BackgroundRhinovirus (RV) infections trigger wheeze episodes in children. Thus, understanding of the lung inflammatory response to RV in children with wheeze is important.ObjectiveTo examine the associations of RV on lung lavage (BAL) granulocyte patterns and biomarkers of inflammation with age in children with treatment-refractory, recurrent wheeze (n=616).MethodsChildren underwent BAL to examine viral nucleic acid sequences, bacterial cultures, granulocyte counts, and phlebotomy for both general and type-2 inflammatory markers.ResultsDespite the absence of cold symptoms, RV was the most common pathogen detected (30%), and when present, was accompanied by BAL granulocytosis in 75% of children. Compared to children with no BAL pathogens (n=341), those with RV alone (n=127) had greater (p < 0.05) isolated neutrophilia (43% versus 16%), mixed eosinophils and neutrophils (26% versus 11%), and less pauci-granulocytic (27% versus 61%) BAL. Children with RV alone furthermore had biomarkers of active infection with higher total blood neutrophils and serum c-reactive protein (CRP), but no differences in blood eosinophils or total IgE. With advancing age, the log odds of BAL RV alone were lower, 0.82 [0.76-0.88, p < 0.001], but higher, 1.58 [1.01-2.51, p = 0.04], with high-dose daily corticosteroid treatment.ConclusionsChildren with severe recurrent wheeze often (22%) have a silent syndrome of lung RV infection with granulocytic bronchoalveolitis and elevated systemic markers of inflammation. The syndrome is less prevalent by school age, and not informed by markers of type-2 inflammation. We speculate that dysregulated mucosal innate antiviral immunity is a responsible mechanism.

Background: Histamine-releasing factor (HRF) is implicated in allergic diseases. We previously showed its pathogenic role in murine models of asthma. Objective: We aim to present data analysis from 3 separate human samples (sera samples from asthmatic patients, nasal washings from rhinovirus [RV]-infected individuals, and sera samples from patients with RV-induced asthma exacerbation) and 1 mouse sample to investigate correlates of HRF function in asthma and virus-induced asthma exacerbations. Methods: Total IgE and HRF-reactive IgE/IgG as well as HRF in sera from patients with mild/moderate asthma or severe asthma (SA) and healthy controls (HCs) were quantified by ELISA. HRF secretion in culture media from RV-infected adenovirus-12 SV40 hybrid virus transformed human bronchial epithelial cells and in nasal washings from experimentally RV-infected subjects was analyzed by Western blotting. HRF-reactive IgE/IgG levels in longitudinal serum samples from patients with asthma exacerbations were also quantified. Results: HRF-reactive IgE and total IgE levels were higher in patients with SA than in HCs, whereas HRF-reactive IgG (and IgG1) level was lower in asthmatic patients versus HCs. In comparison with HRF-reactive IgE(low) asthmatic patients, HRF-reactive IgE(high) asthmatic patients had a tendency to release more tryptase and prostaglandin D-2 on anti-IgE stimulation of bronchoalveolar lavage cells. RV infection induced HRF secretion from adenovirus-12 SV40 hybrid virus transformed bronchial epithelial cells, and intranasal RV infection of human subjects induced increased HRF secretion in nasal washes. Asthmatic patients had higher levels of HRF-reactive IgE at the time of asthma exacerbations associated with RV infection, compared with those after the resolution. This phenomenon was not seen in asthma exacerbations without viral infections. Conclusions: HRF-reactive IgE is higher in patients with SA. RV infection induces HRF secretion from respiratory epithelial cells both in vitro and in vivo. These results suggest the role of HRF in asthma severity and RV-induced asthma exacerbation.

Infection with rhinovirus (RV) is a major risk factor for disease exacerbations in patients with allergic asthma. This study analysed a broad set of cytokines in the noses of children and adults with asthma during RV infection in order to identify immunophenotypes that may link to virus‐induced episodes.

