Platelets and immunity: From physiology to pathology

Blood platelets are cells acting during primary haemostasis. The thrombocytopenia observed in many different types of infectious processes begs the question of the relationship between cells and infectious pathogens and the role of platelets in the detection of biological hazards. This in turn brings us back to the role of platelets – via their molecular, membrane and secretory arsenal – in the detection and repair of vascular hazards. The common denominator between a breakdown of haemostasis and the risk of infection has been shown to be a cutoff point in the inflammatory continuum between physiology and physiopathology. The trophic role of platelets – as topical factor and as platelet transfusions – and their inflammatory complexities appear to correlate this proposed model, as reported in this short review.