Multiple sclerosis (MS) is a degenerative autoimmune disease that causes damage to the protective insulation that surrounds nerves, called the myelin sheath. The symptoms and severity of the disease can vary widely between patients depending upon which nerves are affected. New research has shown that a biomarker can predict which MS patients are more likely to experience more severe symptoms that can lead to impairments, about one to two years in advance. The biomarker is a molecule called neurofilament light chain (NfL), which has been proposed to be an indicator of neurodegeneration, and it is part of the cellular cytoskeleton. The findings have been reported in JAMA Neurology.
It's estimated that about 2.8 million people around the world have MS. The disease can impede mobility, impair coordination, and cause weakness, or incontinence. There is no cure for the disease, although some recent studies have suggested that it may be possible to delay some of the worst symptoms.
This new biomarker may be particularly useful, because it can indicate when treatments or interventions can be applied so that the most severe problems can be prevented, suggested co-first study author Ahmed Abdelhak, MD, of the UCSF Department of Neurology and the Weill Institute for Neurosciences.
In this work, the researchers assessed worsening disability in about 1,900 patients who went to around 13,000 doctor visits in the Europe and the US. The researchers defined worsening disability as when patients experienced six or more months of progressive impairment and increasing scores when analyzed on what is known as the Expanded Disability Status Scale. This is different from disabilities that may worsen and relapse from time to time. There were 570 patients who had disabilities that worsened, independent of relapses.
The scientists found that abnormally high levels of NfL were associated with a 91 percent increase in the risk of worsening disabilities within one year and a 49 percent increased risk within two years.
"We think that NfL elevation occurs earlier in disability worsening without relapse," said Abdelhak.
The variation in the pattern could be indicative of, "a more prolonged process that decreases in intensity in advance of increased impairment," said co-senior author Ari Green, MD, medical director of the UCSF Multiple Sclerosis and Neuroinflammation Center.
Nerve cell death is also a slow process that gradually leads to permanent disabilities. But it may also be possible to intervene, and prevent those problems, added Green.
Sources: University of California San Francisco, JAMA Neurology