长春地区TT病毒的基因分型及其临床意义

为调查各种急、慢性肝炎中TT病毒的感染状况及临床意义，并检测TTV基因的分型。利用半套式PCR（semi-nested PCR）方法检测了TTV-DNA。利用邻近丁（neighbor-joining）法画出系统树。TTV-DNA的阳性率在非甲非乙非丙型急性肝炎中为42.3%，在非乙非丙型慢性肝炎中为45.5%。基因型可分为1a、1b、2a、2b等型。TTV-DNA在非甲非乙非丙型急性非乙非丙型慢性肝炎中的感染率最高；在TT病毒与乙型、丙型肝炎病毒混合感染的慢性肝炎中，TT病毒干涉乙型及丙型肝炎病毒造成的肝细胞损伤的可能性很小。

Genotype of TT virus in Chang-Chun area and its clinical significance in hepatic diseases

Recently a novel hepatitis virus, TT virus(TTV),has been isolated as a candidate for non A to G hepatitis virus. To elucidate the clinical significance of TTV infection in liver diseases and genotyping assay in Changchun area, the prevalence of TTV infection was studied. TTV DNA was determined by semi-nested PCR. The nucleotide sequences were determined by a dideoxy chain termination method. The phylogenetic analysis was performed by the neighbor-joining methed. TTV DNA was detected in 11 of 26 (42.3%) patients with a diagnosis of non-A-C acute liver diseases, 5 of 11 (45.5%)patients with noB,noC chronic liver diseases, and 8 of 79 (11.4%) blood donors. No statistically significant difference was found in mean age, sex, alanine aminotransferase (ALT)levels, HBV DNA polymerase activity, HCV RNA levels between the patients of TTV DNA positive and the negative patients with hepatitis B virus or hepatitis C virus. The phylogenetic analysis indicated that there were four genotypes which were type la (25%),type 1b(37.5%),type 2a(16.7%),type 2b (20.8%).TTV DNA was frequent in the patients with non-A to C acute liver diseases and non B to C chronic liver diseases in Changchun area. TT virus coinfection seems not to interfere with the initiation and progression of hepatic injury in chronic liver diseases with hepatitis B virus and hepatitis C virus.