Induced sputum cell count and cytokine profile in atopic and non-atopic children with asthma

Abstract

Background and aim: Sputum induction is a semi-invasive technique used to detect and monitor airway inflammation. In this study, the cell profile, and Th1 and Th2 cytokine levels in induced sputum of asthmatic and healthy children (HC) are compared.

Methods: Sputum induction was performed in healthy and asthmatic children by inhalation of hypertonic saline solution. Differential cell count in the specimen obtained was carried out using optic microscopy. IFN-γ, IL-2, IL-10, IL-8, IL-6, IL-4, IL-5, IL-1β, TNF-α, and IL-12p70 levels were determined in sputum sample supernatants by flow cytometry.

Results: Sputum induction was performed in 31 HC and 77 asthmatic children (60 atopic and 17 non-atopic asthma, NAA). Twenty-four samples were obtained in HC and 64 in patients. Median eosinophil count in atopic asthma (AA; 2%) was higher than in NAA (P = 0.02) or HC (P = 0.01). IL-4, IL-5, IFNγ, IL-2, and IL-12p70 concentrations were higher in AA than in NAA or HC. IL-8 was higher in asthmatic children (atopic and non-atopic) than in healthy ones. IL-10 was higher in the healthy group than in the AA group (P = 0.02).

Conclusions: As compared to HC, the inflammatory profile in induced sputum of children with asthma showed an increase in proinflammatory cytokines. Concentrations of IL-10, an anti-inflammatory cytokine, were lower in children with AA than in HC.

Keywords: allergy; asthma; bronchial inflammation; children; induced sputum.