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Allergy

Wiley

Preprints posted in the last 30 days, ranked by how well they match Allergy's content profile, based on 23 papers previously published here. The average preprint has a 0.03% match score for this journal, so anything above that is already an above-average fit.

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Circulating miR-29a as a new biomarker of food anaphylaxis and endothelial glycocalyx regulation

Munoz-Callejas, A.; Moreno-Vidal, A.; Henar-Izquierdo, A.; Palacio-Garcia, L.; Fernandez-Bravo, S.; de Maria-Camacho, I.; Di Giannatale, A.; Gomez-Lopez, A.; Rodriguez Del Rio, P.; Julio Laguna, J.; Benito-Martin, A.; Nunez-Borque, E.; Esteban, V.

2026-04-08 immunology 10.64898/2026.04.06.716635 medRxiv
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To the editorO_ST_ABSBackgroundC_ST_ABSAnaphylaxis is an acute and potentially life-threatening hypersensitivity reaction often involving the cardiovascular system. Circulating microRNAs (miRNAs/miR), including those carried by extracellular vesicles (EVs), are emerging biomarkers that display regulatory functions in allergy. This study aims to investigate the role of miR-29a in anaphylaxis. MethodsMiR-29a (3p and 5p) levels were assessed by qPCR from acute and baseline samples of serum and EVs from 70 patients with food- and drug-mediated anaphylaxis. EVs purification was confirmed by Western blot, electron microscopy, and NanoSight. MiR-29a-3p target genes were studied in silico using systems biology analysis (SBA). Moreover, miR-29a levels were evaluated in vitro in endothelial cells (ECs) exposed to anaphylactic mediators. Additionally, a panel of endothelial glycocalyx (eGCX)-associated mRNA was analyzed after transfection with a miR-29a-3p inhibitor. ResultsPatients with food-induced anaphylaxis exhibited reduced miR-29a-3p levels in both serum and EVs during the acute reaction. In contrast, miR-29a-5p levels were decreased in serum but not in EVs. No significant modulation of either miRNA was observed in drug-induced anaphylaxis. SBA of miR-29a-3p identified molecular pathways, biological processes and functional networks associated with eGCX remodelling. Intracellular levels of miR-29a-3p were modulated in vitro in ECs following exposure to anaphylactic mediators. Inhibition of miR-29a-3p significantly reduced ESM1 expression. ConclusionsThe miR-29a-3p levels are decreased in serum and EVs from patients with acute food-induced anaphylaxis, suggesting its potential as a promising biomarker. Moreover, a role for miR-29a-3p in eGCX integrity under anaphylactic conditions was demonstrated, potentially regulating ESM1. Key MessageMiR-29a-3p is selectively reduced in serum and extracellular vesicles during acute food-induced anaphylaxis and may regulate endothelial glycocalyx-related pathways, which supports its potential as a novel biomarker and molecular mediator of vascular involvement in anaphylactic reactions.

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Skin As A Potential Entry Point For SARS-COV-2

Trubestskoy, D.; Grudzien, P.; Chudakova, D.; Klopot, A.; Bhalla, P.; Perez-White, B.; Budunova, I.

2026-04-08 immunology 10.64898/2026.04.07.717019 medRxiv
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The primary route of SARS-CoV-2 entry is via respiratory epithelium. However, many COVID-19 patients developed dermatological lesions, and SARS-CoV-2 RNA has been detected in the patients skin. Inflammatory skin diseases, psoriasis and atopic dermatitis (AD), significantly increased the risk of COVID-19. To evaluate the potential role of skin in SARS-CoV-2 host interactions, we utilized 3D human skin organoids (HSO) generated from human epidermal keratinocytes, as well as neonatal skin explants. HSO were treated with cytokines involved in acute and chronic skin inflammation and cytokine storm in severe COVID-19 disease, TNF-, IL-6, IL-1{beta}, and IFN-{gamma}, individually and in combination. HSO were also treated with Th1 (TNF- + IL-17) and Th2 (IL-4 + IL-13) cocktails inducing pro-psoriasis and pro-AD HSO changes, respectively. All individual cytokines, and especially their combinations, elevated the expression of ACE2 and TMPRSS2 at mRNA/protein levels. The Th2 induced only TMPRSS2, the Th1 predominantly induced ACE2. Topically applied Spike-pseudotyped lentiviral Tomato reporter, which binds ACE2 similarly to SARS-CoV-2, successfully infected control and cytokine-treated HSO as well as neonatal skin explants. Cytokine treatment, especially TNF- + IL-6 + IL-1{beta} + IFN-{gamma} and the Th1, significantly increased viral entry. Transcriptomic analysis further revealed partial overlap between gene expression signatures induced by Spike-mediated entry in inflamed HSO and those observed in lung tissue from COVID-19 patients, supporting the biological relevance of skin models. Together, these findings demonstrate that inflammation enhances the permissiveness of human skin to SARS-CoV-2 entry, suggesting that the skin may represent a previously underappreciated interface in viral host interactions.

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To comprehensively evaluate the evolution of global childhood and adolescent asthma (ages 0-19) disease burden from 1990-2023, explore spatiotemporal patterns, influencing factors, health equity, and predict future trends.

yin, h.; He, S.; Wu, Z.; Tan, W.; Du, F.; Yang, C.; Yu, H.

