细胞毒性T淋巴细胞相关抗原4基因多态性与甲巯咪唑致Graves病患者肝损害的相关性

Relationship between the cytotoxic T lymphocyte-associated antigen 4 gene polymorphisms and the liver injury caused by methimazole in patients with Graves disease

目的探讨细胞毒性T淋巴细胞相关抗原4(CTLA-4)基因多态性与甲巯咪唑(MMI)致山东地区汉族Graves病(GD)患者肝损害的相关性。方法研究对象选自2011年3月至2012年4月到青岛大学医学院附属医院内分泌科就诊或住院的GD患者(GD组)和同期到体检中心查体的健康人(健康对照组)。GD组分为3个亚组:单纯性GD组、MMI致肝损害组和甲亢性肝损害组。收集受试者外周非抗凝静脉血血凝块,提取基因组DNA,应用聚合酶链反应-限制性片段长度多态性技术测定CTLA-4基因第一外显子49位点和启动子区-318位点基因型,计算各组的基因型和等位基因频率。结果共收集到GD患者160例,其中单纯性GD组65例,男10例,女55例,平均年龄(40.4±14.4)岁;MMI致肝损害组40例,男11例,女29例,平均年龄(40.5±13.7)岁;甲亢性肝损害组55例,男9例,女46例,平均年龄(38.0±12.9)岁。健康对照组64例,其中男20例,女44例,平均年龄(40.7±10.7)岁。各组性别、年龄差异无统计学意义(P>0.05)。GD组和健康对照组CTLA-4基因第一外显子49位点AG+GG基因型频率分别为91.9%(147/160)和78.1%(50/64),G等位基因频率分别为74.4%(238/320)和59.4%(76/128),组间差异有统计学意义(χ2=8.153,P=0.004;χ2=6.259,P=0.012);启动子区-318位点的CT+TT基因型和T等位基因频率分布组间差异无统计学意义(P>0.05)。GD组的3个亚组之间两两比较,CTLA-4基因第一外显子49位点AG+GG基因型和G等位基因频率,启动子区-318位点CT+TT基因型和T等位基因频率差异均无统计学意义(均P>0.05)。结论 CTLA-4基因第一外显子49位点及启动子区-318位点多态性与山东地区汉族人群MMI所致肝损害无明显相关性,第一外显子49位点A/G多态性与GD的发生可能相关。

Objective To explore the relationship between the cytotoxic T lymphocyte-associated antigen 4 gene（CTLA-4） polymorphisms and the liver injury caused by methimazole（MMI） in the Chinese Han patients with Graves disease（GD） in Shandong district.Methods The subjects were selected from out-and in-patients with GD at the Department of Endocrinology（the GD group）,and the healthy people receiving physical examination at the medical center（the healthy control group） in the Affiliated Hospital of Qingdao University from March 2011 to April 2012.The GD group comprised 3 subgroups： the simple GD group,the MMI-induced liver injury group,and the hyperthyroidism-related liver injury group.Clot of non-anticoagulated blood from a peripheral vein in each subject was collected,genomic DNA was extracted,and genotypes at position 49 in exon 1 and position-318 in promoter region of CTLA-4 gene were detected using polymerase chain reaction-restriction fragment length polymorphism.The genotype and allele frequencies in all groups were calculated.Results A total of 160 GD patients were collected.Of them,65 patients were in the simple GD group,including 10 males and 55 females with an average age of（40.4±14.4） years;40 patients in the MMI-induced liver injury group,including 11 males and 29 females with an average age of（40.5±13.7） years;55 patients in the hyperthyroidism-related liver injury group,including 9 males and 46 females with an average age of（38.0±12.9） years.Sixty-four healthy people were in the healthy control group,including 20 males and 44 females with an average age of（40.7±10.7） years.The differences in gender and age among all groups were not statistically significant（P0.05）.The genotype frequencies of AG＋GG at position 49 in exon 1 of CTLA-4 gene in the GD and the health control groups were 91.9%（147/160）and 78.1%（50/64）,respectively;the allele frequencies of G were 74.4%（238/320） and 59.4%（76/128）,respectively;the differences in the 2 groups were statistically significant（χ2=8.153,P=0.004;χ2=6.259,P=0.012）.The genotype frequencies of CT＋TT and the allele frequencies of T at position-318 in promoter region of CTLA-4 gene between the GD and the health control groups were not statistically significant（P0.05 for all comparisons）.The differences in the genotype frequencies of AG＋GG and the allele frequencies of G at position 49 in exon 1 of CTLA-4 gene,the genotype frequencies of CT＋TT and the allele frequencies of T at position-318 in promoter region of CTLA-4 gene among the 3 subgroups in the GD group were not statistically significant（P0.05 for all comparisons）.ConclusionIn Chinese Han patients with GD in Shandong district,the polymorphisms of CTLA-4 gene at position 49 in exon 1 and-318 promoter region are not significantly related to MMI-caused liver injury,and the polymorphism of A/G at position 49 in exon 1 might be related to the pathogenesis of GD.