Abstract: AIM: To observe the concentration of serum vitaminA and discuss the effects of vitamin A on the immune function in infants with acute bronchiolitis in vitro.MEDHODS:16 cases of bronchiolitis with RSV infection and 13 controls were studied.Serum vitamin A level of acute bronchiolitis patients and control infants were measured.The cytokines in supernatant of bronchiolitis, PBMC, IL-12 and IFN-γ, were measured by ELISA after treatment with vitamin A.RESULTS: Serum vitamin A level of patients was lower than control group.Pretreatment with lower level of vitamin A (1×10_-10mol/L) in vitro lead to higher level of IL-12 in supernatant, and significantly promoted IFN-γ secretion. Vitamin A at 1×10^-7 mol/L in vitro inhibited IL-12 secretion.CONCLUSION: The study suggested that serum concentration of vitamin A decreases at acute stage of bronchiolitis, Vitamin A associate with the level of IL-12 negatively in vitro.When vitamin A was at 1×10_-10 mol/L, it reverse the function of TH2 of bronchiolitis infants in vitro.

Key words: bronchiolitis, vitamin RA, IL-12, IFN-γ