Early relapse remains a major challenge after autologous bone marrow transplant for malignant lymphoma (ML). It is postulated that consolidative immunotherapy with interleukin 2 (IL-2) with or without lymphokine-activated killer (LAK) cells administered after autologous bone marrow (ABMT) or peripheral blood stem cell transplantation (PBSCT) for ML might eradicate residual disease and reduce relapse rates. A previous trial identified an IL-2 regimen that could be administered early after ABMT. This paper presents the clinical results of 16 patients with ML, who participated in a study to determine whether LAK cells could be administered after ABMT with this IL-2 regimen, as well as 6 patients who received IL-2 alone after ABMT or PBSCT. Seventeen patients with non-Hodgkin's lymphoma (NHL), and 5 with Hodgkin's disease (HD), underwent ABMT (20 patients) or PBSCT (2 patients). At the time of transplantation, 7 patients were in untreated or chemotherapy-sensitive first relapse, 3 were in CR2, and 12 were beyond CR2. Beginning 22-85 days (median 43) after ABMT/PBSCT, patients received IL-2 at 3.0 x 10(6) U/m2/day by continuous infusion days 1-5 of the IL-2 protocol. On protocol days 7-9 the first 16 patients underwent apheresis for LAK cell generation. The cells were cultured in IL-2 for 5 days and were infused on days 12-14. Low-dose IL-2 (0.9 x 10(6) IU/m2/day) was administered on days 12-21 in the outpatient department. Patients received a median of 148 (62-279) x 10(9) LAK cells. LAK cell infusions were associated with transient fevers, chills and dyspnea in most patients.(ABSTRACT TRUNCATED AT 250 WORDS)