title: Spontaneous neutrophil activation in HTLV-1 infected patients.
abstract: Human T cell lymphotropic Virus type-1 (HTLV-1) induces lymphocyte activation and proliferation, but little is known about the innate immune response due to HTLV-1 infection. We evaluated the percentage of neutrophils that metabolize Nitroblue tetrazolium (NBT) to formazan in HTLV-1 infected subjects and the association between neutrophil activation and IFN-gamma and TNF-alpha levels. Blood was collected from 35 HTLV-1 carriers, from 8 patients with HAM/TSP (HTLV-1- associated myelopathy); 22 healthy individuals were evaluated for spontaneous and lipopolysaccharide (LPS)-stimulated neutrophil activity (reduction of NBT to formazan). The production of IFN-gamma and TNF-alpha by unstimulated mononuclear cells was determined by ELISA. Spontaneous NBT levels, as well as spontaneous IFN-gamma and TNF-alpha production, were significantly higher (p<0.001) in HTLV-1 infected subjects than in healthy individuals. A trend towards a positive correlation was noted, with increasing percentage of NBT positive neutrophils and levels of IFN-gamma. The high IFN-gamma producing HTLV-1 patient group had significantly greater NBT than healthy controls, 43+/-24% and 17+/-4.8% respectively (p< 0.001), while no significant difference was observed between healthy controls and the low IFN-gamma-producing HTLV-1 patient group (30+/-20%). Spontaneous neutrophil activation is another marker of immune perturbation resulting from HTLV-1 infection. In vivo activation of neutrophils observed in HTLV-1 infected subjects is likely to be the same process that causes spontaneous IFN-gamma production, or it may partially result from direct IFN-gamma stimulation.
authors.affiliation: Universitary Hospital Prof. Edgard Santos, Federal University of Bahia, Salvador, BA, Brazil.
authors.forename: Jaqueline B
authors.initials: JB
authors.lastname: Guerreiro
authors.forename: Maria Aurélia F
authors.initials: MA
authors.lastname: Porto
authors.forename: Silvane B
authors.initials: SB
authors.lastname: Santos
authors.forename: Lino
authors.initials: L
authors.lastname: Lacerda
authors.forename: John L
authors.initials: JL
authors.lastname: Ho
authors.forename: Edgar M
authors.initials: EM
authors.lastname: Carvalho
mesh_terms: D016022:Case-Control Studies; D015490:HTLV-I Infections / Q000097:blood / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000737:chemistry*; D018375:Neutrophil Activation / Q000276:immunology*; D009580:Nitroblue Tetrazolium; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D009580:Nitroblue Tetrazolium; D007371:Interferon-gamma