Stimulation of Human Haemopoietic Cells by Colony Stimulating Factors: Sensitivity of Leukaemic Cells

Abstract

The sensitivity of populations of human granulocyte precursors to factors with colony stimulating activity (CSA) was assessed in agar culture in vitro. The mean threshold of stimulation was estimated by analysis of dose-response curves of clone growth against concentration of CSA. This method of assessment had the advantage that CSA production by cells contaminating the population under test did not affect results. Marrow cells from patients with acute myeloid leukemia were less sensitive to CSA than marrow cells from normal individuals. Sensitivities of cells from chronic granulocytic leukemia and from chronic myelomonocytic leukemia were within the normal range, but this group also tended to require more CSA than controls. Sensitivities of granulocyte precursors from patients with acute myeloid leukemia were closely related to the culture pattern, and thus to the remission probability. The significance of this relationship was discussed.