IL13 and Increased total eosinophil count: Thus, although all mepolizumab-treated patients in this study met criteria for eosinophilic asthma based on their pre-treatment peripheral blood eosinophil counts, peripheral eosinophilia does not necessarily correlate with airway eosinophilia and patients with higher IL-13 levels at baseline may have higher airway tissue eosinophilia and be more likely to respond to anti-eosinophil agents like mepolizumab.