Direct evidence for a functional role of HLA-DRB1 and -DRB3 gene products in the recognition of Dermatophagoides spp. (house dust mite) by helper T lymphocytes

The contribution of the HLA-DRB1, -B3, and -BS gene products in the recognition of Dermatophagoides spp. (house dust mite) by helper T cells Isolated from an atopic individual (HLA-DRw12, DR7; DRw52b) with perennial rhinitis was investigated. Using a panel of histocompatlble and histoincompatible accessory cells, the restriction specificity obtained for a long term T cell suggested that a component of the dust mite reactive repertoire recognized antigen in association with DRB3 gene products. Ollgonucleotide DNA typing of the presenting cell panel demonstrated a correlation between the DRw52b allele and T cell responsiveness. Murine fibroblasts expressing DRw52b, but not DRw52a or -c molecules, presented antigen to both the T cell line and cloned T cells (DE26) derived from the line, Indicating that the supertypic specificity DRw52b was able to restrict recognition of dust mite antigens. Additional T cell clones (DE9 and DE41) also isolated from the line were restricted by the products of the B1 gene locus (DRw12B1) as determined by murine fibroblasts transfected with the appropriate HLA-DR genes. Clone DE9 was degenerate in Its restriction specificity, also recognizing dust mite presented by accessory cells expressing the DR2 subtypes. Presentation by fibroblasts transfected with DRw12B1, DR2Dw2B5 genes and EBV-transformed B cell lines expressing DR2Dw21B1 and -B5 indicated that the functional site restricting recognition may be associated with residues 70 and 71 of the DR/3 chain helical wall of the antigen combining site. Furthermore, we have recently demonstrated that both T cell clones DE9 and DE26 induce allergen dependent IgE synthesis in vitro. Thus these results demonstrate directly that the DRB1, -B3, and -B5 gene products are functional in the restriction of T cell recognition of dust mite antigen

Update on inborn errors of immunity

Ever since the first description of an inherited immunodeficiency in 1952 in a boy with gammaglobulin deficiency, new insights have progressed rapidly in disorders that are now referred to as inborn errors of immunity. In a field where fundamental molecular biology, genetics, immune signaling, and clinical care are tightly intertwined, 2022-24 saw a multitude of advances. Here we report a selection of research updates with a main focus on (1) diagnosis and screening, (2) new genetic defects, (3) susceptibility to severe coronavirus disease 2019 infection and impact of vaccination, and (4) treatment. Importantly, new pathogenic insights more rapidly affect treatment outcomes, either through an earlier and more precise diagnosis or through implementation of novel, personalized treatment. The field is growing rapidly, so awareness, communication, and collaboration are key to improving treatment outcomes.</p

A Single Multiplex CytoBas Assay Incorporating Eight Major Components for Accurate Detection of Allergen Sensitization in Asthma and Allergic Rhinitis

Background: Allergic rhinitis and asthma can be triggered by a variety of aeroallergens, including house dust mites (HDM), tree and grass pollen, and household pets. Identification of the relevant allergen is critical for lifestyle changes and treatments, including allergen immunotherapy. We here assessed the diagnostic performance and clinical utility of a single flow cytometry staining of basophils with major aeroallergen components (AeroDiff CytoBas). Methods: In 156 atopic patients with allergic rhinitis/asthma and 21 non-atopic individuals, allergen-specific IgE levels were determined by ImmunoCAP, and component-specific IgE by ELISA. PBMCs were analyzed by flow cytometry with basophil markers and eight fluorochrome-conjugated allergen component tetramers. Results: Patients were stratified for sensitization to each of the four allergens. Allergen-component staining in a single multiplex CytoBas assay and component-specific IgE serology performed similarly for Der p 2, Lol p 1, Fel d 1, and Can f 1 (ROC AUC: 0.76–0.97 vs. 0.73–0.93). CytoBas had greater diagnostic accuracy than component-specific IgE serology (p &lt; 0.001) for HDM sensitization using Der f 1 or Der p 1, and grass pollen using Lol p 5 or Phl p 1. Furthermore, the combined evaluation of Der p 1 and Der p 2 with CytoBas was 96.3% sensitive and 90.7% specific for HDM sensitization. The combined evaluation of Lol p 1 and Lol p 5 achieved 95.4% sensitivity and 96.4% specificity for ryegrass pollen sensitization. Conclusion: AeroDiff CytoBas has similar to superior diagnostic accuracy compared to singleplex IgE serology, with the additional advantage of a single assay to evaluate multiple allergens. This enables precise and efficient component-resolved diagnosis of aeroallergen sensitization to guide personalized treatment for patients with allergic rhinitis and/or asthma.</p

