The effect of thalidomide on experimental autoimmune myasthenia gravis

Thalidomide in cutaneous lupus erythematosus

For nearly 50 years, thalidomide has struggled between success and controversy. After causing an epidemic of phocomelia and other birth defects during the 1960s, affecting thousands of neonates, thalidomide was used as a sedative in selective disorders including leprosy. The potent anti-inflammatory properties of thalidomide were serendipitously discovered while treating patients with erythema nodosum leprosum, and the drug is now approved by the US FDA for the treatment of this disease. Subsequently, the immunosuppressant effects of thalidomide, including the complex modulation of many cytokines, have been recognized. One promising application of thalidomide has been the treatment of cutaneous lupus erythematosus. Among the largest series reviewed, the drug has been found to ameliorate cutaneous lupus erythematosus in 90% of patients, on average. Remission is achieved in approximately 15-20% of patients with cutaneous lupus erythematosus at doses between 50-400 mg daily. Contraceptive concerns and the recognized neuropathic effects of thalidomide limit the use of the drug in patients with cutaneous lupus. Physicians who prescribe thalidomide in the US must be registered with the drug manufacturer. With appropriate control of drug access and close physician monitoring, thalidomide provides a needed therapeutic option for the treatment of refractory cases of cutaneous lupus erythematosus.

Generating hypotheses by discovering implicit associations in the literature: a case report of a search for new potential therapeutic uses for thalidomide

The availability of scientific bibliographies through online databases provides a rich source of information for scientists to support their research. However, the risk of this pervasive availability is that an individual researcher may fail to find relevant information that is outside the direct scope of interest. Following Swanson's ABC model of disjoint but complementary structures in the biomedical literature, we have developed a discovery support tool to systematically analyze the scientific literature in order to generate novel and plausible hypotheses. In this case report, we employ the system to find potentially new target diseases for the drug thalidomide. We find solid bibliographic evidence suggesting that thalidomide might be useful for treating acute pancreatitis, chronic hepatitis C, Helicobacter pylori-induced gastritis, and myasthenia gravis. However, experimental and clinical evaluation is needed to validate these hypotheses and to assess the trade-off between therapeutic benefits and toxicities.

Theoretical basis for the activity of thalidomide

The revival of thalidomide began shortly after the drug was withdrawn from the market because of its teratogenic properties. Therapeutic effects of thalidomide were found accidentally in leprosy patients with erythema nodosum leprosum (ENL). Subsequent research widened the understanding of the activity of thalidomide, and with improved methodology and the augmented background knowledge of immunology it was possible to interpret the properties of thalidomide more coherently. Effects on tumour necrosis factor-alpha (TNFalpha) release play an important role in the ability of thalidomide to affect the immune system. Alteration of synthesis and release of cytokines such as interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12 and interferon-gamma is involved in the complex mechanisms of thalidomide. Thalidomide targets leucocytes, endothelial cells and keratinocytes, affecting them in a different manner and at different cellular levels. Changes in the density of adhesion molecules alter leucocyte extravasation and the inflammatory response in the tissue involved. Several mechanisms for the teratogenic action of thalidomide are currently under review, but this mode of action of the drug still remains unclear and we review evidence-based hypotheses for the teratogenicity of thalidomide. Thalidomide shows significant clinical impact in several diseases such as ENL in lepromatous leprosy, chronic graft-versus-host disease, systemic lupus erythematosus, sarcoidosis, aphthous lesions in HIV infection, wasting syndrome in chronic illness, inflammatory bowel disease, multiple myeloma and some solid tumours. In 1998 the US Food and Drug Administration approved thalidomide exclusively for the treatment of ENL, and strict conditions were stipulated for its use in order to prevent teratogenic adverse effects. However, despite the promising findings of thalidomide at the molecular level, namely its anti-TNFalpha properties and its intercalation with DNA, and activity in clinical trials, there is still a great need for more intensive research.

Thalidomide prolongs experimental autoimmune neuritis in Lewis rats

Thalidomide is reported to have immunomodulatory and anti-inflammatory effects, which have led to its use in the treatment of a number of immune-mediated disorders, including leprosy, discoid lupus and Behcet's disease, and to prevent immunological rejection phenomena following skin and bone marrow grafts. Experimental autoimmune neuritis (EAN) is a CD4+ T-cell-mediated demyelinating autoimmune disease, which represents an animal model for the study of the immunopathogenesis and immunotherapy of Guillain-Barré syndrome (GBS) in humans. We examined the effect of thalidomide in Lewis rats with EAN, which was induced by immunization with bovine peripheral nerve myelin (BPM) and complete Freund's adjuvant (CFA). Thalidomide prolonged clinical EAN when given at a dose of 200 mg/kg/day by gavage. This clinical effect was associated with increased numbers of inflammatory cells in sciatic nerve sections and elevated numbers of interferon-gamma (IFN-gamma) mRNA-expressing cells among lymph node mononuclear cells from thalidomide-treated EAN rats on day 17 postimmunization, i.e. at the peak of clinical EAN. The finding that thalidomide prolongs clinical EAN is in agreement with the clinical polyneuropathy reported in patients receiving treatment with thalidomide and limits its clinical usefulness.