Cellsorba is a leukocyte removal filter developed by Asahi Medical Co., which adsorbs white blood cells through the perfusion of peripheral blood by means of simple extracorporeal circulation. Leukocytapheresis (LCAP) therapy using the Cellsorba column has been reported to show therapeutic effects for many autoimmune related and inflammatory diseases, such as inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, neurologic disease, and so on. At present, Cellsorba is listed as a medical device covered by the Japanese national health insurance system for the treatment of active ulcerative colitis (UC) in Japan, and contributes to the improvement of quality of life in many UC patients. This paper reviews the use of Cellsorba and introduces several reports on therapeutic results.