BACKGROUND:Preschool children with treatment-refractory wheeze often require unscheduled acute care. Current guidelines advise treatment of persistent wheeze with inhaled corticosteroids. Alternative treatments targeting structural abnormalities and specific inflammatory patterns could be more effective. OBJECTIVE:To apply unsupervised analysis of lung lavage (bronchoalveolar lavage [BAL]) variables to identify clusters of preschool children with treatment-refractory wheeze. METHODS:A total of 155 children 6 years or younger underwent bronchoscopy with BAL for evaluation of airway structure, inflammatory markers, and pathogens. Variables were screened with factor analysis and sorted into clusters by Ward's method, and membership was confirmed by discriminant analysis. RESULTS:The model was repeatable in a 48-case validation sample and accurately classified 86% of cases. Cluster 1 (n = 60) had early-onset wheeze, 85% with structural abnormalities, mostly tracheamalacia, with low total IgE and agranulocytic BAL. Cluster 2 (n = 42) had later-onset wheeze, the highest prevalence of gastroesophageal reflux, little atopy, and two-third had increased BAL lipid-laden macrophages. Cluster 3 (n = 46) had mid-onset wheeze, low total IgE, and two-third had BAL viral transcripts, predominately human rhinovirus, with BAL neutrophilia. Cluster 4 (n = 7) was older, with high total IgE, blood eosinophilia, and mixed BAL eosinophils and neutrophils. CONCLUSIONS:Preschool children with recurrent wheeze refractory to inhaled corticosteroid treatment include 4 clusters: airway malacia, gastroesophageal reflux, indolent human rhinovirus bronchoalveolitis, and type-2high inflammation. The results support the risk and cost of invasive bronchoscopy to diagnose causes of treatment-refractory wheeze and develop novel therapies targeting airway malacia, human rhinovirus infection, and BAL neutrophilia in preschool children.

Antibodies of the IgG4 isotype are strongly associated with allergic disease but have several properties such as not precipitating with allergens, not activating complement and poor binding to Fcγ receptors that argue against a pro-inflammatory role. In keeping with that, IgG4 antibodies are a striking feature of the response to immunotherapy. In two naturally occurring situations IgG4 antibodies are common with low or absent IgE antibodies. The first example is children raised in a house with a cat and the second is eosinophilic esophagitis (EoE). In many population-based cohorts, the ownership of a cat in early childhood is associated with a decreased prevalence of a cat allergy at age 10. The second example (i.e., EoE) is a novel form of food allergy that is not mediated by IgE and is related to consuming cow's milk or wheat. In EoE, patients have IgG4 to milk proteins in high > 10 µg/mL or very high > 100 µg/mL titers. Enigmatically these patients are found to have deposits of IgG4 in the wall of their inflamed esophagus. The factors that have given rise to EoE remain unclear; however, changes in food processing over the past 50 years, particularly ultra-heat treatment and the high pressure homogenization of milk, represent a logical hypothesis.

Background: IgE to alpha-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that alpha-Gal sensitization is prevalent but has been little investigated. Objective: We sought evidence for the cause(s) of alpha-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya. Methods: IgE to alpha-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG(4) to alpha-Gal and antibodies to regionally representative parasites were assessed in a subset of children. Results: In Ecuador (32%) and Kenya (54%), alpha-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had alpha-Gal specific IgE. Levels of alpha-Gal specific IgG(4) were not high in Ecuador, but were greater than in children from the United States. Conclusions: These results suggest that in areas of the developing world with endemic parasitism, alpha-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.

Over the past decade, there have been substantial advances in our understanding about how viral infections regulate asthma. Important lessons have been learned from birth cohort studies examining viral infections and subsequent asthma and from understanding the relationships between host genetics and viral infections, the contributions of respiratory viral infections to patterns of immune development, the impact of environmental exposure on the severity of viral infections, and how the viral genome influences host immune responses to viral infections. Further, there has been major progress in our knowledge about how bacteria regulate host immune responses in asthma pathogenesis. In this article, we also examine the dynamics of bacterial colonization of the respiratory tract during viral upper respiratory tract infection, in addition to the relationship of the gut and respiratory microbiomes with respiratory viral infections. Finally, we focus on potential interventions that could decrease virus-induced wheezing and asthma. There are emerging therapeutic options to decrease the severity of wheezing exacerbations caused by respiratory viral infections. Primary prevention is a major goal, and a strategy toward this end is considered.

