Intestinal helminth infestation is associated with increased bronchial responsiveness in children

• Published in: Pediatric pulmonology Vol. 43; no. 7; pp. 662 - 665
• Main Authors: da Silva, Emerson R., Sly, Peter D., de Pereira, Marilyn U., Pinto, Leonardo A., Jones, Marcus H., Pitrez, Paulo M., Stein, Renato T.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.07.2008; Wiley-Liss
• Subjects: Animals; Ascariasis - complications; Ascariasis - immunology; Ascaris lumbricoides - immunology; Ascaris lumbricoides - isolation & purification; asthma; Asthma - immunology; Asthma - parasitology; Biological and medical sciences; Brazil; Bronchial Hyperreactivity - immunology; Bronchial Hyperreactivity - parasitology; bronchial hyperresponsiveness; Bronchial Provocation Tests; Child; children; Chronic obstructive pulmonary disease, asthma; Female; General aspects; helminthes; Humans; Male; Medical sciences; Pneumology; Brazil; Human; Lung disease; Pediatrics; Respiratory disease; Gut; Bronchus; helminthes; Asthma; Association; children; Bronchus disease; Obstructive pulmonary disease; bronchial hyperresponsiveness; Child; Pneumology
• ISSN: 8755-6863; 1099-0496
• DOI: 10.1002/ppul.20833

Non‐atopic asthma is the predominant phenotype in non‐affluent parts of Latin America. We recently reported that infestation with Ascaris lumbricoides increased the risk of non‐atopic asthma in less affluent areas of Brazil but the mechanism is unclear. The present study was conducted to determine whether helminth infestation is associated with heightened bronchial responsiveness (BHR), a common finding in asthma. A random sample of 50 asthmatic and 50 non‐asthmatic controls (mean age 10.1 years) were selected from a larger cohort (n = 1,011) without knowledge of their helminth infestation status. Three stool samples were collected from each child on different days and each sample was analyzed by the Kato‐Katz method for quantitative determination of helminth eggs. Bronchial provocation tests were performed with inhaled 4.5% hypertonic saline using the ISAAC Phase II standardized protocol. There was no difference between the prevalence of positive BHR in the asthmatics (20.4%) compared with the controls (14.6%) (P = 1.0). Helminth infestation was detected in 24.0% of children, with A. lumbricoides being the most common. Children with high load infestation (≥100 eggs/g) were five times more likely to have BHR than children with low load or no infestation. Despite the small sample size the results of the present study suggest that the link between high load helminth infestation and non‐atopic asthma may be mediated via heightened bronchial responsiveness, possibly due to an inflammatory response to the pulmonary phase of the helminth life cycle. Pediatr Pulmonol. 2008; 43:662–665. © 2008 Wiley‐Liss, Inc.