DISEASE CHARACTERISTICS: Histologically proven non-Hodgkin's lymphoma at first presentation No documented CNS involvement (i.e., primary CNS or meningeal lymphoma) Positive serologic test for HIV antibodies required No opportunistic infection unless effectively treated Disease relapsed, refractory, or unresponsive to first-line chemotherapy No more than 1 prior combination chemotherapy regimen Chemotherapy consisted of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or a CHOP-like regimen, ACVBP, or other similar regimen