Vaccine Therapy and Sargramostim Compared With Placebo and Sargramostim Following Rituximab in Treating Patients With Non-Hodgkin's Lymphoma

DISEASE CHARACTERISTICS: * Histologically confirmed follicular B-cell non-Hodgkin's lymphoma (NHL) * Grade 1, 2, or 3 * Meets 1 of the following criteria for treatment with rituximab: * Treatment naïve * Relapsed or refractory disease after prior chemotherapy * Relapsed after a prior documented response (i.e., complete or partial response) to rituximab of at least 6 months duration * Tumor accessible for biopsy OR existing biopsy material (taken within the past 6 months) suitable for vaccine preparation * Measurable or evaluable disease after tumor tissue procurement for vaccine production * No more than 2 prior treatment regimens for NHL * Single regimens include any of the following: * Maintenance rituximab * Rituximab administered once weekly for 8 courses * Cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus rituximab\* NOTE: \*CHOP followed by rituximab at time of relapse is considered 2 treatment regimens * No history of CNS lymphoma or meningeal lymphomatosis PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-1 Life expectancy * Not specified Hematopoietic * Absolute granulocyte count ≥ 1,500/mm\^3 * Platelet count ≥ 75,000/mm\^3 (unless related to bone marrow involvement by lymphoma) * Hemoglobin ≥ 10g/dL Hepatic * Not specified Renal * Not specified Cardiovascular * No congestive heart failure Pulmonary * No compromised pulmonary function Immunologic * HIV negative * No prior allergic response to GM-CSF * No active bacterial, viral, or fungal infection Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No psychiatric disorder that would preclude study participation * No other malignancy within the past 2 years except nonmelanoma skin cancer or carcinoma in situ of the cervix * No other serious nonmalignant disease that would preclude study participation PRIOR CONCURRENT THERAPY: Biologic therapy * See Disease Characteristics * See Chemotherapy * At least 4 weeks since prior immunotherapy * No prior radiolabeled anti-lymphoma antibody (e.g., iodine I 131 tositumomab or ibritumomab tiuxetan) * No prior autologous or allogeneic stem cell transplantation * No prior lymphoma-specific idiotype immunotherapy (e.g., Id vaccine) * No prior investigational vaccine or immunotherapeutic containing keyhole limpet hemocyanin (KLH) Chemotherapy * See Disease Characteristics * At least 4 weeks since prior chemotherapy * More than 9 months since prior fludarabine * More than 2 years since prior chemotherapy/rituximab combination therapy (e.g., CHOP/rituximab or cyclophosphamide, vincristine, and prednisone \[CVP\]/rituximab) * No more than 6 total prior treatment courses with fludarabine Endocrine therapy * No concurrent steroids for allergic reaction to sargramostim (GM-CSF) Radiotherapy * See Biologic therapy * At least 4 weeks since prior radiotherapy Surgery * Not specified Other * At least 4 weeks since prior experimental therapy * No concurrent systemic immunosuppressive therapy * No other concurrent anti-lymphoma therapy