Evidence of Meningeal Inflammation in Multiple Sclerosis: a Combined in Vivo 11C-PBR28 MR-PET and Post-Mortem Study

In multiple sclerosis (MS), neuropathological studies suggest that meningeal inflammation involving T-, B-lymphocytes, plasma cells, macrophages may trigger underlying cortical neuroinflammation and demyelination. Using MR-PET targeting the18kDa mitochondrial translocator protein, which is overexpressed in activated glia/macrophages, we detected in 49 MS patients cortical inflammatory changes along with neuroinflammation in both meninges and juxtacortical white matter. Meningeal inflammation correlated with worse neurological disability and cognitive performance. Histochemistry performed in meningeal tissue from 40 post-mortem progressive MS cases confirmed in vivo findings. This study provides in vivo PET imaging evidence implicating meningeal neuroinflammation in the pathophysiology of MS.