Inflammatory proteins in Rasmussen’s encephalitis (RE). Immunolabeling of CD3ϵ revealed minimal immunoreactivity in (A) the non-RE case and likewise (C) CD8, (E) CD68, and (G) vimentin immunoreactivity was infrequently detected in non-RE brain sections compared to (B) marked perivascular CD3ϵ-positive T cell abundance, numerous (D) CD8+ T cells, (F) CD68+ macrophages, and (H) hypertrophied astrocytes in the RE sections. Sections from the non-RE case showed negligible (I) MHC class II, (K) IL-1β, (M) caspase-1, and (O) ASC immunostaining, while (J, L, N, P) the RE white matter exhibited robust immunoreactivity for all proteins. IL-1β immunoreactivity was evident on cells resembling microglia in RE tissue (L, arrowheads); IL-1β (blue) was co-localized with MHC class II (brown) immunopositivity, as indicated by the arrow (L, inset). Original magnification: panels (A,B,C,D) x100, panels (E,F,G,H,I,J,K,L,M,N,O,P) x200; size bar 10 μm, inset x600; size bar 2 μm). ACS, alanine/serine/cysteine; MHC, major histocompatibility complex; RE, Rasmussen’s encephalitis.