Profiles of Platelet Volume Distributions in Normal Individuals and in Patients with Acute Leukemia

Abstract

Several investigations have demonstrated that human platelets contain subpopulations of heavy–large (young) elements that are hemostatically more effective than subpopulations of lighter–smaller (old) platelets. By means of a multichannel particle size discriminator the authors could visualize such platelet subpopulations and were able to monitor the fluctuations that occur within different volume compartments in patients with acute leukemia. The subjects for this study included 55 blood bank donors (27 male) and 17 untreated patients with acute leukemia. Platelet volume distribution profiles were obtained with a multichannel particle size analyzer (100 channels) attached to an electronic particle counter. Platelet volumes monitored in all channels were averaged into groups of ten compartments consisting of discrete increments of 2 μm³ each, to yield a ten-dimensional vector profile for each subject. The mean platelet volume distribution profile of normal individuals was represented by a skewed curve. Platelet volumes ranged from 1 to 21 μm³, with a median of 8.4 μm³. Small platelets (μm³) represented less than 7.5% of the population. In contrast, the mean platelet volume distribution profile of the leukemic patients demonstrated a skewed curve with a median platelet volume of only 4.9 μm³ where small platelets comprised 25–30% of the population. These changes were statistically significant. In addition, the authors devised a single-value numerical index, the platelet volume distribution score, to summarize the entire range of values obtained for profiles of each individual. This value served as a sensitive index when comparing the extents of abnormality in the profiles of leukemic patients with the profile of normal donors.