Effect of Bacille Calmette Guerin inoculation with or without IFN-γ/Vit A on immunologic status of infant with bronchiolitis

AIM: To discuss the effects of Bacille Calmette Guerin(BCG) inoculation with or without supplement of vitamin A/IFN-γ on tubercle bacillus protein purified derivative(PPD) skin test,wheezing episode and in vitro the cytokine levels of peripheral blood mononuclear cells(PBMC) in infants with acute bronchiolitis.METHODS: 44 acute bronchiolitis infants(ABI) were treated with BCG alone or BCG combined with Vitamin A/IFN-γ.19 ABI treated without BCG as control.PPD skin test,in vitro production of IL-10、IL-12、IL-18、IL-4 and IFN-γ by supernatant of PBMC of bronchiolitis measured by ELISA,and expression of lymphocyte activation gene-3(LAG-3) mRNA from PBMC of bronchiolitis measured by semi-quantitative RT-PCR were observed before and 3 months after BCG inoculation.Follow up for average 12 months was to observe the wheezing episodes.RESULTS: The diameters of PPD skin test in ABI after BCG inoculation combined with IFN-γ/VitA were larger than those of ABI before inoculation and control group.The frequencies and persistence of wheezing were lower in interfered infants with acute bronchiolitis either by BCG alone or BCG combined with IFN-γ/VitA than those of control group by 1 year.IL-12、IL-18 and IFN-γ activities in ABI treated with BCG or BCG combined with IFN-γ/Vitamin A in vitro were higher than those of pre-treatment bronchiolitis infants;the level of IL-4 was lower;the level of IL-10 was a little bit lower,and expression of LAG-3 mRNA was stronger.Frequency of wheezing episode in 1 year in acute bronchiolitis infants with BCG or BCG combined with IFN-γ/Vitamin A was lower than that of control group.There were no difference between ABI with BCG or BCG combined with IFN-γ/ Vitamin A.Clinical manifestation and the level of cytokines do not show superiority in BCG with IFN-γ/Vitamin A.CONCLUSION: BCG inoculation is able to enhance PPD skin test response,promote Th1 reactivity,and prevent from recurrent wheezing after acute bronchiolitis.The level of IL-10 was degraded lightly after BCG intervention,presumably concerning with regular T cells(CD_4+CD_(25)+Tr)induced by BCG inoculation.