2026-03-31 epidemiology 10.64898/2026.03.28.26349599 medRxiv
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Methods: Using Global Burden of Disease (GBD) data, we analyzed prevalence, incidence, mortality, and disability-adjusted life years (DALYs) rates across global and 21 GBD regions from 1990-2023. Joinpoint regression identified temporal trends, age-period-cohort models analyzed effect contributions, Das Gupta decomposition quantified demographic and epidemiological impacts, inequality indices assessed health equity, and Bayesian models projected 2024-2038 trends. Results: In 2023, the global number of children and adolescents with asthma reached 131 million, with an age-standardized prevalence rate (ASPR) of 1,789.9 per 100,000. From 1990 to 2023, the global ASPR and age-standardized incidence rate (ASIR) of asthma in children and adolescents showed an upward trend, while the age-standardized mortality rate (ASMR) and age-standardized disability-adjusted life years (DALYs) rate (ASDR) exhibited a downward trend. Among the 0-14 age group, the disease burden was greater in males than in females, whereas in the 15-19 age group, males had a lower disease burden than females. Projections indicate that over the next 15 years, the overall disease burden will continue to decline; however, female mortality rates and DALYs rates are projected to show an upward trend. Conclusions: The increasing prevalence and incidence rates, coupled with declining mortality and DALYs rates of asthma among children and adolescents globally, underscore the necessity for targeted public health interventions. These findings provide crucial insights for early diagnosis, treatment optimization, and global health policy formulation.

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Incident psoriasis in atopic dermatitis: A large-scale cohort study of disease- and treatment-associated risks

Thaqi, F.; Bieber, K.; Kerniss, H.; Kridin, K.; Curman, P.; Ludwig, R.

2026-04-20 dermatology 10.64898/2026.04.18.26351181 medRxiv
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BackgroundClinical and genetic evidence on the association between atopic dermatitis (AD) and subsequent psoriasis remains conflicting, and it is unclear whether this risk is modified by systemic treatments. Recent reports suggest type 2-targeted biologics may unmask psoriasis in AD patients, but data are limited. We thus aimed to assess whether AD is associated with incident psoriasis and whether this risk differs by systemic treatment, particularly biologics versus conventional systemic immunosuppressants (cvIS). MethodsScoping analyses informed a locked analytic design, preregistration at OSF, and confirmatory execution. Propensity score-matched analyses compared AD with non-AD controls and biologics with cvIS. Sensitivity analyses, Cox model triangulation, and control outcomes assessed robustness. FindingsAmong [~]300,000 matched pairs, AD was associated with increased psoriasis risk (primary HR 3.81, 95% CI 3.35-4.34), consistent across all 8 sensitivity analyses and model triangulation. Biologic treatment was associated with reduced psoriasis risk versus cvIS (primary HR 0.20, 95% CI 0.11-0.35), consistent across 6 of 7 evaluable sensitivity analyses and Cox triangulation. Positive and negative control outcomes showed expected directional patterns. InterpretationAcknowledging limitations including residual confounding and coding misclassification, AD was associated with increased psoriasis risk and biologics with lower psoriasis risk than cvIS. FundingDFG (EXC2167, SFB1526, LU877/25-1), Schleswig-Holstein Excellence-Chair Program, Swedish Society for Dermatology and Venereology, and the Tore Nilson Foundation. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSAtopic dermatitis (eczema) and psoriasis are the two most common chronic inflammatory skin diseases worldwide. For a long time, doctors and researchers assumed these two conditions could not occur in the same person, as they were thought to involve opposing immune responses. However, this view has been challenged over the past decade. Some large studies, including population-based cohorts from Taiwan and the United Kingdom, have found that people with eczema may be at higher risk of developing psoriasis over time, while other studies, including genetic analyses, have suggested the opposite: that the two diseases may actually protect against each other. This conflicting picture has left clinicians uncertain about the true relationship between the two diseases in everyday clinical practice. A separate but related concern has emerged with the introduction of a new class of highly effective treatments for eczema, biologics, particularly dupilumab. Case reports and observational studies, including a large study published in JAMA Dermatology in 2025, have raised the possibility that these medications might trigger psoriasis in some patients, potentially by shifting the immune system from one inflammatory pattern to another. However, prior studies on this question had important methodological limitations: they were not pre-planned and registered before data collection, they did not always tightly link treatment use to an eczema diagnosis, and critically, none compared biologic treatment directly against conventional immunosuppressant medications, the most relevant clinical comparator. Added value of this studyThis study is a large and methodologically rigorous investigation of both questions: whether eczema itself increases the risk of developing psoriasis, and whether the type of systemic treatment used for eczema influences that risk. Using a database of over 110 million electronic health records from across the United States, we matched approximately 300,000 patients with eczema to 300,000 patients without eczema and followed them for up to seven years. We also compared nearly 5,500 patients treated with biologics to an equal number treated with conventional immunosuppressants. Crucially, our study was pre-registered before any data were analyzed, meaning the research questions, methods, and analyses were locked in advance and could not be adjusted based on what the data showed. We also used a range of additional analyses to test whether our findings were robust, including checks using outcomes that should not be affected by eczema or its treatment (such as appendectomy and hearing loss), which confirmed that our results were not likely explained by bias alone. We found that eczema was associated with an increased risk of developing psoriasis, but that this risk was substantially influenced by the choice of comparison group, ranging from approximately 1.4-fold to nearly 4-fold depending on the analytical approach. More strikingly, we found that patients treated with biologics had a markedly lower risk of developing psoriasis compared with those treated with conventional immunosuppressants, the opposite of what prior reports had suggested. This finding was consistent across nearly all additional analyses performed. Implications of all the available evidenceTaken together with existing evidence, these findings suggest two important conclusions. First, clinicians should be aware that eczema, particularly moderate-to-severe eczema requiring systemic treatment, may carry an elevated risk of developing psoriasis over time. This does not mean that all patients with eczema need to be screened for psoriasis routinely, but it does support clinical awareness and monitoring in higher-risk patients. Second, and perhaps most importantly for treatment decisions, biologics do not appear to increase the risk of psoriasis compared with conventional immunosuppressants and may in fact be associated with a lower risk. This provides reassurance for patients and clinicians considering biologic therapy and challenges the narrative that these medications trigger psoriasis. Future research should aim to confirm these findings in other populations, investigate the biological mechanisms underlying the relationship between eczema and psoriasis, and examine whether specific biologic agents differ from one another in their effects on psoriasis risk.

