| Objectives: As one of the common respiratory infection diseases in infants, bronchiolitis is associated with the occurrence of asthma. Previous studies suggest that imbalance of helper T cells (TH) subsets such as TH1 and TH2 function existing in bronchiolitis patients contributes to their susceptibility to asthma. As a non-specific immune stimulator, BCG has high impact on TH1 polarization to be used as asthma vaccine. The traditional approaches for bronchiolitis therapy include administration anti-infection, bronchiole dilation and glucocorticoid agents. In order to further explore the mechanism of dysfunction of TH subsets of bronchiolitis patients and find novel approach to interfere the prognosis of bronchiolitis, The monocyte-derived cytokines (IL-18, IL-10 and IL-12), TH1/TH2-derived cytokines (IL-4, and interferon-γ) and expression of lymphocyte activation gene-3 (LAG-3) from the peripheral blood mononuclear cells (PBMC) of bronchiolitis were investigated in comparison with normal controls. Furthermore, in vivo, the effects of Bacillus-Calmette Guerin (BCG) and BCG combined with interferon γ (IFN-γ) and vitamin A (Vit A) on the purified protein derivative(PPD) skin test, clinical symptom and immune function of bronchiolitis patients were observed. Moreover, in vitro, we investigated the effects of BCG, IFN-γ, Vit A, and BCG plus IFN-γand Vit A on phagocytosis, CD11b expression, monocyte-derived cytokine and TH-derived cytokine production of PBMC from bronchiolitis patients.Methods:1．45 infants with bronchiolitis and 21 healthy babies who had inoculated BCG during neonate stage enrolled in this study.2. PBMC were isolated by Ficoll and stimulated by PHA or LPS. BCG , IFN-γ, Vit A and BCG combined with IFN-γ/ Vit A were used to stimulated PBMC or monocytes in vitro. 3. For in vivo interference observation, 0.125 ml BCG was inoculated by intradermal injection after acute stage of bronchiolitis in 13 ill infants. Except BCG, 25000u Vit A was taken per day for 14 days and 1 million u IFN-( was injected every day for continual 5 days in other 12 patients. 4. ELISA was used to detect the monocyte-derived and TH-derived cytokines(IL-18,IL-12,IL-10,IL-4,IFN-γ) in supernatant and serum IgE level.5. The phagocytosis of adherent monocytes was determined by Indian ink endocytotic test. Expression of surface protein CD11b and LAG-3 mRNA were assayed by immunohistochemistry and semi-quantitative RT-PCR respectively. Results: 1. Compared to normal controls, there were significantly higher levels of IL-4, IL-10 in supernatant of PBMC from bronchiolitis patients in vitro and of IgE in serum. Lower levels of LAG-3 mRNA expression on PBMC, monocyte-derived cytokine IL-12 and IL-18 in supernatant of PBMC were found in infants with bronchiolitis.2. In vitro study, incubated with BCG 50 μl /ml for 72 hours, adherent monocytes of bronchiolitis patients had the highest endocytotic function. CD11b expression , the levels of IL-12, IL-18 and IFN-( were increased, but IL-4 and IL-10 were decreased in comparison with the controls. As elevating the concentration of BCG up to 75μl/ml, IL-12, IL-18, IFN-( production still kept high levels,while IL-10 and IL-4 were not effected.3. In vivo study, IFN-γ and Vit A had no effect on phagocytosis and CD11b expression. In vitro study, Vit A was significantly able to enhance the production of IL-10 and further reduce IL-12,IL-18 and IFN-γproduction. The lower LAG-3mRNA expression and lightly decreased IL-4 induced by Vit A were found. 4. In terms of monocyte-derived cytokines, BCG and IFN-γ up-regulated production of IL-12 and IL-18, down-regulated the level of IL-10 and IL-4, and PBMC LAG-3mRNA expression in vitro.5.The behaving of cytokine production induced by BCG combined with IFN-γ/VitA was as same as that induced by BCG or IFN-γ alone. 6. After interfered either with BCG (5.5±2.4mm)or BCG plus IFN-γ and VitA(9.0±4.2mm), PPD skin test of bronchiolitis patients was enhanced ascomparingto pre- (... |
PDF Full Text Request