白细胞介素-18基因多态性与肺结核病易感性的关系

目的：通过病例-对照研究，探讨白细胞介素-18（IL-18）基因启动子区-607C/A、-137G/C位点单核苷酸多态性（SNP）与肺结核病的关系。方法：采用序列特异性引物PCR（PCR-SSP）及测序技术检测深圳地区汉族人群肺结核患者200例及健康对照者197例IL-18启动子区-607 C/A 、-137G/C位点多态性基因型。采用直接计数法计算各组基因型频率及等位基因频率，进行χ2 检验。以P值＜0.05为具有统计学意义。结果：肺结核患者IL-18启动子区-607位点A/A纯合子、A/C杂合子、C/C纯合子基因型频率分别为19.5%、55.0%、25.5% ；A、C等位基因频率分别为47.0%、53.0%。健康对照者A/A纯合子、A/C杂合子、C/C纯合子基因型频率分别为22.8%、46.7%、30.5%；A、C等位基因频率分别为46.2%、53.8%。两组人群-607位点基因型及等位基因分布无明显差异(P>0.05)。肺结核患者IL-18启动子区-137G/C位点C/C纯合子、C/G杂合子、G/G纯合子基因型频率分别为4.5%、18.5%、77.0%；C、G等位基因频率分别为13.8%、86.2%。健康对照者C/C纯合子、C/G杂合子、G/G纯合子基因型频率分别为5.6%、25.9%、68.5%；C、G等位基因频率分别为18.5%、81.5%。两组人群-137位点基因型分布无明显差异(P>0.05)。结论：IL-18启动子区-607、-137位点基因多态性与中国汉族人群肺结核病易感性无关。

Relationship between polymorphisms of interleukin-18 gene promoter region and susceptibility to pulmonary tuberculosis

Objective: To investigate the association of IL-18 gene promoter region polymorphisms at position -607C/A and -137G/C with susceptibility to pulmonary tuberculosis（PTB）by a case-control study. Methods: Using polymerase chain reaction with sequence specific primer(PCR-SSP)/sequencing method, the single nucleotide polymorphisms (SNPs) of the promoter region of IL-18 gene at position -607 and -137 were detected in 200 pulmonary tuberculosis patients(group PTB) and 197 normal healthy subjects(group NHS) in the Han population from Shenzhen of China. The genotype frequencies and allele frequencies had been directly count out and χ2 test was used to find out the difference of genotype frequencies distribution between two groups (the value of P <0.05 as statistically significant). Results: The genotype frequencies of A/A homozygote，A/C heterozygote and C/C homozygote at position -607 in the promoter region of IL-18 gene in patients with pulmonary tuberculosis were 19.5%,55.0% and 25.5% respectively. The frequencies of A and C Allele were 47.0% and 53.0% respectively. In normal healthy subjects the genotype frequencies of A/A homozygote，A/C heterozygote and C/C homozygote were 22.8%，46.7% and 30.5% respectively. A and C allele frequencies were 46.2% and 53.8% respectively. The genotype frequencies of C/C homozygote, C/G heterozygote and G/G genotype at position -137 in the promoter region of IL-18 gene in patients were 4.5%，18.5% and 77.0% respectively. The frequencies of C and G Allele were 13.8% and 86.2% respectively. In normal healthy subjects the genotype frequencies of C/C homozygote, C/G heterozygote and G/G heterozygote were 5.6%, 25.9% and 68.5% respectively. C and G allele frequencies were 18.5% and 81.5% respectively. There was no significant difference in genotype distribution of IL-18 gene promoter region at position -607(C/A) and -137(G/C) between two groups (P>0.05). Conclusion: The polymorphisms at position -607 and -137 in promoter region of IL-18 gene in Chinese Han population were not associated with susceptibility to pulmonary tuberculosis.