To the Editor:
We read with interest the comprehensive, combined retrospective and prospective study on eosinophilia in asthma by Schleich et al. [1]. As compellingly demonstrated by Schleich et al. [1] concomitant elevation of sputum and blood eosinophil numbers is an important factor in poorly controlled asthma. These data agree with the view that both local airway “inflammation” and blood eosinophilia contribute as risk factors in asthma [2]. However, there are additional eosinophil features, other than just counts, that characterise asthma. Here we draw attention to the potential roles of primary lysis/necrosis of eosinophils as blood biomarkers and bronchial-pathogenic mechanisms, especially in uncontrolled asthma.
Schleich et al. [1] briefly discuss previous findings on eosinophil numbers reported by Volbeda et al. [3]. However, a principal message of the latter study concerned …