Atopic eczema (AE) is an inflammatory skin disease with involvement of genetic, immunological, and environmental factors. One hallmark of AE is a skin barrier disruption on multiple, highly interconnected levels: filaggrin mutations, increased skin pH, and a microbiome dysbiosis towards Staphylococcus aureus overgrowth are observed in addition to an abnormal type 2 immune response. Extrinsic factors seem to play a major role in the development of AE. As AE is a first step in the atopic march, its prevention and appropriate treatment is essential. Although standard therapy remains topical treatment, powerful systemic treatment options emerged in the last years. However, thorough endotyping of the individual patients is still required for ideal precision medicine approaches in the future. Therefore, novel microbial and immunological biomarkers were described recently for the prediction of disease development and treatment response. This review summarizes the current state of the art in AE research.

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Background: The shrimp Litopaneus vanammei is an important source of food allergens but its allergenic repertoire is poorly characterized. Cross reactivity between crustacean and mites has been characterized, with tropomyosin, the most relevant allergen involved. The aim of this study was the structural and immunological characterization of an allergen belonging to the Fatty Acid Binding Protein (FABP) family from L. vannamei (LvFABP). Methods: ELISA, skin prick test (SPT) and basophil activation assays were performed to determine IgE reactivity and allergenicity of LvFABP. LC-MS/MS and Circular Dichroism experiments were done for structural analysis. B-cell epitope mapping with overlapping peptides, and cross-inhibition studies using human sera were done to identify antigenic regions and cross-reactivity. Results: The recombinant LvFABP showed IgE reactivity in 27% of allergic patients tested and showed allergenic activity when tested for basophil activation and SPT in shrimp sensitized patients. CD-spectroscopy of LvFABP revealed that the protein is folded with a secondary structure composed of mainly β-strands and a smaller fraction of  helices. This is consistent with molecular modelling results, which exhibit a typical β barrel fold with two α-helices and ten β-strands. Epitope mapping identified two IgE binding antigenic regions and inhibition assays found high cross reactivity between LvFABP and Blo t 13, mediated by the antigenic region involving amino acids 53 to 73. Conclusions: Our results support LvFABP as an allergen with cross reactivity with the allergen Blo t 13. This new allergen could help to understand new mechanisms of sensitization to seafood such as shrimp.

Background: Nonimmediate (delayed) allergic reactions to penicillins are common and some of them can be life-threatening. The genetic factors influencing these reactions are unknown/poorly known/poorly understood. We assessed the genetic predictors of a delayed penicillin allergy that cover the HLA loci. Methods: Using next-generation sequencing (NGS), we genotyped the MHC region in 24 patients with delayed hypersensitivity compared with 20 patients with documented immediate hypersensitivity to penicillins recruited in Italy. Subsequently, we analyzed in silico Illumina Immunochip genotyping data that covered the HLA loci in 98 Spanish patients with delayed hypersensitivity and 315 with immediate hypersensitivity compared to 1,308 controls. Results: The two alleles DRB3*02:02:01:02 and DRB3*02:02:01:01 were reported in twenty cases with delayed reactions (83%) and ten cases with immediate reactions (50%), but not in the Allele Frequency Net Database. Bearing at least one of the two alleles increased the risk of delayed reactions compared to immediate reactions, with an OR of 8.88 (95% CI, 3.37–23.32; P <0.0001). The haplotype (ACAA) from rs9268835, rs6923504, rs6903608, and rs9268838 genetic variants of the HLA-DRB3 genomic region was significantly associated with an increased risk of delayed hypersensitivity to penicillins (OR, 1.7; 95% CI: 1.06–1.92; P=0.001), but not immediate hypersensitivity. Conclusion: We showed that the HLA-DRB3 locus is strongly associated with an increased risk of delayed penicillin hypersensitivity, at least in Southwestern Europe. The determination of HLA-DRB3*02:02 alleles in the risk management of severe delayed hypersensitivity to penicillins should be evaluated further in larger population samples of different origins.

