凋亡相关基因FAS-1377和FAS-670及其配体FASL-844位点基因多态性与中国汉族煤工尘肺的关系

目的探讨FAS／FASL基因多态性在煤工尘肺患者发病遗传易感性中的作用及其与煤工尘肺纤维化程度的联系。方法选择340例汉族煤工尘肺为观察对象，312例汉族煤尘接触者为对照组，应用多聚酶链反应-限制片段多态性（PCR—RFLP）技术检测FAS-1377G〉A、FAS-670A〉G位点及FASL-844T〉C位点的基因多态性。结果煤工尘肺组FAS．1377、FAS-670及FASL-844各基因及等位基因分布频率与对照组比较，差异无统计学意义（乃0．05）。以接尘工龄／〉25年为对照，工龄〈25年的煤工尘肺患者FAS-1377GA／AA型者发生尘肺的危险性是GG型的1．463倍（P=0．098，95％CI：0．932～2．298）；FAS-670AG型发生尘肺的危险性是GG型者的1．494倍（P=0．098，95％C／：0．928～2．404）：FASL-844TT型和TC型发生尘肺的危险性分别是CC型的5,455倍（P=0．039，95％CI：1,088-27．358）及1,338倍（P=0．098，95％CI：0．852-2．101）。接尘工龄〈25年FASL-844基因分布频率和工龄≥25年比较，差异有统计学意义（P〈0．05），FASL-844Tr型发生煤工尘肺的危险性是CC／TC型的4．810倍（P=O．054，95％CI：0．971-23．833）；接尘工龄≥25年为对照，工龄〈25年组FASL-844TT／CT＋FAS-1377GA型发生煤工尘肺的危险性是FASL-844CC＋FAS-1377GG型的1．810倍；FASL-844TT／CT＋FAS．670AG型是FASL-844CC＋FAS-670AA型的2．117倍；FASL-8TT／CT＋FAS-1377GA／AA＋FAS-670AG／GG型发生煤工尘肺的危险性是FASL-844CC＋FAS-1377GG＋FAS-670AA型的2．043倍。结论FAS．1377G〉A、FAS-670A〉G及FASL-844T〉C3个位点的基因多态性在中国汉族煤工尘肺发病的遗传易感性中不起主要作用，但这3个多态性位点及位点的联合作用对病变的发展有影响。     

TNF基因多态性与矽肺易感性

目的探讨肿瘤坏死因子(TNF)α和β基因多态性与矿工矽肺遗传易感性的关系。方法采用病例对照设计,以男性矽肺病人183例为病例组,111例无矽肺的男性接尘矿工为对照组。应用聚合酶链反应—限制性片段长度多态性分析(PCR-RFLP)技术检测TNFα-308、-238和TNFβ 252位点的多态性。结果TNFα-308、-238和TNFβ 252各位点基因型在病例组和对照组间的分布差异均无统计学意义(P>0.05),但吸烟且携带-308A等位基因的接尘工人更易发生矽肺(OR=2.50,95%CI=1.17~5.37)。病例组中-308G/-238 G/ 252G和-308A/-238 G/ 252A单倍型分布频率显著高于对照组(P<0.01)。结论TNFα-308、-238和TNFβ 252位点基因多态在矽肺发病的遗传易感性中不起主要作用,但TNFα-308多态性与吸烟有交互作用。单倍型-308G/-238G/ 252G和-308A/-238G/ 252A可能是矽肺发生的易感性标记。     

职业医学

教工尘肺样改变3例报告;尘肺病患者血清PDGF和PⅢNP含量的测定;煤工尘肺患者血清MMP9与TIMP1的表达;凋亡相关基因FAS-1377和FAS-670及其配体FASL-844位点基因多态性与中国汉族煤工尘肺的关系;尘肺患者生存年限的COX比例风险模型分析.     

