Personalized medicine is a medical model where treatment decisions are tailored to the patient in accordance with the specific characteristics of the individual and their disease. Typically, these decisions are based on the predicted treatment response of the patient, which is based on individual disease features. At present, treatment of multiple sclerosis (MS) relapses is far from personalized medicine: most patients receive 1 or 2 courses of corticosteroids, with treatment of unresponsive relapses escalating to apheresis (either plasma exchange or immunoabsorption).1,2 Predictors of response to either corticosteroids or plasma exchange are limited.