title: Brief report: inhibition of interleukin-6 function corrects Th17/Treg cell imbalance in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  From an immunologic standpoint, the mechanisms by which treatment with tocilizumab (TCZ), a humanized anti-interleukin-6 (anti-IL-6) receptor antibody, results in improvement in rheumatoid arthritis (RA) patients are still not fully understood. In vitro studies and studies in mouse models have demonstrated the critical role of IL-6 in Th17 cell differentiation. Th17 lymphocytes have been shown to be strongly involved in RA pathogenesis, and the purpose of this study was to investigate the effect of IL-6 blockade on the balance between Th17 cells and Treg cells in patients with active RA.
  
  
  METHODS
  Patients with active RA for whom TCZ had been prescribed by a rheumatologist were enrolled in this study. Phenotypic analyses of T cell populations were performed, and the Disease Activity Score in 28 joints (DAS28) was assessed. Serum cytokine levels and other parameters of inflammation were measured before the first infusion and after the third infusion of TCZ (8 mg/kg).
  
  
  RESULTS
  Compared to controls, levels of Th17 cells (CD4+IL-17+) were increased and Treg cells (CD4+CD25(high) FoxP3+) were decreased in the peripheral blood of patients with active RA. The suppressive function of circulating Treg cells was not impaired in patients with active RA. TCZ treatment induced a significant decrease in the DAS28 associated with a significant decrease in the percentage of Th17 cells (from a median of 0.9% to 0.45%; P = 0.009) and an increase in the percentage of Treg cells (from a median of 3.05% to 3.94%; P = 0.0039) in all patients.
  
  
  CONCLUSIONS
  This study demonstrates for the first time that inhibition of IL-6 function by TCZ corrects the imbalance between Th17 cells and Treg cells in patients with RA.
authors.affiliation: INSERM, UMR 1098, Besançon, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Samson
authors.forename: Sylvain
authors.initials: S
authors.lastname: Audia
authors.forename: Nona
authors.initials: N
authors.lastname: Janikashvili
authors.forename: Marion
authors.initials: M
authors.lastname: Ciudad
authors.forename: Malika
authors.initials: M
authors.lastname: Trad
authors.forename: Jennifer
authors.initials: J
authors.lastname: Fraszczak
authors.forename: Paul
authors.initials: P
authors.lastname: Ornetti
authors.forename: Jean-Francis
authors.initials: JF
authors.lastname: Maillefert
authors.forename: Pierre
authors.initials: P
authors.lastname: Miossec
authors.forename: Bernard
authors.initials: B
authors.lastname: Bonnotte
mesh_terms: D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000188:drug therapy / Q000473:pathology*; D016022:Case-Control Studies; D002452:Cell Count; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D019947:Receptors, Interleukin-6 / Q000037:antagonists & inhibitors / Q000187:drug effects; D012720:Severity of Illness Index; D050378:T-Lymphocytes, Regulatory / Q000473:pathology*; D058504:Th17 Cells / Q000473:pathology*; D000093242:Interleukin-6 Inhibitors
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D000093242:Interleukin-6 Inhibitors; C502936:tocilizumab