Despite the overwhelming evidence that multiple sclerosis is an autoimmune disease, relatively little is known about the precise nature of the immune dysregulation underlying the development of the disease. Reasoning that the cerebrospinal fluid from patients might be enriched for cells relevant in pathogenesis, we have completed a high-resolution single-cell analysis of 96,732 cerebrospinal fluid cells collected from 33 patients with multiple sclerosis (n = 48,675) and 48 patients with …