[Effect of interleukin 2 on blast proliferative activity and expression of T-cell markers in patients with acute...

The proliferative activity of blast cells from patients with acute lymphoblastic leukemia was compared with the activity of lymphoid cells of the thymus and blood of healthy subjects. The spontaneous proliferative activity in cells obtained extempore varied widely. On the basis of this index groups of patients with high proliferative activity (group 1) exceeding the level of thymocyte proliferation and with low proliferative activity (group 2) were distinguished. Direct correlation was revealed between the initial spontaneous proliferative activity and the number of leukocytes as well as with the absolute number of blasts in the blood. A decrease in the initial high proliferative activity in the time course of cultivation was noted in some patients of group 1 (group 1B). In the majority of these patients (91%) the administration of interleukin-2 into the cultural medium prevented a decrease in the proliferative activity. In the other patients of group 1 (group 1A) a high spontaneous proliferative activity was not decreased during cultivation. In group 1A a proliferative response to T-cell growth factor was observed in 36% of patients. The patients' blast cells in group 2 did not respond to this lymphokine. The expression de novo of T-cell markers was observed in some patients of group 1 as a result of interleukin-2 action. The role of interleukin-2 in the pathogenesis of acute lymphoblastic leukemia is discussed.