Precision cut intestinal slices, a novel model of acute food allergic reactions.

BACKGROUND: Food allergy affects up to 10% of the pediatric population. Despite ongoing efforts, treatment options remain limited. Novel models of food allergy are needed to study response patterns downstream of IgE-crosslinking and evaluate drugs modifying acute events. Here, we report a novel human ex vivo model that displays acute, allergen-specific, IgE-mediated smooth muscle contractions using precision cut intestinal slices (PCIS). METHODS: PCIS were generated using gut tissue samples from children who underwent clinically indicated surgery. Viability and metabolic activity were assessed from 0 to 24 h. Distribution of relevant cell subsets was confirmed using single nucleus RNA sequencing. PCIS were passively sensitized using plasma from peanut allergic donors or peanut-sensitized non-allergic donors, and exposed to various stimuli including serotonin, histamine, FcɛRI-crosslinker, and food allergens. Smooth muscle contractions and mediator release functioned as readouts. A novel program designed to measure contractions was developed to quantify responses. The ability to demonstrate the impact of antihistamines and immunomodulation from peanut oral immunotherapy (OIT) was assessed. RESULTS: PCIS viability was maintained for 24 h. Cellular distribution confirmed the presence of key cell subsets including mast cells. The video analysis tool reliably quantified responses to different stimulatory conditions. Smooth muscle contractions were allergen-specific and reflected the clinical phenotype of the plasma donor. Tryptase measurement confirmed IgE-dependent mast cell-derived mediator release. Antihistamines suppressed histamine-induced contraction and plasma from successful peanut OIT suppressed peanut-specific PCIS contraction. CONCLUSION: PCIS represent a novel human tissue-based model to study acute, IgE-mediated food allergy and pharmaceutical impacts on allergic responses in the gut.

Considerations on biologicals for patients with allergic disease in times of the COVID-19 pandemic: An EAACI statement.

The outbreak of the SARS-CoV-2-induced coronavirus disease 2019 (COVID-19) pandemic re-shaped doctor-patient interaction and challenged capacities of healthcare systems. It created many issues around the optimal and safest way to treat complex patients with severe allergic disease. A significant number of the patients are on treatment with biologicals, and clinicians face the challenge to provide optimal care during the pandemic. Uncertainty of the potential risks for these patients is related to the fact that the exact sequence of immunological events during SARS-CoV-2 is not known. Severe COVID-19 patients may experience a "cytokine storm" and associated organ damage characterized by an exaggerated release of pro-inflammatory type 1 and type 3 cytokines. These inflammatory responses are potentially counteracted by anti-inflammatory cytokines and type 2 responses. This expert-based EAACI statement aims to provide guidance on the application of biologicals targeting type 2 inflammation in patients with allergic disease. Currently, there is very little evidence for an enhanced risk of patients with allergic diseases to develop severe COVID-19. Studies focusing on severe allergic phenotypes are lacking. At present, noninfected patients on biologicals for the treatment of asthma, atopic dermatitis, chronic rhinosinusitis with nasal polyps, or chronic spontaneous urticaria should continue their biologicals targeting type 2 inflammation via self-application. In case of an active SARS-CoV-2 infection, biological treatment needs to be stopped until clinical recovery and SARS-CoV-2 negativity is established and treatment with biologicals should be re-initiated. Maintenance of add-on therapy and a constant assessment of disease control, apart from acute management, are demanded.

Immunology of COVID-19: Mechanisms, clinical outcome, diagnostics, and perspectives-A report of the European Academy of Allergy and Clinical Immunology (EAACI).

With the worldwide spread of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) resulting in declaration of a pandemic by the World Health Organization (WHO) on March 11, 2020, the SARS-CoV-2-induced coronavirus disease-19 (COVID-19) has become one of the main challenges of our times. The high infection rate and the severe disease course led to major safety and social restriction measures worldwide. There is an urgent need of unbiased expert knowledge guiding the development of efficient treatment and prevention strategies. This report summarizes current immunological data on mechanisms associated with the SARS-CoV-2 infection and COVID-19 development and progression to the most severe forms. We characterize the differences between adequate innate and adaptive immune response in mild disease and the deep immune dysfunction in the severe multiorgan disease. The similarities of the human immune response to SARS-CoV-2 and the SARS-CoV and MERS-CoV are underlined. We also summarize known and potential SARS-CoV-2 receptors on epithelial barriers, immune cells, endothelium and clinically involved organs such as lung, gut, kidney, cardiovascular, and neuronal system. Finally, we discuss the known and potential mechanisms underlying the involvement of comorbidities, gender, and age in development of COVID-19. Consequently, we highlight the knowledge gaps and urgent research requirements to provide a quick roadmap for ongoing and needed COVID-19 studies.

