Immunology

BackgroundHLA-A29-positive birdshot chorioretinitis (BCR) is an inflammatory eye disorder that is generally assumed to be caused by an autoimmune response to HLA-A29-presented peptides from retinal arrestin (SAG), yet the epitopes recognized by CD8+ T cells from patients remain to be identified. ObjectivesThe identification of natural ligands of SAG presented by HLA-A29. To quantify CD8+ T cells reactive to antigenic SAG peptides presented by HLA-A29 in patients and controls. MethodsWe performed mass-spectrometry based immunopeptidomics of HLA-A29 of antigen-presenting cell lines from patients engineered to express SAG. MHC-I Dextramer technology was utilised to identify antigen-specific CD8+ T cells reactive to SAG peptides in complex with HLA-A29 in a cohort of BCR patients, HLA-A29-positive controls, and HLA-A29-negative controls. ResultsWe report on the naturally presented antigenic SAG peptides identified by sequencing the HLA-A29 immunopeptidome of antigen-presenting cells of patients. We show that the N-terminally extended SAG peptide precursors can be trimmed in vitro by the antigen-processing aminopeptidases ERAP1 and ERAP2. Unexpectedly, no antigen engagement by CD8+ T cells upon stimulation with SAG peptides was observed in patients or HLA-A29-positive controls. Multiplexed HLA-A29-peptide dextramer profiling of a case-control cohort revealed that CD8+ T cells specific for these SAG peptides were neither detectable in peripheral blood nor in eye biopsies of patients. ConclusionsCollectively, these findings demonstrate that SAG is not a CD8+ T cell autoantigen and sharply contrast the paradigm in the pathogenesis of BCR. Therefore, the mechanism by which HLA-A29 is associated with BCR does not involve SAG.

BackgroundEpstein-Barr virus (EBV) infection is a known trigger and risk factor for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-COVID syndrome (PCS). In previous studies, we found enhanced IgG reactivity to EBV EBNA4 and EBNA6 arginine-rich sequences in postinfectious ME/CFS (piME/CFS). ObjectiveThis study aims to investigate IgG responses to arginine-rich (poly-R) EBNA4 and EBNA6 sequences and homologous human sequences in PCS and ME/CFS. MethodsThe IgG responses against poly-R EBNA4 and EBNA6 and corresponding homologous human 15-mer peptides and respective full-length proteins were analyzed using a cytometric bead array (CBA) and a multiplex dot-blot assay. Sera of 45 PCS patients diagnosed according to WHO criteria, with 26 patients fulfilling the Canadian Consensus criteria for ME/CFS (pcME/CFS), 36 patients with non-COVID post-infectious ME/CFS (piME/CFS), and 34 healthy controls (HC) were investigated. ResultsAutoantibodies to poly-R peptide sequences of the neuronal antigen SRRM3, the ion channel SLC24A3, TGF-{beta} signaling regulator TSPLY2, angiogenic regulator TSPYL5, as well as to full-length -adrenergic receptor (ADRA) proteins were more frequent in patients. Several autoantibodies were positively associated with key symptoms of autonomic dysfunction, fatigue, cognition, and pain. ConclusionCollectively, we identified autoantibodies with new antigen specificities with a potential role in PCS and ME/CFS. Clinical ImplicationThese finding should prompt further studies on the function of these autoantibodies, their exploitation for diagnostic use, and of drugs targeting autoantibodies. Capsule summaryOur study reveals elevated autoantibodies to EBV-related poly-R sequences and their human homologues in PCS and ME/CFS patients associated with symptom severity, suggesting a potential role in disease pathogenesis.

