Trajectories of adiposity indicators and association with asthma and lung function in urban minority children

BACKGROUND

A relationship between adiposity and asthma has been described in some cohort studies, but little is known about trajectories of adiposity throughout early childhood among children at high risk for developing asthma in urban United States cities. Moreover, early life trajectories of adipokines that have metabolic and immunologic properties have not been comprehensively investigated.

OBJECTIVE

Our objective was to characterize trajectories of adiposity in a longitudinal birth cohort of predominately Black and Latinx children (n = 418) using several different repeated measures including body mass index (BMI) z score, bioimpedance analysis, leptin, and adiponectin in the first 10 years of life.

METHODS

In a longitudinal birth cohort of predominately Black and Latinx children, we used repeated annual measures of BMI, bioimpedance analysis (ie, percentage of body fat), leptin, and adiponectin to create trajectories across the first 10 years of life. Across those trajectories, we compared asthma diagnosis and multiple lung function outcomes, including spirometry, impulse oscillometry, and methacholine response.

RESULTS

Three trajectories were observed for BMI z score, bioimpedance analysis, and leptin and 2 for adiponectin. There was no association between trajectories of BMI, percentage of body fat, leptin, or adipokine and asthma diagnosis or lung function (P > .05).

CONCLUSIONS

Trajectories of adiposity were not associated with asthma or lung function in children at high risk for developing asthma. Risk factors related to geography as well as social and demographic factors unique to specific populations could explain the lack of association and should be considered in obesity and asthma studies.

Heterogeneity of magnitude, allergen immunodominance, and cytokine polarization of cockroach allergen-specific T cell responses in allergic sensitized children

BACKGROUND

Characterization of allergic responses to cockroach (CR), a common aeroallergen associated with asthma, has focused mainly on IgE reactivity, but little is known about T cell responses, particularly in children. We conducted a functional evaluation of CR allergen-specific T cell reactivity in a cohort of CR allergic children with asthma.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from 71 children, with mild-to-moderate asthma who were enrolled in a CR immunotherapy (IT) clinical trial, prior to treatment initiation. PBMC were stimulated with peptide pools derived from 11 CR allergens, and CD4+ T cell responses assessed by intracellular cytokine staining.

RESULTS

Highly heterogeneous responses in T cell reactivity were observed among participants, both in terms of the magnitude of cytokine response and allergen immunodominance. Reactivity against Bla g 9 and Bla g 5 was most frequent. The phenotype of the T cell response was dominated by IL-4 production and a Th2 polarized profile in 54.9% of participants, but IFNγ production and Th1 polarization was observed in 25.3% of the participants. The numbers of regulatory CD4+ T cells were also highly variable and the magnitude of effector responses and Th2 polarization were positively correlated with serum IgE levels specific to a clinical CR extract.

CONCLUSIONS

Our results demonstrate that in children with mild-to-moderate asthma, CR-specific T cell responses display a wide range of magnitude, allergen dominance, and polarization. These results will enable examination of whether any of the variables measured are affected by IT and/or are predictive of clinical outcomes.

Trends in cannabis use among adults with children in the home in the United States, 2004-2017: impact of state-level legalization for recreational and medical use

BACKGROUND AND AIMS

Cannabis use among parents may be increasing with legalization, but perception of associated risk has declined. The study investigated the association between cannabis legalization and cannabis use among adults with children in the home over time in the United States (US).

DESIGN

A difference-in-difference approach was applied to public and restricted-use data from the 2004-2017 National Survey on Drug Use and Health (NSDUH), an annual cross-sectional survey.

SETTING

A representative sample of the United States.

PARTICIPANTS/CASES

Respondents ages 18+ with children living in the home drawn from the NSDUH (n = 287,624), which is administered to non-institutionalized civilians in the 50 states and District of Columbia.

MEASUREMENTS

Exposures were year and state-level cannabis policy in state of residence annually. Outcomes were past-30-day cannabis use and daily cannabis use. Sociodemographic variables included age, gender, marital status, annual family income, race/ethnicity, educational attainment, and strength of state-level tobacco control.

