Aldesleukin (IL-2) is a substance that is similar to a substance made by the body in all individuals. Under normal circumstances, the body makes small amounts of aldesleukin (IL-2) that help white blood cells fight infection. It is now possible to make aldesleukin (IL-2) in the laboratory and give humans much higher doses than their own body makes. There is evidence in the laboratory and in animals that aldesleukin (IL-2) increases the anti-cancer effect of monoclonal antibodies like ch14.18/CHO. We wish to study whether aldesleukin (IL-2) can help improve the effectiveness of ch14.18/CHO in humans.