On level 3, the abundance of genes related to Th1 and Th2 cell differentiation, Vitamin B6 metabolism were higher in untreated asthma group than CON group, contrastingly, the abundance of SNARE interactions in vesicular transport, transforming growth factor-beta (TGF-β) signaling pathway, Stilbenoid, diarylheptanoid and gingerol biosynthesis, Flavonoid biosynthesis, Fluorobenzoate degradation were lower in untreated asthma group than CON group (Additional file 15: Fig. S6b). Here, TGFB1 is linked to asthma.