BackgroundImmunoglobulin E (IgE) plays a fundamental role in the pathogenesis of allergic disease, including asthma. The IgE-producing plasma cells (PCs) are thought to persist indefinitely, providing a sustained source of allergen-specific IgE. Although these cells can accumulate in the bone marrow (BM), after prolonged allergen exposure, their frequency remains remarkably low, and the mechanisms that regulate their migration are poorly understood. ObjectiveTo investigate the chemokine receptor profile and the migration potential of the human IgE-producing cells. MethodsTonsil B cells were stimulated with IL-4 and anti-CD40 to induce class switching to IgE and IgG1. The chemokine receptor profile of IgE+ and IgG1+ switched cells was determined using flow cytometry and migration towards relevant chemokines was quantified using transwell chemotaxis assays. Chemokine expression was also validated by re-analysis of a published single cell RNA sequencing (scRNAseq) dataset of PCs isolated from nasal polyps (NP) of patients with allergic fungal rhinosinusitis. ResultsIgE PCs exhibit significantly reduced expression of the BM-homing chemokine receptor CXCR4 and impaired migration towards its ligand, CXCL12. While IgE+ PCs can upregulate CCR10 and respond to its ligand, CCL28, this behaviour is similar to IgG1+ PCs. Strikingly, however, IgE PCs selectively upregulate CCR2 and migrate robustly towards its ligand CCL2. Re-analysis of NP scRNAseq data confirmed that IgE PCs express significantly higher levels of CCR2 compared with PCs of all other isotypes. ConclusionsThese findings identify CCR2 as a key regulator of IgE PC migration and provide insights into their homing preferences that may shape the nature of the IgE responses.

IntroductionGlobal WHO data indicate that Sub-Saharan African (SSA) countries, such as Kenya, experienced reduced coronavirus disease 2019 (COVID-19) severe-morbidity and mortality burdens relative to their more affluent counterparts in Europe, Asia, and North America. MethodsWe analysed peripheral blood mononuclear cells (PBMC) samples collected from Kenya and Sweden before and during COVID-19. Pre-COVID-19 samples were available for 80 adults and 10 infants from Kenya, and 20 adults from Sweden. COVID-19 samples were available for 39 Kenyan adults. The samples were analysed for ex vivo IFN-{gamma} secretion using an Enzyme-Linked Immunosorbent (ELISpot) assay following in vitro stimulations with overlapping SARS-CoV-2 spike-protein peptides. T-cells expressing IFN-{gamma}, IL-2, TNF-, CD154, and CD107a were assessed following similar stimulations, using intracellular cytokine staining (ICS) and multiparameter flow cytometry. Results55.7% of the Kenyan pre-COVID-19 adults were classified as responders by ELISPOT responses to spike-protein peptides, compared with 28% of Swedish pre-COVID-19 adults (p = 0.04). The frequencies for SARS-CoV-2 spike-specific TNF- CD4+, TNF- CD8+ and IFN-{gamma} CD8+ T-cell responses, tended to be higher in the Kenyan adults although these differences did not reach statistical significance. ConclusionPre-COVID-19 T-cell responses could contribute to lower morbidity and mortality associated with SARS-CoV-2 infections in SSA relative to Europe, Asia, and North America. HighlightsO_LIHigher frequencies of cross-reactive IFN-{gamma}-secreting cells among Kenyan pre-COVID-19 adults compared to Sweden. C_LIO_LITrends of higher TNF- and IFN-{gamma} T-cell responses among Kenyan adults. C_LIO_LIPresence of pre-existing T-cell immunity in Sub-Saharan Africa. C_LI

BackgroundAmong the members of the Transient Receptor Potential (TRP) family, TRPV1 is distinguished as the primary receptor involved in thermal pain perception, closely associated with temperature changes. Acting as a critical nociceptor and thermosensitive receptor, TRPV1 is pivotal in the domain of allergic diseases. Despite its significance, there is a discernible lack of comprehensive reviews exploring the interactions between TRPV1 and allergic conditions in the academic literature. This study aims to thoroughly examine the relationship between TRPV1 and allergic diseases using bibliometric and visual analysis techniques. Our goal is to uncover the mechanisms by which TRPV1 influences allergic diseases, providing a robust scientific basis for future research directions and potential therapeutic strategies. MethodsTo investigate the relationship between TRPV1 and allergic diseases, we conducted a comprehensive search in the Web of Science (WoS) database. We employed a suite of analytical tools, including Excel, the WoS online analysis platform, the bibliometrix package in R, and CiteSpace software. These tools facilitated the systematic organization, detailed description, and thorough analysis of the retrieved literature, using co-citation, co-authorship, and co-occurrence visualizations to identify significant patterns and trends. ResultsThis bibliometric analysis encompassed 1,045 articles on TRPV1 and allergic diseases, published by researchers from 57 countries and 1,179 institutions across 369 journals. Publication output remained low until 2008, after which it grew steadily, peaking at 70 articles in 2020. The United States contributed the most publications, followed by China and the United Kingdom. Johns Hopkins University emerged as a central collaborative hub, with Bradley Joel Undem as the most prolific author (30 publications). The most cited study, by Cevikbas et al., explored TRPV1/TRPA1 involvement in T-cell dependent itch. Recent research focuses on mechanisms such as neurogenic pain, itch, sensitization, oxidative stress, and atopic dermatitis, frequently employing mouse models. ConclusionThis study provides a detailed analysis of research characteristics, emerging trends, and future directions in the study of TRPV1 and allergic diseases, offering an objective overview of global contributions in this field. It delivers critical insights to inform future investigations on TRP channels and allergic conditions. As an essential thermosensitive receptor, TRPV1 plays a central regulatory role in allergic diseases, with recent research increasingly directed towards developing animal models and clarifying activation mechanisms. Future research is expected to explore the complexities of sensitization mechanisms and receptor expression more deeply.Given its critical role, TRPV1 stands out as a promising pharmacological target for allergic rhinitis, meriting further study and potential therapeutic development. This focus on TRPV1 could lead to novel interventions that improve management and treatment outcomes for allergic conditions.

