ITGAL (integrin subunit alpha L) encodes the alpha chain of lymphocyte function-associated antigen-1 (LFA-1), a crucial adhesion molecule expressed primarily on leukocytes. ITGAL functions as a receptor for intercellular adhesion molecules (ICAM1, ICAM2, ICAM3, ICAM4) 12 and F11R 3, mediating leukocyte-endothelial cell interactions and transmigration 3. At the immunological synapse, ITGAL acts as a signaling platform translating T cell receptor engagement into graded adhesion responses 4. ITGAL contributes to natural killer cell cytotoxicity 5 and apoptotic neutrophil phagocytosis by macrophages through ICAM3 interaction 6. Dysregulation of ITGAL expression associates with multiple diseases. Genetic variants in ITGAL increase inflammatory bowel disease risk through altered immune activation 7. In cancer contexts, ITGAL expression patterns vary by malignancy: elevated in gastric cancer correlating with immune infiltration and poor prognosis 8, but downregulated in lung adenocarcinoma predicting worse outcomes 9. ITGAL+ macrophages coordinate with cancer-associated fibroblasts in cervical cancer to suppress CD8+ T cell immunity 10. In glioma, microglia ITGAL/CD11a expression supports tumor growth via chemokine production 11. ITGAL emerges as a key inflammatory biomarker in proliferative diabetic retinopathy pathogenesis 12. Therapeutically, LFA-1-expressing engineered extracellular vesicles successfully target ICAM-1+ endothelial cells for drug delivery in inflammatory diseases 13.