凋亡信号通路基因多态性与煤工尘肺易感性

目的 探讨凋亡信号通路基因细胞凋亡基因(FAS)、FAS配体基因(FASL)、半胱氨酸-天冬氨酸蛋白质酶(CASP8)及CASP3单核苷酸多态性(SNP)与煤工尘肺易感性的关系.方法 采用病例-对照的研究方法,选择511例煤工尘肺患者为病例组,530例同单位、同工种、且工龄相近、未患尘肺的煤尘接触者为对照组;聚合酶链反应-限制性片段长度多态性( PCR-RFLP)法检测5个SNP位点的基因型;CASP3 rs 6948位点用荧光定量PCR法进行基因分型.结果 煤工尘肺组和对照组6个多态性位点的各基因型的分布频率比较,差异无统计学意义(P＞0.05).CASP8-652位点的6个碱基缺失(DD型)可明显增加煤工尘肺患病的危险性(调整后OR=1.96,95％ CI=1.15～3.33,P=0.013),其他各基因型对煤工尘肺患病危险性没有明显的影响;对CASP8-652 I＞D基因多态性进行分层分析发现,工龄≥28年组、吸烟组及1期煤工尘肺携带CASP8-652 DD基因型者煤工尘肺的患病危险性明显增高,差异有统计学意义(P＜0.05).6个多态性位点不同基因型之间的相互作用与煤工尘肺患病的关联性分析发现,携带FAS-1377GG/CASP8-652DD型者、携带FAS-670AG/CASP8-652DD型者和携带FASL-844CT/CASP8-652DD型者煤工尘肺患病危险性明显增加;携带FAS- 1377GA/CASP8-652ID型者煤工尘肺患病危险性明显降低.对Ⅰ期煤工尘肺患者中CASP8-652位点II、ID、DD 3种基因型携带者发病前的粉尘暴露时间进行回归分析,差异无统计学意义(P＞0.05).Ⅰ期煤工尘肺患者中不同基因型携带者发病前的粉尘暴露时间比较,差异无统计学意义(P＞0.05).结论 CASP8-652缺失基因型在煤工尘肺病变的发展过程中可能起一定的作用,并且与FAS- 1377、FAS-670及FAL-844存在基因相互作用.     

人类NRAMP1基因单核苷酸多态与接尘工人肺结核易感性

目的 探讨人类自然抵抗相关巨噬细胞蛋白1（NRAMP1）基因多态性与接尘工人肺结核易感性的关系.方法 采用1：2病例对照设计,按年龄相差小于5岁,工种、吸烟、饮酒率、总粉尘接触量和矽肺患病同比例匹配,选择61例男性肺结核患者为病例组（矽肺50例、非矽肺11例）,122例男性无肺结核者为对照组（矽肺100例、非矽肺22例）.应用聚合酶链反应-限制性片段长度多态性分析（PCR-RFLP）技术检测NRAMP1 INT4和D543N位点的多态性.结果 NRAMP1 INT4多态位点野生纯合子（G/G）、杂合子（G/C）和突变纯合子（C/C）在病例组的分布频率分别为63.9%、34.4%、1.6%,与对照组比较,差异有统计学意义（P＜0.05）,NRAMP1 INT4 C等位基因携带者患肺结核的危险性升高（OR=2.73,95% CI：1.32～5.64）,D543N位点多态与接尘工人肺结核易感性之间无关联（P＞0.05）.结论 NRAMP1基因第4内含子G＞C单核苷酸可能是接尘工人肺结核的易感因素.     

