Therefore, a secondary infection model was established, and the levels of the following seven serum cytokines were investigated in this study using enzyme-linked immunosorbent assay (ELISA): pro-inflammatory/Th1 [interferon (IFN)-γ], anti-inflammatory/Th2 (IL-4, IL-5, and IL-13), Treg [IL-10, transforming growth factor (TGF)-β], and Th17 (IL-17). The gene discussed is IL4; the disease is infection.