesis that substance P may induce ACS. In transgenic sickle mice, unlike control mice, intravenous injection of substance P caused lethal crises with dose-dependent acute lung injuries. Activation of Fc{varepsilon}R1 with MAR-1 had similar effects, suggesting a role for mast cell or basophil activation and degranulation. Pretreatment of sickle mice with cromolyn, a stabilizer of mast cells and basophils, prevented lethal crisis and lung injuries induced by substance P injection. In SCD patients, blood cellular histamine levels and increased histidine decarboxylase activity were consistent with an involvement of circulating basophils. Flow cytometry analysis revealed higher basophil counts with increased activation and degranulation markers in patients compared with healthy controls. During vaso-occlusive crisis, absolute basophil counts tended to decrease, suggesting their recruitment outside the vascular compartment. The same results were observed in sickle mice after hypoxia-reoxygenation, intravenous hemin injection or substance P injection. Immunohistochemistry revealed the presence of mast cells and basophils in the lungs of sickle mice, but not in control mice, with further basophil recruitment and degranulation after intravenous substance P injection. In SCD patients, we observed extremely high levels of substance P in the sputum collected during ACS, consistently with mast cell and basophil degranulation in the lungs. In vitro, substance P was shown to be a potent chemoattractant for basophils via NK1R. Gene expression analysis on sorted circulating basophils from SCD patients revealed an increased expression of several chemokine receptors, including CCR3 and FPR1, which was confirmed by spectral flow cytometry and could contribute to the recruitment of basophils in the lungs. The two substance P receptors, NK1R and MRGPRX2, were also overexpressed, promoting the vicious cycle of substance P release and pain in SCD patients. Our results reveal a novel mechanism that contributes to the understanding of ACS pathogenesis and highlights the potential role of mast cells and basophils in SCD pathophysiology.

The host response to traumatic injury is varied and unpredictable. Patients with subjectively similar injuries progress along divergent clinical paths, from uncomplicated recovery to extended hospitalisation, multiple organ dysfunction, and life-long ill health. The temporal certainty of trauma nonetheless provides immediate opportunity to predict clinical trajectory and intervene therapeutically. We demonstrate using machine-learning that the hyperacute plasma proteome can function as a physiology-driven indicator of injury severity. Moreover, it identifies two serious-injury endotypes that differentially predict unfavourable clinical trajectories. Notably, a prominent neuronal guidance protein signature, that reports vascular dysfunction and immune activation, together with an anti-coagulation/pro-fibrinolytic state, identify those patients who progress to adverse clinical outcomes. Together, these mechanistic insights into immediate host responses to serious trauma reveal tractable targets for future therapeutic interventions.

Identification of early interventions to reduce/eliminate asthma - the most common chronic disease among children - could significantly reduce burden on the healthcare system. Large-scale asthma Exposome-Wide Association Studies (ExWAS) could identify potential interventions, however integration of diverse data is required to address association confounders. The CHILD Cohort Study has followed 3,454 healthy Canadian children and their families from early pregnancy, collecting exceptionally diverse data including 24,852 variables from participant questionnaires, clinical data, household and neighbourhood-level exposures, and sample-derived chemical analytic/omic datasets. Here, we report integration of these datasets into the CHILDdb database platform, and use these data to perform ExWAS and machine learning analyses, identifying and further characterizing associations between childhood asthma and 2,954 diverse early exposures (pregnancy to age 5). Significant asthma associations include antibiotic use, human milk components, DEHP phthalate, and mothers prenatal cleaning product/disinfectant exposure. Subsequent analysis revealed epigenetic changes in the cord blood at birth, after prenatal cleaner exposure, and different microbiome and/or inflammatory cytokine changes associated with different asthma-associated exposures in the child. Collective results support asthma as a heterogeneous condition involving multiple etiologies, with associated endotypes, including prenatal exposures with potential transgenerational effects, and suggest targets for early interventions.