Genes & Immunity

Abstract/SummaryInnate immune responses are crucial for host defence but vary markedly between individuals. Although determinants of this variation are well characterised in adults, data from healthy children remain scarce. We therefore profiled whole-blood cytokine responses to innate immune stimulation in 286 children aged approximately four years and examined genetic, host-intrinsic, and environmental correlates of response. Cytokine responses showed marked inter-individual heterogeneity and stimulus-specific patterns. The top 50 genetic variants explained a substantial proportion ([~]20-45%) of this variance across many stimulus conditions, including a biologically coherent association of the STING locus with cGAMP-induced cytokine production. In contrast, sex, age, adiposity, and perinatal variables showed limited or modest associations. Systemic inflammatory biomarkers of systemic inflammation (hsCRP, glycoprotein acetyls, granulocyte-to-lymphocyte ratio) were strongly positively associated with cytokine responses. Finally, seasonal population-level viral infection burden was positively associated with antiviral and inflammatory cytokine responses. Collectively, these findings advance our understanding of variation in early-life whole-blood cytokine responses, underscoring this developmental period as a critical window for understanding immune development trajectories relevant to long-term health.

Celiac disease (CD) is strongly associated with specific HLA DQ heterodimers, formed by HLA DQA1 and HLA DQB1 proteins. In particular DQ2.5 (DQB1*02 associated to DQA1*05) and DQ8 (DQB1*03:02 with DQA1*03) are present in virtually all celiac patients. HLA DQB1*02 is considered the main single genetic susceptibility marker and has been reported in 90 to 95% of CD patients. However, the distribution of these alleles may vary across populations, potentially impacting the performance of genetic screening strategies. In this study, we evaluated the prevalence of HLA DQ2.5 and DQ8 genotypes in celiac patients (n = 41) and an unbiased general population cohort (n = 60) from San Luis, Argentina, using a PCR-based genotyping approach. In addition, we assessed the feasibility of a simplified saliva direct PCR protocol for large scale testing. Overall, 95.1% of CD patients carried DQ2.5 and/or DQ8. Notably, 41.5% of patients were DQ8(+)/DQ2.5(-), and 36.6% lacked the DQB1*02 allele, indicating that DQB1*02 based screening alone would have reduced sensitivity in this population. In the general population, 53.3% of individuals carried CD associated genotypes, with a markedly higher prevalence of DQ8 compared to European cohorts. Genotype distributions deviated from Hardy Weinberg equilibrium in CD patients but not in the general population. We show that DQB1*03:02 is a reliable proxy for DQ8, allowing simplification of genotyping strategies, whereas DQA1*05 typing remains essential to discriminate DQ2.5 from other lower risk DQB1*02 carrying heterodimers. We also describe a saliva direct PCR approach showing a performance comparable to purified DNA based assays. These findings highlight the importance of population specific genetic data for optimizing CD screening strategies and foster the development of simplified, cost effective genotyping approaches for large scale applications.

Macrophage activation syndrome (MAS) is driven by a hyperinflammatory response characterized by aberrant activation of lymphocytes and phagocytes. While monocytes and macrophages are thought to be important in MAS pathogenesis, their role remains poorly understood. We used bulk and single-cell RNA sequencing (RNA-Seq) on sorted monocytes from children with MAS and healthy controls to identify transcriptional changes during MAS. We defined a MAS signature in classical monocytes that correlated with ferritin and was elevated in monocytes from systemic lupus erythematosus and COVID-19 patients. We also identified a subset of classical monocytes with high levels of interferon-stimulated genes (ISGs) that expanded during MAS. Surprisingly, the transcriptional signature of these cells was driven by type I IFNs, rather than IFN{gamma}. Consistent with this finding, we detected increased levels of circulating IFN{beta} during MAS, suggesting that IFN{beta} plays an unrecognized role in driving MAS monocyte responses. We also identified a MAS-associated CD8+ T cell population with a distinctive transcriptional signature. We used cell-cell communication algorithms to predict increased immunoregulatory interactions between monocytes and T cells during MAS. Together, these results provide new evidence for a role for type I IFN during MAS and identify a unique CD8+ T cell population that may contribute to MAS pathophysiology.

