Modifying the biological response in acute myeloid leukemia. II. Effect of BCG and leukemic cells on lymphocyte response to mitogens, and on helper and suppressor activity.

Lymphocyte response to mitogens and to lymphocyte suppressor and monocyte helper activity was studied in 18 patients with acute myeloid leukemia in complete remission, and in 17 healthy controls. Ten patients were maintained with chemotherapy alone (CT), and eight received chemoimmunotherapy with BCG + leukemic cells (CIT). In late remission the mitogen responsiveness was increased in CT patients and decreased in CIT patients. No significant difference in lymphocyte suppressor activity could be demonstrated between patients and controls, or between CT and CIT. When autologous CIT monocytes were added to mitogen-stimulated lymphocytes they acted as helper cells. CT monocytes, in contrast, seemed to act as suppressor cells. Control monocytes also acted as helper cells, but to a significantly lesser degree than CIT monocytes.