Rituximab and its Use in Autoimmune Bullous Disorders (original) (raw)

2011, Dermatologic Clinics

Rituximab is a chimeric murine-human monoclonal antibody against the CD20 antigen of B lymphocytes 1,2 (anti-CD20 mAb). It is used in multiple medical conditions and its therapeutic role in dermatology has been increasing in the last decade. Initially used in the treatment of non-Hodgkin B-cell lymphoma, the scope of rituximab has been expanded to include autoimmune diseases such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and chronic immune thrombocytopenic purpura syndrome. 3,4 Because the B cells produce immunoglobulins, which in turn have a pathogenic role in autoimmune diseases, their depletion is surmised to result in improved symptoms and disease control. Depleting B cells inevitably decreases the activation of antigen-presenting cells and the transmission of signaling pathways to other key mediators, such as T cells. MECHANISM OF ACTION The B-cell antigen CD20 is a transmembrane glycoprotein expressed on nearly all B cells and most B-cell lymphomas. 5,6 However, it is not found on early pre-B cells or stem cells. 5 B cells, originally arising from the bone marrow, mature by migrating through peripheral blood, lymph nodes, and spleen. In bone marrow (BM) they are known as plasma cells. CD20, specific for B cells, is expressed on B cells between the pre-B cell and pre-plasma stages. 7,8 Because rituximab targets CD20, plasma cells in the BM responsible for antibody production 6 are spared. Once rituximab binds A version of this article was previously published in Dermatologic Clinics 29:4.