Autoimmune diseases result from immune responses against self-antigens but exhibit marked phenotypic diversity shaped by genetic and environmental factors. Genome-wide association studies (GWAS) have identified susceptibility loci that inform polygenic scores (PGS) for risk prediction. This study integrates phenotypic and genetic data from the UK Biobank(UKB) to characterize disease overlap, genetic heterogeneity, and shared biological mechanisms across autoimmune conditions. Comorbidity patterns were further assessed using patient records from UKB and the TriNetX(TNX). Phenotypic data from 502,371 UKB participants were used to evaluate diagnostic overlap, with a subset of 104,544 individuals analyzed for PGS distributions. Significant variants were identified using genome-wide thresholds, allele frequency, and predicted impact, and shared genes were subsequently mapped to pathways using Hallmark gene sets. Comorbidity across rare and common autoimmune diseases was assessed in the UKB and TNX using ICD-10 codes, focusing on White individuals (71,069,654 in TNX; 502,371 in UKB). Odds ratios for 15 diseases were estimated, and cross-cohort comparisons evaluated reproducibility and cohort-specific differences. PGS analyses revealed both shared and distinct genetic architectures, indicating partial genetic overlap and supporting poly-autoimmunity. Integration of common, rare and impactful variants identified both known and novel gene associations, while pathway analysis highlighted systemic and tissue-specific immune dysregulation. Cross-dataset comparisons confirmed consistent comorbidity patterns but underscored the impact of dataset-specific factors, emphasizing the need for standardized approaches in autoimmune disease research.

Angiotensin-converting enzyme 2 (ACE2) is a key regulator of the renin-angiotensin-aldosterone system (RAAS). It also acts as a receptor for SARS-CoV-2 and stabilises the B0AT1 amino acid transporter at the cell surface. Therefore, surface expression of ACE2 is crucial for these physiological processes. ACE2 is released as a soluble, catalytically active form, partly through ectodomain shedding. This process mainly involves the sheddases ADAM10 and ADAM17, but the exact regulatory mechanisms remain unclear. We assessed 11 naturally occurring single-point mutations in the ACE2 stalk region. Most variants showed significantly reduced release compared to wild-type (WT) ACE2; however, the single point mutations P734L and G726R significantly increased their release. ACE2_P734L also exhibits higher surface expression, directly increasing the surface levels of B0AT1. Despite B0AT1 and ACE2 forming a tight tetrameric complex, this did not affect ACE2 shedding. This suggests that complex formation does not restrict sheddase access. Overall, these data identify the ACE2 stalk region as a major determinant of shedding efficiency. Naturally occurring variants in this region can substantially affect the release of soluble ACE2, potentially contributing to interindividual differences that are relevant for pathophysiological processes.

Thyroid cancer is a heterogeneous malignancy with variable outcomes, highlighting the need for reliable biomarkers and effective risk stratification. In this study, we implemented a multi-step integrative framework to identify distinct prognostic biomarker sets using transcriptomic data from 572 thyroid cancer patients. Correlation analysis followed by false discovery rate (FDR) correction revealed significant associations of genes. Notably, MAFF (r = 0.25, p = 1.34x10-, FDR = 2.46x10-), NR4A3 (r = 0.24, p = 1.26x10-, FDR = 9.25x10-), and SRF showed strong positive correlations, whereas LOC728264 (r = -0.21, p = 7.39x10-, FDR = 6.36x10-) and VAMP1 (r = -0.20, p = 1.20x10-, FDR = 1.3x10-) exhibited negative correlations with OS. Univariate Cox regression identified several survival-associated genes, including TMEM90B (HR = 10.66, p = 2.88x10-) and PTH1R (HR = 9.88, p = 5.55x10-). LASSO regression further identified 31 key prognostic genes, including 13 potential drug targets predominantly functioning as inhibitors. Machine learning models based on seven independent 20-gene biomarker sets effectively predicted Class 0 (0-1 years), Class 1 (1-3 years), Class 2 (3-5 years), and Class 3 (>5 years), achieving AUC values of 0.91-0.94 and Kappa up to 0.76. An ensemble model further improved prediction (AUC = 0.95, Kappa = 0.72). Incorporating clinical variables (age, gender, stage) enhanced model performance (AUC = 0.96, Kappa = 0.80). Reduced 10- and 5-gene subsets demonstrated consistent yet slightly lower performance (AUC = 0.90 and 0.86, respectively). Collectively, the 20-gene set exhibited the strongest predictive and prognostic potential, highlighting the importance of integrating molecular and clinical features for risk stratification in thyroid cancer.All data and code are openly available (https://github.com/raghavagps/THCA_prognostic_biomarkers), supporting future research in thyroid cancer prediction.

