Cellular Analysis of Induced Sputum to Diagnose Asthma and Evaluate the Direct Effects of Inhaled Corticosteroid on Airway in Children with Asthma

Oh, Jae Won; Koh, Young Jae; Kim, Eun Ah; Lee, Ha Baik; Kang, Jung Oak; Lee, Sang Il

Abstract

PURPOSE
Asthma is characterized clinically not only by episodic wheeze and reversible airway obstruction but also by excessive airway secretion. Oppenshaw- Warwick found that 77% of asthmatic subjects reported sputum production as a prominent symptom. Invasive assessment for the airway inflammation in children has been frequently limited. Induced sputum by inhalation of hypertonic saline allows monitoring of airway inflammation in children with asthma in a non-invasive way.
METHODS
Thirty subjects with asthma were selected by asthma questionares and divided two groups as 14 current symptomatic asthmatics (FEV(1)<85%: PD15) and 16 stable non-symptomatic asthmatics with 4.5% hypertonic saline challenge test, and 14 normal controls were selected. They all inhaled 4.5% hypertonic saline for 10 minutes by ultrasonic nebulizer. The expectorated sputum and saliva were collected from all subjects and collected 3 hours after corticosteroid (Beclomethasone diproprionate 200microgramX2) inhalation for asthmatics and were reduced by dithiotreitol. Total cell counts and differentials were determined.
RESULTS
Sputum from current asthmatics contained a significantly higher proportion of eosinophil than stable asthmatics or normal controls (7.9+/-6.0 vs. 3.8+/-4.5% vs. 0.8+/-1.4%, P<0.05). The induced sputum after corticosteroid inhalation showed significant decrease in total cell count, eosinophil proportion in current asthma and stable asthma.
CONCLUSION
The cellular analysis of induced sputum was a useful non-invasive and safe study for the diagnosis of childhood asthma and assessment for the direct effects of inhaled corticosteroid on airway inflammation in children with asthma.