Patients will participate in this study twice within a period of up to a year, once when the patient's disease is active, and again 6 to 12 months later when the disease is less active. Each of the two study periods will last two nights and two days. Patients will be admitted to the hospital the first night, and a small IV port will be inserted in the patient's arm the first morning to allow for multiple blood draws without additional needle sticks. Patients will receive oral prednisolone the first morning and IV methylprednisolone the second morning. Baseline blood draws will be performed prior to administration of drug, with 13 additional draws over a 6 hour period following drug administration. Following the final blood draw on the second day, the IV port will be removed from the patient's arm and the patient will be discharged from the hospital.