Viscous Behavior of Leukocytes

Abstract

Over the past few years, enormous progress has been made toward understanding the Theological behavior of leukocytes or white blood cells, and more specifically, the neutrophils. White blood cells have been found to be more resistant to flow and to have more complex functions and structures than red blood cells. In addition to the complexities of the internal structure, the white blood cells can activate under various conditions. During activation, pseudopods (solid like protrusions) are formed on the surface of the leukocyte’s membrane. In the passive state, leukocytes are spherical in outline with a ruffled membrane and are modeled as deformable spheres. In this chapter, a short overview of the viscous behavior of leukocytes is given with an emphasis on the mechanical modeling of passive neutrophils and lymphocytes, and in particular, the modeling of the recovery of these cells after large deformations. Most of the work on the rheological properties of leukocytes has been focused on the neutrophils and has used the micropipet technique. The main thrust of the studies on white blood cells is to understand their roles and functions in health and disease. Rheological studies of leukocytes other than neutrophils and lymphocytes are sparse (Sung et al., 1988), and will not be discussed in this chapter.