Abnormalities in the gut microbiome, intestinal permeability, and the gut-immune-brain axis are increasingly linked to neuropsychiatric disorders, neurodegenerative disorders, inflammatory bowel disease (IBD), and other immunologic/autoimmune conditions. We investigated these phenomena in 128 youth with Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS) and individuals with autism spectrum disorder (ASD) and other neurodevelopmental disorders (NDD) characterized by profound, unexplained deteriorations/regressions in developmental, neuropsychiatric, and behavioral functioning. Previous studies we have carried out showed that immune dysregulation and DNA damage response (DDR) gene mutations are implicated in a subset of these patients. The current study examines the role of genetic variants affecting intestinal homeostasis. We report a series of patients exhibiting both neuropsychiatric deterioration and gastrointestinal symptoms. Genetic analysis identified ultrarare (minor allele frequency < 0.001) pathogenic or likely pathogenic variants in eight genes primarily expressed in the intestines and associated with IBD, dysbiosis, or intestinal permeability. Across thirteen patients, mutations were identified in DUOX2 (n=4), SLC10A2 (n=2), UNC45A, TTC7A, LGALS4, SI, CCR9, MEP1B, and BACH2. While these findings suggest a potential role for genetic variants governing intestinal homeostasis in these cases of neuropsychiatric decline, their presence in only a small subgroup necessitates larger, prospective cohorts to determine whether these variants are statistically significant and play a definitive role in the pathogenesis of these disorders.

BackgroundHigh-titer glutamic acid decarboxylase 65 (GAD65) antibodies are found in patients with GAD65 antibody-associated neurological disorders, including stiff-person syndrome (SPS), GAD65 cerebellar ataxia (CA), and GAD65 epilepsy. Given the intracellular localization of the antigenic target, a direct pathogenic role for GAD65 autoantibodies is unlikely. Instead, the autoantibody may be a biomarker for the existence of pathogenic anti-GAD65 autoreactive CD8+ T cells. MethodsPBMC-derived dendritic cells (DCs) from 20 GAD65 antibody-positive patients with neurological manifestations (SPS, n=10; CA, n=7; epilepsy, n=3) and 15 healthy controls were pulsed with full-length GAD65 protein, full-length GAD67 protein, overlapping 15-mer peptide pools spanning GAD65 and GAD67, individual GAD65 15-mer peptides, or GAD65 9-mer peptides selected from predicted class I binding hotspots. T cell activation was quantified by flow cytometry-based activation-induced marker (AIM) assays using CD69 upregulation. Class I and class II HLA haplotypes were determined by high resolution typing. NetMHCpan v4.2c was used to generate residue-level peptide:HLA binding density maps across GAD65, and candidate 9-mers were validated for HLA binding by peptide:MHC monomer affinity testing. GAD65-peptide-HLA-restricted CD8+ T cells were identified by co-staining with two separately assembled tetramers carrying the same peptide:HLA complex on different fluorophores (APC and BV421), with double-positive events scored as antigen-specific. HLA-restricted cytotoxicity was measured by coculture of patient CD8+ T cells with GAD65-expressing HEK-293T cells reconstituted with defined HLA class I alleles using AAV-delivered Cre-dependent HLA-2A-eGFP cassettes. ResultsCD8+ T cells from GAD65 antibody-positive patients showed increased activation in response to DCs pulsed with full-length GAD65 relative to healthy controls (P=0.0157, Welchs t-test), whereas responses to GAD67 did not differ significantly between groups. CD4+ T cells responded to both GAD65 (P=0.0004) and GAD67 (P=0.0051). Peptide pool screening of GAD65 identified discrete CD8+ and CD4+ immunogenic regions, with refinement using individual 15-mers localizing CD8+ activity to multiple subdomains within GAD65(205-300), GAD65(316-435), and GAD65(447-520). HLA class I haplotyping in 16 non-Hispanic White GAD65+ patients revealed enrichment of HLA-B*08:01 (3.0-fold) and HLA-B*40:01 (4.1-fold) relative to USA NMDP European Caucasian reference frequencies (both BH q < 0.05), with suggestive enrichment of HLA-C*03:04 (2.9-fold; q = 0.09). Additionally, 44% of patients carried the HLA-A*01:01, HLA-B*08:01, and HLA-C*07:01 8.1 ancestral haplotype, approximately four-fold higher than the expected population frequency. Dual-fluorophore tetramer staining identified CD8+ T cells in GAD65+ subjects that bound a subset of HLA-A*11:01- and HLA-B*08:01-restricted GAD65 9-mers, with the clearest disease-skewed signals localized to GAD65(213-221), GAD65(257-265), and GAD65(529-537). In an HLA-reconstituted target-cell killing assay, CD8+ T cells from an HLA-B*08:01-positive GAD65+ patient mediated antigen- and HLA-restricted depletion of GAD65-expressing HEK-293T cells, with HLA-restricted target loss also observed in single-donor experiments across additional HLA-A, -B, and -C contexts. ConclusionsPatients with GAD65 antibody-associated neurological disorders harbor circulating CD8+ T cells that recognize discrete HLA class I-restricted GAD65 peptides and that are capable of cytotoxicity against GAD65-expressing HLA-matched target cells. We characterize the immunogenetic and cellular features of class I-restricted CD8+ T cell responses in GAD65 autoimmunity, including overrepresentation of the 8.1 ancestral haplotype, complementing the historical focus on antibodies and CD4+ T cell help, and we provide a panel of validated GAD65 peptide:HLA tetramers for prospective isolation, clonotypic analysis, and longitudinal monitoring of candidate pathogenic CD8+ T cell populations across the GAD65 antibody-associated neurological disease spectrum.

