Comparing Interleukin-2 (IL-2) Combined With Rituximab (Rituxan) to Rituximab Alone in Subjects With Non-Hodgkin's Lymphoma (NHL)

Inclusion Criteria: * CD20+ follicular B-cell non-hodgkin's lymphoma with at least 1 site of measurable disease. * Previous treatment with 1 to 4 prior chemotherapy regimens * ECOG performance status of greater than or equal to 2 * Life expectancy of greater than 18 weeks * Meet safety lab requirements and organ function tests Exclusion Criteria: * Prior treatment with rituximab or IL-2 * Prior radioimmunotherapy including Zevalin or Bexxar * 5 or more prior chemotherapy regimens * Clinically significant cardiac disease, lung dysfunction, autoimmune disease, thyroid disease, active infection, unstable psychiatric condition, or HIV infection. * History of allogenic bone marrow transplant * Female subjects that are pregnant or breast feeding * Immunosuppressive therapy including corticosteroids or investigational agents within 4 weeks prior to the planned start of study treatment