Background Rhinovirus frequently causes asthma exacerbations among children and young adults who are allergic. The interaction between allergen and rhinovirus-induced symptoms and inflammation over time is unclear. Objective Our aim was to compare the response to an experimental inoculation with rhinovirus-16 in allergic asthmatics with the response in healthy controls and to evaluate the effects of administrating omalizumab before and during the infection. Methods Two clinical trials were run in parallel. In one of these trials, the response to an experimental inoculation with rhinovirus-16 among asthmatics with high levels of total IgE was compared to the response in healthy controls. The other trial compared the effects of administering omalizumab versus placebo to asthmatics in a randomized, double-blind placebo-controlled investigation. The primary outcome for both trials compared lower respiratory tract symptoms (LRTSs) between study groups over the first 4 days of infection. Results Frequent comparisons of symptoms, lung function, and blood eosinophil counts revealed differences that were more pronounced among allergic asthmatics than among controls by days 2 and 3 after virus inoculation. Additionally, an augmentation of upper respiratory tract symptom scores and LRTS scores occurred among the atopic asthmatics versus the controls during the resolution of symptoms (P < .01 for upper respiratory symptom tract scores and P < .001 for LRTS scores). The beneficial effects of administering omalizumab on reducing LRTSs and improving lung function were strongest over the first 4 days. Conclusions LRTSs and blood eosinophil counts were augmented and lung function was reduced among allergic asthmatics early after rhinovirus inoculation but increased late in the infection during symptom resolution. The effect of administering omalizumab on the response to rhinovirus was most pronounced during the early/innate phase of the infection.

Human rhinoviruses cause the common cold and exacerbate chronic respiratory diseases. Although infection elicits neutralizing antibodies, these do not persist or cross-protect across multiple rhinovirus strains. To analyze rhinovirus-specific B cell responses in humans, we developed techniques using intact RV-A16 and RV-A39 for high-throughput high-dimensional single-cell analysis, with parallel assessment of antibody isotypes in an experimental infection model. Our approach identified T-bet+ B cells binding both viruses that account for similar to 5% of CXCR5- memory B cells. These B cells infiltrate nasal tissue and expand in the blood after infection. Their rapid secretion of heterotypic immunoglobulin G (IgG) in vitro, but not IgA, matches the nasal antibody profile post-infection. By contrast, CXCR5+ memory B cells binding a single virus are clonally distinct, absent in nasal tissue, and secrete homotypic IgG and IgA, mirroring the systemic response. Temporal and spatial functions of dichotomous memory B cells might explain the ability to resolve infection while rendering the host susceptible to re-infection.

Background: Allergic asthmatic subjects are uniquely susceptible to acute wheezing episodes provoked by rhinovirus. However, the underlying immune mechanisms and interaction between rhinovirus and allergy remain enigmatic, and current paradigms are controversial. Objective: We sought to perform a comprehensive analysis of type 1 and type 2 innate and adaptive responses in allergic asthmatic subjects infected with rhinovirus. Methods: Circulating virus-specific T(H)1 cells and allergenspecific T(H)2 cells were precisely monitored before and after rhinovirus challenge in allergic asthmatic subjects (total IgE, 133-4692 IU/mL; n = 28) and healthy nonallergic controls (n = 12) using peptide/MHCII tetramers. T cells were sampled for up to 11 weeks to capture steady-state and postinfection phases. T-cell responses were analyzed in parallel with 18 cytokines in the nose, upper and lower airway symptoms, and lung function. The influence of in vivo IgE blockade was also examined. Results: In uninfected asthmatic subjects, higher numbers of circulating virus-specific PD-1(+) T(H)1 cells, but not allergenspecific T(H)2 cells, were linked to worse lung function. Rhinovirus infection induced an amplified antiviral T(H)1 response in asthmatic subjects versus controls, with synchronized allergen-specific T(H)2 expansion, and production of type 1 and 2 cytokines in the nose. In contrast, T(H)2 responses were absent in infected asthmatic subjects who had normal lung function, and in those receiving anti-IgE. Across all subjects, early induction of a minimal set of nasal cytokines that discriminated high responders (G-CSF, IFN-gamma, TNF-alpha) correlated with both egress of circulating virus-specific T(H)1 cells and worse symptoms. Conclusions: Rhinovirus induces robust T(H)1 responses in allergic asthmatic subjects that may promote disease, even after the infection resolves.

