GM-CSF and Rituximab in Treating Patients With Previously Untreated Follicular Non-Hodgkin Lymphoma

RATIONALE: Biological therapies, such as GM-CSF, may stimulate the immune system in different ways and stop cancer cells from growing. Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some block the ability of cancer cells to grow and spread. Others find cancer cells and help kill them or carry cancer-killing substances to them. Giving GM-CSF together with rituximab may kill more cancer cells. PURPOSE: This phase II trial is studying how well giving GM-CSF together with rituximab works in treating patients with previously untreated follicular non-Hodgkin lymphoma.