Monocyte induces alkaline phosphatase synthesis in neutrophils of chronic myeloid leukemia and myelofibrosis with myeloid metaplasia patients.

Studies were done to test the neutrophil alkaline phosphatase (NAP) synthesizing capacity of the neutrophils of patients with chronic phase chronic myeloid leukemia (CML) and of patients with stable-phase myeloid metaplasia (MM) and to test the NAP synthesis-inducing capacity of monocytes (Mos) of patients with CML. Suspension cultures of the blood light density (LD) cells, LD cells depleted of T-cells and Mos (LD-T-Mo), and cocultures of LD-T-Mo with Mos were performed. NAP synthesis occurred in a normal fashion in LD cell cultures of five of seven patients with CML and of two patients with MM. The NAP synthesis was very slight or did not occur in cultures of LD-T-Mo cells of all patients with chronic-phase CML and MM. However, addition of allogeneic or autologous Mos to the LD-T-Mo cultures restored the NAP synthesis. These results confirm the previous finding that the low or absent NAP in CML is caused by a relative reduction in the monocyte mass and they further indicate the mechanism to be the same for the low or absent NAP in patients with MM. The results also indicate that the NAP-synthesizing capacity of neutrophils of CML and MM patients and the NAP synthesis-inducing capacity of the Mos of patients with CML are normal.