High-dose interleukin-2 (IL-2) therapy is currently indicated for treatment of metastatic renal cell carcinoma and metastatic malignant melanoma, and has been associated with a 5-15% long-term clinical response. In addition, IL-2 therapy is showing promise in treatment of acute myelogenous leukemia, non-Hodgkin's lymphoma, and breast cancer, and in improving immunologic function in patients with AIDS. However, the major dose-limiting toxicity of IL-2, hypotension, severely limits the usefulness of IL-2 therapy.