Analysis of bronchoalveolar lavage fluid components in children with chronic cough and wheezy diseases

Objective Today the technique of bronchoalveolar lavage (BAL ) has been widely used as a useful research tool in studying the airway inflammation of airway diseases by investigating inflammatory cells and inflammatory mediators in bronchoalveolar lavage fluid (BALF ) in adults, but there have been very few the similar studies in pediatric cases. The purpose of this prospective study was to analyze the components of BALF in children with chronic cough and wheezy diseases. Methods Fiberoptic bronchoscopy was performed on 39 children aged 1 year to 11 years, who were divided into 4 groups with regard to clinical data: asthma (n=13), chronic cough (n=10), infantile wheezing (n= 8), and control (n= 8). BAL was performed with 3×1 ml/kg body weight of normal saline warmed to body temperature. Differential cell counts were obtained from smears stained with May-Grunwald-Giemsa method. Activated eosinophils and T cells were marked with EG2 and CD45RO monoclonal antibodies, respectively, using immunohistochemical method. Interleukin-5 (IL-5) was measured with a sandwich ELISA using a mouse monoclonal antibody. Statistical analysis was conducted with the SPSS 8.0 software. P< 0.05 was considered statistically significant. Results The mean (±s) recovery of BALF was (77±6)% and no difference was found between the groups. Eosinophils 3.0%(0.7%-8.8%), EG2-positive cells 2.0% (0.8%-7.5%), and epithelial cells 3.0% (0.7%-12.0%) in BALF were significantly increased in children with asthma by comparison with chronic cough, infantile wheezing and control subjects (P< 0.01, respectively). The cell profile of children with chronic cough was similar to that of control children, but increased eosinophils and EG2-positive cells were also found in two of them. Activated T cell (CD45RO+ ) counts were significantly increased in asthmatic children as compared with controls (P< 0.05 ) but no significant difference was found when compared with children with chronic cough and infantile wheezing. Neutrophils were significantly increased in asthmatic children and infantile wheezers in comparison with controls (P<0.05, respectively). IL-5 (1.6 ng/L; 0, 16.0 ng/ml) levels were significantly increased in asthmatic children as compared with controls and children with chronic cough(P< 0.05, respectively). CD45RO-positive cell counts, EG2-positive cell counts and IL-5 levels in BALF correlated positively with one another (r= 0.785 3, P<0.001; r= 0.918 7, P<0.001; r= 0.759 1, P<0.001, respectively). Conclusions Eosinophils and epithelial cells in BALF were significantly increased in children with asthma in comparison with chronic cough, infantile wheezing and control subjects; some children with chronic cough also had increased eosinophil counts; neutrophil was the main significantly increased cell in BALF in the children with infantile wheezing. Key words: Child; Bronchoalveolar lavage fluid; Granulocytes; Asthma; Cough