Viral infections in allergy and immunology: How allergic inflammation influences viral infections and illness

Allergen Immunotherapy: The Evidence Supporting the Efficacy and Safety of Subcutaneous Immunotherapy and Sublingual Forms of Immunotherapy for Allergic Rhinitis/Conjunctivitis and Asthma

Allergen immunotherapy (AIT) is a recognized key therapeutic modality for the treatment of allergic respiratory disease. Definitive studies have provided evidence-based data to demonstrate its effectiveness in allergic rhinitis and asthma due to the inhalation of proteinaceous allergic substances from specific seasonal pollens, dust mites, animal allergens, and certain mold spores. Over the ensuing decades, laboratory investigations have provided objective evidence to demonstrate immunologic changes, including production of protective IgG antibody, suppression of IgE antibody, upregulation of regulatory T cells, and induction of a state of immune tolerance to the offending allergen(s). Tangential to this work were carefully designed clinical studies that defined allergen dose and duration of treatment, established the importance of preparing extracts with standardized allergens (or well-defined extracts) based on major protein moieties, and used allergen provocation models to demonstrate efficacy superior to placebo. In the United States, the use of subcutaneous immunotherapy extracts for AIT was grandfathered in by the Food and Drug Administration based on expert literature review. In contrast, sublingual tablet immunotherapy underwent formal clinical development programs (phase I-III clinical trials) that provided the necessary clinical evidence for safety and efficacy that led to regulatory agency approvals for the treatment of allergic rhinitis in properly characterized patients with allergy. The allergy specialist's treatment options currently include traditional subcutaneous AIT and specific sublingual tablets approved for grass, ragweed, house dust mites, trees belonging to the birch-homologous group, and Japanese cedar. Tangential to this are sublingual drops that are increasingly being used off-label (albeit not approved by the Food and Drug Administration) in the United States. This article will review the evidence-based literature supporting the use of these forms of AIT, as well as focus on several current controversies and gaps in our knowledge base that have relevance for the appropriate selection of patients for treatment with specific AIT.

Dysfunctional neutrophil type 1 interferon responses in preschool children with recurrent wheezing and IL-4-mediated aeroallergen sensitization

Background

The innate mechanisms associated with viral exacerbations in preschool children with recurrent wheezing are not understood.

Objective

We sought to assess differential gene expression in blood neutrophils from preschool children with recurrent wheezing, stratified by aeroallergen sensitization, at baseline and after exposure to polyinosinic:polycytidylic acid (poly(I:C)) and also to examine whether poly(I:C)-stimulated blood neutrophils influenced airway epithelial gene expression.

Methods

Blood neutrophils were purified and cultured overnight with poly(I:C) and underwent next-generation sequencing with Reactome pathway analysis. Primary human small airway epithelial cells were treated with poly(I:C)-treated neutrophil culture supernatants and were analyzed for type 1 interferon gene expression with a targeted array. Symptoms and exacerbations were assessed in participants over 12 months.

Results

A total of 436 genes were differently expressed in neutrophils from children with versus without aeroallergen sensitization at baseline, with significant downregulation of type 1 interferons. These type 1 interferons were significantly upregulated in sensitized children after poly(I:C) stimulation. Confirmatory experiments demonstrated similar upregulation of type 1 interferons in IL-4-treated neutrophils stimulated with poly(I:C). Poly(I:C)-treated neutrophil supernatants from children with aeroallergen sensitization also induced a type 1 interferon response in epithelial cells. Children with aeroallergen sensitization also had higher symptom scores during exacerbations, and these symptom differences persisted for 3 days after prednisolone treatment.

Conclusions

Type 1 interferon responses are dysregulated in preschool children with aeroallergen sensitization, which is in turn associated with exacerbation severity. Given the importance of type 1 interferon signaling in viral resolution, additional studies of neutrophil type 1 interferon responses are needed in this population.

Association between allergic conditions and COVID-19 susceptibility and outcomes

BACKGROUND

The relationship between underlying type 2 inflammation and immune response to COVID-19 is unclear.

OBJECTIVE

To assess the relationships between allergic conditions and COVID-19 susceptibility and outcomes.

METHODS

In the Optum database, adult patients with and without major allergic conditions (asthma, atopic dermatitis [AD], allergic rhinitis, food allergy, anaphylaxis, or eosinophilic esophagitis) and patients with and without severe asthma/AD were identified. Adjusted incidence rate ratios for COVID-19 were compared among patients with vs without allergic conditions or severe asthma/AD vs non-severe asthma/AD during April 1, 2020, to December 31, 2020. Among patients with COVID-19, adjusted hazard ratios (aHRs) of 30-day COVID-19-related hospitalization/all-cause mortality were estimated for the same comparisons during April 1, 2020, to March 31, 2022.

RESULTS

Patients with (N = 1,273,231; asthma, 47.2%; AD, 1.5%; allergic rhinitis, 58.6%; food allergy, 5.1%; anaphylaxis, 4.1%; eosinophilic esophagitis, 0.9%) and without allergic conditions (N = 2,278,571) were identified. Allergic conditions (adjusted incidence rate ratios [95% CI], 1.22 [1.21-1.24]) and asthma severity (1.12 [1.09-1.15]) were associated with increased incidence of COVID-19. Among patients with COVID-19 (patients with [N = 261,076] and without allergic conditions [N = 1,098,135] were matched on age, sex, region, index month), having an allergic condition had minimal impact on 30-day COVID-19-related hospitalization/all-cause mortality (aHR [95% CI] 0.96 [0.95-0.98]) but was associated with a lower risk of mortality (0.80 [0.78-0.83]). Asthma was associated with a higher risk of COVID-19-related hospitalization/all-cause mortality vs non-asthma allergic conditions (aHR [95% CI], 1.27 [1.25-1.30]), mostly driven by higher hospitalization.

CONCLUSION

Allergic conditions were associated with an increased risk of receiving COVID-19 diagnosis but reduced mortality after infection.

Tezepelumab decreases airway epithelial IL-33 and T2-inflammation in response to viral stimulation in patients with asthma

BACKGROUND

Respiratory virus infections are main triggers of asthma exacerbations. Tezepelumab, an anti-TSLP mAb, reduces exacerbations in patients with asthma, but the effect of blocking TSLP on host epithelial resistance and tolerance to virus infection is not known.

AIM

To examine effects of blocking TSLP in patients with asthma on host resistance (IFNβ, IFNλ, and viral load) and on the airway epithelial inflammatory response to viral challenge.

METHODS

Bronchoalveolar lavage fluid (BALF, n = 39) and bronchial epithelial cells (BECs) were obtained from patients with uncontrolled asthma before and after 12 weeks of tezepelumab treatment (n = 13) or placebo (n = 13). BECs were cultured in vitro and exposed to the viral infection mimic poly(I:C) or infected by rhinovirus (RV). Alarmins, T2- and pro-inflammatory cytokines, IFNβ IFNλ, and viral load were analyzed by RT-qPCR and multiplex ELISA before and after stimulation.

RESULTS

IL-33 expression in unstimulated BECs and IL-33 protein levels in BALF were reduced after 12 weeks of tezepelumab. Further, IL-33 gene and protein levels decreased in BECs challenged with poly(I:C) after tezepelumab whereas TSLP gene expression remained unaffected. Poly(I:C)-induced IL-4, IL-13, and IL-17A release from BECs was also reduced with tezepelumab whereas IFNβ and IFNλ expression and viral load were unchanged.

CONCLUSION

Blocking TSLP with tezepelumab in vivo in asthma reduced the airway epithelial inflammatory response including IL-33 and T2 cytokines to viral challenge without affecting anti-viral host resistance. Our results suggest that blocking TSLP stabilizes the bronchial epithelial immune response to respiratory viruses.

Association of behaviors and asthma control in a sample of Lebanese adolescents with asthma

BACKGROUND

The relationship between behavioral problems and asthma is bidirectional; while the presence of a chronic disease such as asthma might predispose the person to stress, anxiety, and other behavioral issues, behavioral problems might in turn cause uncontrolled asthma through nonadherence to asthma management strategies. In Lebanon, behavioral problems and uncontrolled asthma could be of significant concern for adolescents. Consequently, we found it necessary to evaluate association between behavioral problems and uncontrolled asthma in a sample of Lebanese adolescents.

