In Vivo Splenic Clearance Correlates with In Vitro Deformability of

Recent experimental and clinical studies suggest a crucial role of mechanical splenic filtration in the host’s defense against ma-laria parasites. Subtle changes in red blood cell (RBC) deformability, caused by infection or drug treatment, could influence the pathophysiological outcome. However, in vitro deformability measurements have not been directly linked in vivo with the splenic clearance of RBCs. In this study, mice infected with malaria-inducing Plasmodium yoelii revealed that chloroquine treat-ment could lead to significant alterations to RBC deformability and increase clearance of both infected and uninfected RBCs in vivo. These results have clear implications for the mechanism of humanmalarial anemia, a severe pathological condition affect-ing malaria patients. The spleen serves as the largest filter of blood in the human bodyby initiating immune responses against blood-bornemicroor-ganisms and removing abnormal blood cells (1). Twomajor struc-tural features of the spleen enable its critical functions: the white pulp (including the marginal zone), which contains the majority of immune effector cells, and the red pulp, a reticular meshwork that filters abnormal red blood cells (RBCs) (2). In humans, 76 to 79 % of the spleen is made of red pulp, a dense meshwork com-posed of splenic cords and splenic sinuses. Previous studies o