Abstract:
Objective
To study the mechanism of the susceptibility to influenza in children with recurrent respiratory tract infection(RRTI) of different syndrome types and the effect of Yupingfeng powder on it.
Methods
A total of 150 children with RRTI treated between Mar. 2015 and Mar. 2017 were  chosen, and they were divided into five groups according to their TCM syndrome types: lung-spleen qi-deficiency group(A), qi-yin-deficiency group(B), lung-deficiency group(C), spleen-deficiency group(D), and spleen-kidney-deficiency group(E), with 30 children in each group. At the same time, 30 healthy children were selected as the normal control group. All the RRTI children took Yupingfeng powder orally; before and after taking the medicine, the level of serum IgG1 and IgG3,SAα2-6Gal and SAα2-3Gal in saliva was determined, which was compared with that of normal contral group.
Results
Compared with the normal control group, the level of IgG1 and IgG3 of RRTI children in group A, B and C was decreased before treatment, which was significantly increased after treatment with Yupingfeng powder, and there was statistical difference(P<0.05). Compared with normal control group, the level of SAα2-6Gal and SAα2-3Gal was obviously decreased in group A,D and E before treatment, which was significantly increased after treatment with Yupingfeng powder, the difference being statistical(P<0.05).
Conclusion
The changes in the immune indexes of RRTI children are related to the TCM syndrome types. The determination of IgG1,IgG3, SAα2-6Gal and SAα2-3Gal can be used as the reference evidence of syndrome differentiation and the evaluation indexes of susceptibility to influenza. Yupingfeng can regulate the level of IgG1, IgG3, SAα2-6Gal and SAα2-3Gal in RRTI children of different syndrome types, and reduce their susceptibility to influenza virus.

Key words: Recurrent respiratory tract infection（RRTI）, Susceptibility, Yupingfeng powder, TCM syndrome type, Children