All patients in the study will continue to take their current medicines at the start of the study. In addition, one group of patients will receive Zenapax and a second group will receive a placebo. The drug or placebo will be infused into the vein at the start of the study and every two weeks for the next six weeks, and then every four weeks for the rest of the study period (24 months). Each infusion lasts about 15 minutes. Patients will have eye examinations at the time of every treatment, and medicines will be added if needed to control eye disease. Drugs will be tapered after six months in patients whose eye disease is quiet, and readjusted as necessary. Neither the doctors nor the patients will know who is receiving placebo and who is receiving Zenapax until the study ends.