Journal of Clinical Immunology

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.

Introduction: Synthetic oligopeptides provide a rapid and cost-efficient approach to developing antibodies and diagnostics for emerging viral variants. Methods: This study computationally and experimentally characterized a synthetic peptide analog of the SARS-CoV-2 spike subdomain 2 major disulfide loop (SD2MDL), designated S621 (CPVAIHADQLTPTWRVYSTC). Binding affinity was computationally estimated using the Heuristic Affinity Prediction Tool for Immune Complexes (HAPTIC), while experimental validation was performed using enzyme-linked immunosorbent assay (ELISA) with rabbit-derived antipeptide antibodies. Clinical diagnostic accuracy testing was done using plasma samples from RT-PCR-confirmed COVID-19 patients and pre-COVID-19 controls. Results: S621 demonstrated nanomolar binding affinity (Kdapp = 1.14 nM) and high avidity (3.67 nM), closely matching HAPTIC predictions (3.54 nM). Diagnostic evaluation yielded a sensitivity of 89.92% and specificity of 27.79%, corresponding to an overall accuracy of 71.79%. Discussion: These findings demonstrate that a single synthetic peptide derived from a conserved spike subdomain can function as a high-affinity surrogate for full-length antigens, supporting its potential application in rapid peptide-based immunodiagnostics.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious condition associated with pediatric SARS-CoV-2 infection. While COVID-19 vaccines prevent infection and reduce severity, less conclusive evidence exists regarding their role in preventing MIS-C during breakthrough infections. This systematic review assessed the impact of SARS-CoV-2 vaccination on MIS-C risk during breakthrough infection. Cross-sectional studies, surveillance studies, and cohort studies were included. Of the 944 studies identified, 6 were included. A significant protective effect was seen in patients who received two doses of SARS-CoV-2 vaccination after exclusion of a biased sample (d= 0.71 [95% CI 0.07 to 1.35; p=0.03]). A trend towards a protective effect was seen after one dose of vaccination, but this effect was not statistically significant. Current literature supports a protective effect of two doses of SARS-CoV-2 vaccination against development of MIS-C in breakthrough COVID-19. The evidence supports clinician advocacy for continued vaccination of children against SARS-CoV-2.

Japanese encephalitis virus (JEV) causes significant encephalitis across the Asia-Pacific region. Current vaccines target historical genotype III strains, but emerging genotypes,potentially driven by vaccine-mediated selective pressure, threaten vaccine effectiveness through altered envelope protein sequences that may reduce antibody cross-neutralisation. This study employed integrated sequence and structural analyses to identify E protein mutations affecting neutralising antibody binding and protein stability. The study curated JEV polyprotein sequences from NCBI, performed multiple sequence alignment, and used Shannon entropy to pinpoint highly variable positions. Mutations occurring at [&ge;]1% frequency within high-entropy regions were selected for analysis. From 34 initially identified mutations, four candidates were prioritized based on structural stabilization potential. Mutations were evaluated through FoldX stability predictions, molecular docking with antibody 2H4 using HADDOCK3, and molecular dynamics simulations. Binding energies were calculated using MM-GBSA analysis. Results demonstrated that all mutant E-2H4 complexes remained stable during simulations, with root-mean-square deviation plateauing after equilibration and minimal localized changes in root-mean-square fluctuation. These findings suggest that EDIII substitutions represent important candidates for further investigation to understand genotype-specific variations and inform next-generation vaccine development strategies against emerging JEV strains.

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.

MERS-CoV poses a constant pandemic risk, as its viral lineages continue evolving, and zoonotic spillover events could lead to random viral polymorphisms that might lead to human adapted variants. Currently, no small animal model reliably recapitulates both disease progression and transmission dynamics, which are critical aspects for counter-viral measures like vaccine development. Although the Syrian hamster is an optimal animal model for SARS-CoV-2 infection and transmission, it is naturally resistant to MERS-CoV infection. Dipeptidyl peptidase-4 (DPP4) is the functional receptor for MERS-CoV infection, and is highly expressed in human kidney, intestine, liver, and lung tissues. Here, we evaluated the suitability of a human DPP4 (hDPP4) transgenic Syrian hamster model for MERS-CoV research. We used two different MERS-CoV strains (EMC/2012 and D10540/2023) for intranasal inoculation of hamsters. Both strains replicated efficiently, led to comparable severe clinical outcomes, and had similar viral transmission efficiencies. MERS-CoV RNA and nucleoprotein antigen were mainly detected in the brain and the respiratory tract. In summary, we validated a novel hDPP4-transgenic hamster as a suitable model for MERS-CoV infection enabling vaccine and transmission research.