FINDINGS

In 2017, past-month cannabis use (11.9%, 9.3%, and 6.1%) and daily cannabis use (4.2%, 3.2%, and 2.3%) were more common in states with recreational marijuana laws (RML), followed by states with medical marijuana laws (MML) and without legal cannabis use, respectively. RML and MML were associated with significantly higher prevalence of past-month cannabis use (adjusted odds ratio [AOR] = 1.28, 95% confidence interval [CI] = 1.12-1.46; AOR = 1.12, 95% CI = 1.03-1.22) and daily cannabis use (AOR = 1.25, 95% CI = 1.03-1.51; AOR = 1.16, 95% CI = 1.02-1.32), respectively. The impact of MML was particularly salient among adults ages 50+ and the highest income and education subgroups.

CONCLUSIONS

Among adults with children living in the home, cannabis use appears to be more common in US states with legalized cannabis use compared with states with no legal cannabis use. Recreational legalization appears to increase use among adults with children in the home broadly across nearly all sociodemographic groups, whereas the effect of legalization for medical use is heterogeneous by age and socioeconomic status.

Validation of a Questionnaire to Identify Respiratory Tract Infections in Children With Sickle Cell Disease

BACKGROUND

No validated questionnaires have been published that are specific for identifying respiratory infections in children with sickle cell disease (SCD).

METHODS

A questionnaire was developed that included 6 respiratory symptoms (difficulty breathing, wheezing, fever, cough, runny or stuffy nose, and sore throat) to identify respiratory events for a clinical trial. The questionnaire results were compared with identification of viral respiratory pathogens from nasal samples by reverse transcriptase polymerase chain reaction.

RESULTS

Eighty questionnaire responses (40 with symptom/s and 40 without) paired with isolation of viral respiratory pathogen from nasal samples were obtained from 53 children with SCD, ages 4 to 18 years over 2 separate periods in different seasons. The questionnaire yielded a sensitivity of 82%, specificity of 72% with an overall accuracy of 76%. The kappa value was 0.53, indicating moderate agreement, and the Fleiss' kappa test statistic was 4.77 with P<0.001, indicating that agreement between the 2 methods was not by chance.

CONCLUSION

These results provide evidence for validity of this 6-symptom respiratory questionnaire in identification of respiratory viral infections for use in SCD-related research.

Longitudinal data reveal strong genetic and weak non-genetic components of ethnicity-dependent blood DNA methylation levels

Epigenetic architecture is influenced by genetic and environmental factors, but little is known about their relative contributions or longitudinal dynamics. Here, we studied DNA methylation (DNAm) at over 750,000 CpG sites in mononuclear blood cells collected at birth and age 7 from 196 children of primarily self-reported Black and Hispanic ethnicities to study race-associated DNAm patterns. We developed a novel Bayesian method for high-dimensional longitudinal data and showed that race-associated DNAm patterns at birth and age 7 are nearly identical. Additionally, we estimated that up to 51% of all self-reported race-associated CpGs had race-dependent DNAm levels that were mediated through local genotype and, quite surprisingly, found that genetic factors explained an overwhelming majority of the variation in DNAm levels at other, previously identified, environmentally-associated CpGs. These results indicate that race-associated blood DNAm patterns in particular, and blood DNAm levels in general, are primarily driven by genetic factors, and are not as sensitive to environmental exposures as previously suggested, at least during the first 7 years of life.

Inducible expression quantitative trait locus analysis of the MUC5AC gene in asthma in urban populations of children

BACKGROUND

Mucus plugging can worsen asthma control, lead to reduced lung function and fatal exacerbations. MUC5AC is the secretory mucin implicated in mucus plugging, and MUC5AC gene expression has been associated with development of airway obstruction and asthma exacerbations in urban children with asthma. However, the genetic determinants of MUC5AC expression are not established.

OBJECTIVES

This study sought to assess single-nucleotide polymorphisms (SNPs) that influence MUC5AC expression and relate to pulmonary functions in childhood asthma.