肿瘤坏死因子-a及其Ⅱ型受体基因多态性与矽肺

目的探讨肿瘤坏死因子-a(TNF-a)及其Ⅱ型受体(TNFRⅡ)基因多态性在矽肺发病遗传易感性中的作用及其与二氧化硅暴露的交互作用.方法选择259例矽肺患者和341例矽尘接触者(对照)为研究对象,对其职业史、尘肺病史、既往病史等进行问卷调查;拍摄其高仟伏X射线后前位胸片,根据尘肺病诊断标准进行诊断和分期;采集每个研究对象的外周静脉血,应用聚合酶链反应-限制性片断长度多态性(PCR-RFLP)技术检测其TNF-a及TNFRⅡ基因多态性.结果在成组或11配对分析中,矽肺患者和矽尘接触者两组间TNF-a基因-308位点G/A+A/A基因型和TNFRⅡ196位点T/G+G/G基因型分布频率的差异均无统计学意义(P＞0.05).当接尘工龄＜15年时,G/A+A/A基因型携带者发生矽肺的危险性是G/G基因型的6.74倍,95%CI1.01～44.99.结论TNF-α和TNFRⅡ基因多态性在汉族人群矽肺发病的遗传易感性中不起主要作用.TNF-α基因-308位点基因多态性在矽肺发病过程中与接尘工龄存在交互作用,当累积接尘量较低时,G/A+A/A基因型携带者发生矽肺的危险性较G/G基因型明显增加.     

IL-4基因多态性与HBV遗传易感性的研究

目的 探讨白介素4(interleukin-4,IL-4)基因的单核苷酸多态性(single nucleotide polymorphisms,SNPs)与皖汉族人群乙型肝炎病毒(hepatitis B virus,HBV)遗传易感性的关系.方法 采用病例对照研究,501位慢性乙型肝炎(chronic hepatitis B,CHB)患者和301位急性自限性HBV感染者分别组成病例组和对照组;采用多重单碱基延伸SNP分型技术(Multiplex SNaPshot),检测两组人群的IL-4基因rs2227284G/T、rs2243283C/G和rs2243288A/G 3个标签SNPs位点的单核苷酸多态性,分析两组间的等位基因频率、单体型频率、基因型是否存在统计学差异.结果 IL-4基因3个多态位点的基因型频率在两组间差异均无统计学意义(均有P＞0.05);IL-4基因3个态位点最小等位基因及其频率在两组间差异均无统计学意义(均有P ＞0.05);4个单体型GCA、TCA、TCG及TGG两组间差异均无统计学意义(均有P＞0.05).结论 皖汉族人群中IL-4基因的3个tagSNPs(rs2227284,rs2243283和rs2243288)位点的基因多态性与HBV感染的基因易感性可能无相关性.     

肿瘤坏死因子-α及其Ⅱ型受体基因多态性与矽肺

目的 探讨肿瘤坏死因子-α(TNF-α)及其Ⅱ型受体(TNFR Ⅱ)基因多态性在矽肺发病遗传易感性中的作用及其与二氧化硅暴露的交互作用。方法 选择259例矽肺患者和341例矽尘接触者(对照)为研究对象,对其职业史、尘肺病史、既往病史等进行问卷调查;拍摄其高仟伏X射线后前位胸片,根据尘肺病诊断标准进行诊断和分期;采集每个研究对象的外周静脉血,应用聚合酶链反应-限制性片断长度多态性(PCR-RFLP)技术检测其TNF-α及TNFR Ⅱ基因多态性。结果 在成组或1:1配对分析中,矽肺患者和矽尘接触者两组间TNF-α基因-308位点G/A A/A基因型和TNFRⅡ196位点T/G G/G基因型分布频率的差异均无统计学意义(P>0.05)。当接尘工龄<15年时,G/A A/A基因型携带者发生矽肺的危险性是G/G基因型的6.74倍,95％CI:1.01-44.99。结论TNF-α和TNFRⅡ基因多态性在汉族人群矽肺发病的遗传易感性中不起主要作用。TNF-α基因-308位点基因多态性在矽肺发病过程中与接尘工龄存在交互作用,当累积接尘量较低时,G/A A/A基因型携带者发生矽肺的危险性较G/G基因型明显增加。     

