TTV 部分传播途径的初步研究及西安地区TTV部分片段测序分析

目的研究输血传播肝炎病毒(TTV)有否直接垂直传播途径及尿液传播的可能性,初步了解西安地区TTV结构部分特点.方法参照文献[1]在TTV DNA ORF1区设计一套套式PCR引物,建立TTV DNA套式PCR检测方法,对16例血清检测TTV DNA阳性的患者尿液做了TTV DNA检测,对52 例正常顺产孕妇血清及其婴儿脐带血同时检测TTV DNA; 并且对西安地区1例原因不明而TTV阳性肝炎患者的TTV套式PCR扩增终产物纯化直接测序.结果 16例血清检测TTV DNA阳性的患者尿液TTV DNA检测未发现1例阳性; 在52例顺产妇外周血中,9例TTV DNA阳性TTV基因检测阳性率为17.3%(9/52);而新生儿脐带血TTV基因检测阳性率为7.7%(4/52); 其中,母子同时TTV DNA阳性2 例,单纯母亲血TTV DNA 阳性7例; 单纯婴儿脐带血TTV DNA 阳性2例.直接测序法测序,测得的143bp序列用DNAsis分析软件中国1株(BDH1)序列比较,二者同源性为65.0%,差异率为35.0%(>30%).结论 TTV可能不能通过尿液传播,但能经胎盘直接垂直传播, 西安地区TTV流行毒株可能存在新的TTV基因型.

Preliminary study on partial transmitted routes of TTV and sequence analysis of part of TTV genome in Xi''''an region

Objective To investigate whether transfusion transmitted virus (TTV) transmites through maternal infant way and through unrine and study the molecular speciality of TTV DNA in Xi'an region. Methods A nested polymerase chain reaction (PCR) assay with 2 pairs of primers complemented to OFR1 of TTV genome was established to detect TTV DNA in urine samples from 16 hepatitis patients whose sera were TTV DNA positive and in the serum samples from 52 normal pregnant women and their children's umbilical cords. A target fragment in the agarose was cut down and the amplified product was purified and sequenced directly, then the data were analyzed with DNAsis program with computer. Results The 16 urine samples were all TTV DNA negative. TTV DNA was detected in 9 pregnant women's sera and in their 4 children's umbilical cord blood. Two pregnant women and their children were TTV DNA positive together. Two children were TTV DNA positive while their mothers were TTV DNA negative. Seven pregnant women were TTV DNA positive while their children were TTV DNA negative. The partial TTV DNA fragment of 143 bp was detected. Compared with complete sequence of BDH1 with DNAsis program,it was found that homology between BDH1 and partial sequence of TTV in Xi'an was 65%. Conclusion TTV may transmit through placental barrier directly and may not transmit through urine. Sequencing results suggest that the new genotype of TTV may exist in Xi'an region.