GFAP and myeloid sarcoma: Whilst these results suggest that acute focal MS inflammation and smoldering neuroinflammation are two distinct biological processes, they also suggest the need for novel measures for correlative assessment of clinical effects of neuroprotection: measures of axonal viability, of CNS neuroinflammatory load/spread, and of amount of remyelination; and exploration of how these correlate with biological biomarkers such as NfL and GFAP.