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Brain scans reveal marker for severe MS

The ability to detect aggressive forms of MS would enable researchers to test and assess potential therapies.andresr / E+ via Getty Images

Multiple sclerosis (MS) affects more than 2 million people worldwide. It’s caused by the immune system attacking the protective coating around nerve cells in the brain and spinal cord.

MS can affect each person differently. Initial symptoms may include blurred or double vision and problems with muscle strength, balance, and coordination. Some people have a longer lasting, progressive form of the disease, which can cause debilitating problems including paralysis, loss of bladder control, and problems with attention, thinking, and memory. 

The immune system’s attack on the nervous system produces lesions that appear as spots on MRI scans of a patient’s brain. While some lesions heal, completely or partially, others remain chronically inflamed. Chronically inflamed lesions have a dark outer rim surrounding them on MRI scans and appear to actively expand for many years. These dark rims accumulate brain immune cells called microglia, which can sustain low-grade, or “smoldering,” inflammation.

To investigate the role these chronic active lesions play in MS, a team led by Drs.Martina Absinta and Daniel S. Reich at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) followed 192 patients with MS and assessed lesions and disease severity over seven years. Results were published online on August 12, 2019, in JAMA Neurology.

Dark rimmed spots, representing ongoing “smoldering” inflammation, may be a hallmark of more disabling forms of multiple sclerosis.Reich lab, NIH/NINDS

Most of the study participants (56%) had at least one chronic active lesion—including those who were receiving the most current treatment options. The researchers classified the patient results into three groups: no rims (84 people); one to three rims (66 people); and four or more rims (42 people). 

Patients with multiple chronic active lesions showed a more aggressive form of MS. Those with four or more rim lesions were 1.6 times more likely to have MS that progressed compared with those without any rim lesions. They were also more likely to experience physical and cognitive disabilities at a younger age.

“We found that it is possible to use brain scans to detect which patients are highly susceptible to the more aggressive forms of multiple sclerosis. The more chronic active lesions a patient has, the greater the chances they will experience this type of MS,” Absinta says. “We hope these results will help test the effectiveness of new therapies for this form of MS and reduce the suffering patients experience.”

In addition, the findings suggest that future studies on new treatments could target the brain’s unique immune system, particularly microglia.