CYP1A1和CYP1B1基因多态性与RPL易感性

目的 探讨CYP1A1、CYP1B1基因多态性与复发性流产(RPL)遗传易感性关系,为预防和治疗该病提供新靶点.方法 本研究采用等位基因特异性PCR (As-PCR)和聚合酶链反应-限制性片断长度多态性(PCRRFLP)方法,针对CYP1A1基因MspI酶切位点和CYP1B1 L432V多态位点,检测81例患有原因不明RPL病例组和98名有生育史健康女性对照组之间差异.结果 RPL组和对照组CYP1A1 MspI位点3种基因型m1/m1、m1/m2、m2/m2分布频率差异无统计学意义(x2=0.335,P＞0.05);CYP1B1 L432V多态位点3种基因型C/C、C/G、G/G在病例组和对照组分布差异有统计学意义(x2=7.467,P＜0.05);2组间C、G等位基因分布差异有统计学意义(x2=9.129,P=0.003);G/G、C/G基因型与C/C基因型比较,RPL危险度分别提高2.620、1.954倍;等位基因G使RPL危险性增加2.038倍.结论 CYP1B1 L432V突变基因型增加RPL发病风险,尚不能认为CYP1A1基因MspI位点多态性与RPL易感性有关.     

FASL-844T/C多态性与宫颈癌易感性的Meta分析

目的:探讨FASL-844T/C多态性与宫颈癌易感性的关系。方法:全面检索相关文献,收集2012年1月以前有关FASL-844T/C多态性与宫颈癌易感性的病例对照研究,使用Stata 10.0进行Meta分析。结果:最终纳入病例对照研究6项,累计病例2 158例,对照1 471例。在显性模型、隐性模型、加性模型中,Meta分析的OR值及95%CI分别为1.13(0.92～1.39)、1.11(0.83～1.50)、1.12(0.91～1.36)。敏感性分析进一步表明该结果具有良好的稳定性。结论:FASL-844T/C多态性与宫颈癌易感性之间无显著关联。     

白细胞介素-6基因多态性与尘肺的相关性

目的 研究白细胞介素-6（IL-6）（-634C/G）基因多态性与尘肺的关系.方法 选择确诊的104例Ⅰ期男性矽肺患者66例（矽肺组）、煤工尘肺患者38例（煤工尘肺组）为研究对象,以接触同性质粉尘、非尘肺的122名男性接触矽尘工人77例（矽尘组）、接触煤尘工人45例（煤尘组）为对照;采集外周静脉血,应用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术检测IL-6（-634C/G）基因多态性.结果 IL-6（-634C/G）基因型（CC、CG、GG）在矽肺组、矽尘组、煤工尘肺组和煤尘组分布频率分别为66.7%、19.7%、13.6%,42.9%、42.9%、14.2%,73.7%、18.4%、7.9%和51.1%、35.6%、13.3%.成组分析和1：1配对分析中均发现IL-6（-634C/G）基因型分布频率在矽肺组和矽尘组间差异有统计学意义（P＜0.05）.结论 IL-6（-634 C/G）基因多态性与矽肺发病相关.     

Fas and FasL promoter polymorphisms and susceptibility to HBV infection: A systematic review and meta-analysis

Apoptosis is a universal cellular defense mechanism against senescent, damaged, genetically mutated, or virally-infected cells. It also is critical for the maintenance of liver health. Fas and FasL system act as a major death pathway that triggers apoptosis cascade in the liver. In this systematic review and meta-analysis, we aimed to investigate the relationship between four major polymorphisms of Fas and FasL genes with susceptibility to or clearance of HBV infection.All the eligible studies were extracted from PubMed and Scopus with no date and language restriction. ORs with 95% CIs were used to evaluate the strength of the association based on the following genetic models: (1) the allelic, (2) the homozygote, (3) the dominant, and (4) the recessive models.Totally 7 related articles were included in this meta-analysis; 5 studies of 7 related articles investigated FasL -844C/T (rs763110) polymorphism, 4 studies investigated FasL IVS2nt-124, 6 studies investigated Fas -670 A/G (rs1800682), and 4 studies investigated Fas -1377 A/G (rs2234767) polymorphism. This meta-analysis showed that there is no statistically significant association between the risk or clearance of HBV infection and four studied Fas and FasL polymorphisms in their allelic comparison or genetic models.Fas -670, Fas -1377, FasL -124, and FasL -844 polymorphisms did not show any significant association with the clearance or risk of HBV infection. Therefore, it seems that susceptibility to HBV infection or clearance of it is not affected by Fas and FasL genetic polymorphisms. But, to reach a definitive conclusion, further studies with a larger sample size of different ethnicity are still needed.     

