Totally, the primary outcome of meta-analysis of the relationship between the IL-4-590C > T polymorphism and the susceptibility to asthma was as follows: initially, the results showed no significant relationship between the TT genotype of IL-4-590C > T and the increased susceptibility to asthma in the random effects model (dominant model: OR = 1.31, 95% CI = 0.68–2.53) (Figure 2). Here, IL4 is linked to asthma.