Department of Immunology, School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
Department of Hematology, School of Medicine, Tarbiat Modares University (TMU), Tehran, Iran.
BMC Med Genet. 2020 Nov 23;21(1):232. doi: 10.1186/s12881-020-01169-w.
Previous studies evaluated the association of IL-4 C33T polymorphism and risk of bronchial asthma but failed to establish a consistent conclusive association. In the present meta-analysis, we intend to define a more reliable estimate of the association in the presence of filling published literature.
An exhaustive search in Web of Science, Scopus, and PubMed databases was performed to identify all relevant publications before September 2020, and 24 publications (28 studies) with 6587 cases and 8408 controls were included in final analysis. The association between polymorphism and risk of asthma were measured by Odd ratios (ORs) and 95% confidence intervals (CIs). Moreover, Cochran's Q and the I statistics were used to evaluate the degree of heterogeneity between studies.
In the overall study populations, a significant positive association was detected under all genotype models and announced the IL-4 C33T polymorphism as a potential risk factor in the pathogenesis of asthma. In the subgroup analysis by age, a significant association between IL-4 C33T polymorphism and risk of asthma in different age groups was identified in allelic model, which highlighted the predisposing role of the T allele for the asthma risk in all three age groups. Furthermore, the results of subgroup analysis by continent were heterogenous. Accordingly, IL-4 C33T polymorphism was a risk factor in Europeans (all models except heterozygote comparison), Americans (all models except recessive and homozygote comparison) and Asians (just recessive and allelic model). Finally, the ethnicity-specific analysis disclosed a significant association between IL-4 C33T polymorphism and asthma risk in Caucasians (all genotype models except heterozygote comparison), while this association was not significant in African-Americans.
This study suggests that IL-4 C33T polymorphism potentially acts as a risk factor for asthma in different ethnicities and age groups.
先前的研究评估了 IL-4 C33T 多态性与支气管哮喘风险之间的关联，但未能建立一致的结论性关联。在本荟萃分析中，我们打算在填补已发表文献的情况下，对这种关联做出更可靠的估计。
在 2020 年 9 月之前，我们在 Web of Science、Scopus 和 PubMed 数据库中进行了全面搜索，以确定所有相关的出版物，最终纳入了 24 篇出版物（28 项研究），其中包括 6587 例病例和 8408 例对照。采用比值比（ORs）和 95%置信区间（CIs）来衡量多态性与哮喘风险之间的关联。此外，还使用 Cochran's Q 和 I 统计量来评估研究之间的异质性程度。
在总体研究人群中，所有基因型模型均显示出显著的阳性关联，表明 IL-4 C33T 多态性是哮喘发病机制中的一个潜在危险因素。在按年龄进行的亚组分析中，在等位基因模型中，IL-4 C33T 多态性与不同年龄组哮喘风险之间存在显著关联，这突出了 T 等位基因在所有三个年龄组中对哮喘风险的易感性作用。此外，按大陆进行的亚组分析结果存在异质性。因此，IL-4 C33T 多态性是欧洲人（除杂合子比较外的所有模型）、美国人（除隐性和纯合子比较外的所有模型）和亚洲人（仅隐性和等位基因模型）的哮喘风险的危险因素。最后，基于种族的分析表明，IL-4 C33T 多态性与白种人（除杂合子比较外的所有基因型模型）的哮喘风险之间存在显著关联，而在非裔美国人中这种关联不显著。
本研究表明，IL-4 C33T 多态性可能是不同种族和年龄组哮喘的一个危险因素。
