Tackling the century-long mystery of multiple sclerosis
A cure for multiple sclerosis remains elusive, but a decade of technological and scientific advances is starting to shed light on possible causes, better diagnostics and potential treatments for the disease.
Why it matters: MS — a central nervous system disease affecting almost 3 million people globally — has baffled doctors since it was discovered over a century and a half ago.
- The disease can advance silently for years, but then attack myelin, the protective coating around nerve cells, and produce lesions that can cause vision problems, muscle weakness and more. It is unknown why the disease can progress in unpredictable and different ways.
- MS is difficult to study, as many people are asymptomatic for the first several years and don't see a doctor until the disease has progressed, says Daniel S. Reich, neuroradiologist and senior investigator for NIH's National Institute of Neurological Disorders and Stroke.
- FDA-approved treatments are designed to slow the progress of the disease or try to reverse myelin damage, but often have serious side effects, including possible liver damage, an elevated risk of certain cancers and rendering COVID-19 vaccines less effective.
- Autoantigens "may lie at the core of MS" and could help researchers understand what aspects of the immune system MS is targeting, says study co-author Mattias Bronge, a Ph.D. student at Karolinska Institutet.
- While this hasn't been tested yet, it might be possible to increase the immune system's tolerance for some antigens so the disease's effects are reduced, similarly to what is done in allergy treatments, Bronge says, and those four new identified proteins may help advance this idea.
Yes, but: Scientists must first better understand how "the immune system orchestrates damage to brain cells and what is required for the brain to repair itself better," Reich says.
Between the lines: MS is believed to be caused by a mix of genetic susceptibility, faulty immune systems, and environmental factors. A crucial discovery is the probable link of MS with the Epstein-Barr virus, a common herpes virus that infects almost all people by adulthood and is more well-known as a cause of mononucleosis.
- A long-term study of more than 10 million young adults in the military found the risk of developing MS increased 32-fold after infection with EBV but not after infection with other viruses.
- This bolsters the belief that MS may be a rare complication of EBV — but also also leads to questions on why such a small percentage of EBV-exposed people wind up having MS.
- There are about 15 EBV vaccines in development, most in very early phases, as well as trials to transplant immune cells. But, determining whether or not these will help prevent MS will take years with large trials, Reich points out.
Meanwhile, diagnostics and assessments via high resolution MRIs, spinal fluid analysis techniques or genomics continue to rapidly improve, says Reich, whose lab uses MRI imaging in its MS research.
- Some researchers are looking at imaging of the retina or central vein sign to improve early diagnostics.
- "We need to develop MRI technologies that can get us down to the resolution of a few cells. We're not quite there yet, but we're a lot closer than we were five or 10 years ago," Reich says.
What's next: Taken together, these incremental advances will likely begin to answer some fundamental questions in the next few years about why some people get MS and how it might be treated, Reich says.
- "The MS research field is moving forward with great speed at the moment," Bronge says. "I’m absolutely optimistic, and I think we have a very exciting decade ahead of us."