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Microbial metabolism of specific dietary components, such as fiber, contributes to the sophisticated inter‐kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber‐derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision‐making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, the importance of appropriate timing of intervention to target any potential window of opportunity, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions, and outcomes were too heterogeneous for meta‐analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health. [ABSTRACT FROM AUTHOR]

By the April 12, 2022, the COVID‐19 pandemic had resulted in over half a billion people being infected worldwide. There have been 6.1 million deaths directly due to the infection, but the pandemic has had many more short‐ and long‐term pervasive effects on the physical and mental health of the population. Allergic diseases are among the most prevalent noncommunicable chronic diseases in the pediatric population, and health‐care professionals and researchers were seeking answers since the beginning of pandemic. Children are at lower risk of developing severe COVID‐19 or dying from infection. Allergic diseases are not associated with a higher COVID‐19 severity and mortality, apart from severe/poorly controlled asthma. The pandemic disrupted routine health care, but many mitigation strategies, including but not limited to telemedicine, were successfully implemented to continue delivery of high‐standard care. Although children faced a multitude of pandemic‐related issues, allergic conditions were effectively treated remotely while reduction in air pollution and lack of contact with outdoor allergens resulted in improvement, particularly respiratory allergies. There is no evidence to recommend substantial changes to usual management modalities of allergic conditions in children, including allergen immunotherapy and use of biologicals. Allergic children are not at greater risk of multisystem inflammatory syndrome development, but some associations with Long COVID were reported, although the data are limited, and further research is needed. This statement of the EAACI Section on Pediatrics provides recommendations based on the lessons learnt from the pandemic, as available evidence. [ABSTRACT FROM AUTHOR]

Immune modulation is a key therapeutic approach for allergic diseases, asthma and autoimmunity. It can be achieved in an antigen‐specific manner via allergen immunotherapy (AIT) or in an endotype‐driven approach using biologicals that target the major pathways of the type 2 (T2) immune response: immunoglobulin (Ig)E, interleukin (IL)‐5 and IL‐4/IL‐13 or non‐type 2 response: anti‐cytokine antibodies and B‐cell depletion via anti‐CD20. Coronavirus disease 2019 (COVID‐19) vaccination provides an excellent opportunity to tackle the global pandemics and is currently being applied in an accelerated rhythm worldwide. The vaccine exerts its effects through immune modulation, induces and amplifies the response against the severe acute respiratory syndrome coronavirus (SARS‐CoV‐2). Thus, as there may be a discernible interference between these treatment modalities, recommendations on how they should be applied in sequence are expected. The European Academy of Allergy and Clinical Immunology (EAACI) assembled an expert panel under its Research and Outreach Committee (ROC). This expert panel evaluated the evidence and have formulated recommendations on the administration of COVID‐19 vaccine in patients with allergic diseases and asthma receiving AIT or biologicals. The panel also formulated recommendations for COVID‐19 vaccine in association with biologicals targeting the type 1 or type 3 immune response. In formulating recommendations, the panel evaluated the mechanisms of COVID‐19 infection, of COVID‐19 vaccine, of AIT and of biologicals and considered the data published for other anti‐infectious vaccines administered concurrently with AIT or biologicals. [ABSTRACT FROM AUTHOR]

Background: The COVID‐19 pandemic has affected health care systems unexpectedly. However, data focusing on practical considerations experienced by health care professionals (HCPs) providing care to allergic patients is scarce. Methods: Under the framework of the European Academy of Allergy and Clinical Immunology (EAACI), a panel of experts in the field of immunotherapy developed a 42‐question online survey, to evaluate real‐life consequences of the COVID‐19 pandemic in allergy practice. Results: The respondents in the survey were 618. About 80% of HCPs indicated being significantly affected in their allergy practice. A face‐to‐face visit reduction was reported by 93% of HCPs and about a quarter completely interrupted diagnostic challenges. Patients with severe uncontrolled asthma (59%) and anaphylaxis (47%) were prioritized for in‐person care. About 81% maintained an unaltered prescription of inhaled corticosteroids (ICS) in asthmatics. About 90% did not modify intranasal corticosteroids (INCS) in patients with allergic rhinitis. Nearly half of respondents kept biological prescriptions unmodified for asthma. About 50% of respondents kept their allergen immunotherapy (AIT) prescription patterns unchanged for respiratory allergies; 60% for insect venom allergies. Oral immunotherapy (OIT) for food allergies was initiated by 27%. About 20% kept carrying out up‐dosing without modifications and 14% changed to more prolonged intervals. Telemedicine practice was increased. Conclusions: HCPs providing care to allergic patients were affected during the pandemic in diagnostic, management, and therapeutic approaches, including AIT for respiratory, insect‐venom, and food allergies. Most HCPs maintained controller treatments for both asthma, and allergic rhinitis consistent with international recommendations, as well as biological agents in asthma. Remote tools are valuable in delivering allergy care. [ABSTRACT FROM AUTHOR]

