广西苗族、侗族儿童乙肝疫苗免疫应答与TLR2、TLR4基因多态性关联的研究

Hepatitis B vaccination is the most efective messure for prevention of Hepatitis B Virus(HBV) infection. Although the prevalance of surface antigen of the hepatitis B virus(HBsAg) was lower than 1% in children under 5 years old in China，a study performed in 2011 showed that the prevalance of HBsAg was 3.62% in children under 5 years old in Guangxi, and 34.2% children under 5 years old had no response to hepatitis B vaccination, which was higher than that of other province in China(15-20%).The non response rate to hepatitis B vaccination in Miao and Dong children was extrmely high(63.6% and 45.8%, respectively). This phenomenon should be further studied.New study confirmed that Toll-like receptors 2(TLR2) and Toll-like receptors 4(TLR4) single-nucleotide polymorphism(SNPs) are associated with immune response of vaccine, however, the association between SNPs of TLR2 and TLR4 and hepatitis B vaccination in Miao and Dong children were not demonstrated. .In this study, we perform a hospital base 1:1 case control study in Miao and Dong children in Guangxi after Hepatitis B vaccination.The children who have low or no response to hepatitis B vaccine are enroled as cases, while those who have normal response are enroled as controls. The SNPs of TLR2 and TL4 are genotyped by SNaPshot.We explore the association between SNPs of TLR2 and TLR4 gene and immune response to hepatitis B vaccine in a large population, which would provide scientific evidence for the genetics mechanism of low or no immune response to hepatitis B vaccine.

.接种乙肝疫苗是预防HBV感染的最有效措施。2006年我国5 岁以下儿童HBsAg 感染率已降至低于1％，但2011年广西同龄儿童HBsAg感染率仍高达3.62%，乙肝疫苗无应答率为34.20%，远高于其它省的15～20%，尤其是苗族和侗族同龄儿童更高，分别为63.60%和45.80%，其原因值得深入研究。最新研究表明Toll 样受体2(TLR2) 和4(TLR4)的基因多态性(SNPs)与疫苗免疫应答有关，但TLR2和TLR4基因SNPs与苗族、侗族儿童乙肝疫苗免疫应答的关联尚未明确。.本研究采用1:1病例对照研究方法，以完成全程接种乙肝疫苗后的广西苗族和侗族儿童作为研究对象，分别选择低/无应答者、正常应答者作为病例和对照，采用PCR和SNaPshot技术做基因分型，从群体水平探讨TLR2、TLR4基因SNPs与乙肝疫苗免疫应答的关联，为了解乙肝疫苗免疫低/无应答的遗传学机制提供科学依据。

乙型肝炎是重要的公共卫生问题，接种乙肝疫苗是预防和控制HBV感染和病毒传播最有效的措施。乙肝疫苗全程免疫后，约有5%～10%的健康人不产生乙肝表面抗体。最新研究表明 Toll 样受体(TLR)可抵抗乙肝病毒感染，触发疫苗接种后适应性免疫的活化，其基因多态性(SNPs)与疫苗免疫应答有关，但 TLR基因 SNPs 与儿童乙肝疫苗免疫应答的关联尚未明确。.本研究采用1:1病例对照研究方法，以按标准免疫规划程序完成全程重组乙肝疫苗接种后的8～9月龄汉族（513例）、苗族（293例）、侗族（279例）儿童作为研究对象，开展流行病学调查，采集研究对象外周静脉血，应用MEIA法定量检测乙肝血清标志物，检测HBV DNA等指标，排除乙肝病毒感染者，根据抗-HBs水平将研究对象分为高应答组和低应答组，应用SNPscanTM多重SNP分型技术检测TLR2、TLR3、TLR4基因10个位点和11个Th1/Th2相关细胞因子基因63个位点SNPs，用非条件Logistic回归分析这些基因的等位基因和基因型与抗-HBs水平的关联。研究结果首次报道TLR3基因rs13126816位点等位基因A可能会降低汉族、苗族儿童产生初次乙肝疫苗免疫应答水平，TLR2基因 rs3804100位点的等位基因C可能会降低苗族儿童产生初次乙肝疫苗免疫应答的水平。首次发现IFNG rs2069728、IL12A rs583911、IL1B rs16944位点与广西汉族儿童初次乙肝疫苗免疫后抗-HBs水平有关（P<0.05），TNF-α rs769178、TNF-βrs1041981、IFNG rs2069728、IL12A rs2243123位点与广西侗族儿童初次乙肝疫苗免疫后抗-HBs水平有关（P<0.05）。.本研究首次在乙肝高流行区开展接种血源乙肝疫苗22～28年后长期免疫效果横断面观察研究，研究结果提示乙肝血源疫苗长期免疫后22～28年，疫苗抗体水平已降至较低水平，疫苗保护HBV感染和发病的效果已显著下降。首针不及时接种组HBsAg阳性率显著高于及时接种组。.本研究初步阐明了TLR基因多态性与乙肝疫苗免疫应答的关联，为进一步了解乙肝疫苗免疫低/无应答的遗传学机制、修订乙肝疫苗加强免疫策略、提高乙肝疫苗免疫保护效果提供了科学依据，为开发新的更有效的乙肝疫苗提供新思路。