METHODS

Data for this cross-sectional study were collected using the snowball sampling technique in July 2023. The questionnaire was developed with Google Forms and distributed to participants via social media platforms and messaging applications. The Asthma Control Test (ACT) was used to check for uncontrolled asthma, and the Youth Self-Report (YSR) scale was used to assess behavioral problems. It yields nine subscales (anxious-depressed, withdrawn-depressed, somatic complaints, social problems, thought problems, attention problems, rule-breaking behavior, aggressive behavior, and other problems) and a total score.

RESULTS

When taking each behavior score as an independent variable, older age was associated with lower ACT scores (more controlled asthma); F(15, 186) = 3.66, P = 0.014, and 95% Confidence Interval (CI) [-0.85, -0.10]. Living in a rural area, compared to urban was associated with higher ACT scores, P = 0.018, and 95% Confidence Interval (CI) [0.28, 2.94]. The intake of the COVID-19 vaccine, P = 0.003 and 95% CI [0.73, 3.55]; waterpipe smoking, P = 0.017 and 95% CI [0.38, 3.85]; and having more somatic complaints, P = 0.005 and 95% CI [0.04, 0.25], also were significantly associated with higher ACT scores (more uncontrolled asthma). When taking the total behavior score as an independent variable, higher YSR scores were associated with higher ACT scores (more uncontrolled asthma), F(10, 191) = 4.30, P = 0.038, and 95% CI [0.003, 0.10].

CONCLUSION

Our findings support the inclusion of mental health treatments for better asthma control and point to a link between behavioral issues and uncontrolled asthma. In a developing nation without a clear established strategy for asthma prevention, the findings of this study could help develop potentially beneficial public health treatments.

Airways Type-2 Related Disorders: Multiorgan, Systemic or Syndemic Disease?

Chronic rhinosinusitis (CRS) has recently undergone a significant paradigm shift, moving from a phenotypical classification towards an "endotype-based" definition that places more emphasis on clinical and therapeutic aspects. Similar to other airway diseases, like asthma, most cases of CRS in developed countries exhibit a dysregulated type-2 immune response and related cytokines. Consequently, the traditional distinction between upper and lower airways has been replaced by a "united airway" perspective. Additionally, type-2 related disorders extend beyond respiratory boundaries, encompassing conditions beyond the airways, such as atopic dermatitis. This necessitates a multidisciplinary approach. Moreover, consideration of possible systemic implications is crucial, particularly in relation to sleep-related breathing diseases like Obstructive Sleep Apnoea Syndrome (OSAS) and the alteration of systemic inflammatory mediators such as nitric oxide. The trends in epidemiological, economic, and social burden are progressively increasing worldwide, indicating syndemic characteristics. In light of these insights, this narrative review aims to present the latest evidence on respiratory type-2 related disorders, with a specific focus on CRS while promoting a comprehensive perspective on the "united airways". It also introduces a novel concept: viewing these conditions as a multiorgan, systemic, and syndemic disease.

Asthma exacerbations and eosinophilia in the UK Biobank: a genome-wide association study

Background

Asthma exacerbations reflect disease severity, affect morbidity and mortality, and may lead to declining lung function. Inflammatory endotypes (e.g. T2-high (eosinophilic)) may play a key role in asthma exacerbations. We aimed to assess whether genetic susceptibility underlies asthma exacerbation risk and additionally tested for an interaction between genetic variants and eosinophilia on exacerbation risk.

Methods

UK Biobank data were used to perform a genome-wide association study of individuals with asthma and at least one exacerbation compared to individuals with asthma and no history of exacerbations. Individuals with asthma were identified using self-reported data, hospitalisation data and general practitioner records. Exacerbations were identified as either asthma-related hospitalisation, general practitioner record of asthma exacerbation or an oral corticosteroid burst prescription. A logistic regression model adjusted for age, sex, smoking status and genetic ancestry via principal components was used to assess the association between genetic variants and asthma exacerbations. We sought replication for suggestive associations (p<5×10-6) in the GERA cohort.

Results

In the UK Biobank, we identified 11 604 cases and 37 890 controls. While no variants reached genome-wide significance (p<5×10-8) in the primary analysis, 116 signals were suggestively significant (p<5×10-6). In GERA, two single nucleotide polymorphisms (rs34643691 and rs149721630) replicated (p<0.05), representing signals near the NTRK3 and ABCA13 genes.

Conclusions

Our study has identified reproducible associations with asthma exacerbations in the UK Biobank and GERA cohorts. Confirmation of these findings in different asthma subphenotypes in diverse ancestries and functional investigation will be required to understand their mechanisms of action and potentially inform therapeutic development.

COVID-19 and Its Impact on Common Diseases in the Allergy Clinics

Coronavirus disease 2019 (COVID-19) is a highly contagious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has various effects on asthma, allergic rhinitis, atopic dermatitis, and urticaria and may change the course of the disease depending on the severity of the infection and control status of the disease. Conversely, these diseases may also impact the course of COVID-19. Patients with chronic urticaria and atopic dermatitis may have COVID-19-induced disease exacerbations and biological treatments reduce the risk of exacerbations. Poor asthma control is linked to severe COVID-19 while allergic asthma is associated with lower risk of death and a lower rate of hospitalization due to COVID-19 compared with nonallergic asthma. The use of intranasal corticosteroids is associated with lower rates of hospitalization due to COVID-19 in patients with allergic rhinitis, whereas the effect of inhaled corticosteroids is confounded by asthma severity. These observations reinforce the importance of keeping allergic diseases under control during pandemics. The use of biologicals during COVID-19 is generally regarded as safe, but more evidence is needed. The pandemic substantially changed the management of allergic disorders such as home implementation of various biologicals, allergen immunotherapy, food introduction, and increased use of telemedicine and even home management of anaphylaxis to reduce emergency department burden and reduce risk of infection. Physicians need to be aware of the potential impact of COVID-19 on allergic diseases and educate their patients on the importance of continuing prescribed medications and adhering to their treatment plans to maintain optimal control of their disease.

Resolution of Eosinophilic Pneumonia after Coronavirus Disease 2019 without Systemic Corticosteroids

Pulmonary and extrapulmonary complications after coronavirus disease 2019 (COVID-19) have been major public health concerns during the COVID-19 pandemic. Although post-COVID-19 pulmonary manifestations cover a wide spectrum, eosinophilic pneumonia (EP) has rarely been reported. To date, only four cases of EP potentially triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been reported, all of which required systemic corticosteroid therapy. We herein report the first case of post-COVID-19 EP resolution without systemic corticosteroid therapy. We also review the literature regarding EP associated with SARS-CoV-2 infection and vaccination.

Immunologic, genetic, and ecological interplay of factors involved in allergic diseases

An allergic or type I hypersensitivity reaction involves a misdirected immune overreaction to innocuous environmental and dietary antigens called allergens. The genetic predisposition to allergic disease, referred to as atopy, can be expressed as a variety of manifestations-e.g., allergic rhinitis, allergic conjunctivitis, atopic dermatitis, allergic asthma, anaphylaxis. Globally, allergic diseases are one the most common types of chronic conditions. Several factors have been identified to contribute to the pathogenesis and progression of the disease, leading to distinctively variable clinical symptoms. The factors which can attenuate or exacerbate allergic reactions can range from genetic heterozygosity, the prominence of various comorbid infections, and other factors such as pollution, climate, and interactions with other organisms and organism-derived products, and the surrounding environment. As a result, the effective prevention and control of allergies remains to be one of the most prominent public health problems. Therefore, to contextualize the current knowledge about allergic reactions, this review paper attempts to synthesize different aspects of an allergic response to describe its significance in the global health scheme. Specifically, the review shall characterize the biomolecular mechanisms of the pathophysiology of the disease based on underlying disease theories and current findings on ecologic interactions and describe prevention and control strategies being utilized. An integrated perspective that considers the underlying genetic, immunologic, and ecologic aspects of the disease would enable the development of more effective and targeted diagnostic tools and therapeutic strategies for the management and control of allergic diseases.

