Influence of vessel geometry on leukocyte adhesion: a Lattice-Boltzmann model

Leukocytes roll and arrest on the vascular endothelium in both normal and pathological immune responses, but the particulate, non-Newtonian nature of blood renders traditional mathematical models of these processes intractable. Here we present a Lattice-Boltzmann approach to quantify the fluid dynamics and forces involved as white blood cells interact with red blood cells in "virtual" blood vessels of various geometries. We report that the normal force imparted by erythrocytes is sufficient to increase leukocyte binding, and that increases in tangential force and torque can promote rolling of previously adherent leukocytes. The ratio of cell diameter to vessel diameter is an important determinant of the form of the interaction. This novel approach can be applied to a large number of biological and industrial problems involving the complex flow of particulate suspensions.