Marrow adherent cell colony-stimulating activity production in acute myeloid leukemia.

Provision of colony-stimulating activity (CSA) by human marrow cells was determined utilizing culture techniques in vitro to assess intramedullary cellular interactions on human granulopoiesis. CSA production from marrow cells of 21 patients with acute myeloid leukemia (AML) was evaluated and compared to normal marrow by testing the capacity of conditioned media from adherent marrow cells to promote granulocytic colony formation in agar of relatively-light-density nonadherent human marrow target cells. Morphologic, cytochemical, density, and phagocytic characteristics of normal marrow cells suggested that marrow CSA production was provided by middensity adherent cells including those of the monocyte-macrophage series. Decreased marrow cell CSA provision was found in 13 of 21 studies of patients with AML at diagnosis or relapse (p < 0.001). Chemotherapy induced complete remission in 7 of 8 patients with normal marrow CSA, whereas this was achieved in only 4 of 13 patients with low marrow CSA. In contrast, 42 of 46 studies in 9 patients during complete remission showed normal or increased marrow CSA. Sequential studies in 3 patients with relatively prolonged remissions had repeated normal or increased marrow CSA, whereas intermittent low and decreasing marrow CSA was found in 6 patients with short remissions. These findings suggest that adequate marrow CSA provision may be essential for sustaining normal granulopoiesis in AML and may reflect persistence of a normal monocyte-macrophage cell population. Monitoring this parameter appears useful for evaluating microenvironmental influences on granulopoiesis and assessing prognosis and clinical status in AML.