白细胞介素-8基因多态性与矽肺易感性研究

目的 探讨白细胞介素(IL)-8基因多态性与矽肺易感性的关系.方法 选择确诊的101例矽肺患者为病例组,以接触同性质粉尘、首次诊断年龄相近的非矽肺的接尘工人为对照(121例).采集外周静脉血,盐析法提取DNA,应用聚合酶链-限制性片段长度多态性(PCR-RFLP)技术检测IL-8(Met31Arg、781C/T、-251A/T、RA+860)4个位点的基因型和等位基因频率并进行分析.结果 两组对象的首次诊断年龄、累积接尘工龄、吸烟率的差异均无统计学意义(P＞0.10).病例组IL-8(Met31Arg)GT基因型的分布频率为12.87%,对照组为2.48%,差异有统计学意义(P＜0.05),病例组和对照组携带等位基因G的频率分别为6.44%和2.07%,差异有统计学意义(P＜0.05).病例组IL-8(-251A/T)从基因型的分布频率为9.90%,对照组为25.62%,差异有统计学意义(P＜0.05).病例组IL-8(781C/T)基因型CC、CT、TT的分布频率分别为38.61%、40.59%、20.79%,与对照组(46.28%、40.50%、13.22%)相比,差异无统计学意义(P＞0.05).病例组IL-8(RA+860)基因型GG、GC、CC的分布频率分别为75.25%、21.78%、2.97%,与对照组(80.17%、14.88%、4.96%)相比,差异无统计学意义(P＞0.05).结论 IL-8的Met31Arg位点和一251MT位点的基因多态性与矽肺易感性有关,携带IL-8(Met31Arg)GT基因型的接尘工人患矽肺的危险性增加;携带IL-8(-251)从基因型的接尘工人患矽肺的危险性降低.未发现IL-8(781C/T和RA+860)位点的基因多态性与矽肺易感性有关.

Abstract：

Objective To explore the relationship between the polymorphisms of interleukin-8(IL-8)and the silicosis susceptibility. Methods The case group consisted of 101 male patients with stage I silicosis diagnosed by the Pneumoconiosis Diagnosis Expert Panel according to the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70-2009). The control group consisted of 121 workers without silicosis exposed to same dusts. The cases and the controls had the same dust exposure history. The peripheral venous blood was drawn from each subject. DNA was extracted from leucocytes by the salting method. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) techniques and PCR were used to examine polymorphism of IL-8(Met31Arg, 781C/T,-251A/T and RA+860). Results There were no the differences of age, cumulative exposure time and smoking between the cases and the controls (P＞0.05). The frequencies of IL-8 (Met31Arg) GT genotypes in cases and controls were 12.87% and 2.48%, respectively, there was significant difference (P＜0.05).The frequencies of allele G in cases and controls were 6.44% and 2.07%, respectively, there was significant difference (P＜0.05). The frequencies of IL-8 (-251A/T) AA genotypes in cases and controls were 9.90% and 25.64%, respectively, there was significant difference (P＜0.05). The frequencies of IL-8 (781C/T) CC, CT, TT genotypes in cases and controls were 38.61%,40.59%,20.79% and 46.28%,40.50%, 13.22%, respectively, there zwas no significant difference (P＞0.05). The frequencies of IL-8 (RA+860) GG, GC and CC genotypes in cases and controls were 75.25%, 21.78%, 2.97%, 80.17%, 14.88%, 4.96%, respectively, there was no significant difference (P＞0.05). Conclusions IL-8 (Met31 Arg and -251A/T) genetic polymorphisms might play a role in the development of silicosis. The risk of pneumoconiosis in workers carrying (Met31 Arg) genotype GT is likely to increase.The risk of pneumoconiosis in workers carrying IL-8 (-251A/T) AA genotype is likely to decrease. The relationship between IL-8 781C/T and RA+860 genes polymorphisms and silicosis is not found.     

