Patients will be evaluated in the outpatient clinic every 4 to 8 weeks until randomization. Patients not taking daclizumab will be followed every 4 to 12 weeks; those taking the drug will be seen every 2 weeks for the first month, every month after that during the 18-month treatment period, and every 4 to 12 weeks until all medications stop. Follow-up evaluations include a physical examination, blood draws and, if medically indicated, X-rays. The total study duration is 60 to 70 months.