title: Increased peripheral T cell reactivity to microbial antigens and collagen type II in rheumatoid arthritis after treatment with soluble TNFalpha receptors.
abstract: OBJECTIVE
  Peripheral T cells from patients with rheumatoid arthritis (RA) are hyporesponsive when stimulated with antigen or mitogen in vitro, possibly owing to increased production of proinflammatory cytokines such as tumour necrosis factor alpha (TNFalpha). This study sought to find out if and how RA T cell reactivity is affected during treatment with etanercept (Enbrel), a soluble TNFalpha receptor.
  
  
  METHODS
  Heparinised blood was collected from patients with RA at baseline, after four and eight weeks of etanercept treatment, and from healthy controls. After density separation spontaneous production of interferon gamma (IFNgamma), TNFalpha, interleukin 6 (IL6), and IL10 by peripheral blood mononuclear cells (PBMC) was detected by ELISPOT. For detection of T cell reactivity, PBMC were stimulated in vitro with mitogen (phytohaemagglutinin (PHA)), microbial antigens (purified protein derivative (PPD), influenza), or an autoantigen, collagen type II (CII). Supernatants were analysed for IFNgamma and IL2 content by enzyme linked immunosorbent assay (ELISA).
  
  
  RESULTS
  In RA the number of cells spontaneously producing IFNgamma was significantly increased after four, but not eight weeks' treatment with etanercept. T cell reactivity, as measured by IFNgamma production to PPD, influenza, and CII was significantly increased after four and sustained after eight weeks' treatment, whereas IFNgamma production induced by PHA remained unchanged. TNFalpha production was significantly higher in patients with RA than in controls and did not change during etanercept treatment.
  
  
  CONCLUSIONS
  Treatment of patients with RA with etanercept may lead to increased peripheral T cell reactivity both to microbial antigens and to self antigens such as CII. These findings indicate that TNFalpha blockade may not only suppress but also stimulate certain aspects of antimicrobial immune defence and autoimmunity.
authors.affiliation: Department of Medicine, Unit of Rheumatology, Karolinska Institute, Stockholm, Sweden. louise.berg@cmm.ki.se
authors.forename: L
authors.initials: L
authors.lastname: Berg
authors.forename: J
authors.initials: J
authors.lastname: Lampa
authors.forename: S
authors.initials: S
authors.lastname: Rogberg
authors.forename: R
authors.initials: R
authors.lastname: van Vollenhoven
authors.forename: L
authors.initials: L
authors.lastname: Klareskog
mesh_terms: D000328:Adult; D000368:Aged; D000956:Antigens, Viral / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology*; D001688:Biological Products / Q000627:therapeutic use*; D016022:Case-Control Studies; D003094:Collagen / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000956:Antigens, Viral; D001688:Biological Products; D015850:Interleukin-6; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma; D003094:Collagen