Researchers at the Netherlands Institute for Neuroscience (KNAW) have discovered a potential key mechanism explaining why multiple sclerosis (MS) progresses rapidly in some patients but follows a mild course in others. In the brain tissue of deceased individuals with severe MS, they found large quantities of so-called "foamy microglia"—immune cells overloaded with lipid droplets after engulfing damaged myelin.
Normally, microglia help clear cellular debris and support brain repair. However, when overloaded, they turn detrimental: they promote inflammation and worsen tissue damage. "Patients with many of these cells more frequently experienced a more severe disease course," explains lead author Daan van der Vliet.
The team analyzed tissue from 28 MS patients from the Netherlands Brain Bank and combined gene activity, protein, and lipid analyses in individual lesions. Certain fats associated with foamy microglia could potentially be detectable in cerebrospinal fluid in the future, serving as a biomarker for rapid disease progression. This would enable doctors to identify at-risk patients earlier and provide individualized treatment.
Initial clinical trials targeting lipid metabolism in chronic MS lesions are already underway in collaboration with Roche. The study was funded by the Dutch Gravitation programs ICI and iCNS.
Source: Netherlands Institute for Neuroscience – KNAW, June 29, 2026. Study in collaboration with Leiden University and Utrecht University.
