To determine the toxicity and effectiveness of adding sargramostim (recombinant granulocyte-macrophage colony stimulating factor; GM-CSF) to a standard chemotherapy drug combination (methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone) known as mBACOD in the treatment of non-Hodgkin's lymphoma in patients who are infected with HIV.