IntroductionThe aims of presenting study were trying to expose the course of SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus) in patients with allergic rhinitis (AR), to compare the prevalence of SARS-CoV-2 infection, hospitalization and pneumonia rates in patients with AR receiving allergen immunotherapy (AIT) and patients did not receive AIT (non-receivers) and to define possible risk factors for SARS-CoV-2 positivity in patients with AR. Materials and MethodsA total of 419 patients with AR who were being followed up in a tertiary allergy clinic between 1 June 2020 and 31 December 2020, were selected for the study. Only patients who were receiving active-continuous treatment for allergic rhinitis during the study period, were included in the study. ResultsSeventy-nine patients (18.9%) became infected with the SARS-CoV-2 [32 patients (19.6%) in AR patients with AIT and 47 patients (19.0%) in non-receivers] and the rate of pneumonia was 2.4% [12.7% of SARS-CoV-2 (+) patients]. There was no significant difference was determined between the AR patients with AIT and the non-receivers in regard to the rate of SARS-CoV-2 infection, pneumonia, and hospitalization (p: 0.864, p: 0.081, p: 0.113). There was a significant difference between the groups in terms of gender, duration of disease, sensitivity to allergens (atopy), and serum IgE levels (p: 0.009, p: 0.001, p: 0.001, and p: 0.001). The accompanying comorbidities, eosinophil count, AIT, and duration of AIT were not found to be associated with an increased risk SARS-CoV-2 PCR positivity. However, the female gender was shown to be associated with a decreased risk for SARS-CoV-2 PCR positivity (OR, 0.571; 95% confidence interval, 0.330-0.987; p: 0.045) ConclusionThe course of SARS-CoV-2 is similar in patients with AR who underwent AIT and patients with AR who did not undergo AIT, and AIT does not seem to increase the risk for SARS-CoV-2 infection.

HLA proteins are pivotal in antigen processing and adaptive immunity. This study investigates the differential expression of class I and II HLAs in human skin, focusing on HLA-Bs role in drug-induced hypersensitivity syndromes (SCARs). Using RNA expression data from the Human Protein Atlas, we identified HLA-B as the highest expressed class I protein in exposed and non-exposed skin, with significant gender- and age-related variations. Male individuals exhibited higher HLA expression in sun-exposed skin, particularly for HLA-B, which aligns with reported higher SCAR incidences in males. Expression levels increased with age, suggesting a potential link to the heightened SCAR prevalence in older populations. Additionally, molecular docking analyses were performed to investigate HLA alleles associated with dapsone hypersensitivity. Using SWISS DOCK and AutoDock Vina, we identified four non-HLA-B13:01 alleles--B13:13, B40:01, B40:10, and B15:25--with significant binding potential, potentially explaining hypersensitivity cases not attributed to HLA-B13:01. These findings offer insights into the molecular basis of hypersensitivity syndromes and the epidemiological variability across populations.

