A blood test may someday replace some of the magnetic resonance imaging (MRI) scans taken by people with multiple sclerosis (MS) — offering an easy, cheap alternative for monitoring disease activity.
A study by Norway’s University of Bergen found that blood levels of a factor called neurofilament light chain, released from damaged neurons, correlated closely with the appearance of new brain lesions. The levels dropped when patients started treatment.
The study, “Neurofilament light chain predicts disease activity in relapsing-remitting MS,” appeared in the journal Neurology, Neuroimmunology and Neuroinflammation. Its findings strengthen the case of neurofilament light chain as a reliable factor for measuring disease activity in MS patients.
“Since MS varies so much from person to person and is so unpredictable in how the disease will progress and how people will respond to treatment, identifying a biomarker like this that can help us make predictions would be very helpful,” Dr. Kristin Varhaug, the study’s first author, said in a press release. “These blood tests could provide a low-cost alternative to MRI for monitoring disease activity.”
Researchers worldwide have realized the potential of neurofilament light chain as an MS marker. Varhaug’s team recruited 85 patients with relapsing-remitting MS (RRMS) to a trial (NCT00360906) exploring how the factor related to disease activity measured by MRI. These patients were in relatively early disease stages and had been ill for an average two years.
During the first six months of the study, participants received no disease-modifying treatment. At six months, all patients began treatment with Rebif (interferon-beta 1a) for the remaining 18 months of the study. Meanwhile, they received monthly MRI scans during the first nine months, followed by a scan at year one and year two. Researchers also gathered blood samples at the beginning of the study, and again at month three, six, 12 and 24.
The analyses revealed that when new brain lesions — both of inflammatory and non-inflammatory types — appeared, levels of the nerve factor jumped. That increase was linked to lesion development up to two months before and one month after the blood measurement.
Once patients started treatment with Rebif, the levels of neurofilament dropped.
“We monitored neurofilament light chain levels in the blood of people with the relapsing-remitting form of MS and found levels of this nerve protein were higher when people had new disease activity and lower when they took medication to reduce the number of symptom flare-ups,” Varhaug said.
Additional statistical analyses showed that for every 10 picograms/mL increase in blood levels of the nerve factor, the risk of developing a new T1 type inflammatory lesion rose by 48 percent. This increase in neurofilament light chain levels was also linked to a 62 percent increased risk of developing a new T2 type lesion (T1 and T2 are two different types of imaging techniques).
In contrast, researchers found no link between levels of the factor and relapses or disability levels.
“Blood tests for this nerve protein may be an effective way to monitor disease activity and how well the treatment is working,” said Varhaug.
Researchers underscored that the study performed MRI scans far more often than is customary in regular MS care. In future studies, they hope to follow patients for a longer period to see how the relevance of the factor plays out in the long term.
Neurofilament light chain, a component of nerve cells, is currently being explored in numerous MS studies and clinical trials. Until it has been properly evaluated, it is, however, not part of standard MS care.