Federal University of Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil.
Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil.
J Med Virol. 2018 Feb;90(2):351-357. doi: 10.1002/jmv.24938. Epub 2017 Sep 22.
Human T-lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The aim of this study was to investigate the intrafamilial transmission of HTLV-1 among Japanese immigrants and their descendants living in a non-endemic area of central Brazil. Six families were investigated. Thirty-seven relatives of the six index cases were tested by ELISA for the presence of anti-HTLV antibodies, and the positive cases were confirmed by Western blot. HTLV-1 isolates were genotyped by partial nucleotide sequencing (5' LTR) of the proviral DNA. All individuals, including index cases and relatives, were asymptomatic. In five families, at least one relative was infected with HTLV-1. In all, eight (22%) relatives (one mother, four wives, one brother, and two brothers-in-law) were infected. However, none of the 22 individuals under 55 years of age was infected. In each family, the HTLV-1 sequences from the relatives were identical or almost identical to that of the index case, except in one case. Pedigrees of the families, together with socio-demographic data of the HTLV-1 infected individuals, strongly suggested the occurrence of both vertical and sexual transmission, with breastfeeding as an important risk factor. Whether and why the virus transmission is less effective among younger generations deserves to be further investigated.
人类 T 淋巴细胞白血病病毒 1 型（HTLV-1）是成人 T 细胞白血病/淋巴瘤和 HTLV-1 相关脊髓病/热带痉挛性截瘫（HAM/TSP）的病因。本研究旨在调查 HTLV-1 在居住在巴西中部非流行地区的日本移民及其后代中的家族内传播。共调查了 6 个家庭。对 6 个索引病例的 37 名亲属进行 ELISA 检测抗 HTLV 抗体，阳性病例用 Western blot 法确认。用 HTLV-1 分离株对前病毒 DNA 的部分核苷酸序列（5'LTR）进行基因分型。所有个体，包括索引病例和亲属，均无症状。在 5 个家庭中，至少有 1 个亲属感染了 HTLV-1。共有 8 名（22%）亲属（1 名母亲、4 名妻子、1 名兄弟和 2 名兄弟）感染。然而，在所有 22 名 55 岁以下的个体中均未感染。在每个家庭中，亲属的 HTLV-1 序列与索引病例的序列相同或几乎相同，除了 1 个病例。家族系谱以及 HTLV-1 感染个体的社会人口统计学数据强烈提示存在垂直传播和性传播，母乳喂养是一个重要的危险因素。病毒在年轻一代中的传播是否以及为何效率较低，值得进一步研究。