METHODS

This study used RNA-sequencing data from upper airway samples and performed cis-expression quantitative trait loci (eQTL) and allele-specific expression analyses in 2 cohorts of predominantly Black and Hispanic urban children, a high asthma-risk birth cohort, and an exacerbation-prone asthma cohort. Inducible MUC5AC eQTLs were further investigated during incipient asthma exacerbations. Significant eQTLs SNPs were tested for associations with lung function measurements and their functional consequences were investigated in DNA regulatory databases.

RESULTS

Two independent groups of SNPs in the MUC5AC gene that were significantly associated with MUC5AC expression were identified. Moreover, these SNPs showed stronger eQTL associations with MUC5AC expression during asthma exacerbations, which is consistent with inducible expression. SNPs in 1 group also showed significant association with decreased pulmonary functions. These SNPs included multiple EGR1 transcription factor binding sites, suggesting a mechanism of effect.

CONCLUSIONS

These findings demonstrate the applicability of organ-specific RNA-sequencing data to determine genetic factors contributing to a key disease pathway. Specifically, they suggest important genetic variations that may underlie propensity to mucus plugging in asthma and could be important in targeted asthma phenotyping and disease management strategies.

Enhanced Neutralizing Antibody Responses to Rhinovirus C and Age-Dependent Patterns of Infection

Rationale: Rhinovirus (RV) C can cause asymptomatic infection and respiratory illnesses ranging from the common cold to severe wheezing.Objectives: To identify how age and other individual-level factors are associated with susceptibility to RV-C illnesses.Methods: Longitudinal data from the COAST (Childhood Origins of Asthma) birth cohort study were analyzed to determine relationships between age and RV-C infections. Neutralizing antibodies specific for RV-A and RV-C (three types each) were determined using a novel PCR-based assay. Data were pooled from 14 study cohorts in the United States, Finland, and Australia, and mixed-effects logistic regression was used to identify factors related to the proportion of RV-C versus RV-A detection.Measurements and Main Results: In COAST, RV-A and RV-C infections were similarly common in infancy, whereas RV-C was detected much less often than RV-A during both respiratory illnesses and scheduled surveillance visits (P < 0.001, χ2) in older children. The prevalence of neutralizing antibodies to RV-A or RV-C types was low (5-27%) at the age of 2 years, but by the age of 16 years, RV-C seropositivity was more prevalent (78% vs. 18% for RV-A; P < 0.0001). In the pooled analysis, the RV-C to RV-A detection ratio during illnesses was significantly related to age (P < 0.0001), CDHR3 genotype (P < 0.05), and wheezing illnesses (P < 0.05). Furthermore, certain RV types (e.g., C2, C11, A78, and A12) were consistently more virulent and prevalent over time.Conclusions: Knowledge of prevalent RV types, antibody responses, and populations at risk based on age and genetics may guide the development of vaccines or other novel therapies against this important respiratory pathogen.

Endotype of allergic asthma with airway obstruction in urban children

BACKGROUND

Black and Hispanic children growing up in disadvantaged urban neighborhoods have the highest rates of asthma and related morbidity in the United States.

OBJECTIVES

This study sought to identify specific respiratory phenotypes of health and disease in this population, associations with early life exposures, and molecular patterns of gene expression in nasal epithelial cells that underlie clinical disease.

METHODS

The study population consisted of 442 high-risk urban children who had repeated assessments of wheezing, allergen-specific IgE, and lung function through 10 years of age. Phenotypes were identified by developing temporal trajectories for these data, and then compared to early life exposures and patterns of nasal epithelial gene expression at 11 years of age.

RESULTS

Of the 6 identified respiratory phenotypes, a high wheeze, high atopy, low lung function group had the greatest respiratory morbidity. In early life, this group had low exposure to common allergens and high exposure to ergosterol in house dust. While all high-atopy groups were associated with increased expression of a type-2 inflammation gene module in nasal epithelial samples, an epithelium IL-13 response module tracked closely with impaired lung function, and a MUC5AC hypersecretion module was uniquely upregulated in the high wheeze, high atopy, low lung function group. In contrast, a medium wheeze, low atopy group showed altered expression of modules of epithelial integrity, epithelial injury, and antioxidant pathways.

