Human T-cell leukemia virus type 2 (HTLV-2) is non-endemic in Japan unlike the related HTLV type 1. Previously, although HTLV-2-seropositivity was identified via western blotting in one male blood donor in Japan, there have been no reports of HTLV-2 provirus detection by nucleic acid testing. In this report, one Japanese pregnant woman was clinically diagnosed as being HTLV-2-infected with a line immunoassay for specific antibodies after primary testing through prenatal screening in Japan. In genomic DNA of her peripheral blood mononuclear cells, HTLV-2 proviral genome was detected by nucleic acid testing (three methods) with quantitative polymerase chain reaction. The full-genome sequence of this strain was successfully determined. The identified virus was interestingly characterized as a presumed progenitor of subtypes a and c by recombination region and phylogenetic tree analyses. In conclusion, the present infection is, to our knowledge, the first case of molecularly identified and genetically characterized HTLV-2 infection found via prenatal screening in non-endemic Japan.

与相关的 HTLV 1 型不同，人类 T 细胞白血病病毒 2 型 (HTLV-2) 在日本是非地方性的。 以前，虽然通过蛋白质印迹法在日本的一名男性献血者身上发现了 HTLV-2 血清阳性，但已经有没有通过核酸检测检测HTLV-2原病毒的报道。在这份报告中，一名日本孕妇在日本通过产前筛查进行初步检测后，通过特异性抗体的线性免疫分析被临床诊断为 HTLV-2 感染。在她的外周血单个核细胞基因组DNA中，通过定量聚合酶链反应的核酸检测（三种方法）检测到HTLV-2前病毒基因组。成功确定了该菌株的全基因组序列。通过重组区域和系统发育树分析，鉴定出的病毒被有趣地表征为 a 和 c 亚型的假定祖先。总之，据我们所知，目前的感染是第一例通过产前筛查在非地方性日本发现的分子鉴定和遗传特征的 HTLV-2 感染病例。