A document by Luise Erpenbeck. Click on the document to view its contents.

Background Protecting the skin barrier in early infancy may prevent atopic dermatitis (AD). We investigated if daily emollient use from birth to 2 months reduced AD incidence in high risk infants at 12 months. Methods This was a single-center, two-armed, investigator-blinded, randomized controlled clinical trial (NCT03871998). Term infants identified as high risk for AD (parental history of AD, asthma or allergic rhinitis) were recruited within 4 days of birth and randomised 1:1 to either twice-daily emollient application for the first 8 weeks of life (intervention group), using an emollient specifically formulated for very dry, AD-prone skin, or to standard routine skin care (control group). The primary outcome was cumulative AD incidence at 12 months. AD <6 months was diagnosed based on clinical presence of AD. The UK Working Party Diagnostic Criteria were applied when diagnosing AD between 6 and 12 months. Results 321 infants were randomised (161 intervention and 160 control), with 61 withdrawals (41 intervention, 20 control). The cumulative incidence of AD at 12 months was 32.8% in the intervention group vs. 46.4% in the control group, p = 0.036 [Relative risk (95%CI): 0.707 (0.516, 0.965)]. One infant in the intervention group was withdrawn from the study following development of a rash that had a potential relationship with the emollient. There was no significant difference in the incidence of skin infections between the intervention and control groups during the intervention period (5.0% vs. 5.7%, P>0.05). Conclusions This study has demonstrated that early initiation of daily specialized emollient use until 2 months reduces the incidence of AD in the first year of life in high-risk infants.

LetterDelta or Omicron BA.1/2-neutralizing antibody levels and T-cell reactivity after triple-vaccination or infectionTo the editor,In Germany, SARS-CoV-2 infections in fall 2021 were caused by the Delta variant of concern (VOC B.1.617.2), which was completely replaced by the Omicron VOC (BA.1, B.1.529.1/BA.2, B.1.529.2) in winter. Meanwhile, the BA.2 sublineage dominates, apparently having a selection advantage1.We studied the kinetics of anti-spike (S) protein IgG and Delta neutralizing antibodies (NA) as well as the release of interferon-gamma (IFN-γ) from SARS-CoV-2-specific T-cells in 152 individuals (117 women, 35 men, median age 41 years) who received two doses of vector vaccine (AstraZeneca, AZD, N=34), mRNA vaccine (BioNTech or Moderna, mRNA, N=62), or a combination of both (N=56) followed by an mRNA vaccine boost (N=81). In a subset of 15 age- and gender-matched vaccinees and in ten triple-vaccinated and two unvaccinated patients with previous BA.1 infection, the Delta- and Omicron BA.1/BA.2 NAs and T-cell reactivity were examined. For comparison, variant-specific antibody responses of unvaccinated patients after infection with Alpha- (N=10) or Beta VOCs (N=1) were included.Within 279 days after the second vaccination, a decrease in anti-S IgG concentrations (Figures S 1A-C) and Delta NA titers (Figure 1A) was measured regardless of the immunization regimen. The booster vaccination led to a significant increase of anti-S IgG concentrations (Figures S1 D-F) and of Delta NA titers (Figure 1B). The IgG levels and Delta NAs reached four weeks after the mRNA vaccine booster were 1.3 - 1.7-fold higher than after the second mRNA dose, but this difference was significant only for IgG (Figures 1A, C; Figures S 1A-C, G-I). The release of IFN-γ as a measure of SARS-CoV-2 T-cell reactivity was demonstrated for months after second vaccination. In contrast to the Delta NA levels, IFN-γ concentrations were independent of the underlying vaccination schedule and increased slightly after the third immunization (Figures 1D, E). The parameters of humoral and cellular immunity decreased again after the booster vaccination (Figures 1C, F; Figures S 1G-I).As reported by others 1-4, NAs to Omicron BA.1 were induced by the mRNA vaccine booster, but also against the predominant BA.2 sublineage, which was previously unclear. The BA.2 NA geometric mean titer (GMT) was higher than the BA.1 NA GMT (Figure 2A). With respect to the results presented in Figures 1C and 2B, we suspect that NAs against the Omicron VOC will decline rapidly after booster vaccination alone. High NA titers against Omicron BA.1/BA.2 and against Delta VOC were exclusively observed in triple-vaccinated individuals two to three weeks after Omicron breakthrough infection (Figure 2A). This indicates broadened immunity covering additional viral variants and may also explain why few BA.2 infections have occurred in this group of individuals to date 5. Because Omicron is a distinct serotype 6, only NAs against this VOC were detectable in two unvaccinated BA.1-infected individuals (Figure 2A), while unvaccinated Alpha- and Beta VOC patients developed isolated NAs against the antigenically more related Delta VOC (Figure S 2A). Accordingly, both BA.1 patients had very low IgG levels against the receptor-binding domain (RBD) of a Wuhan-like virus (Figure S 2B), whereas IgGs against the higher preserved nucleocapsidprotein were barely affected (Figures S 2C, D). The results of a surrogate neutralization assay confirmed very limited humoral immunity after Omicron infection alone (Figure S 2E).The increase of IFN-γ release by mRNA booster vaccination was moderate (Figures 1D, E), while the breakthrough infection insignificantly increased IFN-γ release by a factor of 1.9 - 2.6 (Figure 2C).In conclusion, the importance of pre-existing vaccine-induced immunity is clearly demonstrated. The booster vaccination with the conventional mRNA vaccine resulted in measurable BA.1/BA.2 NAs. However, a multivalent vaccine could induce higher titers, which could provide better protection.

