Figure 5From: Comparative utility of LC3, p62 and TDP-43 immunohistochemistry in differentiation of inclusion body myositis from polymyositis and related inflammatory myopathies pIBM staining patterns. pIBM cases were histologically similar to classic IBM, with endomysial inflammation, fiber invasion, and moderate-severe chronic myopathic features, but without classic RVs (a and f; H&E, frozen material); “rimmed cracks” (white arrowhead in e) were present in a subset of specimens. The majority of pIBM samples (designated pIBM high) showed well-developed labeling for LC3 (b) and p62 (c); TDP-43 immunopositivity was less commonly observed (d; arrow marks a single TDP-43 positive fiber). In the example shown (subject #52), many fibers showed dense coarse puncta and rare RV-like structures (black arrowhead in b). In a smaller subset of samples (designated pIBM low), little or no labeling was seen with all three markers (f- h). a-d, subject #52, e-h, subject #51; scale bar, 50 μM.Back to article page