Scientists may have found a hidden culprit behind rapidly worsening MS: overloaded brain immune cells packed with fat. Credit: Shutterstock Researchers led by Daan van der Vliet, working with teams from the Netherlands Institute for Neuroscience, Leiden University, and Utrecht University, have identified a biological process that may help explain why multiple sclerosis (MS) becomes especially severe in some patients. Examining brain tissue from people with rapidly progressing MS, they found