Comparison of induced sputum inflammatory profiles between childhood and adult-onset asthma

Abstract

The aim of this study was to investigate differences in airway inflammation between childhood and adult-onset asthma. A total of 47 asthmatic subjects were recruited from patients attending outpatient clinic. A group of 32 adults, mean age 42.8 years (yrs) and a group of 15 children, mean age 11.7 yrs were included. The two groups did not differ in respect to gender, dose of inhaled corticosteroids, atopy status or duration of asthma (mean duration 7.75 yr). Lung function tests, and sputum induction were performed. Flowcytometry was used to study cell population and interleukin-8, eosinophilic cationic protein (ECP) and granulocyte-macrophage colony stimulating factor were measured by enzyme-linked immunosorbent assay (ELISA). Three out of 15 (20%) of the children and 6 out of 32 (19%) of the adult patients were unable to produce a sufficient sputum sample. However, all individuals tolerated the procedure well. The viability of induced sputum cells did not differ among adult-onset asthmatics and children with asthma. Children had greater number of total cells in induced sputum compared with adult subjects (P=0.02). No statistical difference in T-lymphocytes subsets was found between the two groups, except for CD25 (P=0.04). A negative correlation was found between forced expiratory volume (FEV1) values and ECP levels (r=0.338, P=0.04) in the whole population (children and adults). Our study showed that the immunopathology of pediatric and adult asthma is similar and sputum induction provides opportunities for comparison of airway inflammation in childhood and adult asthma safely.