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The Human Epidemiology and Response to SARS-CoV-2 (HEROS) is a prospective multi-city 6-month incidence study which was conducted from May 2020-February 2021. The objectives were to identify risk factors for SARS-CoV-2 infection and household transmission among children and people with asthma and allergic diseases, and to use the host nasal transcriptome sampled longitudinally to understand infection risk and sequelae at the molecular level. To overcome challenges of clinical study implementation due to the coronavirus pandemic, this surveillance study used direct-to-participant methods to remotely enroll and prospectively follow eligible children who are participants in other NIH-funded pediatric research studies and their household members. Households participated in weekly surveys and biweekly nasal sampling regardless of symptoms. The aim of this report is to widely share the methods and study instruments and to describe the rationale, design, execution, logistics and characteristics of a large, observational, household-based, remote cohort study of SARS-CoV-2 infection and transmission in households with children. The study enrolled a total of 5,598 individuals, including 1,913 principal participants (children), 1,913 primary caregivers, 729 secondary caregivers and 1,043 other household children. This study was successfully implemented without necessitating any in-person research visits and provides an approach for rapid execution of clinical research.

BACKGROUND AND OBJECTIVES: The relationship between allergic diseases and internalizing disorders has not been well characterized with regard to multiple allergic diseases or longitudinal study. The objective of this study was to examine the association between multiple allergic diseases in early childhood with validated measures of internalizing disorders in the school-age years. METHODS: Children enrolled in the Cincinnati Childhood Allergy and Air Pollution Study underwent skin testing and examinations at ages 1, 2, 3, 4, and 7 years. At age 7, parents completed the Behavior Assessment System for Children, Second Edition (BASC-2), a validated measure of childhood behavior and emotion. The association between allergic diseases at age 4, including allergic rhinitis, allergic persistent wheezing, atopic dermatitis, and allergic sensitization, and BASC-2 internalizing, anxiety, and depression T scores at age 7 was examined by logistic and linear regression, adjusting for covariates. RESULTS: The cohort included 546 children with complete information on allergic disease and BASC-2 outcomes. Allergic rhinitis at age 4 was significantly associated with elevated internalizing (adjusted odds ratio [aOR]: 3.2; 95% confidence interval [CI]: 1.8–5.8), anxiety (aOR: 2.0; 95% CI: 1.2–3.6), and depressive scores (aOR: 3.2; 95% CI: 1.7–6.5) at age 7. Allergic persistent wheezing was significantly associated with elevated internalizing scores (aOR: 2.7; 95% CI: 1.2–6.3). The presence of >1 allergic disease (aOR: 3.6; 95% CI: 1.7–7.6) and allergic rhinitis with comorbid allergic disease(s) (aOR: 4.3; 95% CI: 2.0–9.2) at age 4 had dose-dependent associations with internalizing scores. CONCLUSIONS: Children with allergic rhinitis and allergic persistent wheezing at age 4 are at increased risk of internalizing behaviors at age 7. Furthermore, multiple allergic diseases had a dose-dependent association with elevated internalizing scores.

The respiratory tract is exposed continuously to noxious agents, microbial organisms, particles, and allergens. It has therefore evolved both innate and specific defense mechanisms. The innate host defense mechanisms include components such as collectins, beta-defensins, lactoferrin, and complement, all of which have an important role in modulating the immune response. Immune protection of the lungs by specific antibody is reviewed. The airways are protected by alveolar macrophages, neutrophils, and lymphocytes, and their origins, regulation, functions, and antimicrobial activity are summarized. Antimicrobial peptides and immune-modulating peptides are likely to have a significant therapeutic role for infection and inflammation in the respiratory tract.

The asthmatic response is characterized by elevated production of IgE, cytokines, chemokines, mucus hypersecretion, air-way obstruction, eosinophilia, and enhanced airway hyperreactivity to spasmogens. Clinical and experimental investigations have demonstrated a strong correlation between the presence of CD4+ TH2 cells, eosinophils, and disease severity, suggesting an integral role for these cells in the pathophysiology of asthma. TH2 cells are thought to induce asthma through the secretion of an array of cytokines (IL-4, -5, -9 -1),-13, -25) that activate inflammatory and residential effector pathways both directly and indirectly. In particular, IL-4 and IL-13 are produced at elevated levels in the asthmatic lung and are thought to be central regulators of many of the hallmark features of the disease. The potency of IL-13 in promoting airway hyperreactivity and mucus hypersecretion and the ability of IL-13 blockade to abrogate several critical aspects of experimental asthma have led to the view that this is a critical cytokine in disease pathogenesis. Extensive studies have also demonstrated a central role for chemokines in orchestrating multiple aspects of the asthmatic response. Chemokines are potent leukocyte chemoattractants, cellular activating factors, and histamine-releasing factors, which makes them particularly important in the pathogenesis of allergic inflammation. In particular, the eotaxin subfamily of chemokines and their receptor CC chemokine receptor 3 have emerged as central regulators of the asthmatic response. Recent studies have provided an integrated mechanism by which to explain the coordinate interaction between IL-13 and chemokines in the pathogenesis of asthma. In this regard, chemokines and IL-13 are attractive new therapeutic targets for the treatment of allergic disease. This article focuses on recently emerging data pertaining to the importance of chemokines, especially eotaxins, in promoting IL-13-associated allergic lung responses, as well as the potential for pharmacologically targeting these pathways.

