Participants will come to the NIH Clinical Center once a week for 4 weeks to receive an injection of interferon-beta, fill out questionnaires, and have a symptoms check, physical examination, and blood tests. Patients whose colitis has not worsened at the end of the 4 weeks and who have not had significant drug side effects will continue to receive weekly injections for an additional 8 weeks. Some patients may receive some of the last eight injections outside of NIH, but all patients will visit the Clinical Center visits every 3 to 4 weeks for a physical exam, symptoms check and blood tests.