系统性红斑狼疮与CTLA-4基因多态性的相关性研究

目的:研究细胞毒性T淋巴细胞相关抗原-4(CTLA-4)基因启动子区-1772(T/C)位点和外显子1中的+49(A/G)位点基因多态性与中国汉族人群系统性红斑狼疮(SLE)的相关性。方法:应用聚合酶链反应(PCR)-限制性片段长度多态性(RFLP)方法,对76例SLE患者和100例中国汉族正常对照者进行CTLA-4基因-1772(T/C)位点和+49(A/G)位点多态性检测。结果:与正常对照组比较,SLE患者CTLA-4基因-1772位点TT和CC基因型频率均明显升高(32.9%比14%,χ2=8.938,P=0.003;11.8%比2%,χ2=7.139,P=0.008),TC基因型频率明显降低(55.3%比84%,χ2=17.533,P=0.000);+49位点各基因型频率、等位基因频率和携带者频率总体分布均无显著性差异(P>0.05)。结论:CTLA-4基因+49位点多态性与中国汉族SLE无明显相关性,而-1772位点多态性与中国汉族SLE明显相关,CTLA-4基因可能是SLE的易感基因。

Association of CTLA-4 Gene Polymorphisms with Systemic Lupus Erythematosus

Objective: To investigate the possible association of cytotoxic T lymphocyte-associated antigen 4(CTLA-4) exon 1 +49(A/G)and promoter-1772 gene polymorphism with systemic lupus erythematosus(SLE) of Han population in China. Methods: The restriction fragment length polymorphism-polymerase chain reaction was used to analyze CTLA-4 exon 1(A/G)and promoter-1772 (T/C) polymorphism in 76 SLE patients and 100 healthy controls.Results: The frequency of TT and CC genotype at the-1772 SNP site was statistically higher in SLE patients than in healthy controls(32.9% vs14%,χ2=8.938,P=0.003;11.8% vs 2%,χ2=7.139,P=0.008).But the frequency of TC genotype at the-1772 SNP site was statistically lower(55.3% vs 84%,χ2=17.533,P=0.000).The allele frequency and gene phenotypes of T and C at the-1772 SNP site were not statistic significant between the two grpups(P>0.05).Conclusion: CTLA-4 exon 1+49 polymorphism showed no association with SLE of Han populationin China,but the-1772 polymorphism in the CTLA-4 promoter region appears to be associated with SLE of Han population in China,and CTLA-4 gene maybe one of the predisposing genes for SLE.