BackgroundTrained immunity is a durable functional reprogramming of innate immune cells characterized by enhanced responsiveness upon secondary challenge. While metabolic rewiring and epigenetic remodeling are well-established features of this process, the contribution of ubiquitin-mediated post-translational regulation remains poorly defined. MethodsWe performed an integrative analysis of publicly available human transcriptomic datasets derived from monocytes, macrophages, and PBMCs exposed to established training stimuli ({beta}-glucan, Bacillus Calmette-Guerin [BCG], and hemin-{beta}-glucan) followed by secondary stimulation. A curated panel of deubiquitinating enzymes (DUBs) and E3 ubiquitin ligases with established immune functions was analyzed for differential expression. Gene Ontology (GO) and KEGG pathway enrichment analyses were conducted to evaluate higher-order convergence across independent datasets. ResultsAcross multiple trained immunity models, we identified reproducible transcriptional remodeling of ubiquitin-modifying enzymes. USP25, OTUB1, and TRIM25 were consistently upregulated following restimulation, whereas several chromatin- and cytokine-regulatory DUBs--including USP3, USP4, USP7, USP16, MYSM1, and USP38--were downregulated. Normalization to RPMI-restimulated controls reduced many activation-associated signals; however, USP25 remained persistently elevated, suggesting a stable training-associated signature. Pathway enrichment analysis independently demonstrated significant engagement of ubiquitin-related functional categories across datasets, supporting coordinated reorganization of ubiquitin regulatory networks. ConclusionThese findings identify selective transcriptional remodeling of the ubiquitin- proteasome system as a recurring feature of trained immunity. Integrating ubiquitin signaling into the established metabolic-epigenetic framework expands the conceptual model of innate immune memory and suggests that ubiquitin-modifying enzymes function as modulatory rheostats shaping immune amplitude and stability. Future functional and proteomic studies are required to determine whether these transcriptional signatures directly mediate trained immunity phenotypes.

