Fig. 4

Muscle biopsy findings. A, B Hematoxylin & eosin staining showing dense endomysial lymphocytic aggregates (A), and perimysial fragmentation with plasma cell-rich perivascular infiltrates (B). C–F Immunohistochemical stains showing endomysial aggregates composed of predominant CD20 + B cells (C) and accompanying CD3 + T cells (D); diffuse upregulation of MHC class I (E); and perifascicular upregulation of MHC class II (F). Bar, A–D 50 μm (× 20 objective); E–F 100 μm (× 10 objective). Method for picture acquisition: Olympus BX46 microscope, with UPlanFL objectives with CellSens software (Olympus). The six images were placed in photoshop, in a 600dpi canvas, without further processing, to organize them and include lettering and bars. The final panel was exported as a jpg with 80% quality setting