我国HIV/AIDS患者感染人芽囊原虫的基因多态性和致病性研究

Blastocystis hominis is an anaerobic unicellular eukaryote that can inhabit the intestinaltrack of humans.Numerous cross-secctional surveys have been carried out in different epidemiological settings and hence B.hominis is known to be one of the most frequently found protozoan parasites in human faecal samples, especialy in children, immunocompetent and immunocompromise patients including cancer and HIV/AIDS. Yet, many aspects of this organism remain to be elucidated, including its taxonomy, speciation, pathogenetic potential, life cycle and mode of transmission.Human infections with B.hominis are called Blastocystosis and it present in both asymptomatic and symptomatic in dividuals.Now widely recognized that B. hominis is an opportunistic pathogenic protozoan，When the body's defenses are weakened or immune dysfunction, its reproductive capacity and enhanced pathogenicity, can cause significant clinical symptoms.HIV/AIDS patients co-infected with B. hominis may cause more severe diarrhea and even death.Genotpic varialility has been reported to play an influential role in the pathogenicity of B.hominis.Different sub types of B.hominis may potentially be the pathogenic one.there are at least 9 sub types of B.hominis have been identified.Subtype 3 and 1 have been speculated to cause gastrointestinal symptoms,however, no compelling evidence exists for theis association.its pathogenic role has not been clearly defined.There are some studys on morphology of B.hominis have been carried out in China.Moreover, little is known about the genetic diversity of B. hominis and the pathogenetic potention of different subtypes in China.In 2009, we conducted research in the HIV/AIDS patients shows B. hominis prevalence rate was 17%,much higher than the general population.Here we conducted a molecular epidemiological survey on B. hominis in HIV/AIDS patients in China. The objectives of the present study were (i) to determine the prevalence of B. hominis in HIV/AIDS patients in China; (ii) to assess the relative frequency of different B. hominis subtypes and the pathogenetic; and (iii) to explore the impact on HIV / AIDS progression in patients coinfected with different genotypes B.hominis.

人芽囊原虫是一种常见的寄生于人体肠道的原虫，其感染呈世界性分布，在婴幼儿、免疫力低下、HIV感染者以及免疫缺陷人群中该原虫感染率较高。人芽囊原虫的致病性尚存在争议，目前普遍认为人芽囊原虫为机会性致病原虫，当机体抵抗力下降或免疫功能不全时，其繁殖能力和致病性增强，可引起明显的临床症状和体征。艾滋病人群感染人芽囊原虫可能会引起较严重的腹泻症状，甚至死亡。近年来基因检测分析显示人芽囊原虫存在9种或更多亚种，人芽囊原虫的致病与否或强弱与该虫的基因型有关。国内对人芽囊原虫分离株的基因多态性及生物学特性的研究甚少。HIV/AIDS患者感染的人芽囊原虫不同基因型及其对HIV/AIDS病程进展的影响还未见研究报道。本研究拟通过流行病学和分子生物学的方法，在HIV/AIDS患者中开展人芽囊原虫的基因多态性研究，探索人芽囊原虫不同基因型与其致病性以及感染不同基因型人芽囊原虫对HIV/AID病程进展的影响。

人芽囊原虫是一种常见的寄生于人体肠道的原虫，呈世界性分布，其致病性尚存在 争议，目前普遍认为人芽囊原虫为机会性致病原虫，当机体抵抗力下降或免疫功能不全时， 其繁殖能力和致病性增强，可引起明显的临床症状和体征。近年来基因检测分析显示人芽囊原虫存在9种或更多亚种，人芽囊原虫的致病与否或强弱与该虫的基因型有关。国内对人芽囊原虫分离株的基因多态性及生物学特性的研究甚少。HIV/AIDS 患者感染的人芽囊原虫不同基因型及其对HIV/AIDS病程进展的影响还未见研究报道。本研究拟通过流行病学和分子生物学的方法，在HIV/AIDS患中开展人芽囊原虫的基因多态性研究，探索人芽囊原虫不同基因型与其致病性以及感染不同基因型人芽囊原虫对 HIV/AID 病程进展的影响。2015年1月至2018年12月，先后调查了上海市门诊人群，安徽阜阳市、云南开远市和江西南昌市的HIV感染者，云南腾冲市HIV感染者和医院住院人群，重庆江津区住院人群和小学生六个研究现场共计共调查3119人，其中HIV感染者1565人，在校小学生591人，医院住院人群963人。共发现人芽囊原虫感染病例212例，总的感染率为6.8%。人芽囊原虫感染率最高的为重庆江津小学生人群（15.64%）。感染的人芽囊原虫的基因型有六种，分别为：ST1、ST3、ST4、ST6、ST7和ST12。其中感染率最高的为ST3型；不同地区、不同人群人芽囊原虫感染的基因型分布差异较大。HIV感染者中以ST3型感染为主，其次是ST1型和ST7型，住院人群以ST3、ST1和ST6型为主。重庆江津区以ST6型为主。ST12型为首次在我国发现人感染病例。影响人芽囊原虫感染的主要因素有卫生条件、饲养宠物、营养状况、饮用水和厕所类型等。建立了一个人芽囊原虫阳性队列进行观察性研究，跟踪随访18个月，发现在HIV人群中ST3的致病性高于ST1；在HIV阳性人群中人芽囊原虫感染与CD4+T淋巴细胞和病毒载量水平高度相关。建立了人芽囊原虫实验室体外培养方法和PCR检测方法以及不同基因型人芽囊原虫的实验室保种和复苏技术。