STRUCTURED ABSTRACTO_ST_ABSObjectiveC_ST_ABSTo characterize intestinal transcriptional profiles in gastroschisis, their temporal evolution, and response to fetal intervention. Summary Background DataGastroschisis causes significant intestinal dysfunction, with intra-abdominal bowel dilation clinically shown to correlate with worse outcomes. While inflammation and neurovascular impairment have been implicated, genome-wide transcriptional characterization of disease severity remains lacking. MethodsUsing a fetal ovine model of complex gastroschisis, in which all gastroschisis animals demonstrated significant intra-abdominal bowel dilation at term, bulk RNA sequencing was performed on proximal small intestinal tissue from mid-gestation and term fetuses across three groups: normal, gastroschisis, and prenatally repaired gastroschisis. Differential gene expression (FDR [&le;] .05, |log2 fold change| [&ge;] 1.5) and pathway enrichment analyses were performed, with targeted interrogation of extracellular matrix (ECM), enteric nervous system (ENS), angiogenic, and inflammatory pathways. ResultsAt mid-gestation, gastroschisis intestine showed minimal transcriptional differences (150 differentially expressed genes [DEGs]) and some bowel dilation. By term, dysregulation was substantial (2,423 DEGs) alongside significant dilation. Normal ontogenetic intestinal maturation patterns were altered, with fewer expected developmental gene changes and discordant pathway regulation. ECM pathway aberrations emerged early and persisted, while ENS, angiogenic, and inflammatory pathways were only dysregulated at term. Fetal repair was associated with normalization of gene expression at term (29 DEGs vs controls). ConclusionIntestinal transcriptional changes in experimental gastroschisis parallel progressive bowel dilation, consistent with a mechanical stress contribution to intestinal injury. Prenatal repair normalizes both dilation and gene expression, indicating a dynamic and potentially modifiable transcriptional program that supports the rationale for early fetal intervention. Mini AbstractIn a fetal ovine model, progressive bowel dilation in gastroschisis parallels transcriptomic dysregulation of ECM remodeling, neurovascular impairment, and inflammation which is normalized by prenatal repair.

Preeclampsia (PE) is a leading cause of maternal and neonatal morbidity, with immune dysregulation at the maternal-fetal interface central to its pathogenesis. The highly polymorphic human leukocyte antigen (HLA) region mediates maternal immune tolerance of the semi-allogeneic fetus, yet the contribution of HLA diversity to PE risk remains poorly defined. Whether the HLA heterozygote advantage observed in other immune disorders is relevant to PE has not been systematically evaluated. Using data from the multi-ancestry TOPMed Boston-Colombia Collaborative for Adverse Pregnancy Outcomes (n = 12,790; 4,770 PE, 8,020 controls; 10,808 maternal, 1,982 fetal, including 1,848 pairs), we evaluated associations between heterozygosity across eight classical HLA loci and PE and four sub-phenotypes, adjusting for genetic ancestry. HLA heterozygosity was common across most loci (>80%). No individual maternal HLA locus was associated with overall PE; however, heterozygosity across class I loci showed a protective effect in preterm PE (OR=0.82, 95%CI:0.69-0.97), with a similar pattern for HLA-A heterozygosity (OR=0.78, 95%CI:0.64-0.96). In contrast, fetal heterozygosity at HLA-DQB1 was nominally associated with increased risk of PE (OR=1.36, 95%CI:1.03-1.79) and preterm PE (OR=1.73, 95%CI:1.13-2.73). No individual maternal or fetal HLA alleles were associated with PE. Maternal-fetal mismatch analysis demonstrated locus-specific associations with preterm PE, including increased risk with HLA-DQA1 mismatch and reduced risk with HLA-C mismatch. These findings highlight distinct maternal and fetal immunogenetic contributions to PE risk and underscore the importance of considering HLA diversity-rather than individual alleles alone-in studies of PE etiology.

Background. Polygenic scores (PRS) for coronary artery disease (CAD) are derived almost entirely from European-ancestry data. Their portability to Southeast Asian populations, including the Vietnamese, is largely uncharacterised and clinically consequential when scores are used with risk thresholds. Methods. We evaluated four independent European-derived CAD scores from the PGS Catalog (PGS000058, PGS000349, PGS002809, PGS004198; 70 - 5,723 variants) in 2,504 individuals from the 1000 Genomes Project, focusing on the Vietnamese Kinh (KHV) and Dai (CDX) samples. Per-individual scores were computed with PLINK2 and standardised. We assessed (i) the cross-ancestry distribution (calibration) and (ii) a clinically-relevant consequence: the proportion of each population flagged high genetic risk when the European top-20% threshold is applied (20% if perfectly calibrated). Results. For the primary score (PGS000058) the standardised PRS differed across super-populations (ANOVA F(4, 2499) = 121.1, p < 0.001); the Vietnamese Kinh mean was +0.47 SD above the European mean (Welch t = 7.77, p = 2.0 x 10^ -14). Applying the European top-20% high-risk threshold, the fraction of Vietnamese Kinh flagged ranged from 22.2% to 57.6% across the four scores, and of Dai from 21.5% to 43.0%, versus the intended 20%. Three of the four scores over-flagged Vietnamese (25-58%); the largest score (PGS004198) was approximately calibrated for East/Southeast Asians ([~]22%) but markedly over-flagged Africans (69.3%). Conclusions. European-derived CAD polygenic scores are inconsistently calibrated in Vietnamese and other Southeast Asian samples, and most substantially over-flag high genetic risk when a European threshold is applied. The magnitude and even the direction of miscalibration depend on the specific score, so no such score can be assumed transferable without local validation and recalibration. Distribution shift bounds, but does not by itself quantify, loss of predictive accuracy, which requires phenotyped data.

