Abstract:

Objective To investigate immunological relationship between early induction of food allergy and occurrence of later asthma in mice, and explore the pathological changes in lung tissues. Methods Thirty-seven female BALB/c mice aged 6 weeks were randomly divided into blank control group (n=12), food allergy group (n=13) and asthma group (n=12). After being challenged by ovalbumin (OVA), the levels of serum IgE, IL-4 and INF-γ in bronchoalveolar lavage fluid (BALF) were detected. The numbers of inflammatory cells and eosinophils (EOS) in BALF were counted. Lung tissues were obtained for pathological sections, and thickness of bronchial wall and EOS infiltration were observed. Results The level of serum IgE and level of IL-4, ratio of IL-4/IFN-γ and number of EOS in BALF in food allergy group and asthma group were significantly higher than those in control group (P<0.05). The level of IL-4 and number of EOS in BALF in asthma group were significantly higher than those in food allergy group (P<0.05), while there was no significant difference in serum IgE level between these two groups （P>0.05）, and levels of IFN-γ in BALF in both groups were significantly lower than that in blank control group (P<0.05). There were more EOS infiltration in lung tissues and thicker bronchial wall in food allergy group and asthma group than that in blank control group (P<0.05), and the number of EOS in asthma group was significantly higher than that in food allergy group (P<0.05). Conclusion IgE-mediated immune response is involved in both food allergy and asthma mouse models. Lung immune imbalance of Th1/Th2 and inflammatory cell infiltration caused by food allergy may participate in the occurrence of later asthma.

Key words: food allergy, asthma, eosinophil, Th1/Th2 cytokine, inflammatory cell