Effectiveness, acceptability, and potential of lay student vaccinators to improve vaccine delivery.

SETTING: Task sharing can fill health workforce gaps, improve access to care, and enhance health equity by redistributing health services to providers with less training. We report learnings from a demonstration project designed to assess whether lay student vaccinators can support community immunizations. INTERVENTION: Between July 2022 and February 2023, 27 undergraduate and graduate students were recruited from the University of Toronto Emergency First Responders organization and operated 11 immunization clinics under professional supervision. Medical directives, supported with online and in-person training, enabled lay providers to administer and document vaccinations when supervised by nurses, physicians, or pharmacists. Participants were invited to complete a voluntary online survey to comment on their experience. OUTCOMES: Lay providers administered 293 influenza and COVID-19 vaccines without adverse events. A total of 141 participants (122 patients, 17 lay vaccinators, 1 nurse, and 1 physician) responded to our survey. More than 80% of patients strongly agreed to feeling safe and comfortable with lay providers administering vaccines under supervision, had no concerns with lay vaccinators, and would attend another lay vaccinator clinic. Content and thematic analysis of open-text responses revealed predominantly positive experiences, with themes about excellent vaccinators, organized and efficient clinics, and the importance of training, communication, and access to regulated professionals. The responding providers expressed comfort working in collaborative immunization teams. IMPLICATIONS: Lay student providers can deliver vaccines safely under a medical directive while potentially improving patient experiences. Rather than redeploying scarce professionals, task sharing strategies could position trained lay vaccinators to support immunizations, improve access, and foster community engagement.

RéSUMé: LIEU: Le partage de tâches peut combler les pénuries de personnels de santé et améliorer l'accès aux soins et l'équité en santé en redistribuant les services de santé vers des prestataires ayant moins de formation. Nous rendons compte des enseignements d'un projet de démonstration visant à déterminer si des vaccinateurs étudiants profanes pourraient appuyer l'immunisation communautaire. INTERVENTION: Entre juillet 2022 et février 2023, 27 étudiantes et étudiants de premier cycle et de cycles supérieurs ont été recrutés auprès de l'organisation des secouristes opérationnels de l'Université de Toronto pour gérer 11 cliniques de vaccination sous la supervision de personnel spécialisé. Des directives médicales, appuyées par une formation en ligne et en présentiel, ont permis à ces prestataires profanes d'administrer des vaccins et de les consigner en dossier sous la supervision d'infirmières, de médecins ou de pharmaciens. Les personnes participantes ont été invitées à répondre à un sondage en ligne sur leur expérience. RéSULTATS: Les prestataires profanes ont administré 293 vaccins contre la grippe et la COVID-19 sans manifestations postvaccinales indésirables. En tout, 141 personnes (122 patients, 17 vaccinateurs profanes, 1 infirmière et 1 médecin) ont répondu au sondage. Plus de 80 % des patients ont dit se sentir tout à fait en sécurité et à l'aise de recevoir des vaccins administrés par des prestataires profanes sous supervision, n'avoir aucune inquiétude vis-à-vis des vaccinateurs profanes et être disposés à se présenter à une autre clinique gérée par des vaccinateurs profanes. L'analyse du contenu et des thèmes des réponses aux questions ouvertes a révélé des expériences majoritairement positives, et des thèmes axés sur l'excellence des vaccinateurs, l'organisation et l'efficacité des cliniques, ainsi que l'importance de la formation, des communications et de l'accès à des professionnels réglementés. Les prestataires ayant répondu au sondage se sont dit à l'aise de travailler au sein d'équipes de vaccination collaboratives. CONSéQUENCES: Des prestataires étudiants profanes peuvent administrer des vaccins en toute sécurité en suivant une directive médicale, et cela peut potentiellement améliorer l'expérience des patients. Plutôt que de redéployer des ressources professionnelles limitées, les stratégies de partage de tâches pourraient placer des vaccinateurs profanes formés pour appuyer l'immunisation, améliorer l'accès et favoriser l'engagement communautaire.