Anaplastic thyroid carcinoma (ATC) is one of the most lethal malignancies. Immune dysregulation is believed to play an important role in ATC. Here, we aimed to characterize the systemic inflammation and the function of circulating immune cells of patients with ATC. First, we retrospectively assessed biochemical parameters of patients with ATC and observed that high systemic inflammation correlated with worse survival. Next, we prospectively investigated the inflammatory proteome, single-cell peripheral blood mononuclear cell transcriptome and epigenetic changes. Circulating concentrations of proinflammatory cytokines were increased in ATC patients. This proinflammatory profile was apparent at the level of gene transcription and chromatin accessibility, especially in monocytes. These findings were substantiated by an increased capacity of peripheral blood mononuclear cells of ATC patients to produce IL-6, IL-8 and lactate. As IL-6 is known to promote tumor cell survival, we assessed its capacity to influence ATC cell proliferation. Blocking IL-6/gp130/Jak/STAT3 pathway inhibited proliferation of ATC cell lines in vitro. In conclusion, these findings show that ATC is characterized by inappropriate systemic inflammation and epigenetic and transcriptional reprogramming of circulating monocytes. Proinflammatory cytokines released by monocytes support survival and proliferation of ATC tumor cells, suggesting a therapeutic potential of targeting this pathway in ATC patients.

Background and Aims: The molecular pathogenesis of Inflammatory Bowel Disease (IBD) remains unclear. We aimed to establish a high-resolution immune landscape of treatment-naive IBD to identify central drivers of disease onset and early pathogenic signalling. Methods: We generated a single-cell atlas using intestinal biopsies from a large adult inception cohort of 137 individuals, including treatment-naive Crohn's disease (CD), ulcerative colitis (UC), and symptomatic non-IBD controls. We integrated scRNA-seq (1 million cells) with co-varying neighbourhood analysis (CNA) and unbiased tensor decomposition of cell-cell communication (CCC) networks. Findings were validated in vitro macrophage stimulation model and using serum from patients. Results: The inception cohort exhibited significantly more homogenous compartmental diversity compared to benchmark reference studies (p < 0.001). Inflammation in both CD and UC was characterized by a marked expansion of inflammatory monocytes. Unbiased CCC analysis identified a dominant disease-specific signalling module centred on the Galectin family (LGALS1 and LGALS9). Galectin-9 expression was specifically enriched in inflammatory monocytes, which exhibited distinct. transcriptional programs linked to antigen presentation and microbial sensing. In vitro, Galectin-9 acted as a potent stimulus, driving macrophages toward a pro-inflammatory phenotype. Clinically, serum Galectin-9 levels were significantly elevated in IBD patients and correlated with systemic inflammatory markers and treatment response. Conclusions: Our data identify a galectin-monocyte signalling axis as a unifying inflammatory hallmark of early IBD. Galectin-9 serves as both a functional driver of mucosal inflammation and a dynamic biomarker, offering new opportunities for therapeutic targeting and disease monitoring from diagnosis. Keywords: Inflammatory Bowel Disease; Crohn's Disease; Ulcerative Colitis; Single-cell RNA sequencing; Galectin-9; Inflammatory monocytes.

Previous studies suggest that preexisting chronic disease impairs immune responses to subsequent infection and vaccination. However, the underlying epigenetic mechanisms are understudied. Here, we show that preexisting chronic infection with LCMV clone 13 (CL13) compromised the formation of central memory CD8 T cells (TCM) to subsequent Listeria monocytogenes infection, despite not profoundly impacting effector responses. This correlated with a skewed cytokine milieu. Our chromatin-accessibility profiling of Listeria-specific CD8 T cells showed significant epigenetic skewing of both TCM and effector memory (TEM) in mice with preexisting LCMV-CL13, a skewing that started in memory-precursor effector cells (MPECs) during the effector phase. Transcription-factor binding sites (TFBS) analyses highlighted the interferon regulatory factor (IRF) family as major TFs implicated in this skewing. Thus, our results suggest that preexisting persistent inflammation skews the phenotypic and epigenetic landscape of subsequent memory responses, arguing for interventions to optimize vaccine-induced memory in hosts with preexisting chronic disease.

