Interleukin-4 rs2243250 polymorphism is associated with asthma among Caucasians and related to atopic asthma

Published data on the association between interleukin-4 (IL-4) rs2243250 (C-589T) polymorphism and asthma susceptibility are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 17 studies with 3037 asthma patients and 3032 healthy controls were included. Overall, significantly elevated asthma risk was associated with IL-4 T allele when all studies were pooled into the meta-analysis (CT vs. CC: OR = 1.187, 95% CI = 1.016-1.387; dominant model: OR = 1.213, 95% CI = 1.046-1.405). In the subgroup analysis by ethnicity, significantly increased risk was only found for Caucasians (TT vs. CC: OR = 1.591, 95% CI = 1.032-2.452; dominant model: OR = 1.292, 95% CI = 1.028-1.624). When stratified by asthma type, statistically significantly elevated risk was only found in atopic asthma group (dominant model: OR = 1.313, 95% CI = 1.033-1.667). Despite some limitations, this meta-analysis suggests that T allele at position −589 of the IL-4 gene promoter region is a low-penetrant risk factor for asthma development especially for Caucasians and atopic type.

► We did a meta-analysis on the relation between IL-4 C-589T polymorphism and asthma. ► Elevated asthma risk was associated with T allele when all studies were pooled. ► Subgroup analysis by ethnicity showed risk was only increased in Caucasians. ► Subgroup analysis by asthma type showed risk was only increased in atopic group. ► This suggests IL-4-589T is a low-penetrant risk factor for asthma development.