Subcutaneous adipose tissue (SAT) is the deepest component of the three-layered cutaneous integument. While mesenteric adipose tissue-based immune processes have gained recognition in the context of the metabolic syndrome, SAT has been traditionally considered primarily for energy storage, with less attention to its immune functions. SAT harbors a reservoir of immune and stromal cells that significantly impact metabolic and immunologic processes not only in the skin, but even on a systemic level. These processes include wound healing, cutaneous and systemic infections, immunometabolic and autoimmune diseases, inflammatory skin diseases, as well as neoplastic conditions. A better understanding of SAT immune functions in different processes, could open avenues for novel therapeutic interventions. Targeting SAT may not only address SAT-specific diseases but also offer potential treatments for cutaneous or even systemic conditions. This review aims to provide a comprehensive overview on SAT’s structure and functions, highlight recent advancements in understanding its role in both homeostatic and pathological conditions within and beyond the skin, and discuss the main questions for future research in the field.

Inhaled corticosteroids in early COVID-19 – a tale of many facetsLudger Klimek1, Cezmi A. Akdis2, Marek Jutel3, Torsten Zuberbier4, Jean Bousquet5-71. Center for Rhinology and Allergology, Wiesbaden, Germany.2. Swiss Institute of Allergy and Asthma Research (SIAF), University of Zurich - Christine Kühne - Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.3. Department of Clinical Immunology, Medical University of Wroclaw, ALL-MED Medical Research Institute, Wrocław, Poland.4. Clinic for Dermatology, Venereology and Allergology, Charité - University Medicine Berlin, Berlin, Germany.5. Charité, Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin, Germany6. Comprehensive Allergy Center, Department of Dermatology and Allergy, Berlin Institute of Health, Berlin, Germany7. Centre Hospitalier Universitaire, Montpellier, France

Title : Distinct and mutually exclusive Ca++ flux- and adenyl cyclase-inducing gene expression profiles of G-Protein-Coupled Receptors on human antigen-specific B cellsAuthors : Iris Chang1,2†, Abhinav Kaushik, PhD1,2†, Pattraporn Satitsuksanoa PhD1, Minglin Yang1, Laura Buergi Msc1, Stephan R. Schneider Msc1, Cezmi A. Akdis, MD1, Kari Nadeau MD, PhD2, Willem van de Veen, PhD1, Mübeccel Akdis, MD, PhD1*1 Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland.2 Sean N. Parker Center for Allergy and Asthma Research, Department of Medicine, Stanford University, Palo Alto, CA, USA.† Contributed equally* Corresponding authorB cells play an essential role in allergies by producing allergen-specific IgE, which is a prerequisite for allergen-induced degranulation of mast cells (MCs) and basophils. MCs, basophils, dendritic cells and bacteria are capable of releasing inflammatory mediators including histamine. Histamine is a bioactive amine that exerts its function through binding to histamine receptors (HRs), which are 7-transmembrane G-protein-coupled receptors (GPCRs). There are four types of HRs (HR1-4), wherein HR1 ligation triggers Ca2+ mobilization, HR2 stimulates and increases cAMP concentrations, and HR3 and HR4 inhibit cAMP accumulation1. In the presence of histamine in the environment, high affinity HR1is triggered causing cellular activation, followed by expression of 10 times lower affinity HR2 to regulate the over-inflammatory events. These HRs trigger different intracellular events upon activation, with HR1 as a Ca2+ flux-inducing activating receptor and HR2 as an adenyl cyclase-stimulating suppressive receptor 1,2. Therefore, to explore the response of B-cells in allergic diseases, we analyzed the expression profile of HRs and other GPCRs in B cell clones. We hypothesized that the expression profile of HRs (HR1+ vs HR2+ B cell clones) is associated with significant changes in the expression profile of other GPCRs that govern the downstream cascade of pathways associated with cAMP signaling or Ca2+ mobilization.A total of 27 IgG1 and IgG4 expressing B cell clones were isolated for gene expression analysis under BCR stimulated and unstimulated conditions (Figure 1A and Online Supplementary Methods) . Interestingly, we observed B-cell clones with mutually exclusive expression profile of HRH1 and HRH2 genes (Figure 1B), with more HRH1+ B-cell clones in BCR-stimulated samples than unstimulated samples. The subsequentHRH1+ vs HRH2+ differential gene expression analysis (Figure 1C ), reveal 27 differentially expressed (DE) GPCRs in unstimulated samples, with up-regulated P2RY13  and C5AR1genes  in HRH2 + B-cell clones (Figure 2A) , which are associated with the cAMP signaling and suppressive pathway3,4. To further prioritize the DE GPCRs specifically associated with Ca2+ and cAMP signaling pathways, we reconstructed the co-expression networks and performed the weighted degree analysis across HRH1+ vs HRH2+ clones. The analysis reveals that the purinergic receptor family of GPCRs (i.e. P2RY1 , P2RY13 )  and complement component 5a receptor family of genes (i.e. C5AR1  and C5AR2 ) share highest degree of interactions. These genes are up-regulated inHRH2+ samples and are well-known to affect cAMP signaling pathway3,4 (Figure S1A ). Intriguingly, we also observed upregulation of GPR35  in HRH2 + B cells, which is associated in maintaining a low baseline Ca2+ level5. Similarly, we also observed up-regulation of GPR68 and GPR171 in HRH1 + B cells; both are known to stimulate Ca2+ flux (Online Supplementary Discussion) .Similarly, 28 GPCRs were differentially expressed in BCR-stimulated samples (Figure 2B ), including higher expression of serotonin receptor type 1A (HTR1A ) and HCAR1  (or GPR81 ) inHRH2+ samples, with a cAMP-linked suppressive function. In addition, we also observed upregulation of complement component 5a receptor family of genes (i.e., C5AR1  and C5AR2 ) and GPR35 , in agreement with the trend observed in unstimulatedHRH2 + B-cell clones. Surprisingly, we observed a higher expression of prostaglandin E2 receptor subtype EP4 (PTGER4)  and adenosine A2A receptor (ADORA2A ) in HRH2+ samples3,6, which are known to be associated with activation of cAMP production and share the highest strength of interactions with the cAMP signaling sub-network (Figure S1B ). Among the up-regulated genes in HRH1 + samples, we found three Ca2+ mobilizing genes, i.e., GPR34 ,P2RY10  and PTAFR .The results reported in this study provides data for a novel hypothesis suggesting investigation of co-expressed genes that may play important synergistic or antagonistic regulatory roles in B-cell function.

