VCAM1 and multiple sclerosis: Natalizumab is a recombinant humanized antibody used for the management of inflammatory bowel disease and multiple sclerosis and designed to target the α4 chain of integrin heterodimers on leukocytes to prevent their interactions with vascular cell adhesion molecule 1 (VCAM-1), thus inhibiting leukocyte adhesion and vascular transmigration (12, 13).