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Resolution of systemic inflammation in psoriasis following herring roe oil treatment: a post hoc analysis on inflammatory biomarkers in non-severe psoriatic patients

Ringheim-Bakka, T. A.; Gammelsaeter, R.; Tveit, K. S.

2026-04-22 dermatology 10.64898/2026.04.20.26350934 medRxiv
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BackgroundPsoriasis is a chronic immune-mediated inflammatory disease (IMID) with systemic involvement. In mild-to-moderate disease, circulating cytokines may inadequately capture systemic inflammatory burden. Composite haematological indices derived from complete blood counts, such as the systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI), have emerged as sensitive prognostic markers of systemic inflammation, including in psoriasis. This exploratory post hoc analysis investigated the effects of orally administered herring roe oil (HRO), a phospholipid-rich marine oil, on systemic inflammation in patients with mild-to-moderate psoriasis utilizing these biomarkers. MethodsData were analysed from a randomized, double-blind, placebo-controlled 26-week clinical study which investigated HRO supplementation in patients (N = 64) with mild-to-moderate psoriasis (NCT03359577). SII, SIRI, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) were calculated at baseline, week 12, and week 26 for patients where baseline complete blood counts (CBCs) were available (n = 60). Patients missing baseline CBCs were excluded from the analysis. Continuous changes were assessed using ANCOVA with baseline adjustment. Categorical responder analyses were performed with 25% and 30% reduction thresholds and stratification by baseline biomarker medians were performed to evaluate treatment responses and impact of baseline inflammation. ResultsCompared with placebo, HRO treatment resulted in significant mean reductions in SII, SIRI, and PLR at week 26, with supportive trends and responder effects observed as early as week 12 compared to placebo. Patients with elevated baseline inflammatory indices showed the greatest reductions in systemic inflammation. Stratification by baseline SII further revealed enhanced clinical benefit, with statistically significant PASI50 response rates in the HRO arm at week 26 among patients with lower baseline SII. ConclusionHRO supplementation was associated with a time{square}dependent reduction in systemic inflammatory biomarkers in mild{square}to{square}moderate psoriasis patients. These findings support the utility of composite inflammatory indices for monitoring systemic inflammation and suggest that baseline SII may have utility in predicting treatment response and may be a useful tool for stratification in clinical trials in mild to moderate psoriasis patients. These results could also suggest platform-potential of HRO for resolution{square}oriented interventions across several inflammatory conditions.

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Multi-Ancestry Epigenome-Wide Meta-Analysis Identifies Novel Bulk and Cell-Type-Specific Epigenetic Markers of Asthma with Severe Exacerbations

Perez-Garcia, J.; Martin-Gonzalez, E.; Chen, Z. J.; Martin-Almeida, M.; Witonsky, J.; Gorla, A.; Eng, C.; Lorenzo-Diaz, F.; Bozack, A. K.; Elhawary, J.; Hu, D.; Huntsman, S.; Gonzalez-Perez, R.; Hernandez-Perez, J. M.; Poza-Guedes, P.; Mederos-Luis, E.; Sanchez-Machin, I.; Rodriguez-Santana, J.; Villar, J.; Rifas-Shiman, S. L.; Hivert, M.-F.; Oken, E.; Gold, D. R.; Ziv, E.; Rahmani, E.; Gonzalez Burchard, E.; Cardenas, A.; Pino-Yanes, M.

2026-04-18 allergy and immunology 10.64898/2026.04.16.26350345 medRxiv
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Background: Extreme-phenotype comparisons allowed the discovery of novel asthma genetic risk loci. However, this approach remains unexplored in epigenome-wide association studies (EWAS). We aimed to identify bulk and cell-specific methylation markers of asthma with severe exacerbations across diverse ancestry groups. Methods: We conducted a meta-EWAS of 739,543 CpGs in whole blood among 1,192 African American and Latino pediatric populations, comparing non-asthmatics and asthma exacerbators. Genome-wide CpGs were followed up for replication in a meta-analysis across 1,516 ethnically diverse participants and in a cross-tissue evaluation of 393 nasal samples. We conducted differentially methylated region (DMRs), cell-type-deconvoluted, and quantitative trait loci analyses (whole-genome sequencing n=1,668; RNA-seq n=1,209). We examined enrichment in traits, pathways, and druggable genes, and analyzed DNAm predictors of plasma proteins and aging. Results: DNAm at 505 CpGs and 119 DMRs in whole blood were associated with asthma exacerbations (p<9x10-8, {lambda}=1.05). We replicated 25 CpGs in blood cells, cross-validated 7 in nasal samples, and detected 42 cell-specific DNAm markers mainly driven by T cells. DNAm at 134 CpGs was associated with gene expression in whole blood, including 118 associations with T-cell receptor genes, and 446 CpGs were regulated by [&ge;]1 genetic variant. We found enrichment for previous associations with environmental exposures, immune disorders, immune and inflammatory pathways, and druggable genes by developmental drugs. 21 methylation-predicted plasma proteins, involved in host defense, and one lung aging clock were associated with asthma exacerbations. Conclusions: The first meta-EWAS of extreme asthma phenotypes identified hundreds of novel DNAm markers, suggesting novel methylation biomarkers and candidate drugs for asthma and supporting the role of T cells.

