IL18 and asthma: After reading the full texts of the remaining 28 articles regarding the association between IL-18 polymorphisms and allergic disease, seven articles were excluded, 1 for meta-analysis related to IL-18 promoter polymorphism and asthma risk, 4 with incomplete data (no available genotype frequency), 1 not related to IL-18 polymorphism, and 1 for overlapping data.