Mother's milk microbiota is associated with the developing gut microbial consortia in very-low-birth-weight infants.

Mother's milk contains diverse bacterial communities, although their impact on microbial colonization in very-low-birth-weight (VLBW, <1,500 g) infants remains unknown. Here, we examine relationships between the microbiota in preterm mother's milk and the VLBW infant gut across initial hospitalization (n = 94 mother-infant dyads, 422 milk-stool pairs). Shared zero-radius operational taxonomic units (zOTUs) between milk-stool pairs account for ∼30%-40% of zOTUs in the VLBW infant's gut. We show dose-response relationships between intakes of several genera from milk and their concentrations in the infant's gut. These relationships and those related to microbial sharing change temporally and are modified by in-hospital feeding practices (especially direct breastfeeding) and maternal-infant antibiotic use. Correlations also exist between milk and stool microbial consortia, suggesting that multiple milk microbes may influence overall gut communities together. These results highlight that the mother's milk microbiota may shape the gut colonization of VLBW infants by delivering specific bacteria and through intricate microbial interactions.

Digestion of human milk processed by high pressure processing and Holder pasteurization using a dynamic in vitro model of the preterm infant.

Holder pasteurization (HoP) (62.5 °C, 30 min) of donor human milk is widely used to inactivate potential pathogens but may lead to denaturation and aggregation of bioactive proteins, reducing their functionality. In contrast, high pressure processing (HPP) is a non-thermal technique that minimally affects assessed bioactive components; however, it is unclear how HPP affects protein digestion, and retention of functional bioactive proteins. Raw or processed (HoP; HPP[500 MPa,10 min]) pools of milk (N = 3, from 9 donors) were subjected in triplicate to in vitro digestion simulating the preterm infant gastrointestinal tract. Compared to raw or HPP, HoP increased intestinal proteolysis of lactoferrin and bioactive milk fat globule membrane proteins. Lysozyme activity was impacted by digestion following HoP (72 % to 7 %)-significantly more than HPP (75 % to 34 %) or raw (100 % to 39 %), which did not differ. Proteins in HPP-treated donor milk are digested no different than raw milk, while preserved bioactivity remains functional upon digestion.

Preservation of Anti-cytomegalovirus Activity in Human Milk Following High-Pressure Processing Compared to Holder Pasteurization.

Pasteurized donor human milk is recommended for hospitalized preterm infants when mother's own milk is unavailable. Our aim was to compare the antiviral activity of human milk processed by Holder pasteurization (HoP) or high-pressure processing (HPP) against representative enveloped and non-enveloped viruses including cytomegalovirus and hepatitis A virus. Expressed milk from 20 donors collected from the Ontario Milk Bank was combined into 10 pools, each from two unique donors. Each pool was processed by HoP (62.5°C, 30 min) or HPP (500 MPa, 8 min, 4°C) and subsequently inoculated with cytomegalovirus or hepatitis A virus to achieve a final concentration of 5-log plaque-forming units/mL. Plaque reduction assays were used to quantify detectable virus after 30 min incubation (room temperature). Post hoc experiments using a 4 h incubation time were conducted if reductions were detected at 30 min. Irrespective of processing, cytomegalovirus concentrations declined in all pools after 30 min incubation (P < 0.0001). Milk processed by HoP exhibited significantly less reduction compared to raw milk (P = 0.0069). In post hoc experiments, anti-cytomegalovirus activity was maintained at 4 h, with high inter-pool variability. Hepatitis A virus concentration remained unchanged after 30 min incubation in raw and processed milk. Anti-cytomegalovirus activity in human milk is preserved following HoP and HPP, persisting up to 4 h post-inoculation; anti-hepatitis A virus activity was not observed in raw or processed milk. Further research is needed to understand how HoP or promising alternative processing methods affect the antiviral activity of donated milk, given its potential importance to recipient infants.

A network of immune and microbial modifications underlies viral persistence in the gastrointestinal tract.