CONCLUSIONS

In the first decade of life, high-risk urban children develop distinct phenotypes of respiratory health versus disease that link early life environmental exposures to childhood allergic sensitization and asthma. Moreover, unique patterns of airway gene expression demonstrate how specific molecular pathways underlie distinct respiratory phenotypes, including allergic and nonallergic asthma.

Maternal stress and depression are associated with respiratory phenotypes in urban children

BACKGROUND

Prenatal and early-life exposure to maternal stress and depression is linked to development of recurrent wheezing in young children.

OBJECTIVE

We sought to determine whether maternal stress and depression in early life are associated with nonatopic wheezing phenotype in urban children.

METHODS

The Urban Environment and Childhood Asthma Study examined a birth cohort of children at high risk for asthma in low-income neighborhoods. Prenatal and postnatal (through age 3 years) maternal stress and depression scores were compared with respiratory phenotypes through age 10 years (multinomial regression), self-reported colds (linear regression), and detection of respiratory viruses (Poisson regression).

RESULTS

Scores for maternal depression, and, to a lesser extent, maternal perceived stress, were positively related to multiple wheezing phenotypes. In particular, cumulative measures of maternal depression in the first 3 years were related to the moderate-wheeze-low-atopy phenotype (odds ratio, 1.13; [1.05, 1.21]; P < .01). Considering indicators of respiratory health that were used to identify the phenotypes, there were multiple positive associations between early-life scores for maternal stress and depression and increased wheezing illnesses, but no consistent relationships with lung function and some inverse relationships with allergic sensitization. Cumulative maternal stress and depression scores were associated with cumulative number of respiratory illnesses through age 3 years.

CONCLUSIONS

Among high-risk, urban children, maternal stress and depression in early life were positively associated with respiratory illnesses and a moderate-wheeze-low-atopy phenotype. These results suggest that treating stress and depression in expectant and new mothers could reduce viral respiratory illnesses and recurrent wheeze during the preschool years and some forms of childhood asthma.

Asthma among hospitalized patients with COVID-19 and related outcomes

BACKGROUND

Several underlying conditions have been associated with severe acute respiratory syndrome coronavirus 2 illness, but it remains unclear whether underlying asthma is associated with worse coronavirus disease 2019 (COVID-19) outcomes.

OBJECTIVE

Given the high prevalence of asthma in the New York City area, our objective was to determine whether underlying asthma was associated with poor outcomes among hospitalized patients with severe COVID-19 compared with patients without asthma.

METHODS

Electronic heath records were reviewed for 1298 sequential patients 65 years or younger without chronic obstructive pulmonary disease who were admitted to our hospital system with a confirmed positive severe acute respiratory syndrome coronavirus 2 test result.

RESULTS

The overall prevalence of asthma among all hospitalized patients with COVID-19 was 12.6%, yet a higher prevalence (23.6%) was observed in the subset of 55 patients younger than 21 years. There was no significant difference in hospital length of stay, need for intubation, length of intubation, tracheostomy tube placement, hospital readmission, or mortality between patients with and without asthma. Observations between patients with and without asthma were similar when stratified by obesity, other comorbid conditions (ie, hypertension, hyperlipidemia, and diabetes), use of controller asthma medication, and absolute eosinophil count.

CONCLUSIONS

Among hospitalized patients 65 years or younger with severe COVID-19, asthma diagnosis was not associated with worse outcomes, regardless of age, obesity, or other high-risk comorbidities. Future population-based studies are needed to investigate the risk of developing COVID-19 among patients with asthma once universal testing becomes readily available.

Aeroallergen Sensitization, Serum IgE, and Eosinophilia as Predictors of Response to Omalizumab Therapy During the Fall Season Among Children with Persistent Asthma

BACKGROUND

Perennial aeroallergen sensitization is associated with greater asthma morbidity and is required for treatment with omalizumab.

OBJECTIVE

To investigate the predictive relationship between the number of aeroallergen sensitizations, total serum IgE, and serum eosinophil count, and response to omalizumab in children and adolescents with asthma treated during the fall season.

