This study will examine the safety and effectiveness of the monoclonal antibody efalizumab (Raptiva) for treating sight-threatening uveitis (eye inflammation). Efalizumab controls the activity of white blood cells called lymphocytes that cause inflammation. The drug is currently approved in the United States to treat patients with moderate to severe psoriasis.

Patients 18 and older with sight-threatening intermediate or posterior uveitis of at least 3 months duration, causing persistent macular edema (swelling in the back part of the eye responsible for fine vision) in one or both eyes, may be eligible for this study. The uveitis must require treatment with at least 20 milligrams per day of prednisone, or the equivalent, or a combination of two or more anti-inflammatory treatments such as prednisone, methotrexate, cyclophosphamide, cyclosporine, etc. Patients must have visual acuity of 20/100 or better in at least one eye.

Participants undergo the following tests and procedures:

• Medical history and physical examination.
• Weekly efalizumab treatment. Patients receive an injection of efalizumab under the skin once a week.
• Weekly eye examination, including measurement of vision and pressure in the eyes, dilation of the eyes and examination of the front part of the eye (lens, cornea and pupils) and the back part of the eye (retina and macula).
• Weekly blood tests to measure the number and types of cells in the blood and to check for signs of inflammation and treatment side effects. At some visits, blood samples are collected to measure how much efalizumab remains in the blood and if the body has developed an immune response to the medicine.
• Blood draw at enrollment and at 2 and 4 months for research tests to examine how patients' immune response is operating.
• Fluorescein angiography at enrollment and 1 and 3 months after enrollment, unless additional tests are needed, for medical management. This test checks for abnormalities of eye blood vessels. A yellow dye is injected into an arm vein and travels to the blood vessels in the eyes. Pictures of the retina (the back portion of the eye) are taken with a special camera that flashes a blue light into the eye. The pictures show whether any dye has leaked from the vessels into the retina, indicating possible abnormalities.
• Monthly pregnancy test for women who can become pregnant.

Patients return for treatment and clinic visits weekly for 16 weeks. After 16 weeks, patients whose macular edema has decreased and whose vision may have improved may be offered to continue the injections.