title: Impaired function of human T-lymphotropic virus type 1 (HTLV-1)-specific CD8+ T cells in HTLV-1-associated neurologic disease.
abstract: Despite abundant activated virus-specific cytotoxic T lymphocytes (CTLs), patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) showed a significantly higher frequency of infected T cells than did healthy virus carriers (HVCs). Here, we demonstrate that at a given proviral load, the frequency of CD8(+) T cells that are negative for specific costimulatory molecules was significantly higher in HAM/TSP than in age-matched HVCs and uninfected healthy controls (HCs), whereas the frequency of intracellular perforin-positive CD8(+) T cells was significantly lower in both HAM/TSP and HVCs than in HCs. An inverse correlation between HTLV-1 proviral load (PVL) and percent perforin-positive CD8(+) T cells were observed only in disease-protective allele HLA-A*02-positive HVCs, but not in HAM/TSP patients, whether HLA-A*02 positive or negative, nor in HLA-A*02-negative HVCs. Significantly lower perforin expression was observed in HTLV-1-specific than in cytomegalovirus-specific CD8(+) T cells. Majority of HTLV-1-specific CD8(+) T cells in HVCs showed a CD28(-)CD27(+) phenotype, whereas HAM/TSP showed a CD28(-)CD27(-) phenotype. HTLV-1-specific CD8(+) T cells from HAM/TSP patients showed significantly lower degranulation than HVCs by CD107a mobilization assay. These findings suggest that an impaired function of HTLV-1-specific CTLs is associated with failing antiviral control and disease HAM/TSP.
authors.affiliation: Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Sabouri
authors.forename: Koichiro
authors.initials: K
authors.lastname: Usuku
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayashi
authors.forename: Shuji
authors.initials: S
authors.lastname: Izumo
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Ohara
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Osame
authors.forename: Mineki
authors.initials: M
authors.lastname: Saito
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000473:pathology / Q000821:virology*; D015789:HLA-A2 Antigen / Q000032:analysis; D015490:HTLV-I Infections; D015368:Human T-lymphotropic virus 1 / Q000472:pathogenicity*; D006801:Humans; D016130:Immunophenotyping; D015493:Paraparesis, Tropical Spastic / Q000209:etiology / Q000276:immunology*; D054353:Perforin / Q000032:analysis; D037182:T-Cell Antigen Receptor Specificity; D013602:T-Lymphocytes, Cytotoxic / Q000473:pathology / Q000821:virology; D019562:Viral Load
chemical_list: D015789:HLA-A2 Antigen; D054353:Perforin