GENERATION OF LAK CELLS IN-VITRO IN PATIENTS WITH ACUTE-LEUKEMIA

The in vitro stimulation of lymphocytes with interleukin-2 (IL-2) gene rates lymphokine-activated killer (LAK) cells with tumoricidal potenti al. In this work we studied the cytolytic capacity of LAK cells in 51 acute leukemia patients in complete remission (CR) after chemotherapy (CT), in 24 acute leukemia patients who had undergone autologous bone marrow transplantation (ABMT), and in a control group of 44 normal don ors. In the normal donor control group the effect of non-IL-2-activate d peripheral blood mononuclear cells (PBMC) against blast cells was al ways lower than 10% lysis, which we have taken as a lower limit for po sitive results. In 95% of post-CT patients, the lytic effect of PBMC w as negative. LAK cells produced positive results in 82% of normal dono rs and in 37.5% of post-CT patients. The effect of PBMC against K562, i.e. natural killer (NK) activity, in post-CT patients as well as in p ost-ABMT patients was reduced in comparison with the average for norma l donors. LAK cells from 25% of post-CT patients had no notable activi ty against K562 or Raji, nor was there any positive effect against aut ologous blast cells. In the rest (75%), one-half generated positive ac tivity. We did not observe any correlation between lytic activity in P BMCs or in LAK cells, nor did we observe significant differences betwe en lytic activity in patients with acute lymphoblastic leukemia (ALL) and those with acute myeloblastic leukemia (AML), or between patients who had undergone CT and those receiving ABMTs. These results support the use of IL-2 as a treatment against minimal residual leukemia.