This article has no abstract; the first 100 words appear below.

Multiple sclerosis is a disabling autoimmune disease in which immune cells target central nervous system (CNS) antigens, leading to demyelination, glial activation, and subsequent loss of neurons and axons.1 There are three main subtypes of multiple sclerosis: relapsing–remitting, in which patients recover partly or fully from attacks but go on to have others; secondary progressive, in which patients with relapsing–remitting disease have progression of disability between attacks; and primary progressive, in which patients have continual progression from the time of onset of the disease.2 Over the past two decades, a remarkable number of new therapies have been developed that reduce . . .