Why chronic inflammatory reactions persist in specific sites, such as rheumatoid arthritis in the joints, remains a mystery. Current models of inflammation have concentrated upon the responses of lymphocytes such as B and T cells to specific antigens, and have attempted, often unsuccessfully, to address the causative agent. However recent studies have shown that stromal cells such as macrophages, endothelial cells, and fibroblasts play important roles in the switch that turns a spontaneously resolving acute inflammatory response within a tissue into chronic and persistent disease. Therapeutic manipulation of the stromal microenvironment has been particularly effective in treating cancer and is likely to provide novel therapies to achieve improved control of chronic inflammatory disease.