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Comprehensive Immunophenotyping of Monocytes and Dendritic Cells Suggests Distinct Pathophysiology in Chronic Fatigue Syndrome and Long COVID

Petrov, S. I.; Bozhkova, M.; Ivanovska, M.; Kalfova, T.; Dudova, D.; Todorova, Y.; Dimitrova, R.; Murdjeva, M.; Taskov, H.; Nikolova, M.; Maes, M.

2026-04-12 allergy and immunology 10.64898/2026.04.10.26350613 medRxiv
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Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID are complex chronic conditions that often follow infectious triggers with overlapping clinical features but poorly defined pathophysiological relationships. This study aimed to identify disease-specific immune signatures through multiparameter immunophenotyping of monocytes, dendritic cells, and T-cell subsets. A total of 207 participants were included (ME/CFS: n = 103; long COVID: n = 63; healthy controls: n = 41). Peripheral blood mononuclear cells were analyzed using multiparameter flow cytometry. Statistical analyses included non-parametric testing, age-adjusted ANCOVA, correlation network analysis, and principal component analysis (PCA). Long COVID was characterized by increased M2-like monocyte polarization, elevated CD80 expression across monocyte subsets, expansion of dendritic cells, and reduced expression of activation markers, indicating persistent immune activation with features of immune exhaustion. In contrast, ME/CFS exhibited reduced costimulatory molecule expression, impaired CCR7-mediated immune cell trafficking, and less coordinated activation patterns, consistent with a state of immune suppression. Correlation network analysis revealed more extensive and integrated immune interactions in long COVID, while PCA identified distinct immunophenotypic components and enabled moderate discrimination between the two conditions. These findings demonstrate that ME/CFS and long COVID are characterized by distinct immune profiles, supporting the concept of divergent immunopathological mechanisms. The identified signatures may contribute to biomarker development and guide targeted therapeutic approaches.

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Grading of Erythema and Visual Attributes in Atopic Dermatitis across Diverse Skin Tones Using a Vision AI Pipeline

Abdolahnejad, M.; Kyremeh, M.; Smith, J.; Fang, G.; Chan, H. O.; Joshi, R.; Hong, C.

2026-03-31 dermatology 10.64898/2026.03.30.26349755 medRxiv
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Background: Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease associated with clinical, psychosocial, and economic burden. Accurate severity assessment is essential for guiding treatment escalation and monitoring disease activity, yet clinician-based scoring systems such as the Eczema Area and Severity Index (EASI) are limited by subjectivity and considerable inter- and intra-rater variability. Erythema, a key driver of AD severity grading, is particularly prone to inconsistent evaluation due to differences in ambient lighting, device quality, skin tone, and rater experience, underscoring the need for objective, reproducible assessment tools. Objective: To develop and validate an artificial intelligence (AI) pipeline for grading erythema, excoriation, and lichenification severity in AD from clinical photographs. The study evaluated the level of agreement between AI severity ratings in each category against dermatologists, non-specialists, and a consensus reference standard, with erythema as the primary outcome of interest. Methods: A two-stage AI pipeline was developed using EfficientNet B7 convolutional neural networks (CNNs). The first CNN was trained as a binary AD classifier on 451 AD and 601 non-AD images for lesion detection and segmentation. The second CNN was trained on 173 dermatologist-annotated AD images which were scored on a 0-3 ordinal scale for erythema, excoriation, and lichenification. This CNN had a downstream feature extraction algorithms such red channel contrast for erythema, Law's E5L5 for excoriation, and S5L5 texture maps for lichenification. In a cross-sectional validation study, 41 independent test images were scored by two blinded dermatologists and two blinded physicians. AI predictions were compared to individual rater groups and mode-derived consensus scores using weighted Cohen's kappa, classification accuracy, confusion matrices, and error direction analyses. Results: On internal validation, the severity CNN achieved 84% overall accuracy (averaged across all three attributes), 86% sensitivity, 87% specificity, and a macro-averaged area under the receiver operating characteristic curve (AUC) of 0.90. In the external comparison with blinded human raters, erythema agreement between the AI and dermatologist consensus was substantial (accuracy 80.7%; kappa = 0.68), with no large (>2-point) misclassifications. Physician consensus agreement was lower (accuracy 54.8%; kappa = 0.34), reflecting greater variability among primary care physicians (non-specialists). For excoriation, AI-dermatologist agreement was moderate (accuracy 72.4%; kappa = 0.62); for lichenification, agreement was similar (accuracy 71.4%; kappa = 0.59). Across all features, disagreements were predominantly between adjacent severity categories. The AI was able to generate erythema severity grades for images of darker skin tones that dermatologists typically would not rate and were marked as "unable to assess". Limitations: The validation set was small (41 images), severe cases (score 3) were underrepresented, one rater participated in both training annotation and validation scoring, and sample size was insufficient for robust stratification by skin tone or body site. Conclusion: The AI pipeline demonstrated dermatologist-level accuracy for erythema scoring, consistent moderate agreement for excoriation and lichenification, and a potential advantage in assessing erythema on darker skin tones. These findings support its potential as a standardized, objective tool for AD severity assessment. Prospective validation in larger, more diverse cohorts is warranted.

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The epidermal stem cell-supporting matricellular protein fibulin 7 modulates skin inflammatory response in a psoriasis model

Raja, E.; Machida, T.; Narenmandula, N.; Edlund, K.; Hossain, A. S.; Fan, W.; Tsunezumi, J.; Watanabe, Y.; Asano, K.; Kimura, K.; Natsuga, K.; Sada, A.; Yanagisawa, H.