Potential cancer risk with omalizumab: a disproportionality analysis

Chronic rhinosinusitis (CRS) is a common clinical syndrome that produces significant morbidity and costs to our health system. The study of CRS has progressed from an era focused on phenotype to include endotype based information. Phenotypic classification has identified clinical heterogeneity in CRS based on endoscopically observed features such as presence of nasal polyps, presence of comorbid or systemic diseases and timing of disease onset. More recently, laboratory-based findings have established CRS endotype based upon specific mechanisms or molecular biomarkers. Understanding the basis of widespread heterogeneity in the manifestations of CRS is advanced by findings that the three main endotypes, Type 1, 2 and 3, orchestrate the expression of three distinct large sets of genes. The development and use of improved methods of endotyping disease in the clinic is ushering in an expansion of the use of biological therapies targeting Type 2 inflammation now and perhaps other inflammatory endotypes in the near future. The purpose of this review is to discuss the phenotypic and endotypic heterogeneity of CRS from the perspective of advancing the understanding of the pathogenesis and improvement of treatment approaches and outcomes.

Chemotherapeutic drugs have been widely used in the treatment of cancer disease for about 70 years and, even with the development of new therapies, they are still prescribed by oncologists, alone or in combination with other antineoplastic agents. All chemotherapies are able to provoke hypersensitivity reactions, even with different incidences, depending on the different class of these drugs, and these reactions are the third leading cause of fatal drug-induced anaphylaxis in the United States. In Europe deaths related to chemotherapy have also been reported. In particular, most reactions are provoked by platinum compounds, taxanes, epipodophyllotoxins and asparaginase. However, currently there are different points of view about the best procedures for the diagnosis, treatment and prevention of these reactions. Thus, the European Network on Drug Allergy and Drug Allergy Interest Group of the European Academy of Allergy and Clinical Immunology organized a task force to provide data and recommendations regarding the allergological work up in this field of drug hypersensitivity reactions. The aims of this position paper were to provide consensus on the investigation of HSRs to chemotherapeutic drugs and to give practical suggestions for clinicians that treat these patients, such as oncologists, allergologists and internists. Key sections cover: risk factors, pathogenesis, symptoms, role of skin tests, in vitro tests, indications and contraindications of drug provocation tests and desensitization of neoplastic patients with allergic reactions to chemotherapeutic drugs. Statements, recommendations and unmet needs were discussed and proposed at the end of each section.

