Researchers at UC San Francisco have found that multiple sclerosis damages the brain years before symptoms appear, by analyzing blood proteins. The study identifies key markers like IL-3 and MOG, potentially enabling earlier diagnosis and prevention. This discovery, published in Nature Medicine, could transform how MS is managed.
Multiple sclerosis (MS) often silently injures the brain long before patients notice symptoms. Scientists at UC San Francisco analyzed thousands of proteins in blood samples from 134 individuals who later developed MS. These samples came from the U.S. Department of Defense Serum Repository, allowing examination of blood drawn years before diagnosis.
The research revealed that the immune system begins attacking the brain's protective myelin sheath—the fatty covering that insulates nerve fibers—earlier than previously thought. Seven years prior to diagnosis, there was a spike in MOG (myelin oligodendrocyte glycoprotein), a protein signaling damage to the myelin insulation around nerve fibers. About a year later, neurofilament light chain rose, indicating injury to the underlying nerve fibers themselves.
During this early phase, IL-3 emerged as a key immune protein. It helps recruit immune cells into the brain and spinal cord, where they attack nerve tissue, causing significant damage without symptoms. The team identified around 50 proteins as potential early indicators of MS and has filed a patent for a diagnostic blood test based on the 21 most reliable markers.
"We think our work opens numerous opportunities for diagnosing, monitoring, and possibly treating MS," said Ahmed Abdelhak, MD, assistant professor of Neurology at UCSF and co-lead author of the paper, published in Nature Medicine on Oct. 20. "It could be a gamechanger for how we understand and manage this disease."
Ari Green, MD, chief of the Division of Neuroimmunology and Glial Biology at UCSF and senior author, added: "We now know that MS starts way earlier than the clinical onset, creating the real possibility that we could someday prevent MS—or at least use our understanding to protect people from further injury."
The findings provide the most detailed timeline yet of MS's biological progression, highlighting the potential for preventive strategies.