We then divided the 126 patients into two subgroups by five different ways: according to asthma severity (mild to moderate asthma and severe asthma), the Th2-high and Th2-low subgroups based on both serum IgE levels and a peripheral blood eosinophil counts, the high and low IgE subgroups based on serum IgE levels, the high and low eosinophil subgroups based on peripheral blood eosinophil counts, and the high and low FeNO subgroups based on FeNO levels (Fig. 1 and Additional file 2: Table S2). Here, IGHE is linked to asthma.