Inflammatory bowel disease (IBD) like ulcerative colitis (UC) is an autoimmune disorder, patients with UC are likely to have elevated and activated granulocytes. Active UC is frequently associated with infiltration of large number of granulocytes and macrophages into the bowel mucosa. The infiltrated leukocytes can release degradative enzymes, oxygen derivatives and proinflammatory substances that can cause bowel injury and promote further inflammation. It is believed that much of the watery diarrhea seen in severe IBD is a result of injury to the absorptive epithelium, thus making these cells incapable of absorbing adequate water. These understandings have led some experts to believe that management of excess or activated granulocytes and monocytes / macrophages by apheresis should be a novel new strategy to promote remission of active UC.

This view was supported by a recent multicenter clinical trial that showed Adacolumn apheresis produced remission in a large fraction of patients with severe active UC together with a remarkable safety record. In reality, with Adacolumn apheresis, physicians achieved remission of UC that had been difficult to realize with conventional medications.