Wiskott-Aldrich syndrome (WAS) and X-linked neutropenia (XLN) are caused by genetic variants in the WAS gene. How WAS variants lead to clinical disease remains unsolved in many cases. We expressed human WASp using a spider silk inspired solubility tag (NT*-tag) and inserted patients variants. Native mass spectrometry and pyrene actin assays showed that five variants (L270P, F271S, S272P, I290T, I294T) predicted to cause XLN led to open protein conformation and high actin polymerization rate in the absence of the WASp activator, Cdc42. One previously reported XLN variant (R268W), two loss-of-function WAS variants (A236G, D485N), and one variant of unknown significance (R431W) behaved similarly to wildtype WASp in terms of structural conformation and actin polymerization. Patient CD4+ T cells were used for analysis of WASp expression and phosphorylation, actin polymerization, anti-CD3 induced proliferation capacity, and upregulation of high affinity LFA-1, distinguishing loss-of-function and gain-of-function variants from benign WAS variants. This systematic approach reveals how WAS genetic variants cause severe human disease and stratify variants to guide clinical decision for definitive therapy. Key PointsO_LIGain-of-function WASp variant has extended protein conformation probed by native mass spectrometry and raised pyrene actin polymerization. C_LIO_LIFunctional analysis of patients CD4+ T cells classifies WASp variants as loss-of-function, reduced-function, gain-of-function, and benign. C_LI

High levels of IL-18 have been causally implicated in IBD risk and may represent a unique mechanism driving IBD yet to be therapeutically targeted. To identify individuals predisposed to increased levels of IL-18, we implemented a polygenic approach to predict IL-18 plasma protein levels. Using a dataset with over 50,000 individuals with both genetic and plasma protein levels from Olink, we developed a 27 SNP polygenic score that predicts IL-18 levels and IBD risk. Further, we identified a threshold to classify patients as 'IL-18 High' using a data-driven approach that optimized prediction of both IL-18 and IBD risk. We show that ~30% of the overall IBD patient population is 'IL-18 High', meaning a genetic predisposition towards higher protein levels. The IL-18 PGS and corresponding threshold have the potential to identify IBD patients with IL-18-driven IBD that may respond more effectively to a therapy targeting this mechanism.

