Phenotypes of the inflammatory cells in the induced sputum from young children or infants with recurrent wheezing

Abstract

Background: To identify inflammatory cell types by phenotypic analysis of the inflammatory cells in the induced sputum. Methods: This retrospective study included 1232 children and infants, who were assigned into mild/moderate groups (326) and severe group (602) by clinical symptom scores. Phenotypes of sputum inflammatory cells were analyzed using liquid-based thin-cytologic test and eosinophil-derived neurotoxin (EDN) was quantified by ELISA. Results: Blood eosinophil count, serum total IgE level, and allergen detection rate were significantly higher in the severe group. In the 905 cases of qualified sputum, 526 cases exhibited at least one type of inflammatory cells, including neutrophil (343, 65.2%), eosinophil (161, 30.6%), and mixed granulocytes (22, 4.2%). Levels of neutrophils and eosinophils were significantly higher in the severe group than mild/moderate group, and eosinophil was predominant in the severe group. Serum EDN was 104.8 ± 39.4 μg/l in the eosinophil phenotype group, 112.6 ± 41.2 μg/l in the mixed group, 88.2 ± 36.6 μg/l in the neutrophil phenotype group, and 60.9 ± 34.6 μg/l in the paucigranulocytic phenotype group. Conclusion: Induced-sputum inflammatory cell count may be used to determine phenotype of wheezing. The criteria of classifying adult asthma could be applicable for children and infants.