Divergent adaptive immune responses define two types of long COVID

Background

The role of adaptive immune responses in long COVID remains poorly understood, with contrasting hypotheses suggesting either an insufficient antiviral response or an excessive immune response associated with inflammatory damage. To address this issue, we set to characterize humoral and CD4+ T cell responses in long COVID patients prior to SARS-CoV-2 vaccination.

Methods

Long COVID patients who were seropositive (LC+, n=28) or seronegative (LC-, n=23) by spike ELISA assay were recruited based on (i) an initial SARS-CoV-2 infection documented by PCR or the conjunction of three major signs of COVID-19 and (ii) the persistence or resurgence of at least 3 symptoms for over 3 months. They were compared to COVID patients with resolved symptoms (RE, n=29) and uninfected control individuals (HD, n=29).

Results

The spectrum of persistent symptoms proved similar in both long COVID groups, with a trend for a higher number of symptoms in the seronegative group (median=6 vs 4.5; P=0.01). The use a highly sensitive S-flow assay enabled the detection of low levels of SARS-CoV-2 spike-specific IgG in 22.7% of ELISA-seronegative long COVID (LC-) patients. In contrast, spike-specific IgG levels were uniformly high in the LC+ and RE groups. Multiplexed antibody analyses to 30 different viral antigens showed that LC- patients had defective antibody responses to all SARS-CoV-2 proteins tested but had in most cases preserved responses to other viruses. A sensitive primary T cell line assay revealed low but detectable SARS-CoV-2-specific CD4 responses in 39.1% of LC- patients, while response frequencies were high in the LC+ and RE groups. Correlation analyses showed overall strong associations between humoral and cellular responses, with exceptions in the LC- group.

Conclusions

These findings provide evidence for two major types of antiviral immune responses in long COVID. Seropositive patients showed coordinated cellular and humoral responses at least as high as those of recovered patients. In contrast, ELISA-seronegative long COVID patients showed overall low antiviral responses, with detectable specific CD4+ T cells and/or antibodies in close to half of patients (52.2%). These divergent findings in patients sharing a comparable spectrum of persistent symptoms raise the possibility of multiple etiologies in long COVID.

Omalizumab prevents respiratory illnesses in non-atopic chronic spontaneous urticaria patients: A prospective, parallel-group, pilot pragmatic trial

BACKGROUND

Omalizumab is the recommended treatment for antihistamine-refractory chronic spontaneous urticaria (CSU) and severe allergic asthma. In addition, it has been shown to reduce the frequency of viral respiratory infections in allergic asthma. Respiratory illness is a known trigger for asthma and CSU.

OBJECTIVES

To explore whether the antiviral effect of omalizumab may be extended to CSU patients independent of their atopic status.

METHODS

We conducted a prospective parallel-group pilot pragmatic trial including 30 non-allergic and non-atopic CSU patients (cases) under omalizumab 300 mg Q4-weeks (due to refractory to H1-antihistamines) and 30 age-matched healthy controls. All CSU patients had to have a weekly urticaria activity score UAS7 <15 at least 4 weeks before recruitment. Using the self-filled validated Jackson scale, we evaluated all study participants for common cold symptoms. All cases and controls rated weekly their respiratory symptoms. An increase in the symptom score of at least 4 points compared to baseline (defined as the minimum weekly report of symptoms) was considered an episode suggestive of a viral infection of the upper respiratory tract (URT). The patients were follow-up every 4 weeks throughout the study period (10 months).

RESULTS

CSU patients under omalizumab reported fewer episodes suggestive of an URT viral infection than the healthy controls (median of reported episodes: 0 vs. 1, inter-quartile range 0-1 vs. 1-1, min-max: 0-3 vs. 0-4, respectively; p = 0.0095). The duration of each episode was the same in both cases and controls.

CONCLUSIONS

Omalizumab can reduce the number of common cold episodes in CSU patients and consequently may minimize viral-related CSU exacerbations. This beneficial effect is exerted independently of the atopic status, even in non-asthmatic individuals or non-allergic patients without any evidence of respiratory susceptibility. Further large-scale studies are needed to validate the current findings and elucidate the underlying relevant pathophysiology.

Prevalence of acute infection in adults with asthma exacerbation: A systematic review and meta-analysis

BACKGROUND

Acute respiratory infections are a major trigger of asthma exacerbations. This study sought to estimate the overall proportion of viruses, atypical pathogens, and bacteria detected in adults with asthma exacerbations.

METHODS

PubMed, EMBASE, and Cochrane Library databases and all related studies from the reviews and references were searched from inception to February 13, 2020. Two authors independently performed study selection, data extraction, as well as quality evaluation. Subsequently, meta-analysis, between-study heterogeneity, and publication bias assessment were conducted on RStudio.

RESULTS

Forty-three eligible studies comprising 3511 adults were included, of which 21 publications mentioned multiple infections during acute asthma attacks. Meta-analysis showed an acute infection prevalence of 40.19% (95% confidence interval [CI] 34.53%-45.99%). Viruses, atypical pathogens, and bacteria were detected in 38.76% (95% CI 32.02%-45.71%), 8.29% (95% CI 2.64%-16.27%), and 7.05% (95% CI 3.34%-11.81%) of asthmatics during exacerbations, respectively. Rhinovirus infections are always the dominant trigger for exacerbations with a proportion of 20.02% (95% CI 14.84%-25.73%). Substantial heterogeneity across studies (Cochran Q test: 479.43, P < 0.0001, I2 = 91.2%) was explained by subgroup analysis, indicating that year, region, population, respiratory secretion, detection method, pathogen, and study quality were all influencing factors.

CONCLUSION

This meta-analysis provided the first quantitative epidemiological data for adults, and in the future, more research and health-care supports are necessary in this area.

Inhaled drug delivery for the targeted treatment of asthma

Asthma is a chronic lung disease affecting millions worldwide. While classically acknowledged to result from allergen-driven type 2 inflammatory responses leading to IgE and cytokine production and the influx of immune cells such as mast cells and eosinophils, the wide range in asthmatic pathobiological subtypes lead to highly variable responses to anti-inflammatory therapies. Thus, there is a need to develop patient-specific therapies capable of addressing the full spectrum of asthmatic lung disease. Moreover, delivery of targeted treatments for asthma directly to the lung may help to maximize therapeutic benefit, but challenges remain in design of effective formulations for the inhaled route. In this review, we discuss the current understanding of asthmatic disease progression as well as genetic and epigenetic disease modifiers associated with asthma severity and exacerbation of disease. We also overview the limitations of clinically available treatments for asthma and discuss pre-clinical models of asthma used to evaluate new therapies. Based on the shortcomings of existing treatments, we highlight recent advances and new approaches to treat asthma via inhalation for monoclonal antibody delivery, mucolytic therapy to target airway mucus hypersecretion and gene therapies to address underlying drivers of disease. Finally, we conclude with discussion on the prospects for an inhaled vaccine to prevent asthma.

The Notorious Triumvirate in Pediatric Health: Air Pollution, Respiratory Allergy, and Infection

A plausible association is suspected among air pollution, respiratory allergic disorder, and infection. These three factors could cause uncontrollable chronic inflammation in the airway tract, creating a negative impact on the physiology of the respiratory system. This review aims to understand the underlying pathophysiology in explaining the association among air pollution, respiratory allergy, and infection in the pediatric population and to capture the public's attention regarding the interaction among these three factors, as they synergistically reduce the health status of children living in polluted countries globally, including Indonesia.

