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

RATIONALE: Monoclonal antibodies such as rituximab can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. Vaccines made from a person's cancer cells may make the body build an immune response to kill cancer cells. Colony-stimulating factors such as GM-CSF increase the number of immune cells found in bone marrow and peripheral blood. It is not yet known whether combining rituximab and GM-CSF with vaccine therapy may cause a stronger immune response and kill more cancer cells. PURPOSE: This randomized phase III trial is studying giving rituximab and GM-CSF together with vaccine therapy and comparing it to giving rituximab and GM-CSF alone in treating patients with newly diagnosed, relapsed, or refractory B-cell non-Hodgkin's lymphoma.