ICAM4, also known as CD242, is a member of the immunoglobulin superfamily, the ICAM family. ICAM4 contains 2 Ig-like C2-type (immunoglobulin-like) domains. It is similar to the intercellular adhesion molecule (ICAM) protein family. ICAM4 binds to the leukocyte adhesion LFA-1 protein. ICAM4's first reported receptors were CD11a/CD18 and CD11b/CD18. ICAM4 functions as a ligand for the monocyte/macrophage-specific CD11c/CD18. Deletion of the individual immunoglobulin domains of ICAM4 demonstrated that both its domains contain binding sites for CD11c/CD18. CD11c/CD18 is expressed on macrophages in the spleen and bone marrow. Inhibition of erythrophagocytosis by anti-ICAM4 and anti-integrin antibodies suggests a role for these interactions in the removal of senescent red cells.