Extracorporeal membrane oxygenation (ECMO) and beyond in near fatal asthma: A comprehensive review

The treatment of choice in severe asthma exacerbations with respiratory failure includes ventilatory support, both invasive and/or non-invasive, along with different kinds of asthma medication. Of note, the rate of mortality of patients with asthma has decreased substantially in recent years mainly due to significant advances in pharmacological treatment and other management strategies. However, the risk of death in patients with severe asthma who require invasive mechanical ventilation has been estimated between 6.5% and 10.3%. When conventional measures fail, rescue strategies, such as extracorporeal membrane oxygenation (ECMO) or extracorporeal CO2 removal (ECCO2R) may need to be implemented. While ECMO does not constitute a definitive treatment per se, it can minimize further ventilator associated lung injury (VALI) and can enable diagnostic-therapeutic maneuvers that cannot be performed without ECMO such as bronchoscopy and transfer for diagnostic imaging. Asthma is one of the diseases that is associated with excellent outcomes for patients with refractory respiratory failure requiring ECMO support, as shown by the Extracorporeal Life Support Organization (ELSO) registry. Moreover, in such situations, the use of ECCO2R for rescue has been described and utilized in both children and adults and is more widely spread in different hospitals than ECMO. In this article, we aim to review the evidence for the usefulness of extracorporeal respiratory support measures in the management of severe asthma exacerbations that lead to respiratory failure.

Aeroallergen immunotherapy associated with reduced risk of severe COVID-19 in 1095 allergic patients

Introduction

Allergen immunotherapy (AIT) brings along changes in the immune system, restoring dendritic cell function, reducing T2 inflammation and augmenting the regulatory cell activation. Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, interferes with the immune system causing immune suppression during the first phase and over-activation in more advanced disease. We decided to explore the interaction of both in a real-world observational trial.

Methods

We registered COVID-19 outcomes in patients with allergic disorders in Latin America, treated with and without AIT. The registry was conducted during the first 1.3 years of the pandemic, with most of the data collected before COVID-19 vaccination was concluded in most countries. Data collection was anonymous via a web-based instrument. Ten countries participated.

Results

630/1095 (57.6%) of the included patients received AIT. Compared to patients without AIT, those treated with AIT had a reduced risk ratio (RR) for COVID-19 lower respiratory symptoms (RR 0.78, 95% CI: 0.6703-0.9024; p = 0.001662) and need for oxygen therapy (RR 0.65, 95% CI: 0.4217-0.9992; p = 0.048). In adherent patients on maintenance sublingual immunotherapy/subcutaneous immunotherapy (SLIT/SCIT) the RR reduction was larger [RR = 0.6136 (95% CI 0.4623-0.8143; p < 0.001) and RR: 0.3495 (95% CI 0.1822-0.6701; p < 0.005), respectively]. SLIT was slightly more effective (NS). We excluded age, comorbidities, level of health care attendance, and type of allergic disorder as confounders, although asthma was related to a higher frequency of severe disease. When analyzing patients with allergic asthma (n = 503) the RR reduction favoring AIT was more pronounced with 30% for lower respiratory symptoms or worse (RR 0.6914, 95% CI 0.5264 to 0.9081, p = 0.0087) and 51% for need of oxygen therapy or worse (RR 0.4868, 95% CI 0.2829-0.8376, p = 0.0082). Among severe allergic patients treated with biologics (n = 24) only 2/24 needed oxygen therapy. There were no critical cases among them.

Conclusion

In our registry AIT was associated with reduced COVID-19 severity.

COVID-19 and autoimmune diseases: is there a connection?

PURPOSE OF REVIEW

This review summarizes current evidence on the potential link between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and autoimmunity.

RECENT FINDINGS

Several viral infections are potential triggers of reactive and autoimmune diseases by inducing type II and type IV hypersensitivity reactions. Recent evidence demonstrated that SARS-CoV-2 infection is not an exception, triggering the production of tissue-specific autoantibodies during the acute phase of coronavirus disease 2019 (COVID-19) and leading to autoimmune diseases development as long-term complication. The significant immune dysregulation with cytokine storm and organ damage observed in patients with severe to critical COVID-19 is considered the main mechanism explaining the high levels of autoantibodies, which are also implicated in disease severity and the need for an intensive care assessment. Multisystem inflammatory syndrome in children (MIS-C) is an immune-mediated disease where the recent viral infection leads to systemic inflammation, as already observed in other reactive and autoimmune diseases.

SUMMARY

Autoimmunity may be a complication of SAR-CoV-2 infection. Understanding the pathogenesis of autoimmune manifestations in COVID-19 might help prevent the incidence or exacerbation of autoimmune disorders and design better and more efficient treatment strategies in children and adult populations.

Evaluation of selected aspects of the hygiene hypothesis and their effect on the incidence of allergy

OBJECTIVES

The development of allergic conditions is largely dependent on the interactions between genetic (individual genetic predisposition) and environmental factors (exposure to risk factors). The aim of this study was an attempt to assess the influence of selected elements of the hygiene theory in the development of allergic diseases such as allergic rhinitis and asthma.

MATERIAL AND METHODS

The study group consisted of 5518 women and 3868 men. The method that was used was the European Community Respiratory Health Survey II and International Study of Asthma and Allergies in Childhood questionnaire validated and adapted to Central and Eastern European conditions. The project was conducted in 8 urban areas (Gdańsk, Wrocław, Poznań, Katowice, Kraków, Lublin, Białystok, Warsaw) and 1 rural area (Krasnystaw county). This study had 2 stages; the first stage involved grouping the 22 500 respondents based on their questionnaire responses with the use of a Personal Digital Assistant (PDA); the second stage involved 7000 subjects, who underwent additional assessments: skin prick tests (birch, grasses/cereals, Dermatophagoides pteronyssinus and Dermatophagoides farinae, molds [set I: Botrytis cinerea, Cladosporium herbarum, Alternaria tenuis, Curvularia lunata, Fusarium moniliforme, Helminthosporium], molds [set II: Aspergillus fumigatus, Mucor mucedo, Penicillium notatum, Pullularia pullulans, Rhizopus nigricans, Serpula lacrymans], cat, dog, molds Cladosporium herbarum, Alternaria tenuis) and spirometry tests.

RESULTS

The age at which children attend the nursery school is critical to the development of allergic diseases; in allergic rhinitis, the risk of an IgE-dependent reaction is 2 times higher in the second than in the first year of life (p = 0.00147, p < 0.05), while in asthma, having a large number of siblings increases the risk of developing obstructive disease by almost 6 times (p = 0.00316, p < 0.05).The age at which children attend the nursery school is critical to the development of allergic diseases; in allergic rhinitis, the risk of an IgE-dependent reaction is 2 times higher in the second than in the first year of life (p = 0.00147, p < 0.05), while in asthma, having a large number of siblings increases the risk of developing obstructive disease by almost 6 times (p = 0.00316, p < 0.05).

CONCLUSIONS

The hygiene theory is particularly applicable and can explain the relationship of selected habits in the development of allergic diseases. Int J Occup Med Environ Health. 2023;36(1):69-83.

Antibody Conjugates Bispecific for Pollen Allergens and ICAM-1 with Potential to Prevent Epithelial Allergen Transmigration and Rhinovirus Infection

Allergy and rhinovirus (RV) infections are major triggers for rhinitis and asthma, causing a socioeconomic burden. As RVs and allergens may act synergistically to promote airway inflammation, simultaneous treatment strategies for both causative agents would be innovative. We have previously identified the transmembrane glycoprotein intercellular adhesion molecule 1 (ICAM-1) as an anchor for antibody conjugates bispecific for ICAM-1 and Phleum pratense (Phl p) 2, a major grass pollen allergen, to block allergen transmigration through the epithelial barrier. Since ICAM-1 is a receptor for the major group RVs, we speculated that our bispecific antibody conjugates may protect against RV infection. Therefore, we created antibody conjugates bispecific for ICAM-1 and the major grass pollen allergen Phl p 5 and analyzed their capacity to affect allergen penetration and RV infection. Bispecific antibody conjugates significantly reduced the trans-epithelial migration of Phl p 5 and thus the basolateral Phl p 5 concentration and allergenic activity as determined by humanized rat basophilic leukemia cells and inhibited RV infection of cultured epithelial cells. A reduction in allergenic activity was obtained only through the prevention of allergen transmigration because the Phl p 5-specific IgG antibody did not block the allergen-IgE interaction. Our results indicate the potential of allergen/ICAM-1-specific antibody conjugates as a topical treatment strategy for allergy and RV infections.

