Immune Regulation in Ulcerative Colitis or Crohn s Disease

This study will investigate in patients with Crohn s disease and ulcerative colitis how the body s immune system controls inflammation in the gastrointestinal tract (stomach and intestines)-specifically, how lymphocytes (a type of white blood cell) function in inflammatory responses. This protocol does not involve any experimental treatments. Patients between the ages of 0 and 75 years of age with Crohn s disease or ulcerative colitis or symptoms of inflammatory bowel disease may be eligible for this study. Screening tests may include the following: medical history and physical examination, routine blood tests, examination of stool specimens, X-rays such as barium enema or upper GI series, proctosigmoidoscopy, colonoscopy, gastroduodenoscopy, and small bowel biopsy. Participants will receive medical treatment according to the best generally accepted measures for treating Crohn s disease or ulcerative colitis. This may include anti-inflammatory drugs, immunosuppressive drugs, and antibiotics to treat infections. A surgical consultation may be recommended for patients whose disease does not respond to medical treatment. If surgery to remove intestinal tissue is recommended, a qualified gastrointestinal surgeon will perform the procedure. In addition, participants may undergo the following procedures: * Blood drawing - No more than 450 milliliters (30 tablespoons, or 15 ounces) of blood will be taken from adults over a 6-week period. A maximum of 7 ml (1/2 tablespoon) of blood per kilogram (2.2. pounds) of body weight will be obtained from children within the same time period, with no more than 3 ml/kg taken at any one time. * Leukapheresis - This procedure is done to collect large quantities of white blood cells. Whole blood is collected through a needle in an arm vein, similar to donating blood. The blood is circulated through a machine that separates it into its components, and the white cells are removed. The rest of the blood is returned to the body, either through the same needle or through another needle in the other arm. * Intestinal biopsies - Intestinal tissue will be obtained during colonoscopy with intestinal biopsy in patients who require this procedure as part of their standard medical care. Patients are given a sedative to reduce anxiety, but are conscious during the procedure. A flexible tube is inserted into the rectum and large intestine, allowing the physician to see the intestinal mucosa. At various places, small pieces of tissue are plucked out.