METHODS

This analysis includes inner-city patients with persistent asthma and recent exacerbations aged 6-20 years comprising the placebo- and omalizumab-treated groups in 2 completed randomized clinical trials, the Inner-City Anti-IgE Therapy for Asthma study and the Preventative Omalizumab or Step-Up Therapy for Fall Exacerbations study. Logistic regression modeled the relationship between greater degrees of markers of allergic inflammation and the primary outcome of fall season asthma exacerbations.

RESULTS

The analysis included 761 participants who were 62% male and 59% African American with a median age of 10 years. Fall asthma exacerbations were significantly higher in children with greater numbers of aeroallergen-specific sensitizations in the placebo group (odds ratio [OR], 1.33; 95% confidence interval [CI], 1.11-1.60; P < .01), but not in the omalizumab-treated children (OR, 1.08; 95% CI, 0.91-1.28; P = .37), indicating a significant differential effect (P < .01). Likewise, there was a differential effect of omalizumab treatment in children with greater baseline total serum IgE levels (P < .01) or greater baseline serum eosinophil counts (P < .01). Multiple aeroallergen sensitization was the best predictor of response to omalizumab; treated participants sensitized to ≥4 different groups of aeroallergens had a 51% reduction in the odds of a fall exacerbation (OR, 0.49; 95% CI, 0.30-0.81; P < .01).

CONCLUSIONS

In preventing fall season asthma exacerbations, treatment with omalizumab was most beneficial in children with a greater degree of allergic inflammation.

Treatment Benefit with Omalizumab in Children by Indicators of Asthma Severity

BACKGROUND

Greater severity in childhood asthma negatively impacts functioning and quality of life. Omalizumab is effective in children aged 6 years or older with moderate to severe persistent asthma, but predicting responsiveness in severe disease requires further study.

OBJECTIVE

To assess response to omalizumab treatment among children using indicators of asthma severity.

METHODS

Post hoc analyses of randomized placebo-controlled studies of omalizumab (Inner-City Anti-IgE Therapy for Asthma [ICATA], IA05, and Preventative Omalizumab or Step-up Therapy for Fall Exacerbations [PROSE]) stratified by body mass index, eosinophil count, fractional exhaled nitric oxide levels, and baseline severity indicators (baseline percent predicted FEV₁, previous hospitalizations, asthma exacerbations). Poisson regression analysis examined exacerbation rate reductions for body mass index, biomarkers, and severity indicators.

RESULTS

Children aged 6 to 11 years in IA05 (N = 576; 56% white, 17% black, 26% other/missing), ICATA (N = 237; 55% black, 43% Hispanic), and PROSE (N = 342; 59% black, 35% Hispanic) were included. Trends indicative of greater exacerbation rate change ([omalizumab - placebo]/placebo) were observed for low baseline lung function (IA05 percent predicted FEV₁: <90%, 36% reduction, 95% CI, -53.3 to -13.5; ≥90%, 22% reduction, 95% CI, -52.1 to 27.5), previous hospitalizations (ICATA: 46% reduction with, 95% CI, -69.7 to -3.9; 24% reduction without, 95% CI, -48.1 to 10.3), frequent baseline exacerbations (IA05: ≥3, 42% reduction, 95% CI, -60.4 to -14.1; <3, 20% reduction, 95% CI, -45.2 to -15.9), and high baseline eosinophil count (IA05: ≥300 cells/μL, 39% reduction, 95% CI, -56.4 to -14.7; <300 cells/μL, 5% reduction, 95% CI, -40.6 to 52.1).

CONCLUSIONS

Omalizumab reduces exacerbations in children with moderate to severe persistent allergic asthma, and may provide greater benefit in children with more severe asthma subtypes.

Challenges in managing difficult-to-treat asthma in children: Stop, look, and listen

It is recognized that asthma places a significant economic burden on the United States, with a total cost of $81.9 billion total costs including costs incurred by absenteeism and mortality. Severe asthma places a large burden of morbidity on children and their caregivers, including severe exacerbations, medication side effects, increased missed school days leading to impaired school performance, and lower caregiver quality of life. Therefore, we need to take a careful look at how we can make asthma care more efficient and cost effective, especially for those children with severe asthma. The 2019 American Thoracic Society symposium reported in this theme issue presented four aspects of managing severe asthma in children that merit attention including patient variables that affect severe asthma, understanding patient behaviors around medications, the appropriate use of bronchoscopy in diagnosis and management of severe asthma, and also the rational use of biologic therapy. This editorial will summarize key points in each of these reviews and prompt a more careful reading of each contribution.