A potential immunological silver bullet for COVID-19: the trivalent chimpanzee adenoviral serotype-68 vector (Tri:ChAd)

Background: Although avian coronavirus infectious bronchitis virus (IBV) and SARS-CoV-2 belong to different genera of the Coronaviridae family, exposure to IBV may result in the development of cross-reactive antibodies to SARS-CoV-2 due to homologous epitopes. We aimed to investigate whether antibody responses to IBV cross-react with SARS-CoV-2 in poultry farm personnel who are occupationally exposed to aerosolized IBV vaccines. Methods: We analyzed sera from poultry farm personnel, COVID-19 patients, and pre-pandemic controls. IgG levels against the SARS-CoV-2 antigens S1, RBD, S2, and N and peptides corresponding to the SARS-CoV-2 ORF3a, N, and S proteins as well as whole virus antigens of the four major S1-genotypes 4/91, IS/1494/06, M41, and D274 of IBV were investigated by in-house ELISAs. Moreover, live-virus neutralization test (VNT) was performed. Results: A subgroup of poultry farm personnel showed elevated levels of specific IgG for all tested SARS-CoV-2 antigens compared to pre-pandemic controls. Moreover, poultry farm personnel, COVID-19 patients, and pre-pandemic controls showed specific IgG antibodies against IBV strains. These antibody titers were higher in long-term vaccine implementers. We observed a strong correlation between IBV-specific IgG and SARS-CoV-2 S1-, RBD-, S2-, and N-specific IgG in poultry farm personnel compared to pre-pandemic controls and COVID-19 patients. However, no neutralization was observed for these cross-reactive antibodies from poultry farm personnel using the VNT. Conclusion: We report here for the first time the detection of cross-reactive IgG antibodies against SARS-CoV-2 antigens in humans exposed to IBV vaccines. These findings have implications for future vaccination strategies and possibly cross-reactive T cell immunity.

Humans inhale, ingest and touch thousands of fungi each day. The ubiquity and diversity of the fungal kingdom are in sharp contrast with their complex and relatively blurred taxonomy and scarce knowledge about their distribution, pathogenic effects, and effective interventions at the environmental and individual levels. Here, we present an overview of salient features of fungi as permanent players of the human exposome and key determinants of human health. Improved understanding of the fungal exposome sheds new light on the epidemiology of fungal-related diseases, their immunological substratum, the currently available methods, and biomarkers for environmental and medical fungi. Unmet needs are described and potential approaches are highlighted as perspectives.

A document by Sergio Bonini. Click on the document to view its contents.

Article type: Letter to the Editor

Similar IgE Binding Patterns in Gulf of Mexico and Southeast Asian Shrimp Species in US Shrimp Allergic PatientsSara Anvari1,2*, Shea Brunner1,2*, Karen Tuano1,2, Brenda Bin Su1,2, Shaymaviswanathan Karnaneed3, Andreas L. Lopata3, Carla M. Davis1,21Baylor College of Medicine, Texas Children’s Hospital, Department of Pediatrics, Section of Immunology, Allergy and Retrovirology, Houston, Texas2Baylor College of Medicine, William T. Shearer Center for Human Immunobiology, Houston, Texas3James Cook University, Australian Institute of Tropical Health and Medicine, Centre for Molecular Therapeutics, Douglas, QLD, Australia*co-first authors

