中国部分地区新型肝炎病毒TTV感染的分子流行病学

目的了解我国部分地区新型肝炎病毒ＴＴＶ感染的分子流行病学、ＴＴＶ在人群中的感染分布状况,探讨ＴＴＶ在肝炎发病中的作用和地位。方法采用ＰＣＲ方法检测血清标本中ＴＴＶＤＮＡ,克隆测定不同地理株ＴＴＶ的部分基因序列,分析其基因变异情况。结果检测了南方（广东深圳和江苏南京）和北方（北京和辽宁沈阳）的１１２例非甲～非庚型肝炎病人,其中ＴＴＶＤＮＡ阳性者４８例,阳性率４２．９％,而１０２例甲～庚型肝炎病人中阳性率为２．９％（χ２＝４２．８,Ｐ＜０．０１）。ＡＬＴ异常而无甲～庚型肝炎病毒感染标志的献血员中,ＴＴＶＤＮＡ阳性率（３４６％）明显高于ＡＬＴ正常献血员的阳性率（１６．８％,χ２＝４．５,Ｐ＜０．０１）。南方株（广东深圳ＴＴＶＣＨＮ００２、南京ＴＴＶＮＡＮ００１）和北方株（北京ＴＴＶＳＨＢ０１５）病毒间同源性在９８％以上,日本发表的序列同源性也高于９７％。结论我国北方和南方地区均存在ＴＴＶ感染。ＴＴＶ感染与ＡＬＴ异常有极为密切的关系,可能是导致非甲～非庚型肝炎的重要病原。正常人群中存在ＴＴＶ感染者,类似于ＨＢｓＡｇ的所谓“慢性携带状态”。

Molecular Epidemiology of TT Virus Infection in Some Parts of China

OBJECTIVE: To study the molecular epidemiology of new hepatitis TT virus (TTV) infection, its distribution in population and its role in pathogenesis of hepatitis in some parts of our country. METHODS: TTV DNA in serum samples was detected by nested-polymerase chain reaction, partial gene of various geographic strains of TTV was cloned and sequenced, and their genetic variation was analyzed. RESULTS: Forty-four of 112 cases with non-A to G hepatitis from Shenzhen, Guangdong province, Nanjing, Jiangsu province, Beijing and Shengyang, Liaoning province were positive for TTV DNA with a positive rate of 42.9%, but only three of 102 cases of hepatitis A-G was positive, with a positive rate of 2.9% (chi 2 = 42.8, P < 0.01). Positive rate of TTV DNA was significantly higher in blood donors with abnormal ALT but without infection markers of hepatitis A-G (34.6%) than in those with normal ALT (16.8%) (chi 2 = 4.5, P < 0.05). Sequencing analysis showed that more than 98% of their nucleotides were analogous between strains of TTVCHN002 from Shenzhen and Nanjing, and TTVSHB015 from Beijing, and more than 97% analogous between the above-mentioned strains and Japanese ones. CONCLUSION: There existed TTV infection in both north and south China. TTV infection correlated closely with abnormal ALT, which might be an important pathogen for non-A, non-B, hepatitis G. There were somebodies infected with TTV in the normal healthy population, similar to that of "chronic carrier status" in hepatitis B.