Distinct nasal airway bacterial microbiotas differentially relate to exacerbation in pediatric patients with asthma

BACKGROUND

In infants, distinct nasopharyngeal bacterial microbiotas differentially associate with the incidence and severity of acute respiratory tract infection and childhood asthma development.

OBJECTIVE

We hypothesized that distinct nasal airway microbiota structures also exist in children with asthma and relate to clinical outcomes.

METHODS

Nasal secretion samples (n = 3122) collected after randomization during the fall season from children with asthma (6-17 years, n = 413) enrolled in a trial of omalizumab (anti-IgE) underwent 16S rRNA profiling. Statistical analyses with exacerbation as the primary outcome and rhinovirus infection and respiratory illnesses as secondary outcomes were performed. Using A549 epithelial cells, we assessed nasal isolates of Moraxella, Staphylococcus, and Corynebacterium species for their capacity to induce epithelial damage and inflammatory responses.

RESULTS

Six nasal airway microbiota assemblages, each dominated by Moraxella, Staphylococcus, Corynebacterium, Streptococcus, Alloiococcus, or Haemophilus species, were observed. Moraxella and Staphylococcus species-dominated microbiotas were most frequently detected and exhibited temporal stability. Nasal microbiotas dominated by Moraxella species were associated with increased exacerbation risk and eosinophil activation. Staphylococcus or Corynebacterium species-dominated microbiotas were associated with reduced respiratory illness and exacerbation events, whereas Streptococcus species-dominated assemblages increased the risk of rhinovirus infection. Nasal microbiota composition remained relatively stable despite viral infection or exacerbation; only a few taxa belonging to the dominant genera exhibited relative abundance fluctuations during these events. In vitro, Moraxella catarrhalis induced significantly greater epithelial damage and inflammatory cytokine expression (IL-33 and IL-8) compared with other dominant nasal bacterial isolates tested.

CONCLUSION

Distinct nasal airway microbiotas of children with asthma relate to the likelihood of exacerbation, rhinovirus infection, and respiratory illnesses during the fall season.

Cockroach allergen component analysis of children with or without asthma and rhinitis in an inner-city birth cohort

BACKGROUND

Cockroach is one of the most important sources of indoor allergens and can lead to IgE sensitization and development of rhinitis and asthma.

OBJECTIVE

We sought to perform a cockroach allergen component analysis to determine the allergens and antibody levels and patterns of sensitization associated with asthma and rhinitis.

METHODS

Antibody (IgE, IgG, and IgG₄) levels to total cockroach and 8 cockroach allergens were determined in 2 groups of cockroach-sensitized 10-year-old children with (n = 19) or without (n = 28) asthma and rhinitis. Allergen-specific antibody levels were measured in streptavidin ImmunoCAPs loaded with each of the recombinant allergens from groups 1, 2, 4, 5, 6, 7, 9, and 11, and total cockroach-specific IgE levels were measured with the i6 ImmunoCAP.

RESULTS

IgE antibody levels to cockroach allergens and extract, but not IgG or IgG₄ antibody levels, differed between subjects with and without asthma and rhinitis. Specifically, recognition of more cockroach allergens with higher allergen-specific IgE levels was associated with disease. Variable patterns of sensitization with no immunodominant allergens were found in both groups. There was a good correlation between the sum of allergen-specific IgE and total cockroach IgE levels (r = 0.86, P < .001).

CONCLUSIONS

Component analysis of 8 cockroach allergens revealed significant differences in IgE reactivity associated with the presence of asthma and rhinitis. Allergen-specific IgE titers and sensitization profiles were associated with asthma and rhinitis.

