CHI3L1 and allergic asthma: In this study, we analyzed the gene and protein expression of CHI3L1 and PI3 in peripheral samples (PBMCs and serum) to evaluate their potential as biomarkers for different clinical asthma phenotypes (allergic asthma, AA, and nonallergic asthma, NA) and according to disease severity, building on our previous work [22,23,24,25].