IL18 and systemic lupus erythematosus: When stratification by population and genotyping method in additive genetic model, meta-analysis showed IL-18 rs1946518 A allele might have a protective effect on SLE in Chinese population (OR=0.606, 95%CI =0.396-0.930), and significant association was also found in studies with PCR-RFLP method (OR=0.670, 95%CI =0.454-0.989), but results did not change when stratification by HWE status and sample size.