Human Anti-Tac (Daclizumab) to Treat Juvenile Idiopathic Arthritis (JIA)-Associated Uveitis

This study will examine the safety and effectiveness of a monoclonal antibody called humanized anti-Tac (HAT, also called daclizumab) to treat children and adolescents with uveitis (chronic inflammatory eye disease) associated with juvenile idiopathic arthritis (JIA). Monoclonal antibodies are genetically engineered proteins made in large quantities and directed against a specific target in the body. The HAT antibody is designed to prevent a specific chemical interaction needed for immune cells to produce inflammation. Current treatments for uveitis include steroids and immune-suppressing drugs. These treatments do not always work or they may cause significant side effects. This study will determine whether daclizumab can improve uveitis in children and reduce the need for other medicines. Patients between 6 and 18 years of age with active non-infectious JIA-associated uveitis requiring treatment with anti-inflammatory medications as often as three times a day or more may be eligible for this study. Each candidate is screened with a medical history, physical examination, blood tests, eye examination, and the following specialized tests: * Fluorescein angiography to evaluate the eye's blood vessels. A yellow dye is injected into an arm vein and travels to the blood vessels in the eyes. Pictures of the retina are taken using a camera that flashes a blue light into the eye. The pictures show if any dye has leaked from the vessels into the retina, indicating the presence of inflammation. * Optical coherence tomography to measure retinal thickness. The eyes are examined through a machine that produces cross-sectional pictures of the retina. These measures are repeated during the study to determine changes, if any, in retinal thickening. * Stereoscopic color fundus photography to examine the back of the eye. The pupils are dilated with eye drops to examine and photograph the back of the eye. Upon entering the study, participants receive a 90-minute infusion of daclizu