Introduction: Adenoviral vectors such as chimpanzee ChAdOx1 were selected for COVID-19 vaccines due to their low seroprevalence in humans, minimizing the impact of neutralising anti-vector immunity that could attenuate vaccine responses. However, the influence of pre-existing adenoviral immunity on vaccine response remains incompletely understood. We have previously shown that SARS-CoV-2 spike-specific T cells were enhanced in ChAdOx1 nCoV-19 vaccinated immunodeficient patients compared to mRNA-based BNT162b2. Here, we assess immune cross-reactivity between ChAdOx1 and human adenovirus 5 (HuAd5), and test the hypothesis that in antibody-deficient individuals, cross-neutralisation may be impaired, allowing bystander enhancement of SARS-CoV-2 spike-specific T cell responses following ChAdOx1 nCoV-19 vaccination. Methods: We studied healthy healthcare workers (HCWs) and immunodeficient patients (IDPs) who received homologous ChAdOx1 nCoV-19 or BNT162b2 vaccines. HCWs samples were collected pre-vaccination and 4-6 weeks after the second dose, while IDP samples were obtained 4-6 weeks after the second dose. Serum anti-HuAd5 hexon IgG was quantified using a Luminex multiplex assay, and neutralizing antibodies were assessed using a replication-deficient HuAd5-GFP virus neutralization assay with flow cytometry readout. Ex vivo ELISpot and flow cytometry assays were used to measure T cell responses to HuAd5 hexon. These data were compared with previously published ChAdOx1 nCoV-19 vaccine responses in the same cohorts. Results: HuAd5 hexon-binding IgG titres were significantly higher in ChAdOx1 nCoV-19 compared to BNT162b2 vaccine recipients in both HCWs (p = 0.0043) and IDPs (p = 0.0328). Within ChAdOx1 nCoV-19 vaccine group, titres were lower in IDPs than HCWs (p = 0.0015) but not within the BNT162b2 group (p = 0.1261). HuAd5 neutralisation titres did not differ between cohorts or vaccine groups. In ChAdOx1 nCoV-19 vaccinated IDPs and HCWs, there was a significant negative correlation between HuAd5 hexon IgG titres and SARS-CoV-2 spike-specific T cell responses. Similarly, HuAd5 neutralisation titres showed an inverse correlation with spike-specific T cell responses in ChAdOx1 nCoV-19 vaccinated IDPs and HCWs. ChAdOx1 nCoV-19 vaccination induced significantly higher frequencies of HuAd5 hexon-reactive T cells compared with BNT162b2 vaccination in IDPs (p < 0.0001), consistent with cross-reactive adenoviral T cell responses. In IDPs, HuAd5 hexon-specific T cell frequencies positively correlated with SARS-CoV-2 spike-specific T cell responses following ChAdOx1 nCoV-19 vaccination but not following BNT162b2 vaccination. Functional profiling in ChAdOx1 nCoV-19 vaccinated IDPs demonstrated expansion of HuAd5 hexon-specific CD4IFN-{gamma}TNF T cells in high SARS-CoV-2 spike responders (p = 0.0002) compared to low responders, and the frequency of these cells strongly correlated with spike-specific T cell response. Discussion: ChAdOx1 nCoV-19 has been associated with stronger T cell responses than BNT162b2 in certain populations, including immunodeficient and elderly individuals. While this has been attributed to antigen persistence and innate adjuvant effects, our findings support a mechanism whereby heterologous pre-existing adenovirus immunity modulates vaccine-induced responses. Specifically, cross-reactive HuAd5-specific T cells may enhance spike-specific T cell responses via bystander enhancement, while cross-reactive binding antibodies may exert opposing effects. An implication of this study is that vaccine protocols could incorporate therapies that suppress vector-specific or cross-reactive antibodies while preserving T cell responses especially in cases where T cell-specific responses are most desirable. Also, safe vector-based vaccines can be developed for patient groups with predominant antibody deficiency. Targeted vaccination strategy could be implemented for clinical cohorts based on immune competence.

Background Reactivation of human herpesviruses (HHVs), particularly EBV, is associated with more severe acute SARS-CoV-2 infections and the development of Long COVID (LC). Observations of higher anti-EBV antibody levels in individuals with LC support the idea that chronic reactivation of HHVs could contribute to LC pathology. HHV shedding in saliva has also been previously associated with saliva hormone levels. This study aims to examine the relationship between salivary shedding of HHV DNA and LC symptoms, as well as cortisol, testosterone, and estradiol levels. Methods We enrolled 45 participants with LC, and 45 age-sex-matched controls. Surveys and validated health questionnaires were used to collect demographics, medical history, and symptom profiles. Saliva was self-collected at waking, 15, 30, and 45 minutes, and 8 and 16 hours after waking, across two consecutive days. Salivary cortisol, testosterone and estradiol were measured, and extracted nucleic acid was tested for EBV, HSV 1/2, HCMV and HHV-6 A/B using multiplex qPCR, plus SARS-CoV-2 and RNaseP using RT-qPCR. Findings Detection of salivary EBV and HHV-6 DNA was highest early in the morning. There were no significant differences in salivary cortisol, testosterone, or estradiol, or in EBV or HHV-6 shedding between the LC and control groups. However, salivary HHV-6 DNA levels were positively associated with a greater aggregated LC propensity score, as well as anxiety and depression scores. Interpretation The observed correlation between salivary HHV-6 shedding and symptom severity suggests HHV-6 may contribute to post-acute disease, though mechanisms remain unclear. While our study did not identify a relationship between salivary EBV shedding and LC, EBV may still play a role at earlier time points in the disease course, or in compartments not sampled here. These findings highlight the potential importance of HHV-6 in LC pathophysiology and underscore the need for longitudinal, multi-compartment studies of herpesvirus reactivation in LC.

