婴儿输血传播病毒感染途径的分子病毒学研究

目的　观察产妇和所生婴儿在分娩及母乳喂养 6个月后的输血传播病毒 (TTV)感染情况 ,探讨婴儿TTV感染途径。方法　应用套式PCR对 40 0对正常孕产妇分娩前的血清及其新生儿的脐血血清标本、产妇的乳汁配对进行TTV DNA检测 ,对TTV DNA阳性、坚持母乳喂养的母亲及其婴儿进行 6个月随访 ,克隆其中 13对配对阳性标本的TTV基因 ,通过DNA序列测定比较分析母婴TTV感染株之间的核苷酸序列同源性。结果　 6 2例孕母血清、4例新生儿脐血血清、2 0例母乳TTV DNA阳性 ,TTV阳性母亲的乳汁TTV DNA检出率32 2 % (2 0 / 6 2 )。经 6个月随访孕母血TTV DNA阳性的 42对母乳喂养的母婴 ,母血清TTV DNA阳性率2 1 3 % (9/ 42 ) ,婴儿血清TTV DNA阳性率 40 5 % (17/ 42 ) ,孕母血清TTV DNA阳性的婴儿血TTV DNA由阴转阳率 38 1% (16 / 42 )。配对比较母婴间TTV感染株序列同源性为 97 4%～ 99 8%。结论　孕产妇血清TTV阳性率较正常人高 ,乳腺可能是TT病毒的另一存在部位 ,母乳喂养及母婴间密切接触可能是母 儿间TTV的重要传播途径。

Molecular analysis on the infantile transfusion transmitted virus infection

Objective To investigate the frequency of transfusion transmitted virus(TTV)infection in breast fed infants.Methods Serum TTV DNA were detected by nested PCR were cord blood and breast milk samples from mother infant pairs were collected.Mothers with positive TTV DNA were followed up for 6 months.TTV DNA PCR products from 13 monther infant pairs were cloned and sequenced.Results TTV DNA was found in 4 cord blood,20 breast milk and 62 serum of the pregnant women.TTV DNA was also found in 32 2%(20/62)breast milks of mothers with positive TTV,21 3%(9/42)serums of mothers with positive TTV DNA and 40 5%(17/42)serums of infants after 6 months of follow up.Direct sequence of TTV DNA from 13 mother infant pairs showed the infants had 97 4% to 99 8% of homology in TTV DNA with their mothers.Conclusion TTV infection was higher in the gravid and parturient than that in common people.The breast might be another host of TTV.The breast feed and close contact between mothers and their infants might be an important pathway for TTV.