Elastic properties of passive leukemic white blood cells

The key role of leukocytes (WBC) in pathologic alterations of microcirculation was repeatedly described in the literature. The aim of this study was to compare the mechanical characteristics of WBC of 4 healthy donors and 6 patients suffering from chronic myeloid leukemia (CML). The elastic properties of individual leukocytes in the passive state were studied by the micropipette technique (aspirating pressure delta P = 100 divided by 250 Pa; internal pipette radius Rp = 1.4 divided by 2.6 microns). The passive elastic rigidity of WBC (PER) from 30 cells/donor was characterized by the amplitude of their steady-state deformation (Dp) normalized for the pipette radius (Rp) against the stress parameter delta P * Rp. The effect of a CML-therapy with cytostatics was monitored by way of differential blood counts. A significantly higher rigidity of healthy lymphocytes (PER = 349.7 +/- 125.9 microN/m; n = 45) than that of polymorphonuclear granulocytes (PER = 226.5 +/- 86.7 microN/m; n = 62) was seen which appears to result from their large, solid nucleus. Control leukocytes have a significantly higher rigidity than leukemic WBC. Leukemic granulocytes (PER = 155.1 +/- 67.7 microN/m; n = 61) and lymphocytes (PER = 134.3 +/- 51.9 microN/m; n = 62) do not differ significantly in their values of rigidity.