Relapse during treatment of B-cell acute lymphoblastic leukemia (B-ALL) is a harbinger of poor outcomes. Identifying biomarkers for subsequent relapse risk which are detectable at B-ALL diagnosis remains a priority. Off-target recombination-activating gene (RAG)-mediated structural variants (SVs) generate genomic instability that drives leukemogenesis and may underlie treatment resistance. Leveraging sequencing data in 1,496 pediatric B-ALL patients enriched for relapse status (relapse n=532; non-relapse n=964), we characterized RAG-mediated SVs across B-ALL molecular subtypes and examined their association with patient characteristics and their impact on clinical outcomes. Off-target RAG-mediated SVs were overall frequent, particularly in ETV6::RUNX1, ETV6::RUNX1-like, and Ph-like B-ALL subtypes, while increasing age-at-diagnosis was positively associated with burden of off-target RAG-mediated SVs (P<.001). Off-target RAG-mediated SVs with a recombination signal sequence (RSS) at one breakpoint, a hallmark of off-target RAG activity, were significantly more frequent at diagnosis in patients who subsequently relapsed (P=.001). This association remained significant in multivariable regression analysis (per SV odds ratio [OR]:1.08, 95%CI:1.04-1.12), in minimal residual disease (MRD)-negative patients (OR:1.09, 95%CI:1.04-1.14) and across subtypes. Excluding deletions, MRD-negative ETV6::RUNX1 patients with 3 off-target RAG-mediated SVs had a >3-fold risk of relapse (hazard ratio:3.47, 95%CI:1.86- 6.49). RAG-mediated SVs were also associated with relapse risk in T-cell ALL patients. Off-target RAG-mediated SV burden at diagnosis is a risk factor of relapse in pediatric ALL across molecular subtypes and independent of MRD status.

PRV-101 is a multivalent formalin-inactivated Coxsackievirus B (CVB) vaccine developed to prevent CVB infections, which are associated with increased risk of islet autoimmunity. While PRV-101 induces robust neutralizing antibody responses, its T-cell immunogenicity is unknown. We analyzed peripheral blood mononuclear cells from 25 healthy adults receiving three high or low PRV-101 doses or placebo in a Phase I randomized, placebo-controlled trial. CVB-reactive CD8 T-cell responses were assessed using HLA Class I multimers, and CD4 and T follicular helper (Tfh) responses were measured by activation-induced marker assays following stimulation with a CVB peptide library. PRV-101 elicited minimal CVB-reactive CD8 T-cell responses but robust CD4 and Tfh responses, peaking at week 12 and persisting through week 32. Responses were observed in both seronegative and seropositive individuals, consistent with effective immune priming and boosting. Tfh frequencies correlated with neutralizing antibody titers. Female participants exhibited higher peak Tfh responses than males. We conclude that PRV-101 elicits a CVB-protective immune profile, dominated by Tfh responses supporting durable humoral immunity and devoid of potentially diabetogenic cytotoxic T-cell responses. This profile invites further investigations in vaccine trials for type 1 diabetes prevention.

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.

Human genetic studies have identified defects in multiple mechanisms that predispose the risk of developing inflammatory bowel diseases (IBD), which include alterations in adaptive and innate immune responses, epithelial integrity and regulation of the intestinal mucus layer. Despite the importance of intestinal barrier integrity in the pathogenesis of IBD, essentially all current therapies modulate the immune responses. In this study, we determined the high resolution cryo-EM structure of human NXPE1, a IBD associated protein. Based on the structural homology, we identified NXPE1 as an O-acetyltransferase. Since NXPE1 is a pseudo gene in mouse, we generated knockout mouse model that lacked two of the mouse NXPE1 homologs, Nxpe2 and Nxpe4. The O-acetylation of sialic acid on red blood cells was abolished in the double knockout mice, confirming the sialic acid O-acetyltransferase function of NXPE1 family members. These findings underscore the potential of NXPE1 as a novel therapeutic target of the intestinal barrier functions for the treatment of IBD.