As research in the field of food allergy is gaining momentum with new and emerging therapies there is need for both researchers and clinicians to have a better understanding on how to put all this new information into context in clinical care. We are continuously learning from other fields, such as oncology, that a one-shoe-fits all type approaches are becoming the practice of the past and there is need to incorporate markers of disease activity as well as drug selection into clinical care. In the United States, this can happen in two ways; laboratory developed testing and companion diagnostics, generally former leading the path to the later. The findings in this letter is a collaboration between four CLIA/CAP accredited in-office flow cytometry laboratories in Utah, New York and Virginia that are part of very busy food allergy clinics directed by board certified Allergist/Immunologists. The identification of changes in basophils and B cells during oral food immunotherapy are proving to be potentially useful markers in monitoring these patients. We show a high ratio of CD63 to CD203c and CD73 expression on B-cells, compared to healthy non-allergic controls and patients who have outgrown their food allergies. This ratio of basophil surface markers as well as B cell CD73 expression drops as patients are undergoing food-OIT. Quite interestingly, we see a similar low pattern in patients who have non-releaser basophils. Altogether these biomarkers are providing useful and important information monitoring patients and we have validated these assays for clinical use as laboratory developed tests. The Basophil Activation Test is used much more routinely outside the United States, and the powerful correlation it provides to oral food challenge outcomes is making it a very attractive tool. We have just submitted two manuscripts on the validation of the BAT as well as sample stability which is under review elsewhere. We expect more utility of the BAT in the United States in the future. Incorporating biomarkers to clinical care of patients with food allergies will provide to be important in assessing efficacy as well as complications of various therapies as well as monitoring the natural resolution of the food allergies.

There are majorly two variants of SARS-CoV-2 vaccine that were employed worldwide on emergency basis to contain the COVID-19 pandemic i.e., RNA based or adenovirus construct based Spike protein expression system which was broadly used and the inactivated virus particle composition. Due to emergency usage starting from the onset of 2021, the immunogenicity data pertaining to long term effects of these vaccines is unexplored. Therefore, in this study we assessed the immunogenicity analysis of Covaxin (BBV152), an inactivated virus-based vaccine for a longitudinal time-span of two years. We investigated the humoral and cell-mediated immune responses in 250 subjects for two years by estimating the RBD specific IgG titres and CD4+/CD8+ T-cell responses. We found that anti-RBD IgG titres that were almost reaching at the basal levels within a year of 2nd dose of vaccination, went significantly high immediately after Omicron infection wave in January 2022. Moreover, the pseudo-virus neutralization by the serum of these subjects showed concordant and drastic increase in virus neutralization activity. At the same time, mild or no symptoms were observed in individuals infected with Omicron variant of SARS-CoV-2. These observations strongly suggested that Omicron variant could have been the best SARS-CoV-2 variant for effective vaccine formulations to generate robust protective immune response along with lesser side effects. Interestingly, the CD4+ and CD8+T-cell activity in Covaxin vaccinees depicted mild to moderate but sustained responses. The spike peptivator pool activated PBMCs of vaccinees depicted an enhancement of CD4+ and CD8+ antigenic responses after 2nd and 3rd dose of vaccine administration. In comparison to Covishield, the antibody and T-cell responses were found to be milder in BBV152 vaccinees. This milder antibody and T-cell response could be the reason behind no or less side effects with BBV152 administration than other RNA based vaccines. Overall, our study is one of the first studies profiling the longitudinal humoral and T-cell responses of inactivated virus-based vaccines like COVAXIN, which was predominantly used in India and neighbouring Southeast Asian countries.

BackgroundIn order to determine the immunogenicity of a single dose of the AZD1222/Covishield vaccine in a real-world situation, we assessed the immunogenicity, in a large cohort of health care workers in Sri Lanka. MethodsSARS-CoV-2 antibodies was carried out in 607 naive and 26 previously infected health care workers (HCWs) 28 to 32 days following a single dose of the vaccine. Haemagglutination test (HAT) for antibodies to the receptor binding domain (RBD) of the wild type virus, B.1.1.7, B.1.351 and the surrogate neutralization assay (sVNT) was carried out in 69 naive and 26 previously infected individuals. Spike protein (pools S1 and S2) specific T cell responses were measured by ex vivo ELISpot IFN{gamma} assays in 76 individuals. Results92.9% of previously naive HCWs seroconverted to a single dose of the vaccine, irrespective of age and gender; and ACE2 blocking antibodies were detected in 67/69 (97.1%) previously naive vaccine recipients. Although high levels of antibodies were found to the RBD of the wild type virus, the titres for B.1.1.7 and B.1.351 were lower in previously naive HCWs. Ex vivo T cell responses were observed to S1 in 63.9% HCWs and S2 in 31.9%. The ACE2 blocking titres measured by the sVNT significantly increased (p<0.0001) from a median of 54.1 to 97.9 % of inhibition, in previously infected HCWs and antibodies to the RBD for the variants B.1.1.7 and B.1.351 also significantly increased. Discussiona single dose of the AZD1222/Covishield vaccine was shown to be highly immunogenic in previously naive individuals inducing antibody levels greater than following natural infection. In infected individuals, a single dose induced very high levels of ACE2 blocking antibodies and antibodies to RBDs of SARS-CoV-2 variants of concern. FundingWe are grateful to the World Health Organization, UK Medical Research Council and the Foreign and Commonwealth Office.