锡矿工人接尘与矽肺危险度评价

目的探讨粉尘暴露与矽肺危险度之间的接触效应关系。方法选择广西４个锡矿１９６０～１９６５年间工作１年以上的３０１０名接尘工人进行队列研究。用生存分析法统计累积粉尘接触量和矽肺出现的关系。结果追访到１９９４年底,检出矽肺１０１５例（３３．７％）。矽肺平均潜伏期２１．３年。总粉尘浓度７．５ｍｇ／ｍ３（ＴＷＡ）。拟合生存分析模型表明：矽肺发病危险度与累积接尘量的关系适合Ｗｅｉｂｕｌ分布。累积总粉尘接触量低于１０ｍｇ·ｍ－３·ａ－１时,矽肺危险小于１％;累积总粉尘接触量超过２０ｍｇ·ｍ－３·ａ－１时,矽肺累积危险度升高加快;累积总粉尘接触量达１５０ｍｇ·ｍ－３·ａ－１时,矽肺危险超过６８％。接尘时间与接尘量和矽肺危险度呈正相关。结论矽肺危险度与累积接尘量之间存在接触效应关系。     

白细胞介素-4基因多态性与矽肺易感性的病例对照研究

目的 探讨白细胞介素-4(IL-4)(-33、+45、VNTR、+429、+448)位点基因多态性与矽肺易感性的关系.方法 采用整群病例对照研究,病例组为101名Ⅰ期矽肺患者,对照组为与病例年龄相近、同性别、同民族、同一工作地点、累积接尘工龄相近的非矽肺接尘工人121名.采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)法检测IL-4的5个基因位点的基因型并进行分析.结果 两组对象的年龄、累积接尘工龄、吸烟率比较,差异均无统计学意义(P＞0.05).IL-4(+429)位点仅存在GA 基因型,未发现GG和AA基因型;IL-4(+448)位点仅存在CC基因型,未发现CG和GG基因型.病例组IL-4(+45)位点AA、GG和AG基因型频率分别为55.4%、10.9%和33.7%,与对照组(62.0%、11.6%、26.4%)比较,差异无统计学意义(x2=1.386,P＞0.05);病例组IL-4(VNTR)位点B1B1、B282和B182基因型频率分别为73.3%、1.0%和25.7%,与对照组(68.6%、1.7%、29.8%)比较,差异无统计学意义(x2=0.580,P＞0.05);病例组IL-4(-33)位点TY、CC和CT基因型频率分别为55.4%、11.9%和32.7%,与对照组(69.4%、4.1%、26.4%)比较,差异有统计学意义(x2=6.751,P＜0.05).结论 未发现IL-4(+45、VNTR)与矽肺患病的关系,未发现IL-4(+448、+429)存在多态性现象.IL-4(-33)位点多态性与矽肺患病有关,携带IL-4-33等位基因C的接尘者患矽肺的危险性增加.