There has been an important change in the clinical characteristics and immune profile of COVID-19 patients during the pandemic thanks to the extensive vaccination programs. Here, we highlight recent studies on COVID-19, from the clinical and immunological characteristics to the protective and risk factors for severity and mortality of COVID-19. The efficacy COVID-19 vaccines and potential allergic reactions after administration are also discussed. The occurrence of new variants of concerns such as Omicron BA.2, BA.4 and BA.5 and the global administration of COVID-19 vaccines have changed the clinical scenario of COVID-19. Multisystem inflammatory syndrome in children (MIS-C) has been identified as an important cause of death of children with COVID-19. Perturbations in immunity of T cells, B cells, and mast cells, as well as autoantibodies and metabolic reprogramming may contribute to the long-term symptoms of COVID-19. Atopic diseases, such as allergic asthma and rhinitis, have been shown to be associated with a lower susceptibility and better outcomes of COVID-19. At the beginning of pandemic, EAACI developed guidelines that provided timely information for the management of allergic diseases and preventive measures to reduce transmission in the allergic clinics. The global distribution of COVID-19 vaccines and emerging SARS-CoV-2 variants with reduced pathogenic potential dramatically decreased the morbidity, severity, and mortality of COVID-19. Nevertheless, breakthrough infection remains a challenge for disease control. Hypersensitivity reactions (HSR) to COVID-19 vaccines are low compared to other vaccines, and these were addressed in EAACI statements that provided indications for the management of allergic reactions, including anaphylaxis to COVID-19 vaccines. We have gained a depth knowledge and experience in the over 2 years since the start of the pandemic, and yet a full eradication of SARS-CoV-2 is not on the horizon. Novel strategies are warranted to prevent severe disease in high-risk groups, the development of MIS-C and long COVID.

A document by Marcin Moniuszko. Click on the document to view its contents.

Reply to: “COVID-19 pandemic and environment: not only air pollution”. M.Carminati et al.

Background: The impact of physical activity (PA) on immune response is a hot topic in exercise immunology, but studies involving asthmatic children are scarce. We examine the level of PA and TV attendance (TVA) in asthmatic children to assess the role on asthma control and immune response to various stimulants. Methods: Weekly PA and daily TVA were obtained from questionnaires at inclusion of the PreDicta study. PBMC cultures were stimulated with phytohemagglutinin (PHA), R848, poly I:C and zymosan. Cytokines were measured and quantified in cell culture supernatants using luminometric multiplex immunofluorescence beads-based assay. Results: Asthmatic preschoolers showed significantly more TVA than their healthy peers (58.6% vs. 41.5% 1-3h daily and only 25.7% vs. 47.2% ≤ 1h daily). Poor asthma control was associated with less frequent PA (75% no or occasional activity in uncontrolled vs. 20% in controlled asthma; 25% ≥ 3x weekly vs. 62%). Asthmatics with increased PA exhibited elevated cytokine levels in response to stimulants, suggesting a readiness of circulating immune cells for type-1, -2 and -17 cytokine release compared to low-PA and high-TVA subjects. Low PA and high TVA were associated with increased proinflammatory cytokines. Proinflammatory cytokines were correlating with each other in in-vitro immune responses of asthmatic children, but not healthy controls. Conclusion: Asthmatic children show more sedentary behavior than healthy subjects, while poor asthma control leads to a decrease in PA. Asthmatic children profit from exercise, as elevated cytokine levels in stimulated conditions indicate an immune system prepared for a strong response in case of infection.

Immune-inflammatory proteome of elite ice hockey players before and after SARS-CoV-2 infection

Non-steroidal anti-inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti-inflammatory, antipyretic and analgesic effects are applied against symptoms of respiratory infections, including SARS-CoV-2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID-19 also revealed the gaps in our understanding of their mechanism of action, selectivity and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs-exacerbated respiratory disease (NERD). In this context, the consensus report summarises currently available knowledge, novel discoveries and controversies regarding the use of NSAIDs in COVID-19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID-19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarise the major knowledge gaps and unmet needs in current eicosanoid research.

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: akdism@siaf.uzh.chTel.: +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.

Vaccines are essential public health tools with a favorable safety profile and prophylactic effectiveness that have historically played significant roles in reducing infectious disease burden in populations, when the majority of individuals are vaccinated. The COVID-19 vaccines are expected to have similar positive impacts on health across the globe. While serious allergic reactions to vaccines are rare, their underlying mechanisms and implications for clinical management should be considered to provide individuals with the safest care possible. In this review, we provide an overview of different types of allergic adverse reactions that can potentially occur after vaccination and individual vaccine components capable of causing the allergic adverse reactions. We present the incidence of allergic adverse reactions during clinical studies and through post-authorization and post-marketing surveillance and provide plausible causes of these reactions based on potential allergenic components present in several common vaccines. Additionally, we review implications for individual diagnosis and management and vaccine manufacturing overall. Finally, we suggest areas for future research.