PGAP3 is a glycosylphosphatidylinositol (GPI) phospholipase gene localized within chromosome 17q12-21, a region highly linked to asthma. Although much is known about the function of other chromosome 17q12-21 genes expressed at increased levels in bronchial epithelium such as ORMDL3 and GSDMB, little is known about the function of increased PGAP3 expression in bronchial epithelium in the context of asthma. The aim of this study was therefore to determine whether increased PGAP3 expression in human bronchial epithelial cells regulated expression of mRNA pathways important to the pathogenesis of asthma by utilizing RNA-sequencing and bioinformatic analysis. We performed RNA-sequencing on normal human bronchial epithelial cells transfected with PGAP3 for 24 and 48 hours. PGAP3 regulated genes were compared to asthma and respiratory virus (influenza A, rhinovirus, respiratory syncytial virus) reference data sets to identify PGAP3 target genes and pathways. Approximately 9% of the upregulated PGAP3-induced genes were found in an asthma reference data set, 41% in a rhinovirus reference data set, 33% in an influenza A reference data set, and 3% in a respiratory syncytial virus reference data set. PGAP3 significantly upregulated the expression of several genes associated with the innate immune response and viral signatures of respiratory viruses associated with asthma exacerbations. Two of the highest expressed genes induced by PGAP3 are RSAD2, OASL, and IFN-{lambda}, which are anti-viral genes associated with asthma. PGAP3 also upregulated the antiviral gene BST2, which like PGAP3 is a GPI-anchored protein. We conclude that PGAP3 expression in human bronchial epithelial cells regulates expression of genes known to be linked to asthma, and also regulates the bronchial epithelial expression of genes pertinent to the pathogenesis of respiratory viral triggered asthma exacerbations.

The prevalence of obesity is rapidly increasing worldwide and its impact on future generations must be assessed. We recently showed that colostrum from mothers with obesity contained a significantly reduced B lymphocytes (CD19+) fraction. Here, in a subsequent transversal cohort study of 48 mothers, we exhaustively characterize the B lymphocytes subsets present in peripheral blood and colostrum from obese mothers and describe a pervasive alteration of the B lymphocytes compartment of human colostrum accompanied by a dysregulated antibody composition. We describe significant decreases in regulatory B cells and soluble IgA concentrations, combined with increases in soluble IgG and double negative 2 (CD19+, CD27-, IgD-, CD38-, CD24-, CD21-, CD11c+) B lymphocytes. These alterations correlated with maternal BMI and corporal fat %. We provide evidence for possibly autoimmune IgG present in obese colostrum, and for the proinflammatory consequences of obese colostrum in vitro. Beyond the impact of obesity, we evidence the selective presence of B lymphocyte subtypes in colostrum and in situ production of IgG antibodies, which expands our current understanding of the origin of colostrum IgG. As maternal milk antibodies play a crucial role in regulating neonatal gut immune development, this work uncovers maternal obesity as a potential risk factor for compromised breastmilk immune components, calling for more research on the long-term health of lactating infants.

BackgroundWe have previously isolated a highly mutated VH1-02 antibody termed group C 76-Q13-6F5 (6F5) that targets a conformational epitope on gp41. 6F5 has the capacity to mediate Ab dependent cell cytotoxicity (ADCC). When the VH1-02 group C 76 antibodies variable chain sequence was reverted to germline (76Canc), this still retained ADCC activity. Due to this ability for the 76Canc germline antibody to functionally target this epitope, we sought to identify a protein target for vaccine development. MethodsInitially, we interrogated peptide targeting by screening a microarray containing 29,127 linear peptides. Western blot and ELISAs were used to confirm binding and explore human serum targeting. Autoimmune targeting was further interrogated on a yeast-displayed human protein microarray. Results76Canc specifically recognized a number of acidic peptides. Meme analysis identified a peptide sequence similar to a non-structural protein of Hepacivirus previously implicated in Kawasaki disease (KD). Binding was confirmed to top peptides, including the Hepacivirus-related and KD-related peptide. On serum competitions studies using samples from children with KD compared to controls, targeting of this epitope showed no specific correlation to having KD. Human protein autoantigen screening was also reassuring. ConclusionsThis study identifies a peptide that can mimic the gp41 epitope targeted by 76C group antibodies (i.e. a mimotope). We show little risk of autoimmune targeting including any inflammation similar to KD, implying non-specific targeting of this peptide during KD. Development of such peptides as the basis for vaccination should proceed cautiously.