2026-04-03 cell biology 10.64898/2026.03.31.715486 medRxiv
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ECM composition and organization are greatly altered during inflammation but it is still elusive if ECM dynamics may protect tissue stem cells against aberrant inflammation. Fibulin 7 (encoded by Fbln7) is part of the basement membrane ECM where epidermal stem cells (EpSCs) reside. It supports the long-term potential of fast-cycling EpSCs and moderates aging-related inflammatory markers in keratinocytes. Here, we assessed fibulin 7s role during imiquimod (IMQ)-induced inflammation in 1-year-old mouse dorsal skin. We found that loss of Fbln7 aggravates epidermal inflammation, marked by increased epidermal thickness, proliferation, and phosphorylation of JNK (c-Jun N-terminal kinase). Fast-cycling EpSCs labeled with Slc1a3-creER-TdTomato demonstrated that IMQ-induced proliferation in Fbln7 KO mice is contributed by cell divisions in the suprabasal layers, a hallmark of inflammatory epidermal responses. EpSC transcriptomes further reveal IMQ-modulated genes that are more substantially affected in Fbln7 KO mice, including IL-17 pathway-related genes known in psoriasis pathogenesis. Mechanistically, fibulin 7 directly binds to IL-17A and decreases IL-17A-mediated p38 MAPK activation. In public human psoriasis datasets, FBLN7 is reduced in lesional skin compared with non-lesional or normal skin, and it is significantly correlated with common psoriasis-associated genes. Altogether, fibulin 7 is potentially beneficial to protect against skin inflammation.

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Keratin 7 protein presence in stool is indicative of active pediatric-onset inflammatory bowel disease

Ilomäki, M. A.; Kotharkar, E.; Rovapalo, J.; Lehtonen, N.; Nikkonen, A.; Ventin-Holmberg, R.; Merilahti, J.; Kauko, O.; Kolho, K.-L.; Polari, L.; Toivola, D. M.

2026-04-22 cell biology 10.64898/2026.04.21.719629 medRxiv
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BackgroundInflammatory bowel disease (IBD) is associated with early structural changes in intestinal epithelial cells; however, the associated molecular alterations remain incompletely understood. The cytoskeletal protein keratin (K) 7 was recently found to be focally expressed in the colonic epithelium in IBD, while absent in the healthy colon. Here, we investigated the applicability of K7 as a noninvasive stool biomarker for pediatric IBD. MethodsIn this case-control study including adolescent patients with IBD (n=27) and healthy controls (n=15), stool lysates were analyzed by proteomics, immunoassay and qPCR to determine K7 protein and mRNA content, respectively. Additionally, stool mRNA levels of the simple epithelial keratins, K8, K18, K19 and K20, were measured. ResultsStool proteomic analysis identified focal K7 and K19 in IBD samples. Additionally, 23 differentially abundant proteins, of which 18 were higher in IBD, were identified and Gene Ontology enrichment analysis highlighted immune and inflammatory pathways. K7 specific immunoassay detected fecal K7 protein in all patients with active IBD, including both ulcerative colitis and Crohns disease, while K7 was near or below the detection limit in controls and IBD patients in remission (area under ROC curve=0.88, p<0.0001). While KRT7 mRNA levels were below the detection limit, KRT8 and KRT18 transcripts were elevated in IBD samples compared to controls (p<0.05). ConclusionsK7 protein is elevated in IBD patient stool, reflecting intestinal de novo expression and increased epithelial cell exfoliation. Fecal K7 may provide a novel, noninvasive marker for IBD diagnosis and monitoring.

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Ancestry-specific rewiring of BCR-MAPK signaling in sarcoidosis B cells

Dunn, C. M.; Watkins, C.; Hallum, G.; Pezant, N.; Rasmussen, A.; Gaffney, P. M.; Bagavant, H.; Deshmukh, U. S.; Montgomery, C.

2026-04-22 immunology 10.64898/2026.04.20.718985 medRxiv
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Sarcoidosis is a heterogenous disease of unknown etiology characterized by non-caseating granulomas. Disease prevalence and presentation vary significantly by ancestry and ranges from acute, self-resolving disease to severe, chronic disease. Following previous reports suggesting B cells in the development and pathogenesis of sarcoidosis, we present here results of single-cell RNA sequencing, supporting B cell involvement in sarcoidosis through altered immediate early response, rewiring of MAPK signaling, and ancestry-specific preferential expansion of B cell receptors. Peripheral blood mononuclear cells were obtained from individuals of African or European Ancestry (AA and EA, respectively) including 48 healthy controls, 59 sarcoidosis patients, and 28 systemic lupus erythematosus (SLE) patients. SLE samples were used as a disease control. Differential expression analysis highlighted many differentially expressed genes (DEGs) with almost 5x more in the AA sarcoidosis versus AA control group compared to the EA sarcoidosis versus EA control group. B cells had the most DEGs of all cell types and expression patterns were similar between ancestries, however, sarcoidosis had an opposite transcription pattern than SLE, demonstrating an alternative immune response to acute activation than that seen in a prototypical autoinflammatory disease. This trend was maintained when examining specialized B cell subsets, with the most pronounced effect in the AA sarcoidosis versus AA control comparison. Our results strongly support further investigation of the role of humoral immune response in sarcoidosis and the potential to highlight patient groups likely to benefit from existing B cell therapies.

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Comparative LUSZ Therapeutic Study (LUSZ_AVIST) of Antiviral, Antiretroviral, and Immunosuppressive Treatments in Hospitalized COVID-19 Patients with High-Risk Factors, Biomarkers, and Disease Progression.