Abstract：

Objective To explore the relationship between polymorphisms of interleukin-4 (IL-4)gene (-33,+45,VNTR,+429,+448) and the susceptibility of silicosis. Methods In a case-control study, the case group consisted of 101 patients with silicosis, and was matched with the control group (121 workers without silicosis), according to the age, sex, nationality, working place, exposure to dust. The polymorphisms of IL-4(five locus) detected by the method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. Results There was no difference of age, exposure and smoking between case group and control group (P＞0.05). The two groups had good comparability. Only the GA genotype in the IL-4 (+429)locus was found, the genotypes of AA and GG were not found. The CC genotype in the IL-4 (+448) locus was found, the genotypes of CG and GG were not found. The frequencies of AA, GG and AG of IL-4 (+45) locus in the case and control groups were 55.4%, 10.9%, 33.7% and 62.0%, 11.6%, 26.4%, respectively, there was no the significant difference between case and control groups (P＞0.05). The frequencies of B1B1, B2B2 and B1B2of IL-4 (VNTR) locus in the case and control groups were 73.3%, 1.0%, 25.7% and 68.6%, 1.7%, 29.8%,respectively, there was no the significant difference between case and control groups (P＞0.05). The frequencies of TT, CC and CT in IL-4 -33 locus in the case group were 55.4%, 11.9% and 32.7%, which were significantly higher than those (69.4%, 4.1%, 26.4%) in control group (P＜0.05). Conclusions There was no relationship between IL-4 (+45,VNTR) genotypes and prevalence of silicosis in this study. The polymorphisms of IL-4(+448)site were not found which may be related to the race. The relationship between genetic polymorphism of IL-4(-33) locus and silicosis development was found, Workers with IL-4(-33) allele C are susceptible to the silica.     

Genetic polymorphisms in alveolar macrophage response-related genes, and risk of silicosis and pulmonary tuberculosis in Chinese iron miners

Alveolar macrophages (AMs) play a prominent role in influencing the development of lung inflammation and injury. The aim of this study is to investigate the roles of AMs response-related genes TNF-alpha, iNOS, and NRAMP1 (SLC11A1) in susceptibility to silicosis and pulmonary tuberculosis (PTB), and to analyze the interaction of dust exposure and genetic susceptibility to silicosis, interactions of TNF-alpha-308 and Natural Resistance-associated Macrophage Protein 1 (NRAMP1) INT4, D543N polymorphisms to PTB. Several epidemiological designs were used: retrospective investigations on dust exposure, case-control studies of 184 silicosis cases and 111 miners occupationally exposed to silica dust, and 1:2 matched case-control studies of 61 PTB cases and 122 PTB-free miners. The miners and controls were recruited from an iron mining operation in Anhui province, China. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was applied to detect single nucleotide polymorphisms. Despite the recruitment of high dust exposure among the controls, silicosis patients still had significantly higher dust exposure than controls (242.6 +/- 98.8 vs. 217.6 +/- 100.7 mg a/m(3)). The mutation of iNOS Ser608Leu is associated with protection against silicosis and against severity of silicosis in the miners. There is a 0.47-fold (95% CI: 0.28-0.79) decrease in risk of silicosis for individuals with C/T, T/T genotype compared with the wild-type homozygous (C/C) individuals after adjustment for occupational exposure, smoking, and drinking. The protection effect of the iNOS polymorphism was particularly detected in the > or = 150 mg a/m(3) exposure group (OR: 0.44, 95% CI: 0.22-0.91). However, no interaction of dust exposure with the iNOS polymorphism was observed. Furthermore, the variant NRAMP1 INT4 genotype is significantly associated with PTB in miners. No association of other polymorphisms (NRAMP1 D543N, TNF-alpha-308) and susceptibility to silicosis or PTB in Chinese miners was found. Our data showed a 3.26-fold (95% CI: 1.47-7.23) increased risk of PTB for miners carrying both the NRAMP1 D543N G/G and NRAMP1 INT4 G/C+C/C genotypes. Additionally, in miners with TNF-alpha-308 G/G genotype, the risk of PTB increased 2.38-fold if they carry the NRAMP1 INT4 G/C+C/C genotype (95% CI: 1.14-4.98). In conclusion, the C>T mutation of iNOS Ser608Leu may be an important protective factor to miners. On the other hand, the variant NRAMP1 INT4 may play a role in the development of PTB in Chinese miners. Therefore, the novel information can be used as guideline for further mechanistic investigations and for strengthening specific protection protocols for workers.