title: Plasmacytoid dendritic cells express TRAIL and induce CD4+ T-cell apoptosis in HIV-1 viremic patients.
abstract: Artificial Toll-like receptor 7/8 (TLR7/8) ligands can endow plasmacytoid dendritic cells (pDCs) with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-dependent lytic properties. Keeping in mind that ssRNA serves as natural TLR7/8 ligand, we searched for TRAIL-expressing cells in persons infected with HIV and identified TRAIL+ pDCs in HIV-1 viremic persons, but not in nonviremic and healthy persons. TRAIL expression on pDCs was directly correlated with individual viral loads. Conversely, HIV-1 viremia was found to be associated with the up-regulation of the apoptosis-transmitting receptor TRAIL R1 on activated CD4+ T cells. As a consequence, the latter became susceptible to TRAIL-dependent pDC-mediated killing. In contrast, initiation of antiretroviral therapy led to the up-regulation of apoptosis-inhibiting TRAIL R4 on CD4+ T cells, which subsequently became resistant against pDC-mediated cellular injury. Definition of pDCs as killers of CD4+ T cells implies a new mechanism of disease progression in HIV infection.
authors.affiliation: Department of Dermatology, Division of Immunology, Allergy and Infectious Diseases, Medical University of Vienna, Vienna, Austria. georg.stary@meduniwien.ac.at
authors.forename: Georg
authors.initials: G
authors.lastname: Stary
authors.forename: Irene
authors.initials: I
authors.lastname: Klein
authors.forename: Sabine
authors.initials: S
authors.lastname: Kohlhofer
authors.forename: Frieder
authors.initials: F
authors.lastname: Koszik
authors.forename: Thomas
authors.initials: T
authors.lastname: Scherzer
authors.forename: Leonhard
authors.initials: L
authors.lastname: Müllauer
authors.forename: Heribert
authors.initials: H
authors.lastname: Quendler
authors.forename: Norbert
authors.initials: N
authors.lastname: Kohrgruber
authors.forename: Georg
authors.initials: G
authors.lastname: Stingl
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D015658:HIV Infections / Q000276:immunology* / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000276:immunology / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000276:immunology / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000096:biosynthesis / Q000276:immunology*; D051199:Toll-Like Receptor 7 / Q000276:immunology / Q000378:metabolism; D051200:Toll-Like Receptor 8 / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation / Q000276:immunology; D014766:Viremia / Q000276:immunology* / Q000378:metabolism
chemical_list: D012367:RNA, Viral; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; C495348:TLR7 protein, human; C495349:TLR8 protein, human; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8