Gene-environment interactions and their impact on human health

The molecular processes underlying human health and disease are highly complex. Often, genetic and environmental factors contribute to a given disease or phenotype in a non-additive manner, yielding a gene-environment (G × E) interaction. In this work, we broadly review current knowledge on the impact of gene-environment interactions on human health. We first explain the independent impact of genetic variation and the environment. We next detail well-established G × E interactions that impact human health involving environmental toxicants, pollution, viruses, and sex chromosome composition. We conclude with possibilities and challenges for studying G × E interactions.

Using induced sputum method in clinical practice in patients with bronchial asthma

This article presents an overview of modern statements of the induced sputum method; detailed description of the methods and protocols for taking sputum in adults and children, methods for processing the obtained substance. The paper describes in detail the features of the cellular composition of induced sputum in healthy individuals and in patients with bronchial asthma, emphasizes the importance of the eosinophilia level as a prognostic and diagnostic criterion of asthma and also determines the functions of other induced sputum cells such as neutrophils, macrophages, basophils. The article is illustrated with photographs of sputum microscopy. In addition to sputum cytology, we give accent to the possibility of using other research methods such as an identification of viral and bacterial pathogens, genomics, proteomics, lipidomics, metabolomics, determination of the concentration of various mediators in the sputum supernatant. The paper presents the ideas on biochemical inflammatory markers and remodelling of the respiratory tract in asthma, which can be determined in sputum (C3a anaphylatoxin, clusterin, periostin, eosinophil-derived neurotoxin, folliculin). In addition, we summarize the information on inflammatory phenotypes of bronchial asthma, emphasize their variability and modification depending on the period of the disease, prescribed treatment, intercurrent respiratory infections, and smoking. The article also presents detailed characteristics of eosinophilic, neutrophilic, mixed and small granulocyte phenotypes of bronchial asthma, and describes the most frequent correlations of phenotypes with the severity and course of the disease, with lung function parameters and other indicators. The paper gives an account of the possibilities of using the induced sputum method for a comprehensive assessment of the course, asthma controllability and the effectiveness of drug therapy, as well as for a personalized selection of an antiinflammatory drug considering the inflammatory phenotype.

Mortality Risk in Pediatric Sepsis Based on C-reactive Protein and Ferritin Levels

OBJECTIVES

Interest in using bedside C-reactive protein (CRP) and ferritin levels to identify patients with hyperinflammatory sepsis who might benefit from anti-inflammatory therapies has piqued with the COVID-19 pandemic experience. Our first objective was to identify patterns in CRP and ferritin trajectory among critically ill pediatric sepsis patients. We then examined the association between these different groups of patients in their inflammatory cytokine responses, systemic inflammation, and mortality risks.

DATA SOURCES

A prospective, observational cohort study.

STUDY SELECTION

Children with sepsis and organ failure in nine pediatric intensive care units in the United States.

DATA EXTRACTION

Two hundred and fifty-five children were enrolled. Five distinct clinical multi-trajectory groups were identified. Plasma CRP (mg/dL), ferritin (ng/mL), and 31 cytokine levels were measured at two timepoints during sepsis (median Day 2 and Day 5). Group-based multi-trajectory models (GBMTM) identified groups of children with distinct patterns of CRP and ferritin.

DATA SYNTHESIS

Group 1 had normal CRP and ferritin levels ( n = 8; 0% mortality); Group 2 had high CRP levels that became normal, with normal ferritin levels throughout ( n = 80; 5% mortality); Group 3 had high ferritin levels alone ( n = 16; 6% mortality); Group 4 had very high CRP levels, and high ferritin levels ( n = 121; 11% mortality); and Group 5 had very high CRP and very high ferritin levels ( n = 30; 40% mortality). Cytokine responses differed across the five groups, with ferritin levels correlated with macrophage inflammatory protein 1α levels and CRP levels reflective of many cytokines.

CONCLUSIONS

Bedside CRP and ferritin levels can be used together to distinguish groups of children with sepsis who have different systemic inflammation cytokine responses and mortality risks. These data suggest future potential value in personalized clinical trials with specific targets for anti-inflammatory therapies.

Allergen immunotherapy effectively reduces the risk of exacerbations and lower respiratory tract infections in both seasonal and perennial allergic asthma: a nationwide epidemiological study

BACKGROUND

Allergic asthma is associated with increased risk of respiratory tract infections and exacerbations. It remains unclear whether this susceptibility is conditioned by seasonal or by perennial allergy.

AIM

To investigate perennial allergy compared with seasonal allergy as a risk factor for lower respiratory tract infections and exacerbations in asthma and whether this risk can be reduced by allergen immunotherapy (AIT).

METHODOLOGY

This is a prospective register-based nationwide study of 18-44-year-olds treated with AIT during 1995-2014. Based on the type of AIT and use of anti-asthmatic drugs, patients were subdivided into two groups: perennial allergic asthma (PAA) versus seasonal allergic asthma (SAA). Data on antibiotics against lower respiratory tract infections (LRTI) and oral corticosteroids for exacerbations were analysed before starting AIT (baseline) and 3 years after completing AIT (follow-up).

RESULTS

We identified 2688 patients with asthma treated with AIT, of whom 1249 had PAA and 1439 had SAA. At baseline, patients with SAA had more exacerbations (23.8% versus 16.5%, p≤0.001), but there were no differences in LRTI. During the 3-year follow-up, we observed a highly significant reduction of exacerbations with an average decrease of 57% in PAA and 74% in SAA. In addition, we observed a significant reduction of LRTI in both PAA and SAA: 17% and 20% decrease, respectively.

CONCLUSION

AIT effectively reduced the risk of exacerbations and lower respiratory tract infections in both seasonal and perennial allergic asthma. Perennial allergy is seemingly not a stronger risk factor for respiratory infections and exacerbations than seasonal allergy.

Worsening of asthma control after COVID-19

Background

SARS-CoV-2 enters lung cells via angiotensin-converting enzyme 2 (ACE2) receptor. Several studies suggest that interleukin-13, an important cytokine involved in T2 inflammation, reduces ACE2 expression, and therefore, asthma would not be a significant risk factor for the development of severe COVID-19. However, several asthma-related risk factors should be valued during the concurrent occurrence of asthma and COVID-19. The purpose of this study was to compare the evolution of asthma in patients who had COVID-19 with those who did not have the disease.

Methods

This was an observational and retrospective study involving asthmatic patients followed up at a tertiary center. Patients were assessed for severity of asthma, atopy, comorbidities, and COVID-19. Worsening of asthma was considered when, during the period of Sept 2020 to Oct 2021, patients referred an increasing of asthma symptoms and a need to increment their maintenance therapy.

Results

This study included 208 asthmatic patients, the mean age was 52.75 years, 79.81% were atopic asthmatics, and 59 (28.37%) had laboratory-confirmed coronavirus disease. Of all patients infected with the SARS-CoV-2, eleven (18.64%) needed hospitalization and required oxygen supply with an O2 mask. Comparing the worsening of asthma between patients who had COVID-19 and those who had not the disease, there was a statistically significant difference, 33.90 vs. 11.41%, respectively (p &lt; 0.001). There was no statistical significance regarding asthma comorbidities.

Conclusion

This study assessed a group of asthmatic patients that had COVID-19, and that although the respiratory symptoms related to COVID-19 were mild to moderate, a subgroup of these asthmatic patients evolved with a chronic worsening of their asthma requiring an increment in asthma medication to control the disease.

High prevalence of IgE sensitization to inactivated influenza vaccines, yet robust IgG4 responses, in a healthy pediatric population

BACKGROUND

Anaphylaxis following influenza vaccination is a rare but serious problem. The underlying immune responses are not well understood. This study elucidated the IgE and IgG antibody responses in healthy children and adolescents following inactivated influenza vaccines (IIVs).

METHODS

The efficacy and safety of quadrivalent IIV (QIV) and trivalent IIV (TIV) were compared in healthy subjects aged 0-18 years. Serum IIV-specific IgE, IgG, and IgG4 levels (sIgE, sIgG, and sIgG4) were measured with ImmunoCAP. Hemagglutination inhibition (HI) assay was performed for each influenza virus subtype. Sera from earlier patients who developed anaphylaxis to different IIVs were similarly tested.

