title: Phylogenetic subgroups of human T cell lymphotropic virus (HTLV) type I in the tax gene and their association with different risks for HTLV-I-associated myelopathy/tropical spastic paraparesis.
abstract: The association between human T cell lymphotropic virus (HTLV) type I tax variation and disease outcome was studied. The tax gene was sequenced in 61 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), 55 patients with adult T cell leukemia, and 62 healthy carriers (HCs). Phylogenetic analysis revealed 2 tax gene subgroups that are related on the basis of the long terminal repeat sequence. Further analysis using restriction fragment length polymorphism in 192 patients with HAM/TSP and 200 HCs revealed a higher incidence of 1 tax subgroup (taxA) in HAM/TSP. taxA was present in 30 (15.5%) of 192 patients with HAM/TSP and in 14 (7%) of 200 HCs. The difference was significant (chi2=6.47; P=.014; odds ratio, 2.46; 95% confidence interval, 1.26-4.80). This effect was independent of HLA-A*02, which has been reported to prevent HAM/TSP development. These findings suggest that both host genetic factors and HTLV-I subgroup are associated with different risks for development of HAM/TSP.
authors.affiliation: Third Dept. of Internal Medicine, Faculty of Medicine, Kagoshima University, Kagoshima 890-8520, Japan. furukawy@m2.kufm.kagoshima-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Furukawa
authors.forename: M
authors.initials: M
authors.lastname: Yamashita
authors.forename: K
authors.initials: K
authors.lastname: Usuku
authors.forename: S
authors.initials: S
authors.lastname: Izumo
authors.forename: M
authors.initials: M
authors.lastname: Nakagawa
authors.forename: M
authors.initials: M
authors.lastname: Osame
mesh_terms: D016355:Genes, pX; D015368:Human T-lymphotropic virus 1 / Q000145:classification* / Q000235:genetics; D006801:Humans; D015493:Paraparesis, Tropical Spastic / Q000209:etiology*; D010802:Phylogeny; D012306:Risk; D020079:Terminal Repeat Sequences