Background: Alpha-1 antitrypsin deficiency (AATD) caused by the PI*ZZ mutation (Glu342Lys) results in hepatic accumulation of misfolded AAT-Z protein and reduced circulating AAT levels, leading to progressive liver disease and emphysema. Gene correction therapy represents a potentially curative approach by directly correcting the underlying genetic defect. We report the first case of successful hepatic gene correction with early histological and functional assessment. Methods/Case presentation: We report the case of a 66-year-old male patient with PI*ZZ AATD who underwent gene correction therapy within the YOLT-202 phase I/Ia clinical trial (clinical trial.gov ID NCT07193615). Ten weeks post treatment a liver biopsy was performed to re-evaluate pre-existing F2 liver fibrosis as measured by elastography before entering the study. Serum samples allowed functional assessment of the AAT-mediated elastase inhibition. Results: Liver biopsy did not show signs of hepatic inflammation and demonstrated 54% (Sanger) and 57% (Illumina) gene correction rate of the PI*ZZ variant on the DNA level with no bystander edits or off-target effects. Following a transient elevation of transaminases during the early post-treatment period, liver enzymes normalized. Monthly serum AAT measurements demonstrated biologically active and stable therapeutic levels throughout follow-up. Conclusions: This case demonstrates efficient and precise hepatic gene correction without concerning histological alterations and with substantial improvement of functional parameters, supporting the feasibility and safety of gene editing approaches for AATD.

Currently, the genetic architecture of Middle Eastern populations is underrepresented in global genomic databases. This gap increases the rate of Variants of Uncertain Significance (VUSs) and clinical misinterpretations of genomic data especially in Middle Eastern populations. Whole exome sequencing was conducted on 90 healthy individuals from Jordan and the data were analysed using Principal Component Analysis (PCA) and multi-computational filtering. PCA revealed a double ancestry (EUR-AFR) admixture rather than a triple admixture (EUR-AFR-AMR). More than 3,500 populations-specific variants (PSVs) were identified, of which 72% were singletons. Additionally, 19 variants were significantly enriched compared to the maximum allele frequencies in public global databases (Fisher's exact test with Benjamini-Hochberg false discovery rate correction, p-value < 0.05). Consequently, the results suggest the reclassification of variants of Uncertain Significance (VUS) which reside in the ECE2 gene to likely benign and the variants of Conflicting Classification of Pathogenicity in the genes IL1RN and THPO to benign based on the significant allele frequency (AF=0.0389, p-value < 0.05). Furthermore, a pathogenic ClinVar variant was identified in a healthy individual, warranting careful interpretation. The findings underscore the importance of identifying PSVs in order to minimize or even prevent clinical misdiagnosis and highlight the unique genetic signature in Jordan. The study serves as a foundational resource for precision medicine in the region.

Acute respiratory distress syndrome (ARDS) is a devastating complication of respiratory infections; however, the biological mechanisms that initiate its onset are poorly defined. Here we show that TNFRSF13B polymorphisms increase the risk of ARDS following SARS-CoV-2 infection up to 7.4-fold compared to the WT genotype. The increased risk was not due to immune-deficiency or impaired virus neutralization. On the contrary, TNFRSF13B mutant subjects mounted better antibody neutralization compared to subjects with WT TNFRSF13B. However, IgG from subjects expressing TNFRSF13B variants had less sialic acid, terminal galactose, and fucose than IgG from subjects with a WT genotype. Moreover, IgG from TNFRSF13B mutant subjects exhibited increased recruitment of complement factors. Thus, besides well-known actions governing plasma cell differentiation, TNFRSF13B impacts both affinity maturation and effector functions of IgG in ways that independently govern complement activation controlling inflammatory responses known to trigger ARDS.

