Human T-cell lymphotropic virus type 2 (HTLV-2) infection has been shown to be endemic among intravenous drug users in parts of North America, Europe and Southeast Asia and in a number of Amerindian populations. Despite a 65% genetic similarity and common host humoral response, the human T-cell lymphotropic viruses type 1 (HTLV-1) and 2 display different mechanisms of host interaction and capacity for disease development. While HTLV-1 pathogenicity is well documented, HTLV-2 etiology in human disease is not clearly established. From an evolutionary point of view, its introduction and integration into the germ cell chromosomes of host species could be considered as the final stage of parasitism and evasion from host immunity. The extraordinary abundance of endogenous viral sequences in all vertebrate species genomes, including the hominid family, provides evidence of this invasion. Some of these gene sequences still retain viral characteristics and the ability to replicate and hence are potentially able to elicit responses from the innate and adaptive host immunity, which could result in beneficial or pathogenic effects. Taken together, this data may indicate that HTLV-2 is more likely to progress towards endogenization as has happened to the human endogenous retroviruses millions of years ago. Thus, this intimate association (HTLV-2/human genome) may provide protection from the immune system with better adaptation and low pathogenicity.

在北美，欧洲和东南亚的部分地区以及许多美洲印第安人人群中，静脉注射吸毒者已显示出人类2型T细胞淋巴病毒2型（HTLV-2）感染是地方性的。尽管有65％的遗传相似性和常见的宿主体液反应，但人类T细胞淋巴病毒1型（HTLV-1）和2表现出不同的宿主相互作用机制和疾病发展能力。尽管HTLV-1的致病性已得到充分证明，但尚不清楚人类疾病中HTLV-2的病因。从进化的角度来看，将其引入并整合到宿主物种的生殖细胞染色体中可被视为寄生和逃避宿主免疫的最后阶段。在所有脊椎动物物种基因组中，包括原始人科，内源性病毒序列都非常丰富，提供了这种入侵的证据。这些基因序列中的一些仍保留病毒特征和复制能力，因此潜在地能够从先天和适应性宿主免疫中引发应答，这可能导致有益或致病的作用。综上所述，该数据可能表明HTLV-2更有可能朝着内源性发展，就像数百万年前的人类内源性逆转录病毒一样。因此，这种密切的联系（HTLV-2 /人类基因组）可以提供更好的适应性和低致病性，免受免疫系统的侵害。可能导致有益或致病的作用。综上所述，该数据可能表明HTLV-2更有可能朝着内源性发展，就像数百万年前的人类内源性逆转录病毒一样。因此，这种密切的联系（HTLV-2 /人类基因组）可以提供更好的适应性和低致病性，免受免疫系统的侵害。可能导致有益或致病的作用。综上所述，该数据可能表明HTLV-2更有可能朝着内源性发展，就像数百万年前的人类内源性逆转录病毒一样。因此，这种密切的联系（HTLV-2 /人类基因组）可以以更好的适应性和较低的致病性为免疫系统提供保护。