title: Plasmacytoid dendritic cells, Janus-faced sentinels: progesterone, guilty or innocent?
abstract: Evaluation of: Meier A, Chang JJ, Chan ES et al.: Sex differences in the Toll-like receptor-mediated responses of plasmacytoid dendritic cells to HIV-1. Nat. Med. 15, 955-959 (2009). Stimulation of Toll-like receptor (TLR)7 of plasmacytoid dendritic cells with ssRNA in internalized ribonucleic protein (RNP)-autoantibody complexes causes production of IFN-alpha and IFN signature in several female-dominant autoimmune diseases. This could relate to a gene-dose effect by the X chromosome or disturbances in the systemic endocrine and local intracrine sex steroid production. Meier et al. extend this paradigm to HIV-1-infected women. ssRNA, in oligoribonucleotides or aldrithiol-2-inactivated HIV-1, stimulated plasmacytoid dendritic cells via TLR7 to synthesize high concentrations of IFN-alpha. Women were disfavored and produced more IFN-alpha and subsequently CD38(high)CD8(+) lymphocytes upon similar viral loads in treatment-naive individuals. This predicts rapid progress to AIDS. There was a significant positive correlation between plasma progesterone concentrations and the percentage of responder plasmacytoid dendritic cells. TLR7-related pathways offer many potential targets for the treatment of viral and autoimmune diseases.
authors.affiliation: Department of Medicine, Biomedicum 1, FIN-00029 HUS, Finland. yrjo.konttinen@helsinki.fi
authors.forename: Yrjö T
authors.initials: YT
authors.lastname: Konttinen
authors.forename: Arno
authors.initials: A
authors.lastname: Hänninen
authors.forename: Georg
authors.initials: G
authors.lastname: Fuellen