Dust mites (DM) are a major source of indoor allergens and IgE to DM are strongly associated with allergic asthma. Der p 23 is a recently described major DM allergen but investigations to date have been limited to small cohorts and/or microchip assays. Using ImmunoCAP, we assessed specific-IgE (sIgE) to DM components (Der p 1, 2, 10 and 23) in sera of asthmatic and non-asthmatic children from Costa Rica (CR), Ghana and Ecuador who previously tested positive for sIgE to Dermatophagoides pteronyssinus. IgE to Der p 1, 2, 10 and 23 were common in asthmatics from CR (73%, 76%, 21% and 70%), Ghana (55%, 53%, 26% and 39%) and Ecuador (43%, 48%, 14%, and 36%). Correlations between sIgE to Der p 23 and Der p 1/2 were moderate-strong and using a cut-off of 0.1 IU/mL poly-sensitization to each of Der p 1, 2 and 23 was common (CR 57%, Ghana 65%, and Ecuador 48%) in all three cohorts. Among children in these countries who lived in rural areas with pre-hygiene conditions, sIgE titers to DM components were lower. Der p 23 represents a peritrophin-like-protein of DM that is present in mites at lower levels than Der p1/2, but is nonetheless a major target of IgE. The high frequency of poly-sensitization to these three proteins provides further evidence that DM are potent agents of IgE sensitization. Differences in IgE titers to DM components between pre-hygiene and post-hygiene environments parallel differences in asthma prevalence and provide additional evidence for the hygiene hypothesis.

Patients who are prone to exacerbations of asthma experience significant costs in terms of missed work and school, acute care visits, and hospitalizations. Exacerbations are largely driven by environmental exposures including pollutants, stress, and viral and bacterial pathogens. These exposures are most likely to induce acute severe "asthma attacks" in high-risk patients. These personal risk factors for exacerbations can vary with the phenotype of asthma and age of the patient. In children, allergic sensitization is a strong risk factor, especially for those children who develop sensitization early in life. Airway inflammation is an important risk factor, and biomarkers are under evaluation for utility in detecting eosinophilic and type 2 inflammation and neutrophilic inflammation as indicators of risk for recurrent exacerbations. Insights into inflammatory mechanisms have led to new approaches to prevent exacerbations using mAb-based biologics that target specific type 2 pathways. Challenges remain in developing an evidence base to support precision interventions with these effective yet expensive therapies, and in determining whether these treatments will be safe and effective in young children. Unfortunately, there has been less progress in developing treatments for acute exacerbations. Hopefully, greater understanding of mechanisms relating airway viruses, bacteria, mucin production, and neutrophilic inflammatory responses will lead to additional treatment options for patients experiencing acute exacerbations. (C) 2019 American Academy of Allergy, Asthma & Immunology

BACKGROUND:Rhinovirus (RV) infections exacerbate asthma in part by enhancing an allergic state, and these exacerbations can be mitigated via administration of anti-IgE.OBJECTIVE:We investigated the presence of local IgE production in the nose of allergic and non-allergic subjects and assessed whether this was enhanced by RV.METHODS:Local production of specific IgE was determined by comparing ratios of specific to total IgE concentrations between nasal and serum samples. Our initial studies were performed in subjects presenting to the emergency department for allergic and non-allergic respiratory complaints. Subsequently, we investigated influences of experimental RV infection on nasal sIgE production in an allergic cohort.RESULTS:We found evidence of local sIgE production to Dermatophagoides pteronyssinus in 30.3% and to Blomia tropicalis in 14.6% of allergic subjects. None of the non-allergic subjects demonstrated local IgE. Subjects with active RV infection were more than twice as likely to have local sIgE (45% vs 14%), and subjects with local sIgE being produced were ~3 times more likely to be having an asthma exacerbation. Experimental RV infection was able to induce local sIgE production.CONCLUSION:These studies confirm local IgE production in a large subset of allergic subjects and demonstrate that allergic asthmatics with local IgE are more likely to develop an asthma exacerbation when infected with RV. Our RV challenge studies demonstrate that at least some allergic asthmatics can be induced to secrete locally generated IgE in their nasal airway after RV infection.

