[Rituximab: a original biotherapy in auto-immune disorders]

After several decades of hegemony of the T lymphocyte, recent work has suggested the importance of the B lymphocyte in auto-immune diseases. As a consequence, there has emerged over the last few years the idea of using anti-B lymphocyte therapy, in particular rituximab (a chimeric anti-CD20 monoclonal antibody).

This review addresses various current topics: a) the role of B lymphocytes in auto-immune diseases, notably their capacity to be antigen presenting cells and to be activated by original systems like Blys/Baff; b) the mechanism of action of rituximab (apoptosis, complement-dependent cytotoxicity and antibody-dependent cell cytotoxicity) and the phenomena explaining failures and cases escaping treatment, in particular among lymphoproliferations; c) The results include efficacy and tolerance data for the principal auto-immune affections. Among these, the most promising indications would seem to be for rheumatoid polyarthritis and systemic lupus erythematosis, although some preliminary open studies point to an effect in Goujerot-Sjögren's syndrome, neuropathies, auto-immune cytopenia, idiopathic thrombocytopenic purpura, cryoagglutinins, blistering cutaneous affections...

Controlled studies will be required to determine the true efficacy and tolerance of this molecule, as it is imperative to validate these new immunotherapeutic strategies, above all when they concern innovative and expensive therapy. Nevertheless, these different observations arouse great hopes and at the same time exciting questions, notably as to the role of B lymphocytes in auto-immune diseases.