BackgroundT helper 2 (Th2) lymphocytes orchestrate type-2 immunity and drive allergic diseases that disproportionately affect females. Sexual dimorphism in Th2 responses is well-documented, yet current models attribute sex differences exclusively to circulating gonadal hormones and sex chromosomes. Whether cell-intrinsic steroidogenesis, mediated by the enzyme Cyp11a1, contributes to female-biased Th2 differentiation and function remains unknown. MethodsTranscriptomes of in vitro generated Th2 cells from male and female T cell-specific Cyp11a1-knockout (Cyp11a1fl/fl;Cd4Cre) and control (Cyp11a1fl/fl) mice were compared. Differential expression, hallmark pathway analysis, transcription factor activity scoring, and functional assays were performed across sexes and genotypes. Cyp11a1-dependent differentially expressed genes were integrated with sex-stratified human Th2 transcriptomes obtained from the type-2 inflammatory skin disease atopic dermatitis. ResultsCyp11a1 deletion markedly reduced the transcriptional signature distinguishing female from male Th2 cells. Female Cyp11a1-knockout Th2 cells underwent extensive transcriptomic reprogramming converging toward the male profile, while male cells were largely unaffected. Female-specific pathway changes included reduced inflammatory signatures and enhanced cell-cycle programmes. Functionally, female Cyp11a1-deficient Th2 cells exhibited significantly increased proliferation and elevated IL-13 production; male knockout cells showed no comparable changes. These effects were developmentally stage-specific, emerging during Th2 differentiation but not in naive precursors. Cross-species analysis identified a conserved gene module shared between Cyp11a1-deficient female mouse Th2 cells and female-biased human Th2 cells in atopic dermatitis. ConclusionsCyp11a1-mediated steroidogenesis is a cell-intrinsic regulator of the female-biased Th2 transcriptional and functional state, identifying de novo steroidogenesis as a mechanism of immunological sexual dimorphism with direct relevance for female-predominant allergic disease.

Immunity to P. falciparum malaria develops slowly, requiring repeated infection in areas of high transmission, and wanes rapidly in the absence of parasite exposure. Key to this immunity, is the development of antibodies which is supported by CD4 T follicular helper (Tfh) cells that drive robust germinal centre responses. However, in malaria, the malaria-specific CD4 T cell compartment in peripheral blood is dominated by Type 1 regulatory T cells (Tr1), which produce high levels of IL-10 in response to parasites. Tr1-like Tfh cells (Tfh10) have been reported in several settings of repeated antigen stimulation but have not been investigated in malaria. Here we used single-cell RNA sequencing and multiparameter flow cytometry to characterise malaria-specific Tfh and Tr1 cells in a longitudinal cohort of highly exposed individuals and assessed their persistence after transmission interruption. Malaria-specific Tfh and Tr1 cells shared overlapping profiles, and Tr1 cell-like transcriptional signatures and phenotypes were detectable within the Tfh cell compartment. Tfh10 cell subsets were the dominant phenotype of malaria-specific Tfh cells. Following disruption of malaria transmission, the frequencies of malaria-specific Tr1 and Tfh10 cells declined. These findings highlight a close relationship between Tfh and Tr1 cells and show that the Tfh cell compartment in malaria is dominated by Tfh10 cells. The rapid waning of these cells in the absence of continuous exposure is consistent with requirements of persistent antigen in maintaining regulatory CD4 T cell phenotypes.

