Leukocyte–endothelial adhesion pathway

The leukocyte–endothelial adhesion pathway is a highly regulated, multi-step cascade that governs the movement of leukocytes from the blood into peripheral tissues. This process begins with leukocyte tethering and rolling on the vascular endothelium, primarily mediated by selectins such as E-selectin and P-selectin [Ley et al., 2007, Nature Reviews Immunology]. Following activation by chemokines, leukocytes undergo a conformational change in their surface integrins, allowing for firm adhesion to endothelial ligands like Intercellular Adhesion Molecule-1 (ICAM-1) [Springer, 1994, Cell]. The final stage involves diapedesis, where leukocytes migrate through the endothelial junctions to reach the site of injury or infection [Muller, 2013, Veterinary Pathology]. While essential for host defense, overactivation of this pathway contributes to the pathogenesis of chronic inflammatory conditions, including Crohn's disease and multiple sclerosis. Therapeutic agents targeting specific components of this pathway, such as the integrin antagonist Vedolizumab, are used to treat these diseases by selectively inhibiting leukocyte infiltration [DrugBank, 2024]. However, systemic inhibition of these pathways can lead to significant safety concerns, such as an increased risk of opportunistic infections like progressive multifocal leukoencephalopathy. Understanding the molecular specificity of these interactions is crucial for developing targeted therapies that minimize systemic immunosuppression.

Other names

Leukocyte adhesion cascadeLeukocyte extravasation pathwayLeukocyte recruitment cascadeDiapedesis pathway

Inhibition of leukocyte recruitment by blocking the interaction between leukocyte-expressed integrins and their corresponding endothelial ligands, thereby preventing rolling, firm adhesion, and subsequent transmigration into inflamed tissues.