A patient with multiple myeloma developed periodic blood neutropenia (periodicity of 15–25 days) after 3 yr of intermittent treatment with cytotoxic agents. Peaks of serum colony-stimulating activity (CSA) level coincided with valleys of blood neutrophils. Fraction of marrow neutrophils in the multiplicative pool was high during blood neutrophil valleys and low during neutrophil peaks. In contrast, the maturation storage pool exhibited the reverse pattern. An increased fraction of marrow neutrophilic cells in the multiplicative pool was in active proliferation during a blood neutrophil valley and a decreased fraction during a blood neutrophil peak. These findings suggest that the marrow granulopoiesis was regulated through CSA. The defect causing the periodicity was probably related to the reduced number of neutrophils in the marrow maturation storage pool, which in turn may be related to a reduced and/or defective granulocytic stem cell pool size consequent to the long-term administration of cytotoxic drugs and/or infiltration of the marrow by myeloma cells.

Total body leukemic mass in patients with chronic lymphocytic leukemia (CLL) was measured by quantitation of total body potassium (TBK) with a whole-body counter. In addition, the predicted normal total body potassium (Kp) for each patient was calculated from an empirically derived relationship involving height, weight, age, and sex. Both the absolute TBK and the relative excess of total body potassium (TBK/Kp) were related to the stage of disease. Patients in the early stages of CLL were found to have lower TBK and TBK Kp than patients in the late stages of disease. Both of these parameters increased with the successively advanced stages of the disease. The clinically monitored reduction of leukemic cell mass following therapy was accompanied by reductions in TBK and TBK/Kp. Data presented support the notion that TBK/Kp is a useful indicator of the total body leukemic mass. Furthermore, the results of these studies quantitatively validate the proposed clinical staging system for CLL. Quantitation of TBK by a whole-body counter is an accurate and noninvasive procedure and does not require administration of isotopes.

No abstract