Lack of association of interleukin-18 gene promoter −607 A/C polymorphism with susceptibility to autoimmune diseases: a meta-analysis

Abstract

Objective: Published data on the association between interleukin (IL)-18 gene promoter −607 A/C polymorphism and autoimmune diseases risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed.

Methods: A total of 17 studies, including six studies on type 1 diabetes (T1D), four on rheumatoid arthritis (RA), five on systemic lupus erythematosus (SLE), three on Crohn’s Disease (CD) and three on ulcerative colitis (UC), were available for the meta-analysis. Meta-analysis was performed for genotypes A/A (recessive effect), genotypes A/A + A/C (dominant effect), and A allele in fixed or random-effects models.

Results: Overall, no significantly elevated autoimmune diseases risk was found in all genetic models when all studies were pooled into the meta-analysis. The overall odds ratios (ORs) and 95% confidence intervals (CIs) for A-allele were T1D (OR = 0.938, 95% CI = 0.757–1.162), RA (OR = 0.759, 95% CI = 0.540–1.067), SLE (OR = 0.858, 95% CI = 0.609–1.208), CD (OR = 1.159, 95% CI = 0.975–1.379) and UC (OR = 1.170, 95% CI = 0.977–1.402), respectively. In the subgroup analysis by ethnicity, there was still no significant association detected in all genetic models.

Conclusions: To date, there is still not enough evidence to indicate the association of IL-18 gene promoter −607 A/C polymorphism and the development of autoimmune diseases.