After completing postremission chemotherapy, patients are randomized to a no further treatment group or interleukin-2 (IL-2) immunotherapy. Treatment begins within 5 months of postremission chemotherapy. IL-2 immunotherapy consists of low-dose subcutaneous (SC) IL-2 on days 1-14, 19-28, 33-42, 47-56, 61-70, and 75-90 and high-dose bolus SC IL-2 on days 15-17, 29-31, 43-45, 57-59, and 71-73.