T regulatory cells from people with asthma show a Th2-like phenotypeKirstin Jansen1, Oliver F. Wirz1, Willem van de Veen1,2, Ge Tan1,3, Milena Sokolowska1, Simon D. Message4, Tatiana Kebadze4, Nicholas Glanville4, Patrick Mallia4, Cezmi A. Akdis1,2, Sebastian L. Johnston4, Kari Nadeau5 and Mübeccel Akdis1*1 Swiss Institute of Allergy and Asthma Research (SIAF), University of Zurich, Davos, Switzerland.2 Christine Kühne – Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.3 Functional Genomics Center Zürich, ETH Zürich/University of Zürich, Zürich, Switzerland.4 National Heart and Lung Institute, Imperial College London, United Kingdom.5 Sean N. Parker Center for Allergy and Asthma Research, Department of Medicine, Stanford University, Palo Alto, CA, USA.* Corresponding author:Mübeccel Akdis, MD, PhD.Swiss Institute of Allergy and Asthma Research (SIAF)Herman-Burchard-Strasse 9CH-7265 Davos-Wolfgang, SwitzerlandE-mail: [email protected].: +41 81 410 08 48Declaration of fundingM. Akdis has received research support from the Swiss National Science Foundation No. 320030-159870/310030-179428 and PREDICTA (No: 260895) and the Sean N Parker Center for Allergy and Asthma Research at Stanford University. C.A. Akdis is employed by the Swiss Institute of Allergy and Asthma Research, University of Zurich; the Swiss National Science Foundation No. 310030-156823, and the Christine Kühne – Center for Allergy Research and Education (CK-CARE). M. Sokolowska received research grant from the Swiss National Science Foundation No. 310030_189334/1 and from the GSK. The experimental infection study was supported by a Medical Research Council Clinical Research Fellowship (to S.D.M.), a British Medical Association H.C. Roscoe Fellowship (to S.D.M.), British Lung Foundation/Severin Wunderman Family Foundation Lung Research Program Grant P00/2, Asthma UK Grants 02/027 and 05/067, Welcome Trust Grants 063717 and 083567/Z/07/Z for the Centre for Respiratory Infection, Imperial College, and the National Institute for Health Research (NIHR) Biomedical Research Center funding scheme. S. L. Johnston is the Asthma UK Clinical Professor (grant CH11SJ), is an NIHR Emeritus Senior Investigator and was supported by MRC Centre Grant G1000758, Asthma UK Centre Grant AUK-BC-2015-01 and European Research Council Advanced Grant 788575. K.C. Nadeau is supported by NIH grant U19 AI104209 (Asthma and Allergic Diseases Cooperative Research Center), U01 AI140498 and R01 AI140134 and the Naddisy Foundation.To the editor,Asthma is the most common chronic inflammatory disease of the lung, characterised by wheezing, shortness of breath and variable airflow obstruction. It is a heterogeneous disease that can be classified into different endotypes of which T2-high - allergic asthma is one of the most common forms, especially in children. Allergic asthma is characterised by increased IgE and type-2 cytokines, including IL-5, IL-4 and IL-131.Thus far, it is not completely understood why these type-2 responses are poorly controlled in asthma. T regulatory cells (Treg cells) are key mediators in controlling type 2 responses. However, under certain conditions, Treg cells can display a pathogenic and proinflammatory phenotype and contribute to disease pathogenesis2. Treg cells of food allergic children showed a T helper 2 (Th2)-like phenotype. Whether this Th2-like phenotype of Treg cells is also present in asthmatic individuals is unknown.Therefore, in this exploratory study, we compared the gene-expression profile of Tregs from people with stable allergic-asthma to non-allergic controls without asthma. We isolated PBMCs from 5 people with asthma and 4 controls (Table S1) and sorted Treg cells with flow cytometry (CD3+CD4+D25hiCD127low). Then, we isolated RNA from the sorted Treg cells and performed RNA-seq (See Supplemental information for detailed methods). In total, 369 genes were differentially expressed between Treg cells from asthmatic individuals and controls (P<0.01) (Supplemental Figure 1). We clustered the genes into different groups: Treg cell markers, cytokine receptors, virus related, transcription factors, cytokines and others (Figure 1A). Interestingly, we found that the expression of FOXP3was reduced in Treg cells from asthmatic individuals (Figure 1B). This is in line with a previous study that observed a lower expression ofFOXP3 in Treg cells from individuals with asthma3. Interestingly FOXP3 expression inversely correlated with the IgE levels found in the serum (Figure 2A), supporting the finding that Treg cells can suppress IgE production4.In addition, we found a significant upregulation of IL13 mRNA expression and a trend to increased expression of IL4 andIL5 mRNAs in Tregs in asthma, indicating a Th2-like phenotype as was reported in Tregs from children with food allergies2. Furthermore, we found an upregulation of the prostaglandin D2 receptor (PTGDR2 ) or CRTH2, in line with a previous study that reported an increased amount of CRTH2+ Tregs in asthma5.Interestingly, several cytokine receptors were differentially expressed between Tregs from asthmatic individuals compared to controls. The IL-4 receptor alpha transcript IL4RA was significantly reduced in asthma. The expression of IL4RA also strongly correlated with the levels of IgE in the serum (Figure 2A). Previously, it was shown in mice that IL-4 receptor signalling is essential in controlling Th2 responses and airway inflammation6. Our data suggest a similar role of IL4RA in humans. Likewise, we observed a downregulation of TNF receptor superfamily member 25 (TNFRSF25 ), which was shown to contribute to preventing allergic lung inflammation7 and downregulation of OX40 (TNFRSF4 ).Additionally, we observed a difference in virus/type-I interferon(IFN)-related genes in asthma, which was also observed in single-cell transcriptomic data of allergen-specific Tregs from individuals with asthma8. Curiously, the expression of the type 1 IFN receptors IFNAR1/2 were lower expressed in asthma, which could indicate a deficiency against respiratory viruses and chronicity.Lastly, we performed an enrichment analysis to see up or downregulation of pathway maps, process networks and go processes with MetaCore (Table 1). The pathway maps and process networks included upregulation of pathways related to immune functions already described. However, the affected GO processes were mostly related to epigenetic mechanisms including nucleosome organisation, nucleosome assembly and chromatin organisation. With the tool STRING, we performed a pathway analysis that showed a cluster of histone genes (Figure 2B). So far, there is no data reporting the function of histone genes in Tregs or related to asthma, but perhaps this finding could be related to changes in epigenetics. It was reported that in asthma Tregs have increased CpG methylation of theFOPX3 locus compared to individuals without asathma3.In conclusion, Tregs from individuals with asthma show reduced expression of several molecules related to Treg suppressive functionality, while having increased expression of Th2-like characteristics that could lead to their reduced control of allergic airway inflammation. Further studies are needed to confirm these findings in a larger population and investigate their contribution to disease pathology.References1. Kuruvilla, M. E., Lee, F. E. H. & Lee, G. B. Understanding Asthma Phenotypes, Endotypes, and Mechanisms of Disease. Clinical Reviews in Allergy and Immunology (2019). doi:10.1007/s12016-018-8712-12. Noval Rivas, M. & Chatila, T. A. Regulatory T cells in allergic diseases. Journal of Allergy and Clinical Immunology138 , 639–652 (2016).3. Runyon, R. S. et al. Asthma Discordance in Twins Is Linked to Epigenetic Modifications of T Cells. PLoS One (2012). doi:10.1371/journal.pone.00487964. Meiler, F., Klunker, S., Zimmermann, M., Akdis, C. A. & Akdis, M. Distinct regulation of IgE, IgG4 and IgA by T regulatory cells and toll-like receptors. Allergy Eur. J. Allergy Clin. Immunol.(2008). doi:10.1111/j.1398-9995.2008.01774.x5. Boonpiyathad, T. et al. Impact of high-altitude therapy on type-2 immune responses in asthma patients. Allergy Eur. J. Allergy Clin. Immunol. 75 , 84–94 (2020).6. Khumalo, J., Kirstein, F., Hadebe, S. & Brombacher, F. IL-4Rα signaling in CD4+CD25+FoxP3+ T regulatory cells restrains airway inflammation via limiting local tissue IL-33. JCI Insight (2020). doi:10.1172/jci.insight.1362067. Schreiber, T. H. et al. Therapeutic Treg expansion in mice by TNFRSF25 prevents allergic lung inflammation. J. Clin. Invest.(2010). doi:10.1172/JCI429338. Seumois, G. et al. Single-cell transcriptomic analysis of allergen-specific T cells in allergy and asthma. Sci. Immunol.(2020). doi:10.1126/SCIIMMUNOL.ABA60879. Message, S. D. et al. Rhinovirus-induced lower respiratory illness is increased in asthma and related to virus load and Th1/2 cytokine and IL-10 production. Proc Natl Acad Sci U S A105 , 13562–13567 (2008).10. Dobin, A. et al. STAR: Ultrafast universal RNA-seq aligner.Bioinformatics 29 , 15–21 (2013).11. Liao, Y., Smyth, G. K. & Shi, W. The Subread aligner: Fast, accurate and scalable read mapping by seed-and-vote. Nucleic Acids Res. 41 , e108 (2013).12. Robinson, M. D., McCarthy, D. J. & Smyth, G. K. edgeR: A Bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics 26 , 139–140 (2009).13. Szklarczyk, D. et al. The STRING database in 2017: quality-controlled protein-protein association networks, made broadly accessible. Nucleic Acids Res 45 , D362-d368 (2017).Figure 1: Tregs from asthmatic individuals show a distinct phenotype compared to controls. (A) Genes that are significantly changed in Tregs cells from asthmatic individuals compared to controls (log 2 ratio)– clustered in the groups: Treg markers, cytokine receptors, virus related, transcription factors, cytokines and others. (B) Fragments per kilo base per million mapped reads (FPKM) values of genes of interest (FOXP3, IL13, IL5, IL4, IL4R, PTGDR2, TNFRSF25, TNFRSF4, IFNAR1, IFNAR2) of all donors. N = 4 (healthy), 5 (asthma). *** p<0.001 , ** p<0.01, * p<0.05Figure 2: Phenotype of Tregs might be associated to Treg function . (A) Correlation between expression of FOXP3 (left) and IL4RA (right) with IgE serum levels. (B) Satellite plot showing a cluster of known interactions related to nucleosome assembly. Genes higher expressed in asthmatic individuals are shown in red, and lower expression in blue.

