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Original Article


The -33C/T Polymorphism in the Interleukin 4 Gene Is Associated With Asthma Risk: A Meta-Analysis


Y Liu,1 A Zhuo,2 W Liu,1 S Xu,2 S Li3

1Department of Intensive Care Medicine, No. 411 Hospital of PLA, Shanghai, China
2Department of Respiratory Disease, No. 411 Hospital of PLA, Shanghai, China
3No. 411 Hospital of PLA, Shanghai, China

J Investig Allergol Clin Immunol 2014; Vol. 24(2): 114-121



Objective: The association between the interleukin 4 (IL-4) gene -33C/T polymorphism and asthma risk is a subject of debate. We conducted a meta-analysis to evaluate the association between this polymorphism and asthma susceptibility.

Materials and Methods: A systematic search of electronic databases (Pubmed, EMBASE, Wanfang, China National Knowledge Infrastructure, and Weipu) was performed, and 18 studies involving 5523 cases and 5618 controls were identified. ORs with 95% CIs were used to assess the strength of association.

Results: A significant association between the -33C/T polymorphism and asthma susceptibility was observed for TT vs CT + CC (OR, 1.16; 95% CI, 1.05-1.28; P=.005). In the subgroup analysis by race, a significant association was found among whites (OR, 1.71; 95% CI, 1.14-2.57; P=.01) and Asians (OR, 1.14; 95% CI, 1.01-1.28; P=.04) but not among African Americans. In the subgroup analysis by atopic status, no significant association was found among atopic asthma patients (OR, 1.05; 95% CI, 0.89-1.24; P=.54) or nonatopic asthma patients (OR, 1.16; 95% CI, 0.81-1.67; P=.42). In the age-stratified analysis, an increased asthma risk was found in children (OR, 1.28; 95% CI, 1.01-1.63; P=.04) but not in adults.

Conclusions: The results of this meta-analysis suggest that the IL-4 -33C/T polymorphism is a risk factor for asthma.

Key words: Interleukin-4. Asthma. Polymorphism. Meta-analysis.