Association of Blood Eosinophil and Neutrophil with Asthma Control in Children

Background: Blood eosinophils are marker of eosinophilic airway inflammation and blood neutrophil count may be associated with disease severity and poor asthma control. It has been observed that children with high blood eosinophil counts respond better to inhaled corticosteroids (ICS). Aims and objective: The objective of this study was to determine the association between blood eosinophil and neutrophil count with asthma control. Methods: This retrospective cohort study used medical record data of children who attended pediatric chest clinic (PCC) at tertiary care center in India in last 2 years. We recorded baseline demographic profile, blood eosinophil and neutrophil count. Asthma control was assessed as per GINA guideline on follow up. ICS duration and PEFR were also recorded. Result: A total of 742 children attended PCC in last two years out of which baseline blood eosinophil and neutrophil counts were done in 116 children with asthma. In this study, the median (IQR) blood eosinophil count was 4% (1.3-6.9) and the median blood neutrophil count was 53.5% (42.2-66.4). Eosinophil count was significantly high in children with well controlled asthma [median eosinophil count 4.4 % (IQR 1.7–8.1) vs 3.45 % (0.1-6.2)] [p=0.04]; while neutrophil counts were higher in children with partly/uncontrolled asthma as compared to well controlled asthma [median neutrophil count 59.4 % (IQR 59-69.4) vs 50.4% (38.9-65)] [p=0.02]. Conclusion: Baseline high blood eosinophil counts were associated with better asthma control while baseline high neutrophil counts were associated with poor asthma control.