Unraveling the mystery of the spleen

Abstract

Despite the earliest descriptions of the spleen dating back to 1500 BC, the mechanisms that underlay the functions of the spleen remain shrouded in mystery. 1 At its simplest, the spleen is seen as an extraneous, dispensable organ. A more nuanced viewing of the organ recognizes its complex role human physiology. Approximately 5% of blood volume passes through the spleen with each heartbeat. The red pulp of the spleen serves as an excellent mechanical filter for the blood by removing damaged, senescent, and infected red blood cells from circulation. The immune cells in the white pulp of the spleen are regularly exposed to the entirety of circulating blood, enabling them to serve as the largest immune organ in the body. The spleen mediates immune response to circulating bacteria, organisms without a specific host antibody, and intracellular pathogens. The spleen is far more complicated than is often perceived.In this issue of American Journal of Hematology, a study by Kho et al. explores mechanisms of malarial splenomegaly and highlights the importance of the spleen in worsening anemia during infections with Plasmodium spp. 2 The spleen serves as a reservoir for malaria parasites during