BACKGROUND: Children with severe asthma have frequent exacerbations despite guidelines-based treatment with high-dose corticosteroids. The importance of refractory lung inflammation and infectious species as factors contributing to poorly controlled asthma in children is poorly understood. OBJECTIVE: To identify prevalent granulocyte patterns and potential pathogens as targets for revised treatment, 126 children with severe asthma underwent clinically indicated bronchoscopy. METHODS: Diagnostic tests included bronchoalveolar lavage (BAL) for cell count and differential, bacterial and viral studies, spirometry, and measurements of blood eosinophils, total IgE, and allergen-specific IgE. Outcomes were compared among 4 BAL granulocyte patterns. RESULTS: Pauci-granulocytic BAL was the most prevalent granulocyte category (52%), and children with pauci-granulocytic BAL had less postbronchodilator airflow limitation, less blood eosinophilia, and less detection of BAL enterovirus compared with children with mixed granulocytic BAL. Children with isolated neutrophilia BAL were differentiated by less blood eosinophilia than those with mixed granulocytic BAL, but greater prevalence of potential bacterial pathogens compared with those with pauci-granulocytic BAL. Children with isolated eosinophilia BAL had features similar to those with mixed granulocytic BAL. Children with mixed granulocytic BAL took more maintenance prednisone, and had greater blood eosinophilia and allergen sensitization compared with those with pauci-granulocytic BAL. CONCLUSIONS: In children with severe, therapy-resistant asthma, BAL granulocyte patterns and infectious species are associated with novel phenotypic features that can inform pathway-specific revisions in treatment. In 32% of children evaluated, BAL revealed corticosteroid-refractory eosinophilic infiltration amenable to anti-T(H)2 biological therapies, and in 12%, a treatable bacterial pathogen. (C) 2019 American Academy of Allergy, Asthma & Immunology

The percentage of total IgE specific for an allergen in serum and on basophils has been shown to correlate. We evaluated whether the ratio of specific IgE for peanut/total IgE in serum differs among children who pass or fail a food challenge. Twenty four children ≥ 3 yrs of age underwent a peanut food challenge. Previous reactions to peanut, prick skin test (PST) results, and serum assessments of total IgE, peanut specific IgE, and IgE to peanut components were evaluated. Ten children were sensitized to Arah 1 and/or 2. Five FAILED their challenge (reacting to ≤ 1.8 grams peanut protein); median age and PST size = 4 yrs and 5mm. Five PASSED their challenge; median age and PST size = 5 yrs and 7 mm. Four in each group experienced a previous reaction to peanut. Specific IgE to peanut was 3.4% of the total IgE among those who FAILED their challenge compared to 0.8% among those who PASSED (p = 0.23). By comparison, specific IgE to peanut was 0.3% of total IgE among 14 children who PASSED the challenge and lacked IgE ab to Arah 1 or 2 (p = 0.01 compared to the 5 sensitized to Arah 1 or 2 who FAILED the challenge; p = 0.18 compared to those who PASSED). The percentage of total IgE specific for peanut was higher among children who failed their challenge and may serve to judge the safety of a peanut food challenge.

