Search results for "Leflunomide"
showing 10 items of 13 documents
Effects of leflunomide (HWA 486) on expression of lymphocyte activation markers
1993
Leflunomide (HWA 486), an isoxazol derivative, has been shown to be very effective in combating autoimmune diseases and transplantation rejection in a great number of animal models. The main metabolite of leflunomide, A77 1726, is a potent antiproliferative compound. To further elucidate this effect, lymphocytes of healthy human donors were cultured for 24, 48 or 72 h in the presence of PHA or immobilized anti-CD3 antibody. A77 1726 was added at concentrations between 10 and 100 microM. Flow cytometric evaluation of early activation or proliferation markers (IL-2 and transferrin receptors, respectively) showed that their expression was inhibited in a dose-dependent manner by A77 1726. Toget…
Induction of regulatory T cells by leflunomide in a murine model of contact allergen sensitivity.
2006
Allergic contact dermatitis and contact hypersensitivity (CHS) are characterized by allergen-specific activation of CD8 + and CD4 + T cells and the production of cytokines resulting in an inflammatory response and tissue damage. We show here that the immunosuppressive compound leflunomide ( N -[4-trifluoro-methylphenyl]-5-methylisoxazol-4 carboxamide, HWA 486) (LF) inhibited the contact allergic response induced in mice by epicutaneous application of the haptens dinitrofluorobenzene (DNFB) and oxazolone. The extent of ear swelling remained significantly reduced following repeated challenge with DNFB for up to 18 weeks. LF and DNFB had to be applied simultaneously for inhibition to occur. Th…
Leflunomide (HWA 486), a novel immunomodulating compound for the treatment of autoimmune disorders and reactions leading to transplantation rejection.
1991
Leflunomide has been shown to be very effective in preventing and curing several autoimmune animal diseases. Further, this agent is as effective as cyclosporin A in preventing the rejection of skin and kidney transplants in rats. Preliminary results from patients suffering from severe cases of rheumatoid arthritis demonstrated that clinical and immunological parameters could be improved with leflunomide therapy. Mode of action studies revealed that this substance antagonizes the proliferation inducing activity of several cytokines and is cytostatic for certain cell types. In this light, we could show that tyrosine phosphorylation of the RR-SRC peptide substrate and the autophosphorylation o…
Effects of leflunomide on immune responses and models of inflammation.
1993
Leflunomide is an antiphlogistic and immunomodulating agent that has been shown to be effective in preventing and healing autoimmune disorders and reactions leading to organ graft rejection. From our preliminary clinical data [4], we now have hopes that these effects, observed in experimental animals, can truly be transferred to humans. Although we are far from understanding the mode of action of leflunomide, we are slowly gathering some insight. A good many of the immunosuppressive effects of leflunomide can be attributed to the antagonistic effects it has on responses to many cytokines, most likely through receptor expression and signal transduction (tyrosine kinase inhibition). The inhib…
Inhibition of murine IgE and immediate cutaneous hypersensitivity responses to ovalbumin by the immunomodulatory agent leflunomide
1999
SUMMARYLeflunomide has been identified as an immunoregulatory and anti-inflammatory compound. Allergic disease is characterized by elevated serum IgE levels, production of allergen-specific IgE and the release of inflammatory mediators from mast cells and granulocytes. Here we demonstrate, using an in vivo murine model, the ability of leflunomide to down-regulate levels of total and allergen-specific serum IgE production. Mice receiving leflunomide (45 mg/kg) orally at the time of primary immunization with ovalbumin adsorbed to aluminium hydroxide adjuvant, showed a reduction in total serum IgE levels of 95%, 41% and 32% following primary, secondary and tertiary immunizations, respectively …
Clinical practice format for choosing a second-line disease modifying anti-rheumatic drug in early rheumatoid arthritis after failure of 6 months' fi…
2006
International audience; BACKGROUND: The objective was to develop a clinical practice format for choosing a second-line disease-modifying anti-rheumatic drug (DMARD) after a 6-month course of a first-line DMARD in patients with early RA. METHODS: A panel of 34 experts selected treatment option from various scenarios using the Thurstone pairwise method. The experts had to choose between two proposed DMARDs without proposing other options. The scenarios were obtained using the three items: DAS28, rheumatoid factor status and radiographic structural damage. A sample of 240 among 480 scenarios for each expert was taken at random. Responses given by at least 20% of the experts were considered per…
Inhibition of the epidermal growth factor receptor tyrosine kinase activity by leflunomide.
1993
AbstractThe active metabolite of leflunomide, A77 1726 inhibits the proliferation of a variety of mammalian cell lines in culture. Epidermal growth factor (EGF)-dependent proliferation is inhibited by A77 1726 at an effective dose of 30–40 μM. A77 1726 appears to directly inhibit the EGF receptor tyrosine-specific kinase activity both in intact cells and purified EGF receptors at the same effective dose. These data suggest that leflunomide inhibits cellular proliferation by the inhibition of tyrosine-specific kinase activities.
Survivin is regulated by interleukin-4 in colon cancer stem cells
2010
Colorectal cancer has provided an important model to test the stem cell hypothesis of cancer origin, which implies that cancer arises as a result of genetic aberrations in stem cells leading to deregulation of the proliferation/differentiation balance. We and others have demonstrated that, similarly to other solid tumors, colon carcinogenesis and progression are dictated by highly apoptosis-resistant stem-like cells. Our data have suggested that protection from apoptosis is achieved by autocrine production of interleukin-4 (IL-4) through up-regulation of anti-apoptotic mediators. In this study, we extend our analysis to another apoptosis inhibitor widely expressed in tumors, namely survivin…
Differential effects of leflunomide on leukocytes: Inhibition of ratin vivo adhesion and humanin vitro oxidative burst without affecting surface mark…
1994
Leflunomide has been shown to combat effectively autoimmune diseases in a number of animal models, as well as chronic polyarthritis of humans. Here we report on the effects of this novel drug on the adherence of leukocytes to endothelium, an essential event in establishment and maintenance of inflammation. The entry of cells into tissues is dependent on interactions of adhesion molecules. The process of diapedesis, which these molecules control, involves three phases: tethering, triggering of receptors on endothelial cells and firm attachment of leukocytes to these cells. The interaction of LECAM-1 (constitutively expressed on circulating leukocytes) and P- and E-selectins on the vessel wll…