[Blood parasitosis--mechanisms and limitations of a species-alien coexistence]

Human proto- and metazoa, which spend a part of their life-cycle within erythrocytes or extracellularly in human blood or in monocyte-derived macrophages, are considered as blood parasites. In spite of their individually widely differing habitat, they elicit a common hematological syndrome essentially consisting in hemolytic anemia and splenomegaly. Furthermore, some basic factors of host/parasite interaction are very similar: (1) Specific cell attachment through receptor/ligand mechanisms such as the integrin/RGD-oligopeptide system, (2) competition for essential nutrients such as iron, which may be influenced therapeutically to the disadvantage of the parasite by the use of iron chelators, and (3) provocation of host defense through T-cell dependent, cytokine-mediated macrophage activation.