Association of IL-4 promoter polymorphisms with asthma: a meta-analysis

This study aimed to more precisely assess the correlation between interleukin-4 (IL-4) promoter polymorphisms and the susceptibility risk of asthma. We conducted association studies on IL-4 promoter C-33T, C-589T, and G-1098T polymorphisms with asthma using data obtained from MEDLINE up to September 2011. Results showed that the polymorphisms IL-4 C-33T and C-589T were significantly associated with asthma; however, significant associations were found only in the European population. In addition, the TT+ CT genotype was significantly associated with asthma in adults and no significant association was found in asthma status subgroup analyses. This meta-analysis showed that IL-4 C-589T and C-33T were associated with asthma in Europeans. To further confirm correlations between polymorphisms of the IL-4 promoter with asthma susceptibility, studies involving a larger number of patients worldwide are necessary.