Natalizumab, a disease-modifying therapy for MS, is a humanized IgG4 antibody against the α4-integrin subunit, which works by blocking the interaction between the α4 integrin expressed on lymphocytes and VCAM1 expressed on ECs thus limiting the passage of autoreactive lymphocytes across the vessel walls into the CNS [45]. The gene discussed is VCAM1; the disease is myeloid sarcoma.