Clinical Characteristics of Eosinophilic Asthma Compared to Noneosinophilic Asthma in Children

Background: Asthma is a heterogeneous and complex chronic inflammatory disease of the airways. Asthma can be classified as eosinophilic asthma (EA) or noneosinophilic asthma (NEA). We investigated whether children with EA and NEA manifest different clinical characteristics.

Methods: A total of 158 children with EA and 89 children with NEA were enrolled in this study. We performed pulmonary function and methacholine challenge tests, and measured blood eosinophil count, total serum immunoglobulin E (IgE), serum eosinophil cationic protein (ECP), and sputum cell counts.

Results: There were no significant differences in age, sex, and body mass index between the EA and NEA groups. The blood eosinophil count and serum ECP were higher in EA than in NEA, whereas the total serum IgE was similar in both groups. Pulmonary function, as measured by forced expiratory volume in 1 second (FEV₁), forced expiratory flow at 25–75% of forced vital capacity (FEF_25–75%)_, and postbronchodilator (postBD) FEV₁ were significantly decreased in children with EA compared to those with NEA. In EA, FEV₁, FEF_25–75%, and postBD FEV₁ correlated negatively with sputum eosinophils. In NEA, FEV₁/forced vital capacity (FVC) and FEF_25–75% correlated negatively with sputum neutrophils. Sputum eosinophils (in EA) and sputum neutrophils (in NEA) increased with increase in asthma severity.

Conclusions: The pulmonary function of children with EA is significantly lower than that of children with NEA. In addition, pulmonary function and asthma severity are associated with eosinophilic inflammation in EA and with neutrophilic inflammation in NEA.