Increase in "Null" cells in acute lymphocytic leukemia in remission on long-term immunotherapy

In an attempt to elucidate a possible mode of action of immunotherapy in ALL, we studied the mononuclear subpopulation in a group of patients with all in remission on long-term immunotherapy, a similar group on chemotherapy, and a group of normal individuals. Comparison of the three groups demonstrated a significant increase in the number and percentage of "null" cells in the immunotherapy group relative to the two others. Although the nature of these cells is unknown, circulating stem cells, "K" cells, or modified T, B, or monocytic cells are raised.