As shown in Figure 2, the serum levels of IFN-γ and IL-2 in asthma patients were significantly lower than those in healthy people (P < 0.05, Figure 2(a)), and the levels of IL-4 and IL-5 were significantly higher than those in healthy people (P < 0.05, Figure 2(b)). This evidence concerns the gene IL4 and asthma.