Adhesion molecule that binds to leukocyte adhesion LFA-1 protein LFA-1 (integrin alpha-L/beta-2). ICAM4 is also a ligand for alpha-4/beta-1 and alpha-V integrins (By similarity). Isoform 2 may modulate binding of membrane-associated ICAM4. Belongs to the immunoglobulin superfamily. ICAM family.