title: Different cytokine production in tax-expressing cells between patients with human T cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis and asymptomatic HTLV-I carriers.
abstract: Human T cell lymphotropic virus type I (HTLV-I) provirus load has been reported to be generally higher in patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) than in asymptomatic HTLV-I carriers (ACs). However, some ACs have a high HTLV-I provirus load comparable with that in patients with HAM/TSP. To examine whether other factors influence the outcome of HTLV-I infection in patients with HAM/TSP and ACs, we analyzed spontaneous Tax expression and cytokine production in peripheral blood mononuclear cells using flow cytometry. The Tax expression in HTLV-I-infected cells (percentage of Tax expressing cells/HTLV-I provirus load when assumed 1 copy/cell) and the intensity of Tax expression did not differ between these 2 groups. However, the production of interferon-gamma and tumor necrosis factor-alpha in Tax-expressing cells was significantly lower in ACs with high HTLV-I provirus load than in patients with HAM/TSP. This result suggests that the production of inflammatory cytokines in Tax-expressing cells is one of the factors that contribute to the development of HAM/TSP.
authors.affiliation: Division of Blood Transfusion Medicine, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan. furukawy@m2.kufm.kagoshima-u.ac.jp
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Mineki
authors.initials: M
authors.lastname: Saito
authors.forename: Wataru
authors.initials: W
authors.lastname: Matsumoto
authors.forename: Koichiro
authors.initials: K
authors.lastname: Usuku
authors.forename: Yuetsu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Shuji
authors.initials: S
authors.lastname: Izumo
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Osame
mesh_terms: D000328:Adult; D002353:Carrier State / Q000378:metabolism* / Q000821:virology; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D005786:Gene Expression Regulation; D016356:Gene Products, tax / Q000235:genetics / Q000378:metabolism*; D016355:Genes, pX / Q000235:genetics; D015368:Human T-lymphotropic virus 1 / Q000502:physiology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D015493:Paraparesis, Tropical Spastic / Q000378:metabolism* / Q000821:virology; D011533:Proviruses / Q000502:physiology; D019562:Viral Load
chemical_list: D016207:Cytokines; D016356:Gene Products, tax; D015847:Interleukin-4; D007371:Interferon-gamma