Lymphocyte function-associated antigen-1 – Intercellular adhesion molecule-1 (LFA-1 – ICAM-1) adhesion axis (LFA-1 – ICAM-1 axis)

The LFA-1 – ICAM-1 adhesion axis is a fundamental pathway mediating leukocyte trafficking and the formation of the immunological synapse (UniProt: P20333, P05362). Lymphocyte function-associated antigen-1 (LFA-1), a heterodimeric integrin composed of CD11a and CD18 subunits, is expressed on all leukocytes and binds to its primary ligand, Intercellular Adhesion Molecule-1 (ICAM-1), which is upregulated on endothelial cells and antigen-presenting cells during inflammation (PubMed: 10485902). This binding event is essential for the firm adhesion of T-cells to the vascular wall, allowing them to migrate into peripheral tissues (StatPearls: NBK539824). In disease states, overactivity of this axis drives chronic inflammation in conditions like dry eye disease, psoriasis, and rheumatoid arthritis (NIH: PMC4936699). Pharmacological intervention, such as the small molecule lifitegrast, competitively inhibits this interaction to reduce T-cell mediated ocular surface inflammation (FDA: Xiidra Label). Historically, systemic blockade with monoclonal antibodies like efalizumab was used for psoriasis but was withdrawn due to risks of progressive multifocal leukoencephalopathy (PML) (PubMed: 19230604).

Other names

CD11a/CD18 – CD54 axisIntegrin alpha-L beta-2 – ICAM-1 interactionLFA-1/ICAM-1 pathwayLeukocyte adhesion axis

Competitive inhibition of the protein-protein interaction between the integrin LFA-1 and its ligand ICAM-1, which prevents the stable adhesion, extravasation, and activation of leukocytes at sites of inflammation (PubMed: 10485902).