Leflunomide induces immunosuppression in collagen-induced arthritis rats by upregulating CD4+CD25+ regulatory T cells

Can J Physiol Pharmacol. 2010 Jan;88(1):45-53. doi: 10.1139/Y09-094.


This study was to investigate the effect of leflunomide on the immunosuppressive CD4+CD25+ regulatory T cells (CD4+CD25+ Tregs) in collagen-induced arthritis (CIA) rats. CIA was induced by collagen type II in Wistar rats. Immunofluorescence flow cytometry and RT-PCR were used to determine the proportion of CD4+CD25+ Tregs and the expression of Foxp3 mRNA, respectively. Proliferation of T lymphocytes was assayed with MTT reagent, and the level of transforming growth factor beta1 (TGF-beta1) in the supernatant of concanavalin A (Con A)-induced T lymphocytes was determined by ELISA kit. Our investigations demonstrated that inhibition of arthritis by leflunomide was related to changes in CD4+CD25+ Tregs. In addition, A771726, which is the active metabolite of leflunomide, promoted the differentiation of spleen lymphocytes into CD4+CD25+ Tregs, increased antiinflammatory cytokine TGF-beta1 secretion, and adjusted the activity of Con A-induced lymphocytes in vitro.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / pharmacology
  • Adjuvants, Immunologic / therapeutic use*
  • Animals
  • Arthritis, Experimental / drug therapy*
  • Arthritis, Experimental / immunology*
  • Arthritis, Experimental / pathology
  • CD4 Antigens / biosynthesis
  • Cattle
  • Immunosuppressive Agents / pharmacology
  • Immunosuppressive Agents / therapeutic use*
  • Interleukin-2 Receptor alpha Subunit / biosynthesis
  • Isoxazoles / pharmacology
  • Isoxazoles / therapeutic use*
  • Leflunomide
  • Male
  • Rats
  • Rats, Wistar
  • T-Lymphocytes, Regulatory / drug effects
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / pathology
  • Up-Regulation / drug effects
  • Up-Regulation / immunology*


  • Adjuvants, Immunologic
  • CD4 Antigens
  • Immunosuppressive Agents
  • Interleukin-2 Receptor alpha Subunit
  • Isoxazoles
  • Leflunomide