Makdissy, N.; Makdessi, E. W.; Fenianos, F.; Nasreddine, N.; Daher, W.; El Hamoui, S.

2026-04-13 respiratory medicine 10.64898/2026.04.10.26350587 medRxiv
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COVID-19 has spread rapidly and caused a global pandemic making it one of the deadliest in history. Early identification of patients with coronavirus disease 2019 who may develop critical illness is of immense importance. Therefore, novel biomarkers were needed to identify patients who will suffer rapid disease progression to severe complications and death. Many treatments were adopted including the antiviral Remdesivir, the antiretroviral Lopinavir /Ritonavir and Tocilizumab. Our study aimed not only to specify high-risk factors and biomarkers of fatal outcome in hospitalized subjects with coronavirus but also to compare the efficacy of the three considered treatments to help clinicians better choose a therapeutic strategy and reduce mortality. We divided the population (n=711) into four main groups based according to the WHO ordinal severity scale. The percentage of mortality, in and out the hospital, the length of stay in the hospital, the pulmonary inflammatory lesion and its distribution, the SARS-CoV-2 IgM and IgG variations at admission, the inflammatory markers, the complete blood count, the coagulation factors and enzymes, proteins and electrolytes profile, glucose and lipid profile, and other relevant markers were measured. The significance of the observed variation was assessed by multivariate and ANOVA analyses. We succeeded to establish a novel predictive scoring model of disease progression based on a cohort of Lebanese hospitalized patients relying on the pulmonary inflammatory lesions, inflammation biomarkers such as LDH, D-Dimer, CRP, IL-6 and the lymphocyte count, the number of comorbidities and the age of the patient which all were significantly correlated with the illness severity showing best outcomes with immunomodulatory and anticoagulant treatments by the results. As top tier, Tocilizumab was more efficient than the two other treatments in non-severe cases but none of the used treatments was insanely effective alone to reduce mortality in severe cases.

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Understanding inequalities in COVID-19 vaccination between migrants and non-migrants in Germany: The role of psychological factors of vaccine behaviour

Bartig, S.; Siegert, M.; Hoevener, C.; Michalski, N.

2026-04-17 public and global health 10.64898/2026.04.15.26350844 medRxiv
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Background: Understanding the underlying mechanisms for differences in vaccine uptake between migrants and non-migrants is crucial in order to design targeted interventions encouraging vaccination and to ensure vaccine-related equity. Therefore, this study examined to what extent migration-related disparities in COVID-19 vaccination were associated with psychological factors, based on the established 5C model of vaccine behaviour (Confidence, Complacency, Constraints, Calculation, Collective Responsibility). Methods: Data were obtained from the German study "Corona Monitoring Nationwide - Wave 2" (RKI-SOEP-2 study), which was carried out between November 2021 and March 2022. The association between COVID-19 vaccination and migration status, while considering the psychological factors, was investigated using multivariable binary logistic regressions. A decomposition analysis (Karlson-Holm-Breen method) was conducted to examine the extent to which migration-related disparities in vaccine uptake were associated with the psychological factors of the 5C framework. Results: Migrants were less likely to be vaccinated against COVID-19 compared to non-migrants, especially participants from the Middle East and North Africa (MENA) region. Our decomposition showed that almost two-thirds of the disparities in COVID-19 vaccine uptake between migrants and non-migrants were associated with the psychological factors (first-generation: 61.2%, second-generation: 64.2%). Confidence in safety of the vaccine was the most relevant factor in the 5C framework. Furthermore, the results highlighted the importance of a differentiated analysis regarding country of origin: While the 5C model accounted for only 19.4% of the difference between participants from the MENA region and non-migrants, the proportion for participants from Eastern Europe was 73.5%, suggesting that the underlying mechanisms for the lower uptake in the MENA group need further investigation. Conclusions: Overall, migration-related disparities in COVID-19 vaccination were significantly associated with differences in psychological factors of vaccine behaviour. To increase vaccine acceptance within the heterogeneous group of migrants in general, tailored and proactive health communication interventions are needed.

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A critical role of epithelial MHCII in initiation of autoimmune tumorigenesis and sustaining premalignancy growth in the stomach

Lozano, C. C.; Vazquez, E. N.; Kolev, A.; Honan, A. M.; El-Rifai, W.; Zaika, A.; Chen, Z.

2026-04-03 immunology 10.64898/2026.04.01.715843 medRxiv
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Autoimmunity is emerging as a new etiology for early-onset gastric cancer (GC). However, it remains unclear what molecular pathways drive the initiation and progression of autoimmune tumorigenesis. Given that Major Histocompatibility Complex Class II (MHCII) is the strongest genetic risk factor for many autoimmune diseases, we hypothesized that MHCII-mediated autoantigen presentation drives tumorigenic differentiation of epithelial cells. Here we show that epithelial MHCII, rather than MHCII from immune cells, plays an essential role in the initiation of autoimmunity-driven tumorigenic differentiation of gastric epithelial cells, which was characterized by increased expression of cancer-associated markers with immune-evasive and stem-like features that potentiate premalignant progression. In addition, we show that early gastric premalignancy is reversible upon the removal of epithelial MHCII. This study reveals that epithelial MHCII antigen presentation is essential in the early stages of autoimmune-driven gastric tumorigenesis and highlight epithelial MHCII as a potential biomarker or therapeutic target in early interventions of autoimmunity-driven cancer development.

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Metabolic Drivers of Disease Activity and Complications in Crohns Disease: A Retrospective Cross-Sectional Study

Pan, Y.; Huang, S.; Qin, S.; Liu, Z.; Liang, Y.; Jiang, H.