Microbiota composition and associated metabolic activities are essential for the education and development of a healthy immune system. Microbial dysbiosis, caused by risk factors such as diet, birth mode, or early infant antimicrobial therapy, is associated with the inception of allergic diseases. In turn, allergic diseases increase the risk for irrational use of antimicrobial therapy. Microbial therapies, such as probiotics, have been studied in the prevention and treatment of allergic diseases, but evidence remains limited due to studies with high heterogeneity, strain‐dependent effectiveness, and variable outcome measures. In this review, we sketch the relation of microbiota with allergic diseases, the overuse and rationale for the use of antimicrobial agents in allergic diseases, and current knowledge concerning the use of bacterial products in allergic diseases. We urgently recommend 1) limiting antibiotic therapy in pregnancy and early childhood as a method contributing to the reduction of the allergy epidemic in children and 2) restricting antibiotic therapy in exacerbations and chronic treatment of allergic diseases, mainly concerning asthma and atopic dermatitis. Future research should be aimed at antibiotic stewardship implementation strategies and biomarker‐guided therapy, discerning those patients that might benefit from antibiotic therapy. [ABSTRACT FROM AUTHOR]

Introduction: A substantial number of patients worldwide are affected by allergies. Emerging evidence suggests that the individual microbial composition might contribute to the development of allergies or might even protect from allergic diseases. Areas covered: This review provides a detailed summary regarding available knowledge on the composition of a healthy human microbiome at allergy relevant body sites. It highlights factors influencing the microbiota composition. Furthermore, recent findings on the mutual interaction of the microbiota with the innate and adaptive immune system are reported. In the final part, this knowledge is combined to discuss microbial implications for food allergy, allergic asthma, allergic rhinitis, and skin allergies. Literature for this review was gathered by searching PubMed and Google Scholar databases between October and December 2020. Expert opinion: Due to the highly individual composition, it is currently not possible to define the characteristics of a site-specific microbiome in health and disease. Mainly effects of bacterial communities have been investigated, while fungal or viral influences are not yet well understood. The communication between microbial communities found in different organs impact on allergy development. Thus, a personalized approach is essential to beneficially influence these complex interactions and to modulate the host-specific microbiota in allergies. [ABSTRACT FROM AUTHOR]

The microbiota can play important roles in the development of human immunity and the establishment of immune homeostasis. Lifestyle factors including diet, hygiene, and exposure to viruses or bacteria, and medical interventions with antibiotics or anti‐ulcer medications, regulate phylogenetic variability and the quality of cross talk between innate and adaptive immune cells via mucosal and skin epithelia. More recently, microbiota and their composition have been linked to protective effects for health. Imbalance, however, has been linked to immune‐related diseases such as allergy and cancer, characterized by impaired, or exaggerated immune tolerance, respectively. In this AllergoOncology position paper, we focus on the increasing evidence defining the microbiota composition as a key determinant of immunity and immune tolerance, linked to the risk for the development of allergic and malignant diseases. We discuss novel insights into the role of microbiota in disease and patient responses to treatments in cancer and in allergy. These may highlight opportunities to improve patient outcomes with medical interventions supported through a restored microbiome. [ABSTRACT FROM AUTHOR]

Beta-lactoglobulin (BLG) is a bovine lipocalin in milk with an innate defense function. The circumstances under which BLG is associated with tolerance of or allergy to milk are not understood. Our aims were to assess the capacity of ligand-free apoBLG versus loaded BLG (holoBLG) to protect mice against allergy by using an iron-quercetin complex as an exemplary ligand and to study the molecular mechanisms of this protection. Binding of iron-quercetin to BLG was modeled and confirmed by spectroscopy and docking calculations. Serum IgE binding to apoBLG and holoBLG in children allergic to milk and children tolerant of milk was assessed. Mice were intranasally treated with apoBLG versus holoBLG and analyzed immunologically after systemic challenge. Aryl hydrocarbon receptor (AhR) activation was evaluated with reporter cells and Cyp1A1 expression. Treated human PBMCs and human mast cells were assessed by fluorescence-activated cell sorting and degranulation, respectively. Modeling predicted masking of major IgE and T-cell epitopes of BLG by ligand binding. In line with this modeling, IgE binding in children allergic to milk was reduced toward holoBLG, which also impaired degranulation of mast cells. In mice, only treatments with holoBLG prevented allergic sensitization and anaphylaxis, while sustaining regulatory T cells. BLG facilitated quercetin-dependent AhR activation and, downstream of AhR, lung Cyp1A1 expression. HoloBLG shuttled iron into monocytic cells and impaired their antigen presentation. The cargo of holoBLG is decisive in preventing allergy in vivo. BLG without cargo acted as an allergen in vivo and further primed human mast cells for degranulation in an antigen-independent fashion. Our data provide a mechanistic explanation why the same proteins can act either as tolerogens or as allergens. [ABSTRACT FROM AUTHOR]

Abstract: Neuraminidases act as a virulence factors for several pathogens that invade the human body through Peyer''s patch M-cells. Because of the structural similarity of Aleuria aurantia lectin (AAL) to neuraminidases, we hypothesized that AAL might also target human M-cells. In an in vitro human M-cell co-culture model significantly more particles were transported across the epithelium when microparticles were functionalized with AAL versus those that were not. Moreover, high concentrations of AAL induced no detectable cytotoxic effects on the related intestinal epithelial cell cultures, epithelial Caco2- and HT29-MTX-E12-cells. Upon incubation with AAL, PBMCs of allergic volunteers proliferated in response to AAL and secreted the cytokines, IL-2, IFN-γ, IL-10 and IL-5 in a concentration-dependent manner, indicating immune-stimulatory properties of the lectin. We conclude that AAL-coated microparticles may have the potential to target entrapped antigens to human M-cells for oral vaccination. [Copyright &y& Elsevier]