Many pathogens subvert intestinal immunity to persist within the gastrointestinal tract (GIT); yet, the underlying mechanisms that enable sanctuary specifically in this reservoir are unclear. Using mass cytometry and network analysis, we demonstrate that chronic LCMV infection of the GIT leads to dysregulated microbial composition, a cascade of metabolic alterations, increased susceptibility to GI disease, and a system-wide recalibration of immune composition that defines viral persistence. Chronic infection led to outgrowth of activated Tbet-expressing T reg cell populations unique to the GIT and the rapid erosion of pathogen-specific CD8 tissue-resident memory T cells. Mechanistically, T reg cells and coinhibitory receptors maintained long-term viral sanctuary within the GIT, and their targeting reactivated T cells and eliminated this viral reservoir. Thus, our data provide a high-dimensional definition of the mechanisms of immune regulation that chronic viruses implement to exploit the unique microenvironment of the GIT and identify T reg cells as key modulators of viral persistence in the intestinal tract.

Use of biologicals in allergic and type-2 inflammatory diseases during the current COVID-19 pandemic: Position paper of Ärzteverband Deutscher Allergologen (AeDA)A, Deutsche Gesellschaft für Allergologie und Klinische Immunologie (DGAKI)B, Gesellschaft für Pädiatrische Allergologie und Umweltmedizin (GPA)C, Österreichische Gesellschaft für Allergologie und Immunologie (ÖGAI)D, Luxemburgische Gesellschaft für Allergologie und Immunologie (LGAI)E, Österreichische Gesellschaft für Pneumologie (ÖGP)F in co-operation with the German, Austrian, and Swiss ARIA groupsG, and the European Academy of Allergy and Clinical Immunology (EAACI)H.

BACKGROUND: Since the beginning of the COVID-19 pandemic, the treatment of patients with allergic and atopy-associated diseases has faced major challenges. Recommendations for "social distancing" and the fear of patients becoming infected during a visit to a medical facility have led to a drastic decrease in personal doctor-patient contacts. This affects both acute care and treatment of the chronically ill. The immune response after SARS-CoV-2 infection is so far only insufficiently understood and could be altered in a favorable or unfavorable way by therapy with monoclonal antibodies. There is currently no evidence for an increased risk of a severe COVID-19 course in allergic patients. Many patients are under ongoing therapy with biologicals that inhibit type 2 immune responses via various mechanisms. There is uncertainty about possible immunological interactions and potential risks of these biologicals in the case of an infection with SARS-CoV-2. MATERIALS AND METHODS: A selective literature search was carried out in PubMed, Livivo, and the internet to cover the past 10 years (May 2010 - April 2020). Additionally, the current German-language publications were analyzed. Based on these data, the present position paper provides recommendations for the biological treatment of patients with allergic and atopy-associated diseases during the COVID-19 pandemic. RESULTS: In order to maintain in-office consultation services, a safe treatment environment must be created that is adapted to the pandemic situation. To date, there is a lack of reliable study data on the care for patients with complex respiratory, atopic, and allergic diseases in times of an imminent infection risk from SARS-CoV-2. Type-2-dominant immune reactions, as they are frequently seen in allergic patients, could influence various phases of COVID-19, e.g., by slowing down the immune reactions. Theoretically, this could have an unfavorable effect in the early phase of a SARS-Cov-2 infection, but also a positive effect during a cytokine storm in the later phase of severe courses. However, since there is currently no evidence for this, all data from patients treated with a biological directed against type 2 immune reactions who develop COVID-19 should be collected in registries, and their disease courses documented in order to be able to provide experience-based instructions in the future. CONCLUSION: The use of biologicals for the treatment of bronchial asthma, atopic dermatitis, chronic rhinosinusitis with nasal polyps, and spontaneous urticaria should be continued as usual in patients without suspected infection or proven SARS-CoV-2 infection. If available, it is recommended to prefer a formulation for self-application and to offer telemedical monitoring. Treatment should aim at the best possible control of difficult-to-control allergic and atopic diseases using adequate rescue and add-on therapy and should avoid the need for systemic glucocorticosteroids. If SARS-CoV-2 infection is proven or reasonably suspected, the therapy should be determined by weighing the benefits and risks individually for the patient in question, and the patient should be involved in the decision-making. It should be kept in mind that the potential effects of biologicals on the immune response in COVID-19 are currently not known. Telemedical offers are particularly desirable for the acute consultation needs of suitable patients.