Rhinovirus (RV) infection exacerbates allergic asthma. To understand the nature of CD4+ T cells induced by RV in asthmatics, we precisely tracked circulating Th1 and Th2 cells directly ex vivo during experimental infection. Circulating RV- and allergen-specific T cells were monitored using peptide/MHC tetramers in asthmatics with high IgE (total IgE >500 IU/mL, n=11) and healthy controls (n=13) challenged with RV-A16. Cells were also analyzed in infected asthmatics (total IgE: 125-500 IU/mL) pre-treated with anti-IgE or not (n=10 each) in a double-blind placebo-controlled trial. Before infection, higher numbers of tissue-homing RV-specific Th1 cells were linked to worse lung function in asthmatics (r=-0.51, p=0.0008). Asthmatics with high IgE, but not those with lower IgE who received placebo, mounted an exaggerated and persistent Th1 response after infection along with robust type 1 responses (IFN-α, IP-10, and MIP-1β) in the nose, despite a pre-existing Th2 milieu. By contrast, numbers of allergen-specific Th2 cells only modestly increased, and were unactivated. Th2 cell numbers did not fluctuate in infected asthmatics who received anti-IgE, although activation of RV-specific cells did occur along with downregulation of IgE receptor on dendritic cell types pivotal to Th1 and Th2 responses. Nasal IFN-α levels trended higher in the anti-IgE group after infection versus all other groups. Rhinovirus infection paradoxically boosts Th1 responses in allergic asthmatics. This finding, coupled with the relationship between Th1 numbers and worse lung function even when infection is absent, supports a role for repeated RV exposures in driving Th1-mediated chronic inflammation in allergic asthma.

RV infections are the leading cause of exacerbations of asthma in children and have been ascribed to the worsening of an allergic reaction to concomitantly expressed aeroallergens. Local production of IgE has been described as a pathogenic mechanism contributing to severity of allergic airway disease. We therefore assayed the presence of specific IgE in the nares relevant to exposure history in allergic rhinitis subjects with naturally-occurring and experimental RV infections. Interstitial secretions were collected via absorptive filter paper applied to the inferior turbinates for 5 minutes. Allergen-specific IgE was assayed via immunocap®. To eliminate confounding influences of transudation or transcytosis, data were normalized to total IgE concentrations in the interstitial fluid and ratios compared between nasal and serum samples. Initially, we studied 88 consecutive allergic patients presenting the ED of the Hospital Naçional de Niños in San José, Costa Rica with an asthma exacerbation. Amongst patients without RV, 7/34 (20.6%) demonstrated local nasal production of IgE to dermatophagoides pteronyssinus. In contrast, 23/24 (48.9%) of RV-infected asthma exacerbators demonstrated local nasal-specific IgE production. In our subsequent studies, we evaluated prospectively the development of local IgE production to seasonally relevant allergen after an experimental infection with HRV-16. In 8/12 subjects, increased local IgE production in the nares was observed. Local IgE production is uncommon but demonstrable in allergic rhinitis subjects. The prevalence of local IgE production dramatically increases during a RV infection further supporting the concept that RV-induced asthma exacerbations are related to enhancement of a concomitant bystander allergic reaction.

Rhinovirus (RV) infections frequently cause asthma exacerbations in children and young adults. RV infections are also known to stimulate recruitment of neutrophils into the airways. We speculate that neutrophil mediators will be increased in nasal washes (NW’s) from asthmatics compared to non-asthmatic controls during an experimental infection with RV-16. Sixteen subjects (ages 19-33) were inoculated with RV-16 (dose=300 TCID50). They included 9 allergic-asthmatics (total IgE levels 596-1989 IU/mL), and 7 controls (total IgE levels 5-42 IU/mL). Neutrophil mediators, neutrophil elastase (NE) and myeloperoxidase (MPO), were measured by ELISA in NW’s obtained before and during (Days 1, 2, 3, 4, 7, 14, 21) the infection. The results were compared to symptom scores. Both NE and MPO levels peaked in NW’s on Day 3 of the infection, paralleling the development of peak cold symptoms in both asthmatics and controls. Compared to baseline values before inoculation, mediator values by Day 3 increased 7 and 5-fold for NE and MPO among asthmatics, respectively, and 5 and 3-fold among the controls. Cumulative values (summed over days 1-3 following RV inoculation) trended higher in asthmatics compared to controls (e.g., geometric means for NE=3775ng/mL and 2167ng/mL, respectively, p=0.45; MPO=1375ng/mL and 917.3ng/mL, p=0.66), but this trend was not apparent during resolution of the infection (days 14 and 21). During the early (innate) phase of the infection, a consistent trend in higher levels of neutrophil mediators was observed in nasal washes from asthmatic subjects compared to controls. This increase was no longer seen during resolution of the infection.