Does airway allergic inflammation pre-exist before late onset wheeze in children?

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Bronchoalveolar lavage profiles in uncontrolled wheezy children compared by asthma predictive index

OBJECTIVE

The asthma predictive index (API) predicts later asthma in preschoolers with frequent wheeze. We hypothesized that airway cytology differs between API positive (API+)/negative (API-) children with uncontrolled/recurrent wheezing with dominance of eosinophils in API+ and neutrophils in API- groups respectively. The main objective of this study is to compare bronchoalveolar lavage (BAL) cell profiles in API+/API- children with recurrent wheezing unresponsive to inhaled corticosteroids (ICS).

DESIGN

Retrospective analysis of BAL in 43 children, 3-36 months (median: 14 months) receiving ICS (31 API+, 12 API-). BAL cell differential counts, bacterial/viral cultures, and lipid-laden macrophage percentages were analyzed. Cell counts presented as median (range).

RESULTS

Neutrophil percentages were increased in both groups (API- 16% [1%-76%]; API+ 42% [1%-95%]; p = NS). Cell percentages were similar for lymphocytes (API- 12% [1%-30%]; API+ 7% [1%-37%]), and macrophages (API- 67.5% [12%-97%]; API+ 41% [2%-94%]). Eosinophil percentages were low in both groups (API- 1% [1%-2%]; API+ 1% [1%-11%]). There was no difference in cellular distributions using absolute cell counts comparing API groups. Bacterial cultures were positive in 18 (60%) API+ and 5 (41%) API- patients (p = 0.10).

CONCLUSION

Cell profiles do not differ between API groups in children ≤36 months with recurrent wheezing unresponsive to ICS. Neutrophil percentages and total granulocyte count correlate with positive bacterial cultures independent of API status. Persistent bacterial bronchitis likely plays an important role in the persistence of symptoms unresponsive to ICS therapy regardless of API status with a trend to more positive cultures in API positive children.

Maternal phthalate exposure and asthma, rhinitis and eczema in 552 children aged 5 years; a prospective cohort study

BACKGROUND

Prenatal phthalate exposure has been suggested to alter immune responses and increase the risk of asthma, eczema and rhinitis. However, few studies have examined the effects in prospective cohorts and only one examined rhinitis. We therefore studied associations between maternal urinary concentrations of phthalate metabolites and asthma, eczema and rhinitis in offspring aged 5 years.

METHODS

From 552 pregnant women in the Odense Child Cohort, we quantified urinary concentrations of 12 phthalate metabolites in third trimester. We assessed asthma, rhinitis and eczema in their offspring at age 5 years with a questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC), and conducted logistic regression adjusting for relevant confounders.

RESULTS

7.4% of the children had asthma, 11.7% eczema and 9.2% rhinitis. Phthalate exposure was low compared to previous cohorts. No significant associations between prenatal phthalate exposure and asthma were found. Odds ratios (ORs) of child rhinitis with a doubling in ΣDiNP_m and di-2-ethylhexyl phthalate metabolite (ΣDEHP_m) concentrations were, respectively, 1.15 (95% confidence interval (CI) 0.97,1.36) and 1.21 (CI 0.93,1.58). The OR of eczema when doubling ΣDiNP_m was 1.24 (CI 1.00,1.55), whereas the OR of using medicine against eczema when doubling a di-ethyl phthalate (DEP) metabolite was 0.81 (CI 0.68,0.96).

CONCLUSION

The lack of association between maternal phthalate exposure and asthma in the offspring may be due to low exposure and difficulties in determining asthma in 5-year-olds. The higher odds of rhinitis may raise public concern but further research in larger cohorts of older children is warranted.

Eosinophil cell count in bronchoalveolar lavage fluid in early childhood wheezing: is it predictive of future asthma?

Objective: Increased eosinophil level in bronchoalveolar lavage fluid (BALF) characterizes asthma in school-age children and adults and has been suggested as a marker for disease severity and response to treatment. We aimed to investigate the occurrence and yield of BALF eosinophil cell count in preschool children with recurrent wheezing and its possible relation to future diagnosis of asthma. Methods: BALF was retrospectively studied in young wheezy children and its relation to asthma at age 6 years was evaluated. BALF from children aged 1-48 months (mean = 20.4) was analyzed in preschool wheezy children. Children with anatomical airway obstruction and other lower airway/lung diseases who underwent BALF served as controls. Assessment of asthma was accomplished at 6 years. Results: Eighty-two children were included. The mean age during bronchoscopy and BAL was 20.4 ± 14.4 months (range: 1-48 months). Twenty-six patients had recurrent preschool wheezing, 13 anatomical airway obstruction and 43 had other lower airways/lung diseases. Groups were comparable for age during bronchoscopy and gender. No difference was found between groups for any of the BALF cell types. Eosinophils were very low in all three groups [mean (interquartile range): 0 (0-0.4), 0 (0-0.8), and 0.4 (0-1), respectively, p = 0.25]. No difference in eosinophil levels during bronchoscopy was found between asthmatic children to non-asthmatic as defined at age 6 years. Conclusions: Wheezing in preschool children is not associated with increased BALF eosinophils; hence, at this age, the diagnostic yield of BALF for cell count analysis for diagnosing asthma is limited and is not routinely indicated.

