Last year, LeukoSite Inc. was one of the companies that contributed to the discovery of CCR-5, the chemokine co-receptor used by HIV to enter T cells. Although the finding was outside of LeukoSite's core programs in inflammatory and autoimmune diseases, the work grew out of the company's focus on leukocyte recruitment, the process by which white blood cells are activated, leave the blood stream and enter surrounding tissue.

The company is working on ways to block specific steps in the leukocyte recruitment pathway in order to interrupt the process before leukocytes cause damage in diseases such as inflammatory bowel disease, asthma, allergies, atherosclerosis, stroke and rheumatoid arthritis.