Thalidomide suppresses T- and B-cell responses to myelin antigen in experimental allergic neuritis

CD20 + cells blockage by rituximab delays wound healing in oral traumatic ulcers in rats

OBJECTIVE

Wound healing of oral traumatic ulcers (OTU) is strongly associated with cytokines and inflammatory cells, and the reduction of anti-inflammatory cells, such as lymphocyte B, may interfere with OTU repair. We aimed to evaluate the role of CD20 + cells in the healing process of OTU in rats.

DESIGN

Wistar male rats were divided into four groups: a control group (treated with 0.1 mL/kg of saline) and three groups treated with anti-CD20 rituximab (RTX) at 2.5, 10, or 40 mg/kg 24 h before OTU production. The animals were weighed (day 0) and euthanized on days 3, 7, 14, and 21 after ulceration. With Blood cells (hematological analysis) and the traumatically induced ulcers were clinically measured. The mucosal samples were histologically (scores 0-4), histochemically (collagen assay (picrosirius)), histomorphometrically (cell counting), and immunohistochemically (CD20+, Tumor Necrosis Factor alpha(TNF-α), Interleukin(IL)- 1β, IL-6 and α-smooth-muscle-actin (α-SMA)) analyzed. ANOVA-1-2-way/Bonferroni, Kruskal-Wallis/Dunn, and correlation analyses were performed (GraphPad Prism 5.0, p < 0.05).

RESULTS

RTX leads to leukopenia, lymphocytopenia, and neutropenia (p < 0.001), and high doses reduced the OTU area (p = 0.001), impaired histologic scores (p < 0.05), and delayed polymorphonuclear (p < 0.001) and mononuclear (p < 0.001) cells, and total (p = 0.011), type-I (p = 0.008), and type-III (p = 0.021) collagen.

CONCLUSION

RTX treatment reduced CD20+ cells in OTU (p = 0.001), TNF-α (p = 0.006), and α-SMA (p = 0.022) immunostaining and delayed IL-6 reduction (p = 0.006), with no influence in IL-1β immunostaining. CD20 + cell blockage by RTX reduced cell migration, acute inflammation, and wound healing in OTU.

Thalidomide revisited: pharmacology and clinical applications

Thalidomide is attracting new interest. Since the discovery of its remarkable efficacy in erythema nodosum leprosum, the drug has been used successfully in a variety of dermatologic and other diseases whose apparent common thread is immune dysregulation. Meanwhile, immunomodulatory and anti-inflammatory activities of thalidomide, particularly its inhibition of tumour necrosis factor alpha (TNF-alpha), have been identified and elucidated. The drug has also been found to inhibit angiogenesis. Recent clinical trials have shown thalidomide effective in graft-versus-host disease, Behçet's syndrome and aphthous ulcers and wasting associated with HIV infection. Provocative findings in other diseases, including primary HIV infection, HIV-associated diarrhoea, inflammatory bowel disease, cancer and sepsis, have suggested additional clinical applications. Use of thalidomide in women capable of childbearing is controversial. However, guidelines have emerged for prevention of teratogenicity and peripheral neuropathy, the drug's other major adverse effect. With appropriate safeguards, thalidomide may hold benefit for patients with a broad variety of disorders in which existing treatments are inadequate. Its current use may represent only a small part of its therapeutic potential.

Thalidomide and metabolites: indications of the absence of 'genotoxic' carcinogenic potentials

Because of the reintroduction into human therapeutics of thalidomide, a recognized developmental toxicant in humans, there has been concern about its potential for inducing other health effects as well. The present study is concerned with the possible mutagenicity and carcinogenicity of this chemical. Using the expert system, META, a series of putative metabolites of thalidomide was generated. In addition to the known or hypothesized metabolites of thalidomide (N=12), a number of additional putative metabolites (N=131) were identified by META. The structures of these chemicals were subjected to structure-activity analyses using predictive CASE/MULTICASE models of developmental toxicity, rodent carcinogenicity and mutagenicity in Salmonella. While thalidomide and some of its putative metabolites were predicted to be developmental toxicants, none of them were predicted to be rodent carcinogens. Putative metabolites containing the hydroxamic acid or hydroxylamine moieties were predicted to be mutagens. None of the 'known' metabolites of thalidomide contained these reactive moieties. Whether such intermediates are indeed generated or whether they are generated and are either unstable in the presence of oxygen or react rapidly with nucleophiles is unknown.

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.