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.
Background: From early life, respiratory viruses are implicated in the development, exacerbation and persistence of respiratory conditions such as asthma. Complex dynamics between microbial communities and host immune responses, shape immune maturation and homeostasis, influencing health outcomes. We evaluated the hypothesis that the respiratory virome is linked to systemic immune responses, using peripheral blood and nasopharyngeal swab samples from preschool-age children in the PreDicta cohort. Methods: Peripheral blood mononuclear cells from 51 children (32 asthmatics, 19 healthy controls), participating in the 2-year multinational PreDicta cohort were cultured with bacterial (Bacterial-DNA, LPS) or viral (R848, Poly:IC, RV) stimuli. Supernatants were analyzed by Luminex for the presence of 22 relevant cytokines. Virome composition was obtained using untargeted high troughput sequencing of nasopharyngeal samples. The metagenomic data were used for the characterization of virome profiles and the presence of key viral families (Picornaviridae, Anelloviridae, Siphoviridae). These were correlated to cytokine secretion patterns, identified through hierarchical clustering and principal component analysis. Results: High spontaneous cytokine release was associated with increased presence of Prokaryotic virome profiles and reduced presence of Eukaryotic and Anellovirus profiles. Antibacterial responses did not correlate with specific viral families or virome profile, however, low antiviral responders had more Prokaryotic and less Eukaryotic virome profiles. Anelloviruses and Anellovirus-dominated profiles were equally distributed amongst immune response clusters. The presence of Picornaviridae and Siphoviridae was associated with low interferon-λ responses. Asthma or allergy did not modify these correlations. Conclusions: Antiviral cytokines responses at a systemic level reflect the upper airway virome composition. Individuals with low innate interferon responses have higher abundance of Picornaviruses (mostly Rhinoviruses) and bacteriophages. Bacteriophages, particularly Siphoviridae appear to be sensitive sensors of host antimicrobial capacity, while Anelloviruses are not affected by TLR-induced immune responses.
Functional role of ST6GALNAC1-mediated sialylation of mucins in preserving intestinal barrier integrity and ameliorating inflammation. Authors : Elisa Sánchez-Martínez1*, Manuel Garrido-Romero1,2,*, F. Javier Moreno21Department of Immunology, Instituto de Investigación Sanitaria Hospital Universitario de La Princesa, (IIS-Princesa), Universidad Autónoma de Madrid (UAM), Madrid, Spain.2Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), Madrid, Spain.*Equal contributionCorrespondence to:F. Javier Moreno. Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación, CIAL (CSIC-UAM), Nicolás Cabrera 9, 28049 Madrid, Spain.E-mail:firstname.lastname@example.orgAbbreviations:ST6GALNAC1, ST6; mucin-2, MUC2; dextran sulfate sodium, DSS; wild-type, WT; short-chain fatty acids, SCFA.Funding information : MGR is supported by an EFSA project (Grant agreement GP/EFSA/ENCO/2020/02 – 1) granted to FJM. Conclusions, findings and opinions expressed in this document reflect only the view of the authors and not the official position of EFSA.Keywords: epithelial barrier; MUC2; intestinal mucus; gut microbiota disruption; colitis.
Virus infections and T cell-mediated drug hypersensitivity reactions (DHR) can influence each other. In most instances, systemic virus infections appear first. They may prime the reactivity to drugs in two ways: First, by virus-induced second signals: certain drugs like β-lactam antibiotics are haptens and covalently bind to various soluble and tissue proteins, thereby forming novel antigens. Under homeostatic conditions, these neo-antigens do not induce an immune reaction, probably because co-stimulation is missing. During a virus infection, the hapten-modified peptides are presented in an immune-stimulatory environment with co-stimulation. A drug-specific immune reaction may develop and manifest as exanthema. Second, by increased pharmacological interactions with immune receptors (p-i) : drugs tend to bind to proteins and may even bind to immune receptors. In the absence of viral infections, this low affine binding may be insufficient to elicit T cell activation. During a viral infection immune receptors are more abundantly expressed and allow more interactions to occur. This increases the overall avidity of p-i reactions and may even be sufficient for T cell activation and symptoms. There is a situation, where the virus-DHR sequence of events is inversed: in drug reaction with eosinophilia and systemic symptoms (DRESS), a severe DHR can precede reactivation and viremia of various herpes viruses. One could explain this phenomenon by the massive p-i mediated immune stimulation during acute DRESS, which coincidentally acvitates many herpes virus-specific T cells. Through p-i stimulation, they develop a cytotoxic activity with killing of herpes peptide-expressing cells and release of herpes viruses. These concepts could explain the often transient nature of DHR occurring during viral infections and the often asymptomatic herpes-virus viraemia after DRESS.
Background. Oral immunotherapy (OIT) is an emerging method for treating food allergy in children. However, data regarding adults undergoing this process is lacking. Methods. We retrospectively analyzed the medical records of patients with food allergy aged ≥17 years who completed OIT treatment between April 2010 to December 2020 at Shamir medical Center. Data was compared to that of children aged 4 to <11 years and adolescents aged ≥11 to 17 treated during the same time period. Results. A total of 96 adults at a median age of 22.3 years who underwent OIT for milk (n=53), peanut (n=18), sesame (n=7), egg (n=5) and tree nuts (n=13) were analyzed and compared to 1299 children and 309 adolescents. Adults experienced more adverse reactions requiring injectable epinephrine, both during in-clinic up-dosing (49% vs. 15.9% and 26.5% for children and adolescents respectively, p<0.0001) and during home treatment (22.9% vs. 10.5%, p=0.001 for children, and 14.2%, p=0.06 for adolescents). Most adults (61.5%) were fully desensitized, but rates of full desensitization were significantly lower compared to children (73.4%, p=0.013). Significantly more adults (28.3%) undergoing milk OIT failed treatment compared to children (14.3%, p=0.015) and adolescents (14.1%, p=0.022), while failure rates in adults undergoing OIT for other foods were low (9.3%) and comparable to children and adolescents. Conclusions. OIT is successful in desensitizing most adults with IgE-mediated food allergy. Adults undergoing milk OIT are at increased risk for severe reactions and for OIT failure while failure rates in adults undergoing OIT for other foods are low.