Recent evidence has shown that B cells may play a key role in the pathogenesis of relapsing-remitting multiple sclerosis. Studies in our laboratory have shown a difference in the production of IL-6 and IL-10 by B cells isolated from RRMS patients compared with healthy controls. In order to further characterize the nature of the B cells in RRMS patients, we analyzed samples from patients on no disease modifying treatment for B cell expression of multiple phenotypic and regulatory markers. We observed an increased frequency in the number of circulating B cells, an increase in B1 B cells and a decrease in memory B cells in RRMS patients. These B1 cells showed a significantly higher frequency of CD5 expression and the memory B cells a significant increase in the class-switched IgD-phenotype. We also examined death receptors involved in apoptotic pathways. CD95 frequency was significantly lower in RRMS patients tan healthy controls in all B cell subsets. Conversely, frequency of PD-1 was elevated in both the naive and memory B cell subsets, and PD-L1 was elevated in B1 cells from RRMS patients. Finally, we examined a series of immunoreceptor tyrosine-based inhibition motif (ITIM)-containing inhibitory receptors, including members of the SIGLEC family. Significantly higher levels of CD22, CD305 and CD307d were seen in RRMS patients, while significantly lower levels of SIGLEC-10 were observed. Taken together, these results indicate a potential for differential regulation of B cells in RRMS patients that may provide an avenue for B cell directed therapies for the disease.

Background/ aimMass vaccination seems to be the most effective way to turn back to the pre-pandemic period and end the pandemic. Unfortunately, COVID-19 vaccines have some side effects. In phase studies of currently-approved COVID-19 vaccines, patients with a known allergy or a history of anaphylaxis were excluded from the studies. This situation creates doubts about the course of atopy and the presence of allergic disease related to the side effects of COVID-19 vaccines in patients with allergic diseases. Therefore, our aim with this study was to evaluate local side effects (LSE) and systemic side effects (SSE) after COVID-19 vaccines in patients with allergic diseases and to determine possible risk factors. Materials and MethodsSix hundred forty-eight adult patients who received any COVID-19 vaccine between April 1, 2021 and September 30, 2021 and agreed to participate in the study were included in this case-control retrospective study. ResultsSix hundred forty-eight adult patients [Female: 446 (68.8%), Male: 202 (32.2%)] participated in the study. After the 1st dose of COVID-19 vaccine, 24.1% of patients reported SSE. After the 2nd dose of COVID-19 vaccine, 67 patients (12.3%) developed SSE. Female gender (OR: 1.757, 95%Cl: 1.143-2.702, p: 0.010), history of previous COVID-19 infection (OR: 1.762, 95%Cl: 1.068-2.906, p: 0.026), and COVID-19 vaccine type administered (OR: 4.443, 95% CI: 2.640-7.476, p<0.001) were found to be independent risk factors for SSE after COVID-19 vaccines. Premedication (OR: 0.454, 95% Cl: 0.281-0.733, p<0.001), was found to be a protective factor for SSE developing after COVID-19 vaccines. ConclusionCoronoVac and Pfizer-BioNTech COVID-19 vaccines are shown to be well tolerated. Patients with allergic disease do not have an increased risk for SSE that may develop after COVID-19 vaccines. Moreover, doubts or fears about possible side effects in the allergic patient group should not be an obstacle to COVID-19 vaccination.

Natural killer (NK) cells act as the first line of defense against virus infections. The effector functions of human NK cells are controlled by inhibitory and activating receptors, including NKG2A and NKG2C, which recognize peptides presented by HLA-E. Recent studies have suggested that the SARS-CoV-2 Spike269-277 peptide YLQPRTFLL may modulate NK cell activity. Here, we show that the YLQPRTFLL peptide is poorly presented by HLA-E. Functional interrogation further revealed that loading of target cells with YLQPRTFLL did not affect the effector functions of NKG2A+ nor NKG2C+ NK cells. Our findings thus indicate that the Spike269-277 peptide YLQPRTFLL has a limited influence on human NK cell responses.