The relationship between inflammation and remodeling in childhood asthma: A systematic review

OBJECTIVES

We aimed to perform a systematic review of all studies with direct measurements of both airway inflammation and remodeling in the subgroup of children with repeated wheezing and/or persistent asthma severe enough to warrant bronchoscopy, to address whether airway inflammation precedes remodeling or is a parallel process, and also to assess the impact of remodeling on lung function.

METHODS

Four databases were searched up to June 2017. Two independent reviewers screened the literature and extracted relevant data.

RESULTS

We found 526 references, and 39 studies (2390 children under 18 years old) were included. Airway inflammation (eosinophilic/neutrophilic) and remodeling were not present in wheezers at a mean age of 12 months, but in older pre-school children (mean 2.5 years), remodeling (mainly increased reticular basement membrane [RBM] thickness and increased area of airway smooth muscle) and also airway eosinophilia was reported. This was worse in school-age children. RBM thickness was similar in atopic and non-atopic preschool wheezers. Airway remodeling was correlated with lung function in seven studies, with FeNO in three, and with HRCT-scan in one. Eosinophilic inflammation was not seen in patients without remodeling. There were no invasive longitudinal or intervention studies.

CONCLUSION

The relationship between inflammation and remodeling in children cannot be determined. Failure to demonstrate eosinophilic inflammation in the absence of remodeling is contrary to the hypothesis that inflammation causes these changes. We need reliable, non-invasive markers of remodeling in particular if this is to be addressed.

Nasal epithelial cells can act as a physiological surrogate for paediatric asthma studies

Introduction

Differentiated paediatric epithelial cells can be used to study the role of epithelial cells in asthma. Nasal epithelial cells are easier to obtain and may act as a surrogate for bronchial epithelium in asthma studies. We assessed the suitability of nasal epithelium from asthmatic children to be a surrogate for bronchial epithelium using air-liquid interface cultures.

Methods

Paired nasal and bronchial epithelial cells from asthmatic children (n = 9) were differentiated for 28 days under unstimulated and IL-13-stimulated conditions. Morphological and physiological markers were analysed using immunocytochemistry, transepithelial-electrical-resistance, Quantitative Real-time-PCR, ELISA and multiplex cytokine/chemokine analysis.

Results

Physiologically, nasal epithelial cells from asthmatic children exhibit similar cytokine responses to stimulation with IL-13 compared with paired bronchial epithelial cells. Morphologically however, nasal epithelial cells differed significantly from bronchial epithelial cells from asthmatic patients under unstimulated and IL-13-stimulated conditions. Nasal epithelial cells exhibited lower proliferation/differentiation rates and lower percentages of goblet and ciliated cells when unstimulated, while exhibiting a diminished and varied response to IL-13.

Conclusions

We conclude that morphologically, nasal epithelial cells would not be a suitable surrogate due to a significantly lower rate of proliferation and differentiation of goblet and ciliated cells. Physiologically, nasal epithelial cells respond similarly to exogenous stimulation with IL-13 in cytokine production and could be used as a physiological surrogate in the event that bronchial epithelial cells are not available.

Allergic airway diseases in childhood - marching from epidemiology to novel concepts of prevention

In the past years, a wide range of epidemiological, clinical, and experimental studies have produced remarkable advances in the field of respiratory allergies in childhood. By the recent investigations on epidemiological trends, risk factors, and prevention of asthma and allergic rhinitis, various exiting concepts have been challenged, and novel innovative approaches have been developed. Pediatric Allergy and Immunology (PAI), with a number of highly relevant contributions between 2010 and 2012, has become an important forum in this area. The prevalence of asthma in some developed countries may have reached a plateau, while in developing countries, where the prevalence was previously low, allergic diseases are still on the increase. A wide array of risk and protective factors, including hygiene, infections, outdoor and indoor air pollution, allergen exposure, breast-feeding practices, nutrition, and obesity, play a multifaceted role in shaping the observed worldwide trends of respiratory allergies. Under the guidance of recent research, prediction and prevention strategies in the clinical practice are progressively changing, the focus moving away from avoidance of allergen exposure and toward tolerance induction.

The allergic march: can we prevent allergies and asthma?

The allergic march is a progression of atopic disease from eczema to asthma, and then to allergic rhinoconjunctivitis. It appears to be caused by a regional allergic response with breakdown of the local epithelial barrier that initiates systemic allergic inflammation. Genetic and environmental factors predispose to developing the allergic march. There are data to support 4 possible interventions to prevent the allergic march from progressing to asthma: (1) supplements of dietary probiotics, (2) exclusive breast feeding during the first few months of life, or, alternatively (3) use of extensively hydrolyzed infant formulas, (4) treatment with inhalant allergen immunotherapy by either subcutaneous or sublingual methods.

Food allergies and asthma

PURPOSE OF REVIEW

To consider the possible links between food allergy and asthma.

RECENT FINDINGS

Food allergy and asthma coexist in many children, and recent studies demonstrate that having these comorbid conditions increases the risk for morbidity. Children with food allergies and asthma are more likely to have near-fatal or fatal allergic reactions to food and more likely to have severe asthma.

SUMMARY

Although a causal link has not been determined, increased awareness of the heightened risks of having both of these common childhood conditions and good patient/parent education and management of both conditions can lead to improved outcomes.