2026-04-06 immunology 10.64898/2026.04.01.715942 medRxiv
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BackgroundThis study aims to examine the independent relationships between individual components of metabolic syndrome (MetS) and two key clinical outcomes in patients with Crohns disease (CD): disease activity, as quantified by the Crohns Disease Activity Index (CDAI), and the occurrence of complications. MethodsThis retrospective cross-sectional study included 376 adults with newly diagnosed Crohns disease. Multiple linear regression was used to examine associations between metabolic parameters and CDAI scores, while multivariate logistic regression assessed links to complications. Analyses were also based on clinical CDAI cut-offs. Predictive nomograms were developed and internally validated via bootstrap resampling. ResultsMultiple linear regression indicated that higher CDAI scores were independently associated with lower BMI (B = -5.866, P < 0.001), lower HDL-C levels (B = -81.770, P < 0.001), higher triglycerides (B = 15.618, P = 0.001), and lower ESR (B = -0.375, P = 0.03). Multivariate logistic regression established low HDL-C (OR = 0.042, P < 0.001), low BMI (OR = 0.915, P = 0.034), and high triglycerides (OR = 1.792, P = 0.007) as significant independent risk factors for complications. The developed nomograms demonstrated strong predictive performance, with an adjusted R2 of 0.207 for the CDAI model and an AUC of 0.765 for the complication model. For both predictive tasks, the model incorporating separate TG and HDL-C measurements significantly outperformed the TG/HDL-C ratio model. ConclusionMetabolic disturbances demonstrate a significant association with increased disease severity and a higher risk of complication development in Crohns disease. Core tipO_LIDual-outcome study reveals HDL-C and TG differentially link to CD inflammation and complications, pointing to distinct mechanisms. C_LIO_LILow HDL-C is the strongest independent predictor for CD complications, underscoring its protective role beyond cholesterol transport. C_LIO_LIIndividual TG and HDL-C metrics outperform their ratio in prediction, challenging its use and suggesting independent pathways in CD. C_LIO_LILow BMI independently associates with both adverse outcomes, refining the "obesity paradox" and highlighting malnutritions key role. C_LIO_LIA practical, validated nomogram (AUC=0.765) integrates HDL-C, TG, and BMI to stratify complication risk, aiding clinical decision-making. C_LI

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Muc5ac mediates anti-viral immunity and virus-induced parasympathetic nerve dysfunction

Kornfield, J. M.; Hoffmeister, S. T.; De La Torre, U.; Smith, C. B.; Proskocil, B. J.; Evans, C. M.; Jacoby, D. B.; Fryer, A. D.; Drake, M. G.

2026-04-10 physiology 10.64898/2026.04.10.717757 medRxiv
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Respiratory viruses can induce excessive bronchoconstriction in both asthmatic and healthy airways. Airway mucins such as Muc5ac form the first line of defense against inhaled pathogens. However, when produced in excess, they can also contribute to airway narrowing and mucus plug formation in asthma. In this study, we investigated the role of airway mucins in host defense against parainfluenza virus and in virus-induced airway hyperresponsiveness using Muc5ac-deficient (Muc5ac-/-) C57BL/6 mice. Parainfluenza virus infection induced airway hyperresponsiveness to inhaled methacholine in wild-type mice, an effect that was abolished in Muc5ac-/- mice. Parainfluenza virus-induced airway hyperresponsiveness was reversed by vagotomy, demonstrating it is mediated by parasympathetic nerve dysfunction. Muc5ac-/- mice exhibited higher viral titers, increased bronchoalveolar lavage cellularity, and elevated antiviral cytokine levels, but did not develop airway hyperresponsiveness. We did not see mucus plugging in any of our animals. Together, these findings indicate that Muc5ac is important for host defense against parainfluenza virus but paradoxically is also required for virus-induced airway hyperresponsiveness.

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Ethnic Differences in the Timing and Incidence of Childhood Health Conditions: Evidence from the Born in Bradford Cohort

Santorelli, G.; Cheung, R. W.; Bhopal, S.; Wright, J.

2026-04-01 epidemiology 10.64898/2026.03.31.26349839 medRxiv
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Objective To examine ethnic differences in the incidence and age-related trajectories of childhood health conditions from birth to adolescence within a UK birth cohort. Design Longitudinal population-based birth cohort with linkage to primary care electronic health records. Setting Born in Bradford (BiB), a multi-ethnic birth cohort in Bradford, UK. Participants 13,282 children (36% White British, 44% Pakistani British, 20% other ethnicity) born 2007 to 2011 with linked primary care records and over 1 year follow-up. Main outcome measures Incident diagnoses of atopic conditions (asthma, eczema, allergic rhinoconjunctivitis), overweight/obesity, common mental health disorders (anxiety, depression), and neurodevelopmental disorders (including ADHD and autism). Incidence rates, Kaplan-Meier cumulative incidence, and Cox regression hazards ratios (HRs) were estimated. Results Atopic conditions emerged early (median onset 5 to 6 years) and were more common among Pakistani British children, with higher hazards of eczema (HR 2.29, 95% CI 2.01 to 2.61), allergic rhinoconjunctivitis (HR 2.27, 2.00 to 2.58), and asthma (HR 1.35, 1.22 to 1.50). Overweight/ obesity developed later (median 9 to 10 years) and were also more frequent in Pakistani British children (HR 1.25, 1.16 to 1.35). In contrast, common mental health disorders emerged predominantly in early adolescence (median around 13 years), and both mental health and neurodevelopmental diagnoses were more frequently recorded among White British children; Pakistani British children had lower hazards of neurodevelopmental diagnoses (HR 0.28, 0.23 to 0.35) and mental health disorders (HR 0.53, 0.41 to 0.70). Conclusions Ethnic differences in childhood health are condition-specific and vary by age of onset, emerging at distinct stages. These findings inform the timing of prevention, service planning, and research into underlying mechanism.

