University of California - San Francisco Oct 21 2025 By the time patients start seeking care for multiple sclerosis (MS), the disease has already been damaging their brains for years. But until recently, scientists didn't understand which brain cells were being targeted or when the injury began. Now, by analyzing thousands of proteins found in the blood, scientists at UC San Francisco have created the clearest picture yet of when the disease attacks the myelin sheath that covers the nerve