OBJECTIVE: To study the effect and mechanism of early intervention by polysaccharide nucleic acid fraction of BCG (BCG PSN) for prevention of post bronchiolitis wheezing. METHODS: Forty infants with bronchiolitis were randomly assigned into 2 groups: intervention group (n=19) and non intervention group (n=21). Three months after recovering from bronchiolitis, the infants in the intervention group were given BCG PSN injection 1 ml I.M twice a week, 24 times in all. The infants in the non intervention group did not receive any intervention. Twenty healthy children were used as the normal controls. The levels of IFN γ and IL 4 in the supernatant of cultured peripheral blood mononuclear cells, and serum IgE level were measured using ELISA before intervention and one year after intervention. One year following up was done to observe the frequency of the wheezing episodes. RESULTS: The IFN γ level and IFN γ/IL 4 ratio were significantly lower, and the levels of IL 4 and IgE were significantly higher in both intervention group and non intervention group before intervention than those in the normal controls (P< 0.01 ). After one year of BCG PSN intervention, the IFN γ level [( 986.95 ± 363.20 ) ng/L] and IFN γ/IL 4 ratio ( 16.03 ± 7.11 ) were significantly higher than those of before intervention [( 768.43 ± 288.07 ) ng/L and ( 9.11 ± 4.27 ) respectively]; the levels of IL 4 [( 59.73 ± 16.04 ) ng/L] and IgE [( 48.05 ± 19.57 ) kU/L] decreased significantly compared with those of the pre intervention [( 81.66 ± 21.92 ) ng/L and ( 155.35 ± 76.25 ) kU/L, respectively] (P< 0.01 ) and the IFN γ level was not significantly different from the normal controls (P> 0.05 ). In one year of BCG PSN intervention, 3 cases ( 15.8% ) had two or more times wheezing episodes in the intervention group, less than that in the non intervention group [11 cases ( 52.4% )] (P< 0.05 ).CONCLUSIONS: Early intervention with BCG PSN in post bronchiolitis children may be useful in preventing the infants from recurrent wheezing episodes later. The possible explanation is that BCG PSN can increase IFN γ secretion, inhibit IL 4 activity, increase IFN γ/IL 4 ratio and decrease IgE production."/>
卡介菌多糖核酸对毛细支气管炎喘息反复发作的预防作用
Abstract：OBJECTIVE: To study the effect and mechanism of early intervention by polysaccharide nucleic acid fraction of BCG (BCG PSN) for prevention of post bronchiolitis wheezing. METHODS: Forty infants with bronchiolitis were randomly assigned into 2 groups: intervention group (n=19) and non intervention group (n=21). Three months after recovering from bronchiolitis, the infants in the intervention group were given BCG PSN injection 1 ml I.M twice a week, 24 times in all. The infants in the non intervention group did not receive any intervention. Twenty healthy children were used as the normal controls. The levels of IFN γ and IL 4 in the supernatant of cultured peripheral blood mononuclear cells, and serum IgE level were measured using ELISA before intervention and one year after intervention. One year following up was done to observe the frequency of the wheezing episodes. RESULTS: The IFN γ level and IFN γ/IL 4 ratio were significantly lower, and the levels of IL 4 and IgE were significantly higher in both intervention group and non intervention group before intervention than those in the normal controls (P< 0.01 ). After one year of BCG PSN intervention, the IFN γ level [( 986.95 ± 363.20 ) ng/L] and IFN γ/IL 4 ratio ( 16.03 ± 7.11 ) were significantly higher than those of before intervention [( 768.43 ± 288.07 ) ng/L and ( 9.11 ± 4.27 ) respectively]; the levels of IL 4 [( 59.73 ± 16.04 ) ng/L] and IgE [( 48.05 ± 19.57 ) kU/L] decreased significantly compared with those of the pre intervention [( 81.66 ± 21.92 ) ng/L and ( 155.35 ± 76.25 ) kU/L, respectively] (P< 0.01 ) and the IFN γ level was not significantly different from the normal controls (P> 0.05 ). In one year of BCG PSN intervention, 3 cases ( 15.8% ) had two or more times wheezing episodes in the intervention group, less than that in the non intervention group [11 cases ( 52.4% )] (P< 0.05 ).CONCLUSIONS: Early intervention with BCG PSN in post bronchiolitis children may be useful in preventing the infants from recurrent wheezing episodes later. The possible explanation is that BCG PSN can increase IFN γ secretion, inhibit IL 4 activity, increase IFN γ/IL 4 ratio and decrease IgE production.