Background Cow’s milk protein allergy (CMPA) is one of the most common food allergies in infancy. Most infants with CMPA tolerate baked milk from diagnosis and gradually acquire increased tolerance. Nevertheless, parents often display significant anxiety about this condition and a corresponding reluctance to progress with home introduction of dairy due to concerns about possible allergic reactions. Objective: To evaluate the impact on gradual home introduction of foods containing cows milk after a supervised, single low dose exposure to whole milk at time of diagnosis. Methods Infants less than 12 months old, referred with suspected IgE-mediated cow’s milk allergy were recruited to an open-label randomised, controlled trial of intervention - a single dose of fresh cow’s milk, using the validated dose of milk that would elicit reactions in 5% of CMPA subjects - the ED 05 – vs routine care. Both groups implemented graded exposure to CM (using the 12 step MAP Milk Tolerance Induction Ladder), at Home. Parents completed food allergy quality of life and State and Trait Anxiety Inventories (STAI). Main outcome measures were milk ladder position at 6 months and 12 months post randomisation. Results: Sixty patients were recruited, 57 (95%) were followed to 6 months. By 6 months 27/37 (73%) intervention subjects had reached step 6 or above on the milk ladder compared to 10/20 (50%) control subjects (p=0.048). By 6 months 11/37 (30%) intervention subjects had reached step 12 (ie drinking unheated cow’s milk) compared to 2/20 (10%) of the controls (p=0.049). Twelve months post randomisation 31/36(86%) of the intervention group and 15/19(79%) of the control group were on step 6 or above. However, 24/37 (65%) of the intervention group were at step 12 compared to 7/20 (35%) of the control group (p=0.03). Maternal STAIs were significantly associated with their infants’ progress on the milk ladder and with changes in skin prick test and spIgE levels at 6 and 12 months. Conclusion This study demonstrates the safety and effectiveness of introduction of baked milk implemented immediately after diagnosis of cows milk allergy in a very young cohort. A supervised single dose of milk at the ED 05 significantly accelerates this further, probably by giving parents the confidence to proceed. Maternal anxiety generally reflects infants’ progress towards completion of the milk ladder, but pre-existing high levels of maternal anxiety are associated with poorer progress.

Comment on EAACI guideline: Anaphylaxis (2021 update)Authors :Stefano Miceli Sopo a, Dario Sinattia, Francesco Mastellone b, Giulia Bersani a, Mariannita Gelsomino b.

Objective: There is a need for the immunogenicity of different boosters after widely used inactivated vaccine regimens. We aimed to determine the effects of BNT162b2 and CoronaVac boosters on the humoral and cellular immunity of individuals who had two doses of CoronaVac vaccination. Methods: The study was conducted in three centers (Koc University Hospital, Istanbul University Cerrahpasa Hospital, and Istanbul University, Istanbul Medical School Hospital) in Istanbul. Individuals who had two doses of CoronaVac and no history of COVID-19 were included. The baseline blood samples were collected three to five months after two doses of CoronaVac. Follow-up samples were taken one and three months after third doses of CoronaVac or one dose of mRNA BNT162b2 boosters. Neutralizing antibody titers were detected by plaque reduction assay. T cell responses were evaluated by Elispot assay and flow cytometry. Results: We found a 3.38-fold increase in neutralizing antibody titers (Geometric Mean Titer [GMT], 78.69) one month after BNT162b2 booster and maintained at the three months (GMT, 80). However, in the CoronaVac group, significantly lower GMTs than BNT162b2 after 1 month and 3 months (21.44 and 28.44, respectively) indicated the weak immunogenicity of the CoronaVac booster (p<0.001). In the ELISpot assay, IL-2 levels after BNT162b2 were higher than baseline and CoronaVac booster (p<0.001) and IFN-γ levels were significantly higher than baseline (P<0.001). The CD8+CD38+CD69+ and CD4+CD38+CD69+ T cells were stimulated significantly at the 3 rd month of the BNT162b2 boosters. Conclusion: The neutralizing antibody levels after three months of the BNT162b2 booster were higher than the antibody levels after CoronaVac. On the other hand, specific T cells might contribute to immune protection. By considering the waning immunity, we suggest a new booster dose with BNT162b2 for the countries that already have two doses of primary CoronaVac regimens.

A document by Bernardo Sousa-Pinto. Click on the document to view its contents.

Background. The use of eliciting doses (EDs) for food allergens is necessary to inform individual dietary advice and food allergen risk-management. The Eliciting Dose 01 (ED01) for milk and egg, calculated from populations of allergic subjects undergoing diagnostic Oral Food Challenges (OFCs), are 0.2 mg total protein. The respective Eliciting Dose 05 (ED05) are 2.4 mg for milk and 2.3 mg for egg. As about 70% children allergic to such foods may tolerate them when baked, we sought to verify the EDs of that subpopulation of milk and egg-allergic children. Methods. We retrospectively assessed consecutive diagnostic OFC for fresh milk and egg between January 2018 and December 2020 in a population of baked food-tolerant children. Results. Among 288 children (median age 56 - IQR 36-92.5 months, 67.1% male) included, 87 (30.2%) returned positive OFC results, 38 with milk and 49 with egg. The most conservative ED01 were 0.3 mg total protein (IQR 0.03-2.9) for milk and 14.4 mg total protein (IQR 3.6-56.9) for egg. The respective ED05 were 4.2 (IQR 0.9-19.6) mg for milk and 87.7 (IQR 43-179) mg for egg. Such thresholds are respectively 1.5 (milk ED01), 1.75 (milk ED05), 72 (egg ED01), and 38.35 (egg ED05) times higher than the currently used thresholds. Conclusions The subpopulation of children allergic to milk and egg, but tolerant to baked proteins, displays higher reactivity thresholds than the general population of children allergic to milk and egg. Their risk stratification, in both individual and population terms, should consider this difference. In baked milk-tolerant children, milk causes reactions at lower doses than egg in our group of egg-tolerant children. This could be associated with the relative harmlessness of egg compared to milk in the determinism of fatal anaphylactic reactions in children

