Further support for the involvement of alterations in the peripheral cytokine profile in the pathology contributing to MS comes from studies of natalizumab, which not only inhibits the transmigration of leukocytes into the CNS but also decreases the plasma levels of GM-CSF, IL-6, IL-10 and TNF after 1 year—with IL-8 levels remaining unaltered [46]. This evidence concerns the gene IL6 and myeloid sarcoma.