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) is characterized by prepubertal abrupt onset of obsessive-compulsive disorder (OCD). The sine qua non is group A streptococcus (GAS) infection, which is hypothesized to elicit an IgG-class anti-GAS antibody response that cross-reacts with antigens in the basal ganglia. However, the association between GAS antibody (GAS-IgG) levels and PANDAS has been inconsistent, and qualitative differences in GAS-IgG profiles have not been carefully evaluated in well-phenotyped cohorts. Moreover, independent studies have yet to converge on anti-neural autoantibodies that are specific to PANDAS. Here, we used phage display immunoprecipitation sequencing (PhIP-Seq) to perform ultra-deep anti-pathogen antibody repertoire profiling of serum from definitive pediatric PANDAS patients (N = 34) collected as part of a prior double-blind, placebo-controlled clinical trial of intravenous immunoglobulin (IVIg). PANDAS cases were compared to pediatric controls without a history of neuropsychiatric illness (N = 31). To assess for objective evidence of neuroglial injury, serum neurofilament light (NfL) and glial fibrillary acidic protein (GFAP) levels were compared to healthy pediatric controls. Within PANDAS, NfL and GFAP levels were compared between pre- and post-treatment sera. To evaluate for central autoantibodies, a subset of baseline cerebrospinal fluid (CSF) samples (N = 25) was profiled by full-length human protein microarray. Though GAS reactivity by PhIP-Seq was well correlated with clinical anti-DNaseB and anti-streptolysin O titers, there were no quantitative or qualitative differences in GAS-IgG profiles between PANDAS and controls. Furthermore, NfL and GFAP levels did not differ between cases and controls. Within PANDAS, changes in NfL or GFAP levels at six weeks did not differ between placebo and IVIg groups. However, CSF autoantibody profiling by protein microarray revealed infrequent but notable candidate autoantibodies. In one patient, we identified autoantibodies against Argonaute family proteins (AGO-IgG), a marker of autoimmune sensory neuropathy. Longitudinal measurement of AGO-IgG in sera revealed that titers were unchanged after placebo, but decreased after IVIg, coinciding with symptomatic improvement, including a decrease in that patients CY-BOCS score. Overall, these results do not support an etiologic role for GAS-IgG in PANDAS. However, some individuals diagnosed with PANDAS may harbor anti-neural autoantibodies.

Systemic lupus erythematosus (SLE) is associated with infection susceptibility and altered innate immune function. Monocyte metabolism is linked to appropriate cytokine release and bacterial containment. We investigated cytokine production and metabolic programming in the monocyte population from SLE patients and healthy controls following lipopolysaccharide (LPS) stimulation. SLE monocytes displayed increased IL-10, TNF, and IL-8 production, with impaired IL-1{beta} induction. Metabolic profiling revealed altered substrate use, with increased glucose dependence and reduced fatty acid and amino acid oxidation after LPS stimulation. SLE patients exhibited reduced numbers of classical monocytes, expansion of intermediate monocytes, and dysregulated subset-specific metabolic reprogramming in response to LPS. This descriptive study provides a cornerstone for (i) understanding infection susceptibility in SLE, (ii) subset-resolved immunometabolic profiling as a tool in autoimmunity, and (iii) developing future metabolic-targeted therapeutic strategies HighlightsO_LIDescriptive mapping shows SLE monocytes are proinflammatory with glucose dependence after LPS C_LIO_LIClassical and intermediate SLE subsets show divergent baseline metabolic preferences versus healthy C_LIO_LISLE subsets display aberrant LPS responses, i.e.. increased glucose and reduced fatty acid oxidation C_LIO_LIThis study provides a cornerstone for subset-resolved immunometabolism in infection susceptibility. C_LI

Neurofibromatosis type 1 (NF1) is a common autosomal dominant genetic tumor predisposition syndrome.1 NF1 patients display remarkable phenotypic variability, even within families carrying the same NF1 mutation.2 With few exceptions, the identification of specific genotype-phenotype correlations has remained elusive.3-6 We utilized RNA-seq data and direct DNA sequencing to determine HLA genotypes for individuals with NF1-associated high-grade glioma (HGG, n=25), low-grade glioma (LGG, n=79), and malignant peripheral nerve sheath tumors (MPNST, n=105). Odds ratios (OR), binomial p-values and false discovery values were calculated by comparing observed carrier frequencies against expected frequencies derived from ethnicity-matched population data. We find that specific HLA class I and II alleles are associated with different NF1 tumor types. For example, HLA-B*40:02 is significantly associated with NF1-MPNST (OR=3.71, p=0.001, Q=0.02), increasing the lifetime risks for MPNST from 10% to about 29%. The relative cancer risk for an individual in the general population carrying a risk allele can be high, however, that individuals absolute risk for cancer typically remains very low. In contrast, individuals that carry a risk allele and are also burdened with a tumor predisposition syndrome will have a substantially higher absolute risk to develop a tumor, simply because they start at a higher baseline susceptibility for tumors. The identification of HLA-risk alleles for NF1 tumor development is therefore important, as it will allow for a risk-adapted screening or more aggressive treatment of individuals with a specific HLA haplotype. If confirmed, this study will thus improve clinical care and potential outcomes of individuals with NF1.