Immune adherence clearance is the process by which red blood cells bind bacteria and other pathogens in the blood stream and deliver them to the spleen where they are taken up and degraded by a specialized cell type, the macrophage. Within this project we have investigated the manner by which red blood cell and macrophages make contact in the spleen and how the pathogen is eventually transferred from the red blood cell to the macrophage. In particular, the binding of the pathogen to the red blood cell leads to changes on the surface of the red blood cell that make them “sticky” for the macrophages in the spleen. This event is crucial for the interaction of the red blood cell with the macrophage and the resulting degradation of the pathogen. We have unraveled the receptors that are involved in the recognition and capturing of red blood cells that have bound a pathogen, as a consequence of the changes that take place after red blood cells capture a pathogen. Based on this knowledge we have been able to develop a novel treatment for sepsis patients in which the blood of the patients is filtered and the red blood cell-pathogen complexes, which can be present in numbers that are overwhelming the body’s own capacity to clear them, are removed. This knowledge has led to the development of a novel therapy which will be validated in a future trial in septic patients at the intensive care.

Thesis 2021: Erythrocyte samsara, Thomas Klei