Cell-mediated cytotoxicity as a result of immunotherapy in patients with acute myeloid leukaemia.

Leucocytes from normal individuals and from patients with acute myeloid leukaemia (AML) in remission receiving active immunotherapy with allogeneic AML blasts (AML-I) were cultured for 6 days with AML-I blasts, Burkitt's lymphoma cells (BL) or lymphoblastoid cells (LCL). The leucocytes were then tested for cell-mediated cytotoxicity (CMC) against 51Cr-labelled AML-I, BL or LCL target cells. There was no substantial difference in the CMC of leucocytes from patients and normals cultured without stimulation, and tested against AML-I, BL or LCL targets. Patient's leucocytes stimulated in vitro with AML-I had a greater frequency of positive CMC responses against AML-I, BL and LCL than normal individuals. The results suggest that co-cultivation of leucocytes with AML-I blasts reactivates memory cytotoxic leucocytes in AML patients receiving immunotherapy and that this test may be useful in measuring the effectiveness of immunotherapy.