title: Plasmacytoid dendritic cells and memory T cells infiltrate true sequestrations stronger than subligamentous sequestrations: evidence from flow cytometric analysis of disc infiltrates.
abstract: Herniated nucleus pulposus has been considered to induce an adaptive immune response. Antigen recognition by antigen-presenting-cells (APCs) represents an important step within manifestation of an adaptive immune response. Macrophages have been assumed to function as APC, while importance of plasmacytoid dendritic cells for initiation of an immune response directed towards herniated nucleus pulposus has never been examined. The aim of the present study was to assess importance of plasmacytoid dendritic cells for initiation of immune response directed towards herniated discs.
  
  
  
  Fifteen patients with true sequestrations and three patients with subligamentous sequestrations underwent surgery after their neurological examinations. Disc material was harvested, weighted and digested for 90 min. Separated single cells were counted, stained for plasmacytoid dendritic cells (CD123(+)CD4(+)), macrophages (CD14(+)CD11c(+)) and memory T cells (CD4(+)CD45RO(+)) and analysed by flow cytometry. Both patient groups were compared in cell proportions. Furthermore, patients with true sequestrations (TRUE patients) were subdivided into subgroups based on severity of muscle weakness and results in straight leg raising (SLR) test. Subgroups were compared in cell proportions.
  
  
  
  Plasmacytoid dendritic cells and memory T cells infiltrated true sequestrations stronger than the subligamentous sequestration and plasmacytoid dendritic cells predominated over macrophages in true sequestrations. Highest proportions of plasmacytoid dendritic cells were detected in infiltrates of patients having true sequestrations, severe muscle weakness and negative result in SLR test.
  
  
  
  The findings of the present study indicate that plasmacytoid dendritic cells are involved in initiation of an immune response directed towards herniated nucleus pulposus, while macrophages may reinforce the manifested immune response and mediate disc resorption.
authors.affiliation: Department of Psychology, Biological Psychology, University of Cologne, Bernhard-Feilchenfeld-Straße 11, 50969, Cologne, Germany. geissa@uni-koeln.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Geiss
authors.affiliation: Department of Orthopaedic Surgery, Medizinisches Zentrum StädteRegion Aachen, Mauerfeldchen 25, 52146, Würselen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Sobottke
authors.affiliation: Department of Orthopaedics and Traumatology, University of Halle/Saale, Magdeburgerstraße 22, 06112, Halle, Germany.
authors.forename: Karl Stefan
authors.initials: KS
authors.lastname: Delank
authors.affiliation: Department of Orthopaedics and Traumatology, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.
authors.forename: Peer
authors.initials: P
authors.lastname: Eysel
mesh_terms: D000328:Adult; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007403:Intervertebral Disc / Q000276:immunology*; D007405:Intervertebral Disc Displacement / Q000276:immunology*; D008264:Macrophages; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology
keywords: Macrophages; Memory T cells; Motor weakness; Nucleus pulposus; Plasmacytoid dendritic cells; Sequestration