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Omicron-Enhanced Immunosuppressive Effects of SARS-CoV-2 ORF3a and ORF9b Accessory Proteins on Monocytic Inflammatory Response

Grigas, J.; Padilla-Blanco, M.; Herran, U. M.; Lopez-Ayllon, B. D.; Rius, A. d. L.; Mendoza Garcia, L.; Fernandez Rodriguez, R.; Garcia Garcia, T.; Garrido, J. J.; Pautienius, A.; Stankevicius, A.; Kucinskaite-Kodze, I.; Montoya, M.

2026-04-01 immunology 10.64898/2026.03.31.715496 medRxiv
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This study investigates the poorly understood roles of SARS-CoV-2 accessory proteins using monocytic THP-1 cells expressing individual viral ORFs. ORF3a, ORF7b, and ORF9b were identified as major immunomodulators that suppress host inflammatory signaling. Specifically, cells expressing ORF3a or ORF9b exhibited reduced Toll-like receptor 4 (TLR4)-mediated production of key proinflammatory molecules--CCL2, CCL4, and IL-1{beta}--resulting in diminished immune cell recruitment. Importantly, Omicron-associated mutations in ORF3a (T223I) and ORF9b (P10S+{Delta}E27N28A29) amplified this immunosuppressive effect, leading to stronger transcriptomic suppression consistent with Omicrons reduced pathogenicity and clinical outcomes. These findings suggest that SARS-CoV-2 accessory proteins, particularly ORF3a and ORF9b, play pivotal roles in modulating monocytic immune responses. Enhanced suppression in Omicron variants highlights an evolutionary adaptation contributing to immune evasion and milder disease manifestations.

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A conserved grain-associated immunosuppressive niche in Sudanese patients with mycetoma.

Osman, M.; Ashwin, H.; Calder, G.; O'Toole, P.; Bakhiet, S. M.; Musa, A. M.; Kaye, P. M.; Fahal, A. H.

2026-04-13 infectious diseases 10.64898/2026.04.09.26350374 medRxiv
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Mycetoma is a neglected tropical disease caused by various bacterial and fungal pathogens that has a significant health impact across a broad geographically defined "mycetoma belt" spanning South America, Africa and Asia. Histologically, mycetoma is characterised by invasive and destructive granuloma development in the skin, deep tissues and bone, leading to tissue destruction, deformities and high morbidity. The presence of macroscopic, highly compacted pathogen microcolonies, or "grains," is a key diagnostic feature, and the formation of grains supports pathogen persistence and disease chronicity. However, there is a paucity of information on immune responses in mycetoma patients and on the relative importance of phylogeny and/or grains in establishing the local immune landscape. Here, we used spatial proteomics to examine the distribution of 43 immune-related proteins in surgical biopsies from 11 patients with mycetoma of bacterial (Actinomycetoma; Actinomadura pelletierii and Streptomyces somaliensis; n=6) and fungal (Eumycetoma; Madurella mycetomatis; n=5) origin. Using mixed-effects modelling, an exploratory analysis across species and pathogen classes revealed few significant differences in immune marker expression. In contrast, and independently of pathogen class, the cellular infiltrate closest to grain boundaries had higher per-cell expression of CD66b+, ARG1, and VISTA. The preferential accumulation of CD66b+ARG1+VISTA+ cells at grain boundaries was confirmed by quantitative immunofluorescence analysis. Hence, the local tissue microenvironment surrounding the mycetoma grain represents a specialised immunosuppressive niche, with parallels to the tumour microenvironment.

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Diagnostic performance of fractional exhaled nitric oxide for asthma in children

Sasaki, M.; Goutaki, M.; de Jong, C. C. M.; Heer, P.; Regamey, N.; Moeller, A.; on behalf of the SPAC Study Team, ; Kuehni, C. E.

2026-04-17 respiratory medicine 10.64898/2026.04.16.26351005 medRxiv
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Background Recent guidelines differ in how fractional exhaled nitric oxide (FeNO) is used to diagnose school-age asthma, either as one of several tests with a cut-off at 25 ppb or as a single rule-in test at 35 ppb. Evidence on its diagnostic performance and clinical utility in subgroups remain limited. Methods We analysed data from 1,979 school-age children in the Swiss Paediatric Airway Cohort referred for suspected asthma. We investigated FeNO performance with diagnosis by paediatric pulmonologists as reference standard using receiver operating characteristics curves, selected cut-offs and simulated predictive values across different prevalence. Subgroup analyses considered allergic sensitisation with allergic rhinitis and current inhaled corticosteroid (ICS) use. Results In the overall cohort (asthma diagnosis 70%), FeNO showed poor discrimination for asthma (AUC 0.66; 95% CI 0.64-0.68) with an optimal cut-off at 22 ppb. At 25 and 35 ppb, sensitivity was low (43%, 95% CI 40-46; 31%, 95% CI 29-34) and specificity moderate to high (84%, 95% CI 77-84; 90%, 95% CI 87-92). Positive predictive value at 35 ppb was 88% and was 57% when simulated at a prevalence of 30%. FeNO had no diagnostic value in non-sensitised children and lower performance in sensitised children with allergic rhinitis than in those without (AUC 0.59 vs 0.68). Current ICS use did not influence performance. Conclusion FeNO has limited diagnostic performance as a stand-alone test for school-age asthma, and underlying asthma prevalence and allergic characteristics should be considered in the interpretation.