Platelet-leukocyte interactions: immunoregulatory role and pathophysiological relevance

Blood platelets are the central players in thrombosis and blood coagulation. Moreover, they also exhibit immunoregulatory properties bridge hemostasis immunity. Morphological functional characteristics of ensure continuous surveillance for vascular system, recognition different hazards, development appropriate response recruitment immune cells. Indirect platelet-leukocyte interactions mediated by molecules that released, along with coagulation factors course platelet activation degranulation. Chemokines, cytokines, growth factors, some which synthesized de novo , released from activated modulate cellular functions, thus modulating both innate adaptive response. Activated enter contacts cells to form heterotypic aggregates, i.e., complexes reside circulation other The aggregate formation stabilization is interaction between expressed on surface leukocytes, particular, P-selectin (CD62P) PSGL-1 (CD162). Platelet-monocyte platelet-neutrophil most abundant, platelet-monocyte aggregates being stable. platelet-derived microvesicles interact leukocytes thus, probably, cell functions via transfer non-coding RNA molecules. Formation results into mutual leukocytes. Platelets stimulate phagocytic activity, cytokine secretion, generation reactive oxygen species monocytes neutrophils, inducing neutrophilic extracellular traps procoagulant phenotype monocytes. regulate monocyte differentiation, promote adhesion, as well transmigration lymphocytes NK At sites inflammation, enhance extravasation infiltration damaged tissue. Impaired endothelial layer may underlie pathogenic conditions. Increased level circulating plateletleukocyte observed various disorders including cardiovascular diseases, acute ischemic stroke, respiratory disorders, renal pathologies, liver diabetes, reproductive bacterial viral infections. Further studies warranted unveil mechanisms develop new therapeutic approaches.