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. 2023 Feb 8;14:1108116. doi: 10.3389/fimmu.2023.1108116

Figure 3.

Figure 3

Histopathological and clinical findings in patients with ICI-induced myositis. (A-F) Hematoxylin-eosin (HE) and immunohistochemical staining in a female patient with fatal ICI-induced myositis and myocarditis and positive anti-titin, anti-heart muscle and anti-skeletal muscle autoantibodies. Frozen sections of HE-stained (A) cardiac muscle (D) and skeletal muscle showing necrotic myofibers and lymphocyte infiltration (original magnification x 100). CD8 (large panel, original magnification x 200) and major histocompatibility complex (MHC) class I (inset, original magnification x 100) staining revealing cytotoxic T cell invasion and sarcolemmal overexpression of MHC class I by (B) cardiac and (E) skeletal muscle fibers. CD68 (large panel, original magnification x 200) and MHC class II (inset, original magnification x 100) staining showing macrophage invasion and sarcolemmal as well as sarcoplasmic overexpression of MHC class II by (C) cardiac and (F) skeletal muscle fibers. (G) Comparison of peripheral blood creatine kinase (CK) levels in patients with ICI-induced myositis shows a trend towards higher CK levels in patients with multiple neuromuscular autoantibodies compared to patients without neuromuscular autoantibodies. (H) Sagittal and (I) axial contrast-enhanced magnetic resonance imaging of the lumbar spine with T1-weighted turbo spin echo sequence showing paravertebral contrast enhancement (arrows) as a sign of muscle edema in a patient with ICI-induced myositis and myasthenia. Ab, autoantibody; ICI, immune checkpoint inhibitor; U/l, units per liter.