FIGURE 2.

IFNs and IFN‐II in Inclusion body myositis. (1) Highly differentiated T cells secrete IFN‐II. (2) IFN‐II stimulates the expression of muscle antigens on MHC class I via the immunoproteasome in muscle fibres (3). Cytotoxic CD8+ T cells can be stimulated by the complex of muscle antigens and MHC class I and produce IFN‐II (4). IFN‐II may induce protein aggregates (5). IFN‐II also activates macrophages and MHC class II expression with muscle autoantigen (6). Activated macrophages stimulate CD4⁺ Th1 T cells and (7) are involved in myophagocytosis of necrotic muscle fibres