Deng X, Terunuma H, Handema R, Sakamoto M, Kitamura T, Ito M, Akahane Y
First Department of Internal Medicine, Yamanashi Medical University, Yamanashi, Japan.
J Med Virol. 2000 Dec;62(4):531-7.
Although TT virus (TTV) is transmissible by blood or blood products, many patients with no history of transfusion of blood and blood products have been shown to be infected, suggesting other possible routes of transmission. To investigate the transmission routes and replication sites of TTV, 85 paired saliva and serum samples were studied by semi-nested polymerase chain reaction. The prevalence of TTV DNA was 38% (32/85 samples) and 21% (18/85) in saliva and serum, respectively. Fifteen patients had TTV DNA both in saliva and serum. Six out of fifteen patients had significantly higher viral titers in saliva than in serum, but none had higher titer in serum than in saliva. When the 222 base-pair nucleotide sequences of PCR products amplified from the samples were analyzed, 12 patients had the same genotype/subtype in saliva and serum and exhibited high homology (96-100%). The other 3 had different genotypes/subtypes in saliva and serum, and the homology was 61.9-87.2%. Mixed infection was observed both in saliva and serum. Further studies are required to determine if a subgroup of TTV has tropism to saliva. The high prevalence and viral load of TTV in saliva suggest that salivary fluid may be a possible route of transmission of TTV and that TTV might replicate not only in liver tissue but also in other tissues such as oropharyngeal tissues and/or salivary glands.
尽管TT病毒（TTV）可通过血液或血液制品传播，但许多无输血及血液制品输注史的患者也被证实受到感染，这提示存在其他可能的传播途径。为研究TTV的传播途径及复制部位，采用半巢式聚合酶链反应对85对唾液和血清样本进行了研究。TTV DNA在唾液和血清中的阳性率分别为38%（32/85份样本）和21%（18/85）。15例患者的唾液和血清中均检测到TTV DNA。其中6例患者唾液中的病毒载量显著高于血清，但无一例血清中的病毒载量高于唾液。对样本扩增的PCR产物的222个碱基对核苷酸序列进行分析时，12例患者唾液和血清中的基因型/亚型相同，且具有高度同源性（96 - 100%）。另外3例患者唾液和血清中的基因型/亚型不同，同源性为61.9 - 87.2%。在唾液和血清中均观察到混合感染。需要进一步研究以确定TTV的一个亚组是否对唾液具有嗜性。TTV在唾液中的高阳性率和病毒载量表明，唾液可能是TTV的一种传播途径，且TTV可能不仅在肝组织中复制，还可能在其他组织如口咽组织和/或唾液腺中复制。