RESULTS

A total of 393 subjects were enrolled: 96 were 6 months-2 years old, 100 were 3-5 years old, 100 were 6-12 years old, and 97 were 13-18 years old. No anaphylaxis was observed. Generally, QIV and TIV induced similar antibody responses. IIV-sIgE levels rose significantly after vaccination in the 6 months-2 years old and 3-5 years old groups, did not change in the 6-12 years old group, and decreased in the 13-18 years old group. In contrast, the IIV-sIgG4/sIgE ratio increased significantly after vaccination in all age groups. Sensitized subjects had significantly higher HI titers and IIV-sIgG levels in the youngest age group and higher IIV-sIgG4 levels in all age groups compared with the non-sensitized. The IIV-sIgG4/sIgE ratio in five patients with anaphylaxis was significantly lower than in age-matched healthy subjects.

CONCLUSION

IIVs induce IgE sensitization in healthy children but also robust IgG4 responses that may protect them from anaphylaxis.

Environmental contributions to the interactions of COVID-19 and asthma: A secondary publication and update

An outbreak of coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) started in Wuhan, Hubei Province, China and quickly spread around the world. Current evidence is contradictory on the association of asthma with COVID-19 and associated severe outcomes. Type 2 inflammation may reduce the risk for severe COVID-19. Whether asthma diagnosis may be a risk factor for severe COVID-19, especially for those with severe disease or non-allergic phenotypes, deserves further attention and clarification. In addition, COVID-19 does not appear to provoke asthma exacerbations, and asthma therapeutics should be continued for patients with exposure to COVID-19. Changes in the intensity of pollinization, an earlier start and extension of the pollinating season, and the increase in production and allergenicity of pollen are known direct effects that air pollution has on physical, chemical, and biological properties of the pollen grains. They are influenced and triggered by meteorological variables that could partially explain the effect on COVID-19. SARS-CoV-2 is capable of persisting in the environment and can be transported by bioaerosols which can further influence its transmission rate and seasonality. The COVID-19 pandemic has changed the behavior of adults and children globally. A general trend during the pandemic has been human isolation indoors due to school lockdowns and loss of job or implementation of virtual work at home. A consequence of this behavior change would presumably be changes in indoor allergen exposures and reduction of inhaled outdoor allergens. Therefore, lockdowns during the pandemic might have improved some specific allergies, while worsening others, depending on the housing conditions.

The Microbiome as a Gateway to Prevention of Allergic Disease Development

Allergic diseases exclusively affect tissues that face environmental challenges and harbor endogenous bacterial microbiota. The microbes inhabiting the affected tissues may not be mere bystanders in this process but actively affect the risk of allergic sensitization, disease development, and exacerbation or abatement of symptoms. Experimental evidence provides several plausible means by which the human microbiota could influence the development of allergic diseases including, but not limited to, effects on antigen presentation and induction of tolerance and allergen permeation by endorsing or disrupting epithelial barrier integrity. Epidemiological evidence attests to the significance of age-appropriate, nonpathogenic microbiota development in skin, gastrointestinal tract, and airways for protection against allergic disease development. Thus, there exist potential targets for preventive actions either in the prenatal or postnatal period. These could include maternal dietary interventions, antibiotic stewardship for both the mother and infant, reducing elective cesarean deliveries, and understanding barriers to breastfeeding and timing of food diversification. In here, we will review the current understanding and evidence of allergy-associated human microbiota patterns, their role in the development of allergic diseases, and how we could harness these associations to our benefit against allergies.

In vivo bronchial epithelial interferon responses are augmented in asthma on day 4 following experimental rhinovirus infection

Despite good evidence of impaired innate antiviral responses in asthma, trials of inhaled interferon-β given during exacerbations showed only modest benefits in moderate/severe asthma. Using human experimental rhinovirus infection, we observe robust in vivo induction of bronchial epithelial interferon response genes 4 days after virus inoculation in 25 subjects with asthma but not 11 control subjects. This signature correlated with virus loads and lower respiratory symptoms. Our data indicate that the in vivo innate antiviral response is dysregulated in asthma and open up the potential that prophylactic rather than therapeutic interferon therapy may have greater clinical benefit.

Viral Infection and Airway Epithelial Immunity in Asthma

Viral respiratory tract infections are associated with asthma development and exacerbation in children and adults. In the course of immune responses to viruses, airway epithelial cells are the initial platform of innate immunity against viral invasion. Patients with severe asthma are more vulnerable than those with mild to moderate asthma to viral infections. Furthermore, in most cases, asthmatic patients tend to produce lower levels of antiviral cytokines than healthy subjects, such as interferons produced from immune effector cells and airway epithelial cells. The epithelial inflammasome appears to contribute to asthma exacerbation through overactivation, leading to self-damage, despite its naturally protective role against infectious pathogens. Given the mixed and complex immune responses in viral-infection-induced asthma exacerbation, this review examines the diverse roles of airway epithelial immunity and related potential therapeutic targets and discusses the mechanisms underlying the heterogeneous manifestations of asthma exacerbations.

The health economic impact of cow's milk allergy in childhood: A retrospective cohort study

Background

Cow's milk allergy (CMA) is one of the most common food allergies among children. Whilst avoidance of cow's milk protein is the cornerstone of management, further treatment of symptoms including those affecting the gastrointestinal, skin and respiratory systems plus other allergic comorbidities, maybe required. This study aimed to quantify the wider economic impact of CMA and its management in the United Kingdom (UK).

Methods

We conducted a retrospective matched cohort study on children with CMA (diagnosis read code and/or hypoallergenic formula prescription for ≥3 months) examining healthcare data (medication prescriptions and healthcare professional contacts) from case records within The Health Improvement Network (A Cegedim Proprietary Database) in the UK. A comparative cost analysis was calculated based on healthcare tariff and unit costs in the UK.

Results

6998 children (54% male; mean observation period 4.2 years) were included (n = 3499 with CMA, mean age at diagnosis 4.04 months; n = 3499 matched controls without CMA). Compared to those without CMA, medications were prescribed to significantly more children with CMA (p < 0.001) at a higher rate (p < 0.001). Children with CMA also required significantly more healthcare contacts (p < 0.001) at higher rate (p < 0.001) compared to those without CMA. CMA was associated with additional potential healthcare costs of £1381.53 per person per year.

Conclusion

The findings of this large cohort study suggest that CMA and its associated co‐morbidities presents a significant additional healthcare burden with economic impact due to higher prescribing of additional medications. Further research into management approaches that may impact these clinical and economic outcomes of CMA is warranted.

DNA methylation signatures in airway cells from adult children of asthmatic mothers reflect subtypes of severe asthma

Maternal asthma is one of the most replicated risk factors for childhood-onset asthma. However, the underlying mechanisms are unknown. We identified DNA methylation signatures in bronchial epithelial cells from adults with asthma that were specific to those with a mother with asthma. These maternal asthma-associated methylation signatures were correlated with distinct gene regulatory pathways and clinical features. Genes in 16 pathways discriminated cases with and without maternal asthma and suggested impaired T cell signaling and responses to viral and bacterial pathogens in asthmatic children of an asthmatic mother. Our findings suggest that the prenatal environment in pregnancies of mothers with asthma alters epigenetically mediated developmental programs that may lead to severe asthma in their children through diverse gene regulatory pathways.

Maternal asthma (MA) is among the most consistent risk factors for asthma in children. Possible mechanisms for this observation are epigenetic modifications in utero that have lasting effects on developmental programs in children of mothers with asthma. To test this hypothesis, we performed differential DNA methylation analyses of 398,186 individual CpG sites in primary bronchial epithelial cells (BECs) from 42 nonasthma controls and 88 asthma cases, including 56 without MA (NMA) and 32 with MA. We used weighted gene coexpression network analysis (WGCNA) of 69 and 554 differentially methylated CpGs (DMCs) that were specific to NMA and MA cases, respectively, compared with controls. WGCNA grouped 66 NMA-DMCs and 203 MA-DMCs into two and five comethylation modules, respectively. The eigenvector of one MA-associated module (turquoise) was uniquely correlated with 85 genes expressed in BECs and enriched for 36 pathways, 16 of which discriminated between NMA and MA using machine learning. Genes in all 16 pathways were decreased in MA compared with NMA cases (P = 7.1 × 10⁻³), a finding that replicated in nasal epithelial cells from an independent cohort (P = 0.02). Functional interpretation of these pathways suggested impaired T cell signaling and responses to viral and bacterial pathogens. The MA-associated turquoise module eigenvector was additionally correlated with clinical features of severe asthma and reflective of type 2 (T2)-low asthma (i.e., low total serum immunoglobulin E, fractional exhaled nitric oxide, and eosinophilia). Overall, these data suggest that MA alters diverse epigenetically mediated pathways that lead to distinct subtypes of severe asthma in adults, including hard-to-treat T2-low asthma.

