CHI3L1 and asthma: We included CCL26 (eotaxin-3) and CHI3L1 (chitinase-3-like-1) expression in this panel, as in addition to their involvement in asthma pathogenesis [24, 25], their expression is also linked to epithelial differentiation [26, 27], with both being members of gene families identified as potential asthma biomarkers [28].