细胞因子基因多态性与肺结核并发糖尿病易感性的相关性研究

Association of cytokine genetic polymorphisms with susceptibility to diabetic pulmonary tuberculosis

目的探索细胞因子γ-干扰素（IFN-γ）＋874A／T位点、白细胞介素（IL）-10-1082G／A位点和-592A／C位点基因多态性与肺结核并发糖尿病（pulmonary tuberculosisanddiabetic mellitus，PTB-DM）易感性的关系，以及遗传危险因素在PTB-DM发病机制中的作用，为PTB-DM高危人群基因多态性筛查提供理论依据。方法采用病例对照研究方法，纳入江苏省2013年4月1日至2014年3月31日3个市（县）142例PTB-DM患者（PTB-DM组），同期选取诊断为结核病的患者147例（TB组）和糖尿病患者141例（DM组）作为对照。通过结构式问卷调查获取研究对象社会人口学信息，采集患者血样并提取DNA，采用聚合酶链式反应并限制性片段长度多态性（polymerase chain reaction-restriction fragment length plymorphism，PCR-RFIF）方法检测IFIFN＋874A／T位点、IL-10-1082G／A位点和-592A／C位点基因多态性。采用EpEPiData和SPSS16．O统计软件录入与分析数据，运用单因素方差分析和多因素logistic回归分析I附7＋874A／T位点、IL-10-1082G／A位点和-592A／C位点基因多态性与PT昏DM易感性的相关性。结果IFN-γ十874A／T、IL-10一592A／C、IL-10-1082G／A位点经PCR扩增和基因多态性位点分型鉴定，分别获得等位基因A和T、A和C、G和A，以及基因型AA、AT、TT；AA、AC、CC；GA、AA。基因多态性检测结果显示，仅PT昏DM组IL-10-1082G／A位点A等位基因频率（92．61％，263／284）高于DM组（87．59％，247／282）（χ^2=3．995，P=O．046）、AA基因型频率（85．21％，121／142）高于DM组（75．18％，106／141）[校正OR（αOR）-1．970；95％CI：1．066-3．643；P=0．030]。IL-10-592和-1082两位点间存在连锁不平衡（D=0．959，-0．181，P〈O．001），PTB-DM患者的IL-10 C-A单倍型频率（25．90％）明显高于DM组患者（17．60％）（OR=1．590，95％CI=1．056-2．396，P=0．026）。结论IL-10-1082位点的从基因型可能与PT昏DM易感性有关，为疾病共患的危险因素；IL-10单倍型与PTBDM易感性存在相关性，其C-A单倍型可能使DM患者共患TB的风险上升。而IL-10-592A／c位点和IFN-γ＋874A／T位点可能与DM患者对TB的易感性、或者TB患者对DM的易感性无关。

Objective This study aims to reveal the associations among IFN-γ ＋874 A/T, IL-10 --592 A/C, --1082 G/A SNPs and risk of diabetic pulmonary tuberculosis, and consequently provide further evidence for research on pathogenesis of diabetic pulmonary tuberculosis （PTB-DM） and the screening for diabetic pulmonary tuberculosis patients. Methods A case-control study based on the screening of DM in PTB patients （142 cases） was carried out in 3 counties in Jiangsu Province from 1 April, 2013 to 31 March, 2014. Cases in this study were all diagnosed diabetic pulmonary tuberculosis patients, whereas control groups were PTB patients （147 cases） and DM patients （141 cases） matching with gender and age. Social demographic information was collected by a questionnaireand DNA was extracted from the blood sample collected. The polymorphisms of IFN--＇ -5874 A/T, IL-10 --592 A/C and --1082 G/A were detected by PCR-RFLF methods and followed by direct sequencing. Statistical analyses were conducted using the EpiData and SPSS software version 16.0. Pearson chi-square and logistic regression were used to estimate the associations among IFN-＇I ＋874 A/T, IL-10 -- 592 A/C, -- 1082 G/A SNPs and risk of diabetic pulmonary tuberculosis. Results In the study on IL-10 --1082 G/A, statistical differences were discovered between PTB-DM patients and DM controls （A allele, 92.61- （263/284） versus 87.59% （247/282）（;g2 =3. 995, P=0. 046） ; AA genotype, 85.21G （121/142） versus 75.18G （106/141）. The AA genotype of IL-10 had a 1. 970 fold increased risk for diabetic pulmonary tuberculosis individuals （OR= 1. 970, 95% CI= 1. 066--3. 643, respec- tively）. Linkage disequilibrium was found between IL-10 -- 592 and IL-10 -- 1082 （D＇ = 0. 959, r2 ----- 0. 181, P- 0. 001） and statistical significance was also found in ILl0 --592C/--1082A haplotype between diabetic pulmonary tuberculosis patients and DM controls （25.90-/＇00 versus 17.60%, P= 0. 026）; IL-10 --592C/--1082A haplotype had a 1. 590 fold increased risk for diabetic pulmonary tuberculosis individuals （OR= 1. 590, 95%CI= 1. 056-- 2. 396, respectively）. Conclusion Our results indicated an association between IL-10 -- 1082G/A polymorphism and susceptibility to diabetic pulmonary tuberculosis. Novel risk haplotype of II=10 has been identified, of which --592C/--1082A haplotype was found to be strongly linked to diabetic pulmonary tuberculosis susceptibility. However, no association was found between IL-10 --592 or IFN-7 -I-874 and the risk of diabetic pulmonary tuberculosis.