Background: Although FoxP3+ regulatory T (Treg) cells constitute a highly heterogeneous population, with different regulatory potential depending on the context, distinct subsets or phenotypes remain poorly defined. This hampers the development of immunotherapy for allergic and autoimmune disorders. This study aimed at characterizing distinct FoxP3+ Treg subpopulations involved in the suppression of Th2-mediated allergic inflammation in the lung. Methods: We used an established mouse model of allergic airway disease based on ovalbumin sensitization and challenge to analyze FoxP3+ Tregs during the induction and resolution of inflammation, and identify markers that distinguish their most suppressive phenotypes. We also developed a new knock-in mouse model (Foxp3creCd103dtr) enabling the specific ablation of CD103+FoxP3+ Tregs for functional studies. Results: We found that during resolution of allergic airway inflammation in mice >50% of FoxP3+ Treg cells expressed the integrin CD103 which marks FoxP3+ Treg cells of high IL-10 production, increased expression of immunoregulatory molecules such as KLRG1, ICOS and CD127, and enhanced suppressive capacity for Th2-mediated inflammatory responses. CD103+FoxP3+ Tregs were essential for keeping allergic inflammation under control as their specific depletion in Foxp3creCd103dtr mice lead to severe alveocapillary damage and eosinophilic pneumonia, markedly reducing the lifespan of the experimental animals. Conversely, adoptive transfer of CD103+FoxP3+ Tregs effectively treated disease, attenuating Th2 responses and allergic inflammation in an IL-10-dependent manner. Conclusion: Our study identifies a novel regulatory T cell population, defined by CD103 expression, programmed to prevent exuberant type 2 inflammation and keep homeostasis in the respiratory tract under control. This has important therapeutic implications.

