Characteristics of the case-control studies included in meta-analysis.

*<p>Data for atopic or non-atopic asthma patients could be separately extracted.</p><p>ATS, American Thoracic Society; NHLBI, The National Heart, Lung, and Blood Institute; WHO, The World Health Organization; NIH, National Institutes of Health; SPT, skin prick test to common aeroallergens; RAST, radioallergosorbent test; PCR, polymerase chain reaction; RFLP, restriction fragment length polymorphism; TaqMan-ASA, TaqMan allele-specific amplification method; NA, not available.</p

Meta-analysis with a random-effects model for the association between asthma risk and the <i>CTLA-4</i> +49 A/G polymorphism (AA vs. AG+GG).

<p>Meta-analysis with a random-effects model for the association between asthma risk and the <i>CTLA-4</i> +49 A/G polymorphism (AA vs. AG+GG).</p

Meta-analysis with a random-effects model for the association between asthma risk and the <i>CTLA-4</i> −318 C/T polymorphism (CC+CT vs. TT).

<p>Meta-analysis with a random-effects model for the association between asthma risk and the <i>CTLA-4</i> −318 C/T polymorphism (CC+CT vs. TT).</p

Flow of study identification, inclusion, and exclusion.

<p>Flow of study identification, inclusion, and exclusion.</p

Funnel plot for publication bias in selection of studies on the <i>CTLA-4</i> −318 C/T polymorphism (CC+CT vs. TT).

<p>Funnel plot for publication bias in selection of studies on the <i>CTLA-4</i> −318 C/T polymorphism (CC+CT vs. TT).</p

Distribution of <i>CTLA-4</i> genotype among patients and controls included in the meta-analysis.

a<p>AA or CC;</p>b<p>AG, CT, or AC;</p>c<p>GG, TT or CC.</p><p>HWE, Hardy-Weinberg equilibrium.</p

Funnel plot for publication bias in selection of studies on the <i>CTLA-4</i> +49 A/G polymorphism (AA vs. AG+GG).

<p>Funnel plot for publication bias in selection of studies on the <i>CTLA-4</i> +49 A/G polymorphism (AA vs. AG+GG).</p

Determination of the genetic effects of <i>CTLA-4</i> polymorphisms on asthma and sensitivity analyses.

<p>vs., versus; R, random-effects model.</p

Determination of the genetic effects of <i>IL4RA</i> polymorphisms on asthma and subgroup analysis.

<p>Bonferroni correction was applied (<i>P</i><0.00714). vs., versus; R, random-effects model; F, fixed-effects model; HWE, Hardy-Weinberg equilibrium.</p

Association between <i>Interleukin-4 Receptor α Chain</i> (<i>IL4RA</i>) I50V and Q551R Polymorphisms and Asthma Risk: An Update Meta-Analysis

<div><p>Background</p><p>The associations between the <i>interleukin-4 receptor α chain</i> (<i>IL4RA</i>) I50V and Q551R polymorphisms and asthma risk remained controversial.</p><p>Methods</p><p>We searched the Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases for studies published before February 2013. The strengths of the associations were calculated using odds ratios (ORs) with 95% confidence intervals (CIs).</p><p>Results</p><p>A total of 50 studies were included in this meta-analysis. There was a significant association between the <i>IL4RA</i> I50V polymorphism and asthma risk in a dominant genetic model (OR = 1.13, 95% CI 1.04–1.23, <i>P</i> = 0.005). The <i>IL4RA</i> Q551R polymorphism was associated with a significantly elevated asthma risk in a recessive genetic model (OR = 1.46, 95% CI 1.22–1.75, <i>P</i><0.0001). Subgroup analyses found that the <i>IL4RA</i> I50V polymorphism was significantly associated with asthma risk in Asians (OR = 1.72, 95% CI 1.31–2.25, <i>P</i><0.0001), pediatric asthma risk (OR = 1.50, 95% CI 1.13–1.99, <i>P</i> = 0.005), and atopic asthma risk (OR = 1.88, 95% CI 1.27–2.79, <i>P</i> = 0.002).</p><p>Conclusions</p><p>The results of this meta-analysis suggested that the <i>IL4RA</i> I50V and Q551R polymorphisms may be risk factors for developing asthma.</p></div