Adaptive Biotechnologies and Microsoft have recently partnered to release ImmuneCode, a database containing SARS-CoV-2 specific T-cell receptors derived through MIRA, a T-cell receptor (TCR) sequencing based sequencing approach to identify antigen-specific TCRs. Herein, we query the extent of cross reactivity between these derived SARS-CoV-2 specific TCRs and other known antigens present in McPas-TCR, a manually curated catalogue of pathology-associated TCRs. We reveal cross reactivity between SARS-CoV-2 specific TCRs and the immunodominant Influenza GILGFVFTL M1 epitope, suggesting the importance of further work in characterizing the implications of prior Influenza exposure or co-exposure to the pathology of SARS-CoV-2 illness.

Siglec-1 is a macrophage lectin-like receptor that mediates sialic acid-dependent cellular interactions. It was shown previously to promote inflammation in autoimmune disease through suppressing the expansion of regulatory T cells (Tregs). We have investigated the molecular basis for Siglec-1 binding to these cells using in vitro-induced Tregs. Siglec-1 binding was strongly upregulated on activated cells, but lost under resting conditions. Glycosylation changes that affect Siglec-1 binding were studied by comparing activated and resting Tregs using RNA-Seq, glycomics, proteomics and binding of selected antibodies and lectins. A proximity labelling and proteomics strategy identified 49 glycoproteins expressed by activated Tregs that may function as Siglec-1 counter-receptors. These represent [~]5% of the total membrane protein pool and were mainly related to T cell activation and proliferation. We demonstrate that several of these counter-receptors are upregulated following activation of Tregs and provide initial evidence that their altered glycosylation may also be important for Siglec-1 binding.

Recent biobank based exon sequencing studies included thousands of traits while the mutational spectrum of asthma and allergy associated genes is still unknown. MethodsMeta-analysis of exome data from 281,104 UK Biobank samples that were analyzed for association of mostly rare variants with asthma, allergic rhinitis and atopic dermatitis. Variants of interest (VOI) were tabulated, shared genes annotated and compared to earlier GWAS, WGBS, WES and selected candidate gene studies. Results354 VOI were significantly associated with the traits examined. They cluster mainly in two large regions on chromosome 6 and 17 while there is basically no overlap of atopic dermatitis with both other diseases. After exclusion of the two atopic dermatitis variants, 321 unique VOI remain in 122 unique genes. 30 genes are shared by the group of 87 genes with increased and the group of 65 genes with decreased risk for allergic disease. 85% of genes identified earlier by common SNPs in GWAS can not be replicated. DiscussionMost identified genes are involved in interferon {gamma} and IL33 signaling pathway. They highlight already known but also new pharmacological targets, including the IL33 receptor ST2/IL1RL1, TLR1, ALOX15, GSDMA, BTNL2, IL13 and IKZF3. Future pharmacological studies will need to included these VOI for stratification of the study population.

BackgroundStudies comparing systemic and salivary antibody responses against SARS-CoV-2 between children and adults show conflicting results. Furthermore, it is still unclear whether salivary antibody testing could be a non-invasive approach to evaluate the humoral immune response. Methodsanti-SARS-CoV-2 IgG antibodies were measured in blood and saliva sample pairs from vaccinated adults to investigate whether salivary antibody response could be a non-invasive assessment of immune response. Salivary antibody levels were also compared between vaccinated children and adults to investigate local antibody responses. ResultsSalivary IgG antibody response against SARS-CoV-2 largely reflects the systemic response in vaccinated adults. Salivary and systemic antibody concentrations were higher in vaccinated adults who had been infected, received schedules including mRNA-based vaccines, had more exposures, and a shorter time from last exposure. Salivary antibody detection was associated with schedules including mRNA-based vaccines, time from last exposure, and systemic antibody concentrations. Vaccinated children showed higher salivary antibody concentrations than adults. This difference remained when comparing antibody levels between children and adults under equal conditions (vaccination schedules, number of exposures, time from last exposure, COVID-19 history). Younger age, number of exposures, schedules including mRNA-based vaccines, and shorter time from last exposure were associated with salivary antibody levels in a multivariable linear regression analysis (p< 0.0001). ConclusionsSalivary antibody determination against SARS-CoV-2 could be a non-invasive assessment of the short-term immune response in adults with multiple exposures. Furthermore, the stronger salivary antibody response in children suggests that local immune protection may differ between children and adults, contributing to different outcomes.