Objective: To investigate the association of the single nucleotide polymorphisms of interleukin-18 (IL-18) gene with the susceptibility to systematic lupus erythematosus (SLE) in a Chinese Zhuang population.
Methods: Two single nucleotide polymorphisms of the IL-18 gene promoter were analyzed, namely -137G/C and -607C/A, in 115 patients with SLE and 160 age and sex-matched controls in a Chinese Zhuang population, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy and DNA sequencing.
Results: The IL-18 gene -607C/A polymorphism was significantly different between the SLE and control group (P < 0.05). The relative risk of SLE for -607C allele carrier was 1.619 times of the -607A allele carriers (OR=1.619, 95%CI: 1.150-2.281). Consistent with the results of the genotyping analyses, IL-18 -137G/-607C allele frequencies in patients with SLE was significant higher than that in controls (P < 0.05). The -137G/-607C allele was associated with a significantly increased risk of SLE (OR=1.484, 95%CI: 1.056-2.087). However, there was no difference of the distributions of the -137G/C polymorphism of the IL-18 gene between the SLE and control groups.
Conclusion: IL-18 gene -607C/A polymorphism was associated with SLE, the -607C allele may be a risk factor for SLE.