Allergic diseases like asthma, allergic rhinitis, or food allergy have a high prevalence in women of childbearing age and may affect up to 30% of this age group. A multitude of immunological changes characterizes pregnancy to create the optimal milieu for the unborn child. Both these immunological changes and pre-conceptional, sub-optimal disease control may affect the severity of the respective allergic disease manifestations during pregnancy and pose a risk for mother and child. Due to apparent limitations in conducting clinical trials, safety data on anti-allergic drugs during pregnancy are limited. This lack of clinical evidence demands to counsel between potential and known risks and benefits of anti-allergic drugs. This includes the potential of disease aggravation in the absence of treatment. By doing so, informed decisions and shared decision-making is facilitated. In particular, in patients with severe asthma, education about the risk of uncontrolled asthma for mother and child should be part of regular care. This review focuses on the management of allergic diseases during pregnancy, maternal counseling, and available information/evidence regarding allergic diseases’ management and treatment during pregnancy. Furthermore, we discuss the challenges of treating patients with allergic diseases and covid-19 during pregnancy.

Background The same dosing schedule, 1000 SQ-U times three, with one-month intervals, have been evaluated in most trials of intralymphatic immunotherapy (ILIT) for the treatment of allergic rhinitis (AR). The present studies aimed to evaluate if a dose escalation in ILIT can enhance the clinical and immunological effects, without compromising safety. Methods Two randomized double-blind placebo-controlled trials of ILIT for grass pollen induced AR were performed. The first included 29 patients that had recently ended 3 years of SCIT and the second contained 39 not previously vaccinated patients. An up-dosage of 1000-3000-10 000 SQ-U with one month in between was evaluated. Results ILIT in doses up to 10 000 SQ-U was safe after recent SCIT. The combined symptom-medication scores (CSMS) were reduced by 31% and the grass specific IgG4 levels in blood were doubled. In ILIT de novo, the two first patients that received active treatment developed serious adverse reactions at 5000 SQ-U. A modified up-dosing schedule; 1000-3000-3000 SQ-U appeared to be safe but failed to improve the CSMS, quality of life and nasal provocation response. Flow cytometry analyses could not detect any T-cell changes, while lymph node derived dendritic cells showed increased activation. Conclusion ILIT in high doses after SCIT appears to further reduce grass pollen induced seasonal symptoms and may be considered as an add-on treatment for patients that do not reach full symptom control after SCIT. Up-dosing schedules de novo with three monthly injections that exceeds 3 000 SQ-U should be avoided.