title: Multifunctional T cell reactivity with native and glycosylated type II collagen in rheumatoid arthritis.
abstract: OBJECTIVE
  Type II collagen (CII) is a cartilage-specific protein to which a loss of immune tolerance may trigger autoimmune reactions and cause arthritis. The major T cell epitope on CII, amino acids 259-273, can be presented by several HLA-DRB1 04 alleles in its native or posttranslational glycosylated form. The present study was undertaken to functionally explore and compare CII-autoreactive T cells from blood and synovial fluid of patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Peripheral blood was obtained from HLA-DRB1 04-positive RA patients (n = 10) and control subjects (n = 10) and stimulated in vitro with several variants of the CII(259-273) epitope, i.e., unmodified, glycosylated on Lys-264, glycosylated on Lys-270, or glycosylated on both Lys-264 and Lys-270. Up-regulation of CD154 was used to identify responding T cells. These cells were further characterized by intracellular staining for interleukin-17 (IL-17), interferon-γ (IFNγ), and IL-2 by flow cytometry. Synovial T cells from RA patients were investigated in parallel.
  
  
  RESULTS
  Multifunctional T cell responses toward all examined variants of the CII(259-273) peptide could be detected in RA patients and, to a lesser extent, also in healthy HLA-matched controls (P < 0.001). In RA patients, a comparison between blood- and joint-derived T cell function revealed a significant increase in levels of the proinflammatory cytokine IFNγ in synovial T cells (P = 0.027). Studies of longitudinally obtained samples showed that T cell responses were sustained over the course of disease, and even included epitope spreading.
  
  
  CONCLUSIONS
  The identification of inflammatory T cell responses to both glycosylated and nonglycosylated variants of the major CII epitope in RA patients suggests that CII autoreactivity in RA may be more common than previously recognized.
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Omri
authors.initials: O
authors.lastname: Snir
authors.forename: Johan
authors.initials: J
authors.lastname: Bäcklund
authors.forename: Julia
authors.initials: J
authors.lastname: Boström
authors.forename: Ida
authors.initials: I
authors.lastname: Andersson
authors.forename: Jan
authors.initials: J
authors.lastname: Kihlberg
authors.forename: Jane H
authors.initials: JH
authors.lastname: Buckner
authors.forename: Lars
authors.initials: L
authors.lastname: Klareskog
authors.forename: Rikard
authors.initials: R
authors.lastname: Holmdahl
authors.forename: Vivianne
authors.initials: V
authors.lastname: Malmström
mesh_terms: D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D001773:Blood Cells / Q000473:pathology; D016022:Case-Control Studies; D024043:Collagen Type II / Q000276:immunology*; D018450:Disease Progression; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006031:Glycosylation; D059811:HLA-DRB1 Chains / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008137:Longitudinal Studies; D013582:Synovial Fluid / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*
chemical_list: D024043:Collagen Type II; D018984:Epitopes, T-Lymphocyte; D059811:HLA-DRB1 Chains; C527195:HLA-DRB1*04 antigen; D020381:Interleukin-17; D007376:Interleukin-2; D007371:Interferon-gamma