Adolescence is a critical stage of rapid biological, emotional and social change and development. Adolescents and young adults (AYA) with asthma and allergies need to develop the knowledge and skills to self-manage their health independently. Healthcare professionals (HCP), parents and their wider network play an essential role in supporting AYA in this process. Previous work showed significant limitations in transition care across Europe. In 2020, the first evidence-based guideline on effective transition for AYA with asthma and allergies was published by EAACI. We herein summarize practical resources to support this guideline’s implementation in clinical practice. For this purpose, multi-stakeholder Task Force members searched for resources in peer review journals and grey literature. These resources were included if relevant and of good quality, and were pragmatically rated for their evidence-basis and user friendliness. Resources identified covered a range of topics and targeted healthcare professionals, AYA, parents/carers, schools, workplace, and wider community. Most resources were in English, web-based and had limited evidence-basis. This position paper provides a valuable selection of practical resources for all stakeholders to support effective transitional care for AYA with asthma and allergies. Future research should focus on developing validated, patient-centred tools to further assist evidence-based transition care.
Background: Randomized controlled trials (RCTs) are the gold-standard for benefit-risk assessments during drug approval processes. Real-word data (RWD) and the resulting real-world evidence (RWE) are becoming increasingly important for assessing the effectiveness of drug products after marketing authorization showing how RCT results are transferred into real life care. The effectiveness of allergen immunotherapy (AIT) has been assessed in several RWE studies based on large prescription databases. Methods: We performed a literature search for retrospective cohort assessments of prescription databases in Europe to provide an overview on the methodology, long-term effectiveness outcomes and adherence to AIT. Results: 13 respective publications were selected. AIT was more effective in reducing the progression of allergic rhinitis (AR) compared to a non-AIT control group receiving only symptomatic treatment for AR for up to 6 years. The development and progression of asthma was hampered for most endpoints in patients treated with most preparations compared to the non-AIT group, receiving only anti-asthmatic medication. The results for “time to onset” of asthma were inconsistent. Adherence to AIT decreased during the recommended 3-years treatment period, however in most studies higher adherence to subcutaneous than to sublingual AIT was shown. Conclusion: The analysis of long-term effectiveness outcomes of the RWE studies based on prescription databases confirms the long-term efficacy of AIT demonstrated in RCTs. Progression of rhinitis and asthma symptoms as well as delayed onset of asthma triggered by different allergens, real life adherence to the treatment shows differences in particular application routes.
The incidence of food allergy (FA) has continued to rise over the last several decades, posing significant burdens on health and quality of life. Significant strides into the advancement of FA diagnosis, prevention, and treatment have been made in recent years. In an effort to lower reliance on resource-intensive food challenges, the field has continued work toward the development of highly sensitive and specific assays capable of high-throughput analysis to assist in the diagnosis FA. In looking toward early infancy as a critical period in the development of allergy or acquisition of tolerance, evidence has increasingly suggested that early intervention via the early introduction of food allergens and maintenance of skin barrier function may decrease the risk of FA. As such, largescale investigations are underway evaluating infant feeding and the impact of emollient and steroid use in infants with dry skin for the prevention of allergy. On the other end of the spectrum, the past few years have been witness to an explosive increase in clinical trials of novel and innovative therapeutic strategies aimed at the treatment of FA in those whom the disease has already manifested. A milestone in the field, 2020 marked the approval of the first drug, oral peanut allergen, for the indication of peanut allergy. With a foundation of promising data supporting the safety and efficacy of single- and multi-allergen oral immunotherapy, current efforts have turned toward the use of probiotics, biologic agents, and modified allergens to optimize and improve upon existing paradigms. Through these advancements, the field hopes to gain footing in the ongoing battle against FA.
Allergic diseases are allergen-induced immunological disorders characterized by the development of type 2 immunity and IgE responses. The prevalence of allergic diseases has been on the rise alike cardiovascular disease (CVD), which affects arteries of different organs such as the heart, the kidney and the brain. The underlying cause of CVD is often atherosclerosis, a disease distinguished by endothelial dysfunction, fibrofatty material accumulation in the intima of the artery wall, smooth muscle cell proliferation, and Th1 inflammation. The opposed T-cell identity of allergy and atherosclerosis implies an atheroprotective role for Th2 cells by counteracting Th1 responses. Yet, the clinical association between allergic disease and CVD argues against it. Within, we review different phases of allergic pathology, basic immunological mechanisms of atherosclerosis and the clinical association between allergic diseases (particularly asthma, atopic dermatitis, allergic rhinitis and food allergy) and CVD. Then, we discuss atherogenic mechanisms of type 2 immunity and allergic inflammation including acute allergic reactions (IgE, IgG1, mast cells, macrophages and allergic mediators such as vasoactive components, growth factors and those derived from the complement, contact and coagulation systems) and late phase inflammation (Th2 cells, eosinophils, type 2 innate-like lymphoid cells, alarmins, IL-4, IL-5, IL-9, IL-13 and IL-17).