This proinflammatory cytokine has multiple effects that are relevant to MS.37 It is elevated in plasma and CSF of patients with MS,38 and its CSF levels were used as outcome measures in progressive MS trials.39,40 OPN binds the integrin VLA4 that is the target of the monoclonal antibody NTZ, a high-efficacy MS treatment. The gene discussed is SPP1; the disease is myeloid sarcoma.