Diesel exhaust particles (DEP) are a major component of traffic related air pollution and have been implicated in asthma exacerbations. In mice intra-tracheally exposed 9 times over the course of 3 weeks to either saline, DEP, house dust mite (HDM) or HDM and DEP, we assessed the rate of DEP clearance from the lung and examined its impacts on HDM recall responses. DEP alone did not induce the classic hallmarks of asthma but promoted a Th17 response resulting in long lasting chronic neutrophilia. DEP was still observed in a majority of alveolar macrophages 6 weeks after exposure. Coexposures to HDM and DEP generated a mixed Th2/Th17 response with a more severe asthma phenotype that completely resolved within 4 weeks. However, upon in vitro restimulation with HDM, Th2/Th17 responses were significantly enhanced in lung and draining lymph node cell cultures of HDM+DEP exposed mice compared to mice exposed to HDM alone. In conclusion, the prolonged presence of DEP in the lungs is associated with chronic neutrophilia. DEP-mediated exacerbation of allergen-induced asthma promotes long-term expansion of effector/memory Th17 and Th2 populations.

The serine protease inhibitors SERPINB3 and SERPINB4 have been implicated in allergic disorders. We have recently demonstrated a role for the serine protease inhibitor Serpinb3a (the mouse homolog of SERPINB3 and SERPINB4) in a mouse model of asthma. Elevated levels of SERPINB3 and SERPINB4 are detected in the serum of patients with atopic dermatitis (AD) and they have been proposed as possible biomarkers for AD. Serine proteases are critical for epidermal barrier homeostasis and aberrant expression and/or activity of serine proteases have been associated with AD in human studies. We also observe a significant induction in the expression of Serpinb3a in a mouse model of cutaneous inflammation that has many similarities to AD. However the role of Serpinb3a in the skin is unknown. Using our mouse model of skin inflammation, we observed attenuation in trans-epidermal water loss, skin inflammation scores, decreased levels of total IgE, and pro-inflammatory markers like S100A8 in mice lacking Serpinb3a following exposure to Aspergillus fumigatus extract. In humans, we have identified a single nucleotide polymorphism (SNP) in the locus that encodes SERPINB3 and SERPINB4 that is associated with trans-epidermal water loss (p-val=0.031). In conclusion, we demonstrate that SERPINB3 and SERPINB4 contribute to cutaneous inflammation and work is ongoing to elucidate the role of this protein in regulating the skin barrier.

The factors that promote IL17A production during the pathogenesis of severe asthma remain undefined. Diesel exhaust particles (DEP) are a major component of traffic related air pollution and are implicated in asthma exacerbation. We assessed the impact of DEP exposure on asthma severity in asthmatic children from the Greater Cincinnati Pediatric Clinic Repository. Among high DEP-exposed children with allergic asthma, 32.2% of the children had severe asthma, compared to only 14.2% in the low DEP-exposed group. Similarly, Balb/c mice co-exposed to DEP and house dust mite extract (HDM) markedly demonstrated enhanced airway inflammation and hyperresponsiveness (AHR) compared to HDM alone. Exposure to DEP alone did not induce classic features of asthma but generated a Th17 response. DEP and HDM co-exposures enhanced pulmonary Th2 and Th17 cell numbers compared to HDM alone. High DEP-exposed children with allergic asthma had elevated serum IL17A levels compared with low DEP-exposed children. Finally, IL17A neutralization alleviated DEP-induced exacerbation of AHR. In conclusion, Th17 cells contribute to DEP-mediated exacerbation of allergen-induced asthma. Neutralization of IL17A may be a useful therapeutic strategy to counteract the asthma promoting effects of traffic related air pollution especially in severe asthmatics.

Asthma is a major public health burden worldwide. Excessive mucus production and mucus plugging are key pathologic features of asthma, yet the mechanisms responsible for mucus production remain largely unknown and therapies to effectively target mucus hypersecretion are lacking. Using a murine asthma model, we showed that SerpinB3a, the mouse ortholog of the serine protease inhibitors, SERPINB4 and B3, contribute to house dust mite induced airway hyperresponsiveness (AHR), mucus production and goblet cell hyperplasia and expression of SPDEF, a transcription factor that mediates goblet cell differentiation. Microarray analysis revealed attenuated expression of multiple IL-13 regulated genes that contribute to mucus production in the Serpinb3a null mice and IL-13 treated mice showed attenuated AHR and mucus production. Our data have revealed a novel non-redundant role for SERPINB4 and B3 in mediating mucus production through regulation of SPDEF expression.

The mechanisms underlying the adjuvant effect of diesel exhaust particles (DEP) on allergen-induced airways responses are not well understood. We aim to define how T-cells are affected by exposures to DEP and house dust mite (HDM). Balb/c mice were exposed intra-tracheally to DEP, HDM, or both, three times a week for three weeks. Airway inflammation and FACS analysis of lung and draining lymph node T-cells were assessed 24h or 1 week after the last exposure. Exposure to DEP alone generated airway neutrophilia whereas exposure to HDM was characterized by eosinophilia. Coexposure to HDM and DEP resulted in a significant increase in BALF cells over HDM alone. The percentage of CD4+ T-cells expressing the activation marker CD69 were increased in all three groups over saline exposed mice. However, significantly more activated CD4+ T-cells were observed in the lungs and mediastinal lymph nodes of mice coexposed to HDM+DEP. Alterations in Foxp3+ regulatory T-cells were limited following coexposure to HDM and DEP resulting in a favorable ratio of activated T-cells over Tregs. One week after the last exposure, pulmonary inflammation and DEP containing macrophages could still be observed. Interestingly, levels of activated T-cells remain elevated in all three groups compared to saline exposed control mice, but the further increase observed after coexposure was no longer significant. Taken together, these results suggest that DEP exacerbates the early acute allergic responses.