IL4 and asthma: In our study, the findings demonstrated that Th2 cell and cytokines, including IL-4, IL-5 and IL-13 were significantly increased in OVA-induced asthma model, while nasal mucosa immunization with recombinant Mycobacterium smegmatis significantly decreased the levels of IL-5 and IL-13 in BALF and splenocytes culture supernatant and mediastinal lymph nodes as well as down-regulated the mRNA expression of GATA3, furthermore the population of IL-4-producing Th2 cells was significantly decreased.