As intercellular signaling molecules, cytokines regulate the immune response, mediate inflammatory responses, and participate in tissue repair. Experiments have shown that only the peak values of IFN-α and IL-6 could respectively be detected within 24 and 30 h in the serum of infected animals, as well as in the plasma of pediatric patients with severe influenza [16, 17] . In this experiment, no statistically significant changes were found during the continuous monitoring of serum IL-2, IL-4, IL-6, IL-10, and IFN-γ of patients with severe and moderate H1N1, as well as in the control group. This result might also be related to the immunotolerance of T cells, of which the peak detection might have been missed. The mechanisms responsible for maintaining these relatively constant levels remain unclear.