Influence of erythrocyte aggregation on leukocyte margination in postcapillary expansions: A lattice Boltzmann analysis

Leukocyte rolling on the vascular endothelium requires initial contact between the circulating leukocytes in the blood and the vessel wall. Although specific adhesion mechanisms are involved in leukocyte–endothelium interactions, adhesion patterns in vivo suggest other rheological mechanisms are involved as well. Previous studies have proposed that the abundance of leukocyte rolling in postcapillary venules is due to interactions between red blood cells and leukocytes as they enter capillary expansions as well as red blood cell (RBC) aggregation. We have established a lattice Boltzmann approach to analyze the interactions of RBC aggregates and leukocytes as they flow through a postcapillary expansion. The lattice Boltzmann technique provides the complete solution of the flow field and quantification of the particle–particle forces. Our results show that RBC aggregation strongly influences leukocyte–endothelium interactions.