The Children's Respiratory and Environmental Workgroup (CREW) birth cohort consortium: design, methods, and study population

BACKGROUND

Single birth cohort studies have been the basis for many discoveries about early life risk factors for childhood asthma but are limited in scope by sample size and characteristics of the local environment and population. The Children's Respiratory and Environmental Workgroup (CREW) was established to integrate multiple established asthma birth cohorts and to investigate asthma phenotypes and associated causal pathways (endotypes), focusing on how they are influenced by interactions between genetics, lifestyle, and environmental exposures during the prenatal period and early childhood.

METHODS AND RESULTS

CREW is funded by the NIH Environmental influences on Child Health Outcomes (ECHO) program, and consists of 12 individual cohorts and three additional scientific centers. The CREW study population is diverse in terms of race, ethnicity, geographical distribution, and year of recruitment. We hypothesize that there are phenotypes in childhood asthma that differ based on clinical characteristics and underlying molecular mechanisms. Furthermore, we propose that asthma endotypes and their defining biomarkers can be identified based on personal and early life environmental risk factors. CREW has three phases: 1) to pool and harmonize existing data from each cohort, 2) to collect new data using standardized procedures, and 3) to enroll new families during the prenatal period to supplement and enrich extant data and enable unified systems approaches for identifying asthma phenotypes and endotypes.

CONCLUSIONS

The overall goal of CREW program is to develop a better understanding of how early life environmental exposures and host factors interact to promote the development of specific asthma endotypes.

The association of allergic sensitization patterns in early childhood with disease manifestations and immunological reactivity at 10 years of age

BACKGROUND

Allergy to German cockroach (CR) is common in urban environments and is an important allergen in children with asthma.

OBJECTIVE

We hypothesize that the evolution of allergic sensitization and clinical disease is associated with distinct patterns of allergen-specific T cell reactivity. To test this hypothesis, a subset of high-risk inner-city children participating in the URECA (Urban Environment and Childhood Asthma) birth cohort were selected to evaluate CR-specific T cell reactivity from three distinct groups based on acquisition of aeroallergen sensitivity from ages 2 to 10: low atopy with minimal to no sensitivity (n = 26), early-onset allergic sensitization (n = 25) and late-onset allergic sensitization (n = 25).

METHODS

Using pools of previously identified CR-derived T cell epitopes, we characterized the allergen-specific T cell response in these 76 subjects from blood samples obtained at age 10. CR-specific production of IL-5, IFNγ and IL-10 was measured by ELISPOT following two-week in vitro culture with CR extract.

RESULTS

T cell responses were significantly higher in the early-onset atopy group compared to low atopy (P = 0.01), and a trend for higher cytokine production in the late onset compared to the low atopy cohort was also observed (P = 0.06). T cell responses were similar between early- and late-onset cohorts. Furthermore, a comparison of T cell reactivity between asthmatic and non-asthmatic individuals revealed significantly higher cytokine production in asthmatics compared to non-asthmatics (P = 0.02) within both the CR-allergic and non-allergic cohorts.

CONCLUSIONS AND CLINICAL RELEVANCE

In conclusion, the present study reports that higher T cell reactivity is associated with allergen sensitization and asthma. Interestingly, no significant difference in T cell reactivity was observed in allergic children with early-onset versus late-onset atopy.

Transcriptome networks identify mechanisms of viral and nonviral asthma exacerbations in children

Respiratory infections are common precursors to asthma exacerbations in children, but molecular immune responses that determine whether and how an infection causes an exacerbation are poorly understood. By using systems-scale network analysis, we identify repertoires of cellular transcriptional pathways that lead to and underlie distinct patterns of asthma exacerbation. Specifically, in both virus-associated and nonviral exacerbations, we demonstrate a set of core exacerbation modules, among which epithelial-associated SMAD3 signaling is upregulated and lymphocyte response pathways are downregulated early in exacerbation, followed by later upregulation of effector pathways including epidermal growth factor receptor signaling, extracellular matrix production, mucus hypersecretion, and eosinophil activation. We show an additional set of multiple inflammatory cell pathways involved in virus-associated exacerbations, in contrast to squamous cell pathways associated with nonviral exacerbations. Our work introduces an in vivo molecular platform to investigate, in a clinical setting, both the mechanisms of disease pathogenesis and therapeutic targets to modify exacerbations.