Pro-inflammatory leukocytes and platelets

Pro-inflammatory leukocytes and platelets refer to a complex cellular state where activated platelets and white blood cells (primarily neutrophils and monocytes) physically interact to drive systemic inflammation and thrombosis, a process known as thromboinflammation (Source: NIH/PubMed, PMID: 31649093). This interaction is predominantly mediated by the binding of P-selectin, expressed on the surface of activated platelets, to P-selectin glycoprotein ligand-1 (PSGL-1) found on leukocytes (Source: Ataga et al., NEJM 2017). The resulting formation of platelet-leukocyte aggregates (PLAs) enhances leukocyte recruitment to vascular walls, triggers the release of pro-inflammatory cytokines, and promotes the formation of neutrophil extracellular traps (NETs), which can lead to vascular damage and occlusion. In clinical practice, these interactions are significant drivers of pathology in conditions such as sickle cell disease, where they contribute to painful vaso-occlusive crises, and in atherosclerosis, where they accelerate plaque progression (Source: StatPearls, 'Sickle Cell Anemia'). Drugs like Crizanlizumab target this system by binding to P-selectin, thereby disrupting the bridge between platelets and leukocytes to improve microcirculatory flow and reduce inflammatory episodes. While targeting these cellular interactions offers a potent anti-inflammatory strategy, it requires careful management to avoid compromising primary hemostasis or host defense mechanisms.

Other names

Platelet-leukocyte aggregatesPLAsThromboinflammatory complexesActivated leukocyte-platelet unitsMonocyte-platelet aggregatesNeutrophil-platelet aggregates

Inhibition of cell-cell adhesion by blocking surface receptors such as P-selectin (CD62P) or integrins (e.g., GPIIb/IIIa, Mac-1), which prevents the physical coupling of platelets to leukocytes and reduces the subsequent release of inflammatory mediators and microvascular occlusion.