 Vedolizumab is a new medication being used for the treatment of Crohns disease and Ulcerative colitis. It works by blocking specific white blood cells alpha 4-beta7 lymphocytes from migrating to areas of inflammation in the gastrointestinal tract. Previous studies have shown that patients who have previous exposure to another type of medication for Crohns disease and Ulcerative colitis anti-TNF medications do not respond to vedolizumab as well as those who have never been exposed. This study will investigate biologic markers in the blood and tissue the help identify possible reasons for this difference. 