Background: Group 2 innate lymphoid cells (ILC2s) play a critical role in asthma pathogenesis. Non-steroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is associated with reduced signaling via EP2, a receptor for prostaglandin E 2 (PGE 2). However, the respective roles for the PGE 2 receptors EP2 and EP4 (both share same downstream signaling) in the regulation of lung ILC2 responses has yet been deciphered. Methods: The roles of PGE 2 receptors EP2 and EP4 on ILC2-mediated lung inflammation were investigated using genetically modified mouse lines and pharmacological approaches in IL-33- and Alternaria alternata (A.A.)-induced lung allergy models. The effects of PGE 2 receptors and downstream signals on ILC2 metabolic activation and effector function were examined using in vitro cell cultures. Results: Deficiency of EP2 rather than EP4 augments IL-33-induced lung ILC2 responses and eosinophilic inflammation in vivo. In contrast, exogenous agonism of EP4 but not EP2 markedly restricts IL-33- and Alternaria alternata-induced lung ILC2 responses and eosinophilic inflammation. Mechanistically, PGE 2 directly suppresses IL-33-dependent ILC2 activation through the EP2/EP4-cAMP pathway, which downregulates STAT5 and MYC pathway gene expression and ILC2 energy metabolism. Blocking glycolysis diminishes IL-33-dependent ILC2 responses in mice lacking endogenous PG synthesis but not in PG-competent mice. Conclusion: We have defined a mechanism for optimal suppression of lung ILC2 responses by endogenous PGE 2-EP2 signaling which underpins the clinical findings of defective EP2 signaling in patients with NERD. Our findings also indicate that exogenously targeting the PGE 2-EP4-cAMP and energy metabolic pathways may provide novel opportunities for treating ILC2-initiated lung inflammation in asthma and NERD.

Background: Homologous and heterologous SARS-CoV-2 vaccinations yield different spike protein-directed humoral and cellular immune responses. This study aimed to explore their currently unknown interdependencies. Methods: COV-ADAPT is a prospective, observational cohort study of 417 healthcare workers who received vaccination with homologous ChAdOx1 nCoV-19, homologous BNT162b2 or with heterologous ChAdOx1 nCoV-19/BNT162b2. We assessed humoral (anti-spike-RBD-IgG, neutralizing antibodies, avidity) and cellular (spike-induced T cell interferon‑γ release) immune responses in blood samples up to 2 weeks before (T1) and 2 to 12 weeks following secondary immunization (T2). Results: Initial vaccination with ChAdOx1 nCoV-19 resulted in lower anti-spike-RBD-IgG compared to BNT162b2 (70±114 vs. 226±279 BAU/ml, p<0.01) at T1. Booster vaccination with BNT162b2 proved superior to ChAdOx1 nCoV-19 at T2 (anti-spike-RBD-IgG: ChAdOx1 nCoV-19/BNT162b2 2387±1627 and homologous BNT162b2 3202±2184 vs. homologous ChAdOx1 nCoV-19 413±461 BAU/ml, both p<0.001; spike-induced T cell interferon-γ release: ChAdOx1 nCoV-19/BNT162b2 5069±6733 and homologous BNT162b2 4880±7570 vs. homologous ChAdOx1 nCoV-19 1152±2243 mIU/ml, both p<0.001). No significant differences were detected between BNT162b2-boostered groups at T2. For ChAdOx1 nCoV-19, no booster effect on T cell activation could be observed. We found associations between anti-spike-RBD-IgG levels (ChAdOx1 nCoV-19/BNT162b2 and homologous BNT162b2) and T cell responses (homologous ChAdOx1 nCoV-19 and ChAdOx1 nCoV-19/BNT162b2) from T1 to T2. Additionally, anti-spike-RBD-IgG and T cell response were linked at both time points (all groups combined). All regimes yielded neutralizing antibodies and increased antibody avidity at T2. Conclusions: Interdependencies between humoral and cellular immune responses differ between common SARS-CoV-2 vaccination regimes. T cell activation is unlikely to compensate for poor humoral responses. 

Microbial metabolism of specific dietary components, such as fiber, contribute 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, 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.

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.