Assessment of thunderstorm-induced asthma using Google Trends

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Identification of novel oyster allergens using a combined transcriptomic and proteomic approach for improved component resolved diagnosis

Background: Increasing production and consumption of mollusc is associated with the rise in prevalence of mollusc allergy worldwide, currently ranging from 0.15% to 1.3% of the general population. However, the elucidation of mollusc allergens for better diagnostics still lags behind other seafood groups such as fish and crustacean. Genomic data have been utilized previously for improved identification of non-food allergens by performing similarity searching using the BLAST program. Based on the published genome of the Pacific oyster (Crassostrea gigas) we aimed to identify the complete potential oyster allergen repertoire using ioinformatics analysis, and to investigate identified protein allergenicity using a combination of immuno-chemical methods and proteomic analysis. Results: Ninety-five potential allergenic proteins of the Pacific oyster were discovered using in silico analyses. These proteins were of same protein family and had more than 50% amino acid identity with their homologous allergens. The allergenicity of these proteins was characterized using a combination of immunoassay and transcriptome-derived proteomics analyses. However The 2D-immunoblotting results showed only twenty two IgE-reactive spots in the raw extract of the Pacific oyster, and six spots in the heated extract. The identity of these IgE-reactive proteins was investigated by mass spectrometry. Sixteen allergens were identified, some with two or more isoforms. Conclusions: The combination of genomics coupled to proteomics and IgE-reactivity profiling is a powerful method for the identification of novel allergens from food sources. Using this combination approach we were able to expand the current knowledge on IgE-reactivity to various proteins of the Pacific oyster. These newly identified allergens and knowledge of their gene sequences will facilitate the development of improved component resolved diagnosis and future immunotherapy approach for oyster allergy

Collagen-an important fish allergen for improved diagnosis

Background Fish collagen is widely used in medicine, cosmetics, and the food industry. However, its clinical relevance as an allergen is not fully appreciated. This is likely due to collagen insolubility in neutral aqueous solutions, leading to low abundance in commercially available in vitro and skin prick tests for fish allergy. Objective To investigate the relevance of fish collagen as an allergen in a large patient population (n = 101). Methods Acid-soluble collagen type I was extracted from muscle and skin of Atlantic salmon, barramundi, and yellowfin tuna. IgE binding to collagen was analyzed by ELISA for 101 fish-allergic patients. Collagen-sensitized patients' sera were tested for IgE binding to parvalbumin from the same fish species. IgE cross-linking was analyzed by rat basophil leukemia assay and basophil activation test. Protein identities were confirmed by mass spectrometry. Results Purified fish collagen contained type I α1 and α2 chains and their multimers. Twenty-one of 101 patients (21%) were sensitized to collagen. Eight collagen-sensitized patients demonstrated absence of parvalbumin-specific IgE to some fish species. Collagen induced functional IgE cross-linking, as shown by rat basophil leukemia assay performed using 6 patients' sera, and basophil activation test using fresh blood from 1 patient. Collagen type I α chains from barramundi and Atlantic salmon were registered at www.allergen.org as Lat c 6 and Sal s 6, respectively. Conclusions IgE sensitization and IgE cross-linking capacity of fish collagen were demonstrated in fish-allergic patients. Inclusion of relevant collagen allergens in routine diagnosis is indicated to improve the capacity to accurately diagnose fish allergy

