Figure 2.

Demyelinating cortical lesion and meningeal inflammation in chronic progressive MS. Immunohistochemistry for myelin oligodendrocyte protein (MOG) shows extensive subpial demyelination involving the neocortical grey matter, contiguous to MOG-positive brain tissue (A, black arrowheads). The lesion is in close proximity to inflamed meninges containing an elevated number of CD20+ B cells, either accumulated (B, arrow) or diffused (C), around subarachnoid vessels. Substantial increased density of MHC-class II+ activated microglia can be observed in the most external cortical layers (white arrowheads) at the pia/CSF boundary (D) nearby inflamed meninges. Original magnifications: 50× (A), 100× (D), 200× (B,C).