Clinical picture and long-term symptoms of SARS-CoV-2 infection in an Italian pediatric population

Background

SARS-CoV-2 infection in the pediatric age group has a milder course than in adults, but in some cases even children may present with severe forms or develop long-term consequences. The aim of this study was to analyze the clinical features, long-term effects, lifestyle changes and psychological effects of SARS-CoV-2 infection in a pediatric sample of the Italian population.

Methods

We conducted a telephone survey among 3075 children infected with SARS-CoV-2 in the Latina Local Health Authority. Outcomes included: clinical features of infection, long-term symptoms, lifestyle changes and emotional symptoms during the illness. The information obtained was automatically linked to a spreadsheet and analyzed.

Results

One thousand four hundred thirteen children agreed to participate in the study; the mean age was 112.8 ± 21.9 months. Children were infected mainly inside familial clusters (59.6%; n = 842); 99% (n = 1399) of children were asymptomatic or exhibited mild symptoms. 20% (n = 259) of children experienced long-term symptoms; risk factors were: older age, higher body mass index and longer duration of infection.

Throughout the period of infection, children spent most of the time on devices like tv-video, social media and mobile phone for non-educational activities. 58.8% (n = 620) of parents expressed a negative opinion about distance learning. Finally, we observed that 49,6% (n = 532) of children experienced psychological symptoms during quarantine period.

Conclusion

Despite a lower susceptibility to COVID-19 in children, it is important to keep the focus high in children, both because of the possible long symptoms after infection and the impact on a children’s mental and physical health due to pandemic. We believe that the return to school or other extracurricular activities are important to correct some of the risk factors for the long COVID syndrome, as obesity, and to limit the cultural damage generated by distance learning and psychological effects related to restrictive measures.

Extracellular Nucleotides and Histamine Suppress TLR3- and RIG-I-Mediated Release of Antiviral IFNs from Human Airway Epithelial Cells

Respiratory viruses stimulate the release of antiviral IFNs from the airway epithelium. Previous studies have shown that asthmatic patients show diminished release of type I and type III IFNs from bronchial epithelia. However, the mechanism of this suppression is not understood. In this study, we report that extracellular nucleotides and histamine, which are elevated in asthmatic airways, strongly inhibit release of type I and type III IFNs from human bronchial airway epithelial cells (AECs). Specifically, ATP, UTP, and histamine all inhibited the release of type I and type III IFNs from AECs induced by activation of TLR3, retinoic acid-inducible gene I (RIG-I), or cyclic GMP-AMP synthase-STING. This inhibition was at least partly mediated by Gq signaling through purinergic P2Y2 and H1 receptors, but it did not involve store-operated calcium entry. Pharmacological blockade of protein kinase C partially reversed inhibition of IFN production. Conversely, direct activation of protein kinase C with phorbol esters strongly inhibited TLR3- and RIG-I-mediated IFN production. Inhibition of type I and type III IFNs by ATP, UTP, histamine, and the proteinase-activated receptor 2 (PAR2) receptor agonist SLIGKV also occurred in differentiated AECs grown at an air-liquid interface, indicating that the suppression is conserved following mucociliary differentiation. Importantly, histamine and, more strikingly, ATP inhibited type I IFN release from human airway cells infected with live influenza A virus or rhinovirus 1B. These results reveal an important role for extracellular nucleotides and histamine in attenuating the induction of type I and III IFNs from AECs and help explain the molecular basis of the suppression of IFN responses in asthmatic patients.

Virulence triggered allergies: Pseudomonas gets the Las laugh

The mechanisms of how infectious diseases contribute to allergy remain unanswered. In this issue of Immunity, Agaronyan et al. (2022) show that Pseudomonas aeruginosa drives immune deviation through induction of type 2 immune responses, resulting in niche remodeling that incites allergic responses to innocuous antigens.

Differential susceptibility to SARS-CoV-2 in the normal nasal mucosa and in chronic sinusitis

Human nasal mucosa is susceptible to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and serves as a reservoir for viral replication before spreading to other organs (e.g. the lung and brain) and transmission to other individuals. Chronic rhinosinusitis (CRS) is a common respiratory tract disease and there is evidence suggesting that susceptibility to SARS‐CoV‐2 infection differs between the two known subtypes, eosinophilic CRS and non‐ECRS (NECRS). However, the mechanism of SARS‐CoV‐2 infection in the human nasal mucosa and its association with CRS has not been experimentally validated. In this study, we investigated whether the human nasal mucosa is susceptible to SARS‐CoV‐2 infection and how different endotypes of CRS impact on viral infection and progression. Primary human nasal mucosa tissue culture revealed highly efficient SARS‐CoV‐2 viral infection and production, with particularly high susceptibility in the NECRS group. The gene expression differences suggested that human nasal mucosa is highly susceptible to SARS‐CoV‐2 infection, presumably due to an increase in ACE2‐expressing cells and a deficiency in antiviral immune response, especially for NECRS. Importantly, patients with NECRS may be at a particularly high risk of viral infection and transmission, and therefore, close monitoring should be considered.

Impact of Therapeutics on Unified Immunity During Allergic Asthma and Respiratory Infections

Asthma is a common chronic respiratory disease that affects millions of people worldwide. Patients with allergic asthma, the most prevalent asthma endotype, are widely considered to possess a defective immune response against some respiratory infectious agents, including viruses, bacteria and fungi. Furthermore, respiratory pathogens are associated with asthma development and exacerbations. However, growing data suggest that the immune milieu in allergic asthma may be beneficial during certain respiratory infections. Immunomodulatory asthma treatments, although beneficial, should then be carefully prescribed to avoid misuse and overuse as they can also alter the host microbiome. In this review, we summarize and discuss recent evidence of the correlations between allergic asthma and the most significant respiratory infectious agents that have a role in asthma pathogenesis. We also discuss the implications of current asthma therapeutics beyond symptom prevention.

Effect of the COVID-19 Lockdown on Asthma Biological Rhythms

Asthma has a striking temporal character, in which time-of-day, patient age, and season each influence disease activity. The extent to which rhythms in asthma activity reflect exposure to specific disease triggers remains unclear. In this study, we examined how virus mitigation strategies enacted during the COVID-19 pandemic ("lockdown measures") affected rhythms in asthma clinical activity in children. To this end, we retrospectively analyzed asthma clinical presentations in children aged <18 years to our regional academic medical center, comparing 4 years of medical records prior to COVID-19 lockdown measures with the 12 months immediately after the institution of such measures. We correlated these data to positive viral test results, febrile seizures, and allergic clinical surrogates (allergic reaction visits and Emergency Department [ED] antihistamine prescriptions, respectively) over the same time frame. In the 12 months following the institution of the COVID-19 lockdown, positivity rates for common respiratory viruses dropped by 70.2% and ED visits for asthma among children dropped by 62% compared to pre-COVID years. Lockdown suppressed seasonal variation in positive viral tests and asthma ED visits, while diurnal rhythms in asthma visits were unchanged. Asthma seasonality correlated most strongly with rhinovirus positivity both before and after the institution of COVID lockdown measures. Altogether, our data support a causal role for viruses in driving seasonal variability in asthma exacerbations in children.

Risk of pneumonia in asthmatic children using inhaled corticosteroids: a nested case-control study in a birth cohort

BACKGROUND

Inhaled corticosteroids (ICSs) are important in asthma management, but there are concerns regarding associated risk of pneumonia. While studies in asthmatic adults have shown inconsistent results, this risk in asthmatic children is unclear.

