A common perception among physicians is that new medical knowledge usually moves from 鈥渂ench to bedside,鈥� that is, from laboratory experiments to clinical care. However, in many instances progress has occurred in the other direction, from bedside to bench, beginning with clinical observations. This has been the case for multiple sclerosis (MS), one of the important success stories of modern molecular medicine.

The development of highly effective B cell therapeutics for MS has produced substantial gains for patients with MS, many of whom can now reasonably expect lives free from disability, and has fundamentally reshaped the understanding of pathogenesis of an autoimmune disease that affects nearly 1 million individuals in the US.¹ Multiple sclerosis is a demyelinating disease of the central nervous system (CNS) consisting of 2 distinct but overlapping components, early relapses mediated by inflammation, and late progression due to neurodegeneration.