Inflammatory bowel disease (IBD), consisting of two major forms, Crohn's disease (CD) and ulcerative colitis (UC), affects more than 1.6 million people in the United States alone. Though the precise mechanisms underlying the inflammation and immune responses in IBD are still being investigated, various inflammatory mediators, including pro-inflammatory cytokines, and genes have been implicated in the disease process. At present, there are no reliable mechanisms to predict response to individual IBD medications. The investigators seek to evaluate whether inflammatory cytokines change longitudinally during treatment with anti-cytokine agents in both treatment primary responders and primary non-responders. In addition, the investigators will be evaluating the pharmacogenetics of treatment response to these agents.

Inclusion Criteria:

• Patients that are seen in the Inflammatory Bowel Disease clinic with Crohn's disease who are initiating either treatment as part of their routine clinical care.
• Healthy adults without IBD undergoing colonoscopy for colorectal cancer screening or other non-IBD related indication.

Exclusion Criteria:

• pregnant
• have a known coagulopathy or bleeding disorder
• have known renal or hepatic impairment
• have a history of organ transplantation
• CD patients who are being seen in consultation and do not plan to receive longitudinal care through initiation their new therapy at the Vanderbilt IBD center will be excluded.

Patients who are scheduled for a colonoscopy at the Vanderbilt Endoscopy Laboratory as part of their routine care and who do not meet any of the pre-defined exclusion criteria will be considered for participation in the study as control subjects. Patients who are part of the Vanderbilt IBD practice who initiate therapy on an anti-TNF, ustekinumab, or vedolizumab as part of their routine care will be considered for participation in the study as subjects.