Immune phenotyping represents a pillar in diagnostics, characterization of new genetic defects, and understanding mechanisms of diseases. Cell population distribution often does not cover the intrinsic function changes that may contribute to disease. Outcome of signaling activation can be used as proxy for cell function. To overcome the limitation of sample availability and standardization of signaling assays, we developed a multiplex full spectrum cytometry phosphoflow assay allowing the study of 6 phospho-proteins representing BCR/TCR, MAPK, PI3K/Akt/mTOR and canonical NF-{kappa}B signaling pathways in 18 immune cell subpopulations. Maximal stimulation and temporal dynamics were studied in response to pan-stimuli, activating cells regardless of receptor, and targeted stimuli for T, B, and innate immune cells. We studied healthy individuals between 1-69 years and discovered subpopulations-specific responses. Furthermore, pediatric donors showed broad differences in B cell and T cell function compared to adults. Hence, we established a tool to assess multiple signaling pathways at once and provide age- and subpopulation-specific references for signaling outcome. SummaryMultiplex full spectrum flow cytometry-based phosphoflow assay across 18 immune cell subpopulations, 6 phospho-proteins in response to 6 stimuli at 4 time points in individuals aged 1-69 years, reveals distinct age- and subpopulation-associated signaling patterns in magnitude and dynamics of pathways activation.

Inflammatory skin diseases (ISDs) affect up to 25% of the global population. Yet, large-scale comparative single-cell RNA-sequencing (scRNA-seq) analyses between ISDs are still missing. Here, we integrated scRNA-seq datasets spanning 27 skin diseases from 50 studies, comprising over 2 million cells from 441 samples. Using the healthy skin cell atlas as reference, we could build a robust ISD atlas that enabled us to differentiate universal inflammatory signatures and disease-specific ones. This highlighted, for example, a shared gene program between keratinocytes in atopic dermatitis and parapsoriasis, not present in cutaneous T-cell lymphoma, confirms the plasticity of Th17 cells throughout ISDs, defines specific macrophage signatures in acne, and reveals a yet undescribed role of mural cells in ISDs. This demonstrates the power of the ISD atlas as a resource to resolve disease-specific immune mechanisms. The complete atlas is available through an interactive online portal at https://isd-atlas.derma.meduniwien.ac.at.

Background: Community-acquired pneumonia (CAP) remains a major global health burden disproportionately affecting older adults and people with comorbidities, with Streptococcus pneumoniae as one of the leading bacterial causes in Europe. The Hungarian Occurrence and Burden of PnEumonia (Hungarian-HOPE) study examined the incidence, hospitalization rates, and mortality of CAP between 2016 and 2020 in Hungary. Methods: The National Health Insurance Fund database was used to identify adult CAP patients (all-cause) based on ICD-10 codes J10-18. Outcomes included CAP incidence, 0-15-day hospitalization, and 0-30-day mortality after hospitalization, stratified by age, sex, and comorbidities (chronic obstructive pulmonary disease [COPD], asthma, cardiovascular disease [CVD], and type 1 and 2 diabetes [T1DM, T2DM]). Risk maps visualized relative risk gradients across population strata. Results: During the pre-pandemic period (2016-2019), over 100,000 CAP cases and more than 50,000 hospitalizations were recorded annually. In 2020, recorded cases fell to approximately 98,000, while hospitalizations increased to 66,200. Hospitalization rates increased from 25.1% in 2016 to 29.1% in 2019, then increased to 43.1% in 2020. The 30-day mortality among hospitalized patients rose from 22.7% in 2016 to 23.6% in 2019. Incidence, hospitalization, and mortality all increased with age. Relative to healthy males aged 30-39 years, CAP risk escalated steeply in the [&ge;]80 years cohort (incidence 5-15-fold; hospitalization >3-fold; mortality 11-24-fold) and was further amplified by COPD, CVD, or T2DM, with a lesser effect for T1DM. Conclusions: The results highlight the substantial age- and comorbidity-driven CAP burden in Hungary and support prioritization of preventive strategies including pneumococcal vaccination for older adults and high-risk groups.