Meta-analysis on the association TLR4 Asp299Gly polymorphism with ankylosing spondylitis

Objective To investigate the association of Asp299Gly polymorphism in toll-like receptor 4(TLR4) gene with ankylosing spondylitis(AS) through meta-analysis for supplying evidences with evidence-based medicine in research of the genetic background of AS. Methods Literatures were initially retrieved from CBM disc,CNKI,WANGFANG DATA and PubMed by key words of "ankylosing spondylitis","toll-like receptor 4/TLR4 and polymorphism",and articles related to TLR4 Asp299Gly polymorphism and AS were available by July 2015.Eligible studies were defined as case-control study on full data included in the paper basis,and subjected to meta-analysis.Fixed effects model was used to pool the odd ratio(OR) by homogeneity in the data.Publication bias among the enrolled studies was evaluated using Egger' test to measure the funnel plot asymmetry.Systematic review was performed to estimate the relation of TLR4 Asp299Gly polymorphism with AS. Results Six studies related to TLR4 Asp299Gly polymorphism and AS were finally enrolled for current meta-analysis,involving 851 AS cases and 842 controls.The healthy controls in the 6 studies were agreed on Hardy-Weinberg equilibrium.Genotype distribution(AG+GG vs.AA) for TLR4 Asp299Gly allele was 5.82 by Q-test and I² statistic to estimate the degree of heterogeneity(I²=48.5%,P>0.05).Fixed effects model estimation indicated pooled OR=1.04(95% CI=0.70-1.54,P>0.05).The difference was not significant.No publication bias was found by examining the funnel plot asymmetry using Egger' test(P>0.05).As for the allele G/A in TLR4 Asp299Gly,Q-test and I² statistics showed 6.80(I²=55.9%,P>0.05).Fixed effects model revealed no significant difference(OR=1.02,95% CI=0.70-1.50,P>0.05).No publication bias occurred on allele G/A as the funnel plot asymmetry measured by Egger' test. Conclusion Current findings appear hard to determine the association of TLR4 Asp299Gly polymorphism with AS.