In contrast, CD40 is upregulated in various inflammatory disorders and, through ligand engagement, CD40 triggers pro-inflammatory responses in endothelial cells, vascular smooth muscle cells and epithelial cells that play a key role in the pathogenesis of various disorders such as inflammatory bowel disease, systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, graft rejection, and atherosclerosis (22, 23). The gene discussed is CD40; the disease is rheumatoid arthritis.