Objective

To study the clinical efficacy of Pihui Fanggan Sachet (PHFGS), a sachet of traditional Chinese herbs, in preventing influenza and its immune regulation on mice.
Methods

In clinical study, 239 children from Shanghai Baoshan Xubeihong Art Kindergarten were randomly divided into two groups according to different class; 118 children were treated with PHFGS for 45 days as treatment group and 121 children were as blank control. During the observation period, the incidence rate of influenza, the course of disease and the severity of symptoms were recorded. In experimental study, 40 Kunming mice were randomly divided into normal control group (normal mice treated or not treated with PHFGS), and immunocompromised group (immunocompromised mice treated or not treated with PHFGS). Immunocompromise was induced by intraperitoneal injection of 80 mg/kg cyclophosphamide for 3 days. Some mice in the normal control and immunocompromised groups were then treated with extracted solution of PHFGS through nasal cavity for one week. Spleen index, content of CD₃ ⁺ T cells and CD₄ ⁺ T cells, CD₄ ⁺/CD₈ ⁺ratio, activity of natural killer (NK) cells, serum level of interferon γ (INF-γ) and respiratory level of secretory immunoglobulin A (SIgA) were evaluated.
Results

The incidence rate of influenza in the treatment group was much lower than that in the blank control group (P<0.01), and the average course was shortened as compared with the control group (P<0.01). The fever, rhinocleisis, runny nose, and throat congestion in the treatment group were improved as compared with the blank control group (P<0.05, P<0.01). After injection of cyclophosphamide, the spleen index, content of CD₃ ⁺T cells and CD₄ ⁺T cells, CD₄ ⁺/CD₈ ⁺ ratio, activity of NK cells, serum level of INF-γ and respiratory level of SIgA in the immunocompromised group were significantly lower than those in the normal control group (P<0.05 or P<0.01), which indicated the immunosuppression. After treated with PHFGS for one week, the spleen index and the respiratory level of SIgA in the immunocompromised group were improved significantly. Although the content of CD₃ ⁺ T cells and CD₄ ⁺ T cells, CD₄ ⁺/CD₈ ⁺ ratio and the serum level of INF-γ were improved, the differences did not reach the significant level. No significant effects on immune function of normal mice were observed.
Conclusion

PHFGS can prevent influenza effectively by improving the immunity, especially the respiratory mucosal immune function.

Key words: Influenza, Prevention, Defense mechanisms, Prevalence, Immunologic markers, Mice