Metabolic Response to Infliximab in Pediatric Ulcerative Colitis

Inclusion Criteria: * Male and female children between the ages of six and eighteen years of age * Endoscopic or histologic evidence of ulcerative colitis * Active ulcerative colitis determined by primary pediatric gastroenterologist to require anti-tumor necrosis factor-alpha antibody (infliximab) therapy * Colitis symptom score ≥2 * Screening laboratory tests that meet the following criteria (obtained within 4 weeks of enrollment): 1. Hemoglobin \>8.0 g/dL 2. White blood cell count \>3.5 x 109/L 3. Neutrophils \>1.5 x 109/L 4. Platelets \>100 x 109/L 5. Aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels within 3 times the upper limit of normal. 6. PPD skin test with skin induration \<5 mm. 7. Signed written consent from the parent/legal guardian and assent from the child to be obtained prior to enrollment. Exclusion Criteria: * Female subjects who are pregnant, nursing, or planning pregnancy. * Concomitant diagnosis or history of congestive heart failure. * Serious infection in the 3 months prior to enrollment. * History of prior or current active or latent tuberculosis. * Immune deficiency syndrome, including documented human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS). * History of systemic lupus erythematosus. * A transplanted organ. * Known malignancy or history of malignancy within 5 years of enrollment. * History of demyelinating disease. * History of substance abuse. * History of diabetes mellitus. * Poor tolerability of venipuncture or lack of venous access during the study period. * A live virus vaccination within 3 months of enrollment. * Prior history of infliximab infusion or any other therapeutic agent targeted at reducing tumor necrosis factor-alpha (TNF-alpha). * Hypersensitivity to any murine proteins or other component of the product. * Inability to comply with study procedures