Subcutaneous immunotherapy for bee venom allergy induces epitope spreading and immunophenotypic changes in allergen-specific memory B cells

Background: Allergen immunotherapy (AIT) is the only disease-modifying treatment for allergic disorders. We have recently discovered that allergen-specific memory B cells (Bmem) are phenotypically altered after 4 months of sublingual AIT for ryegrass pollen allergy. Whether these effects are shared with subcutaneous allergen immunotherapy (SCIT) and affect the epitope specificity of Bmem remain unknown.Objective: The study aimed to evaluate the phenotype and antigen receptor sequences of Bmem specific to the major bee venom (BV) allergen Api m 1 before and after ultra-rush SCIT for BV allergy. Methods: Recombinant Api m 1 protein tetramers were generated to evaluate basophil activation in a cohort of individuals with BV allergy before and after BV SCIT. Comprehensive flow cytometry was performed to evaluate and purify Api m 1–specific Bmem. Immunoglobulin genes from single Api m 1–specific Bmem were sequenced and structurally modeled onto Api m 1. Results: SCIT promoted class switching of Api m 1–specific Bmem to IgG2 and IgG4 with increased expression of CD23 and CD29. Furthermore, modeling of Api m 1–specific immunoglobulin from Bmem identified a suite of possible new and diverse allergen epitopes on Api m 1 and highlighted epitopes that may preferentially be bound by immunoglobulin after SCIT. Conclusions: AIT induces shifting of epitope specificity and phenotypic changes in allergen-specific Bmem.<p/

Fourth dose bivalent COVID-19 vaccines outperform monovalent boosters in eliciting cross-reactive memory B cells to Omicron subvariants

Bivalent COVID-19 vaccines comprising ancestral Wuhan-Hu-1 (WH1) and the Omicron BA.1 or BA.5 subvariant elicit enhanced serum antibody responses to emerging Omicron subvariants. Here, we characterized the RBD-specific memory B cell (Bmem) response following a fourth dose with a BA.1 or BA.5 bivalent vaccine, in direct comparison with a WH1 monovalent fourth dose. Healthcare workers previously immunized with mRNA or adenoviral vector monovalent vaccines were sampled before and one month after a fourth dose with a monovalent or a BA.1 or BA.5 bivalent vaccine. Serum neutralizing antibodies (NAb) were quantified, as well as RBD-specific Bmem with an in-depth spectral flow cytometry panel including recombinant RBD proteins of the WH1, BA.1, BA.5, BQ.1.1, and XBB.1.5 variants. Both bivalent vaccines elicited higher NAb titers against Omicron subvariants compared to the monovalent vaccine. Following either vaccine type, recipients had slightly increased WH1 RBD-specific Bmem numbers. Both bivalent vaccines significantly increased WH1 RBD-specific Bmem binding of all Omicron subvariants tested by flow cytometry, while recognition of Omicron subvariants was not enhanced following monovalent vaccination. IgG1+ Bmem dominated the response, with substantial IgG4+ Bmem only detected in recipients of an mRNA vaccine for their primary dose. Thus, Omicron-based bivalent vaccines can significantly boost NAb and Bmem specific for ancestral WH1 and Omicron variants and improve recognition of descendent subvariants by pre-existing, WH1-specific Bmem beyond that of a monovalent vaccine. This provides new insights into the capacity of variant-based mRNA booster vaccines to improve immune memory against emerging SARS-CoV-2 variants and potentially protect against severe disease. One-sentence summary: Omicron BA.1 and BA.5 bivalent COVID-19 boosters, used as a fourth dose, increase RBD-specific Bmem cross-recognition of Omicron subvariants, both those encoded by the vaccines and antigenically distinct subvariants, further than a monovalent booster.</p