OBJECTIVE

Our aim was to determine the association of ICS use with pneumonia risk in asthmatic children.

METHODS

A nested case-control study was performed in the Mayo Clinic Birth Cohort. Asthmatic children (<18 years) with a physician diagnosis of asthma were identified from electronic medical records of children born at Mayo Clinic from 1997 to 2016 and followed until 31 December 2017. Pneumonia cases defined by Infectious Disease Society of America were 1:1 matched with controls without pneumonia by age, sex and asthma index date. Exposure was defined as ICS prescription at least 90 days prior to pneumonia. Associations of ICS use, type and dose (low, medium and high) with pneumonia risk were analysed using conditional logistic regression.

RESULTS

Of the 2108 asthmatic children eligible for the study (70% mild intermittent and 30% persistent asthma), 312 children developed pneumonia during the study period. ICS use overall was not associated with risk of pneumonia (adjusted OR: 0.94, 95% CI: 0.62 to 1.41). Poorly controlled asthma was significantly associated with the risk of pneumonia (OR: 2.03, 95% CI: 1.35 to 3.05; p<0.001). No ICS type or dose was associated with risk of pneumonia.

CONCLUSION

ICS use in asthmatic children was not associated with risk of pneumonia but poorly controlled asthma was. Future asthma studies may need to include pneumonia as a potential outcome of asthma management.

A Pilot Study for IgE as a Prognostic Biomarker in COVID-19

Background

Laboratory biomarkers to estimate the severity of COVID‐19 are crucial during the pandemic, since resource allocation must be carefully planned.

Aim

In the present study, we aim to evaluate the effects of basal serum total immunoglobulin E (IgE) levels and changes in inflammatory parameters on the clinical progression of patients hospitalized with COVID‐19.

Methods

Patients hospitalized with confirmed COVID‐19 were included in the study. Laboratory data and total IgE levels were measured upon admission. Lymphocyte, eosinophil, ferritin, d‐dimer and CRP parameters were recorded on the baseline and on the 3^rd and 14^th days of hospitalization.

Results

The study enrolled 202 patients, of which 102(50.5%) were males. The average age was 50.17 ± 19.68. Of the COVID‐19 patients, 41 (20.3%) showed clinical progression. Serum total IgE concentrations were markedly higher (172.90 [0‐2124] vs 38.70 [0‐912], p<0.001) and serum eosinophil levels were significantly lower (0.015 [0‐1.200] vs 0.040 [0‐1.360], p=0.002) in clinically worsened COVID‐19 patients when compared to stable patients. The optimal cut‐off for predicting clinical worsening was 105.2 ng/L; with 61% sensitivity, 82% specificity, 46.3% positive predictive value and 89.2% negative predictive value (area under the curve=0.729). Multivariable analysis to define risk factors for disease progression identified higher total IgE and CRP levels as independent predictors.

Conclusions

Our single‐center pilot study determined that total IgE levels may be a negative prognostic factor for clinical progression in patients hospitalized due to COVID‐19 infection. Future studies are required to determine the impact of individuals' underlying immune predispositions on outcomes of COVID‐19 infections.

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Prognosis of COVID-19 in respiratory allergy: a systematic review and meta-analysis

Background

Do underlying allergic respiratory diseases such as asthma and rhinitis predispose to a severe coronavirus (COVID-19) infection? We conducted this systematic review to map out and synthesize evidence of published literature.

Main body of the abstract

We searched five bibliographic databases for articles published between 1 January and 15 November 2020 using keywords: “COVID” AND “Allergic disease,” “Prognosis and COVID-19,” “SARS-CoV-2,” “Asthma,” “Allergic rhinitis.” We synthesized 32 eligible articles from a total of 11,376 articles retrieved from the search process. The profile of allergic respiratory conditions was identified, and only seven studies reported on the treatment administered. No significant difference was observed concerning the prevalence of COVID-19 in individuals with allergic asthma and those with non-allergic asthma (RR = 0.61, p = 0.08). The mortality rate significantly decreased in COVID-19-infected patients with asthma than patients without asthma (RR = 0.63, p = 0.04).

Short conclusion

There is little evidence available on the role of asthma medications and risk factors influencing the prognostic outcomes for COVID-19 individuals with respiratory allergies, which invites further research.

The clinical burden of cow's milk allergy in early childhood: A retrospective cohort study

Introduction

Cow's milk allergy (CMA) is common in infants and children. Clinical presentations may vary, with a range of symptoms affecting the gastrointestinal (GI), skin and respiratory systems. Whilst the primary focus of research to date has been on the management of these symptoms, studies investigating the broader clinical burden of CMA are limited.

Methods

We performed a retrospective matched cohort study examining clinical data, including allergic symptoms and infections, extracted from case records within The Health Improvement Network database. A total of 6998 children (54% male) were included in the study, including 3499 with CMA (mean age at diagnosis 4.04 months) and 3499 matched controls without CMA, observed for a mean period of 4.2 years.

Results

GI, skin and respiratory symptoms affected significantly more children with CMA (p < .001), which recurred more often (p < .001), compared with children without CMA. More children with CMA had symptoms affecting multiple systems (p < .001). CMA was associated with a greater probability of these symptoms requiring hypoallergenic formula (HAF) prescription persisting over time (log‐rank test p < .0001, unadjusted hazard ratio [HR]: 0.81, 95% confidence interval [CI]: 0.76–0.85, p < .001), with a longer median duration of symptoms and HAF prescription compared with the duration of symptoms in those without CMA (3.48 vs. 2.96 years). GI, skin, respiratory and ear infections affected significantly more children with CMA than those without, increasing by 74% (p < .001), 20% (p < .001), 9% (p < .001), and 30% (p < .001) respectively. These infections also recurred more often among children with CMA, increasing by 62% for GI infections, 37% for skin and respiratory infections, and 44% for ear infections (p < .001).

Conclusions

This real‐world study provides evidence to suggest that CMA presents a significant clinical burden to children, which has implications for the healthcare system. Further research is warranted to understand the health economic impact of this, and the phenotypes, factors and management approaches which may affect clinical outcomes.

Immunoglobulin E-Dependent Activation of Immune Cells in Rhinovirus-Induced Asthma Exacerbation

Acute exacerbation is the major cause of asthma morbidity, mortality, and health-care costs. Respiratory viral infections, particularly rhinovirus (RV) infections, are associated with the majority of asthma exacerbations. The risk for bronchoconstriction with RV is associated with allergic sensitization and type 2 airway inflammation. The efficacy of the humanized anti-IgE monoclonal antibody omalizumab in treating asthma and reducing the frequency and severity of RV-induced asthma exacerbation is well-known. Despite these clinical data, mechanistic details of omalizumab's effects on RV-induced asthma exacerbation have not been well-defined for years due to the lack of appropriate animal models. In this Perspective, we discuss potential IgE-dependent roles of mast cells and dendritic cells in asthma exacerbations.

Early life inter-kingdom interactions shape the immunological environment of the airways

BACKGROUND

There is increasing evidence that the airway microbiome plays a key role in the establishment of respiratory health by interacting with the developing immune system early in life. While it has become clear that bacteria are involved in this process, there is a knowledge gap concerning the role of fungi. Moreover, the inter-kingdom interactions that influence immune development remain unknown. In this prospective exploratory human study, we aimed to determine early post-natal microbial and immunological features of the upper airways in 121 healthy newborns.

RESULTS

We found that the oropharynx and nasal cavity represent distinct ecological niches for bacteria and fungi. Breastfeeding correlated with changes in microbiota composition of oropharyngeal samples with the greatest impact upon the relative abundance of Streptococcus species and Candida. Host transcriptome profiling revealed that genes with the highest expression variation were immunological in nature. Multi-omics factor analysis of host and microbial data revealed unique co-variation patterns.

CONCLUSION

These data provide evidence of a diverse multi-kingdom microbiota linked with local immunological characteristics in the first week of life that could represent distinct trajectories for future respiratory health.

TRIAL REGISTRATION

NHS Health Research Authority, IRAS ID 199053. Registered 5 Oct 2016. https://www.hra.nhs.uk/planning-and-improving-research/application-summaries/research-summaries/breathing-together/ Video abstract.