The association of IL1α and IL1β polymorphisms with susceptibility to systemic lupus erythematosus: a meta-analysis.

Many epidemiological studies have investigated IL1α and IL1β polymorphisms with SLE risk, but no conclusions are available because of conflicting results. This meta-analysis was performed to more precisely estimate the relationships. The databases of PubMed updated to September 1st, 2012 were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, six case-control studies for IL1β-511C/T, four studies for IL1β+3953C/T, three studies for IL1α-889C/T and three studies for IL1α+4845G/T were involved in this analysis. The results indicated that for IL1α-889C/T polymorphism T allele was associated with decreased risk of SLE (OR (95% CI)) (T vs. C: 0.802 (0.679-0.949); TT+CT vs. CC: 0.615 (0.380-0.995); TT vs. CC: 0.679 (0.466-0.989)). However, when analysis for TT vs. CT+CC was conducted, the result indicated that IL1α-889C/T polymorphism was not associated with SLE (OR (95% CI): 0.847 (0.595-1.205)). Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of SLE (OR (95% CI)) (T vs. C: 1.113 (0.954-1.298); TT vs. CT+CC: 1.146 (0.889-1.447); TT+CT vs. CC: 1.145 (0.903-1.452); TT vs. CC: 1.255 (0.928-1.698)). When subgroup analysis for Asian ethnicity was conducted, the results indicated that IL1β-511C/T polymorphism was associated with SLE only for TT vs. CT+CC (OR (95% CI): 1.468 (1.001-2.152)), but was not associated for T vs. C (OR (95% CI): 1.214 (0.955-1.544)), TT+CT vs. CC (OR (95% CI): 1.112 (0.765-1.615)) and TT vs.CC (OR (95% CI): 1.411 (0.896-2.222)). In addition, overall analyses indicated that IL1β+3953C/T and IL1α+4845G/C polymorphisms were also not associated with risk of SLE (OR (95% CI)) (for IL1β+3953C/T T vs. C: 0.996 (0.610-1.626), TT vs. CT+CC: 0.658 (0.318-1.358), TT+CT vs. CC: 1.021 (0.618-1.687), TT vs. CC: 0.640 (0.309-1.325); for IL1α+4845G/T T vs. G: 1.067 (0.791-1.440), TT+GT vs. GG: 0.934 (0.646-1.351)).This study inferred that IL1α-889C/T polymorphism might be moderately associated with SLE, but no sufficient evidence was available to support any associations between IL1β+3953C/T or IL1α+4845G/C polymorphisms and SLE. We could not draw a definite conclusion between IL1β-511C/T polymorphism and risk of SLE owing to the limited data. Further large sample-sized studies should be required.