The development of an ideal therapy to immunosuppress patients with Behcet's disease, a cause of endogenous uveitis and a major cause of acquired blindness in adults, is an important research goal. Corticosteroids remain the mainstay of therapy for intraocular inflammation; however, many patients are intolerant or resistant to corticosteroid therapy. Although the etiology of Behcet's disease is unknown, evidence suggests that an interleukin-2 receptor bearing auto-aggressive cells may play an important role in this disorder. Zenapax, a humanized anti-TAC (T-cell activated antigen) monoclonal antibody (HAT), has been utilized in Protocol # 96-EI-0096, a pilot Phase I/II study, to evaluate Zenapax administration in the treatment of patients with endogenous sight-threatening uveitis. Long-term results demonstrate a positive therapeutic trend in this trial. We propose a randomized masked pilot trial of Zenapax versus placebo. Twenty patients who are 18 years of age or older with Behcet's disease will be randomly assigned to receive either Zenapax or placebo in addition to their standard immunosuppressive therapy. After six months of quiescent disease, patients will be eligible to taper their standard immunosuppressive therapy. The primary purpose of the study is to investigate the safety and efficacy of Zenapax in controlling the recurrent, explosive nature of ocular manifestations in patients with Behcet's disease. Because this study is a Phase I/II study examining both efficacy and safety, primary outcomes for each are defined. The primary safety endpoint is one of the following: a) development of a life threatening complication, namely an exacerbation of systemic or neurological disease, or b) the development of a severe opportunistic infection. The primary efficacy outcomes of this study are based on the number of ocular attacks experienced and the amount of immunosuppressive medications over the 2 year study period, including the ability to taper the standard immunosuppressive therapy. Secondary efficacy outcomes include the level of inflammation as measured by vitreous haze and anterior chamber cells and flare, the presence or absence of cystoid macular edema, the change from baseline in visual acuity, and quality of life issues as measured through questionnaires.