Pinal-Fernandez I, et al. - Experts aspired to explore whether myositis autoantigen expression correlates with muscle regeneration. Via 20 control subjects and 106 patients with autoantibodies recognizing hydroxymethyl-glutaryl-coenzyme A reductase, signal recognition particles, Jo-1, nuclear matrix protein 2, Mi-2, transcription intermediary factor 1γ, or melanoma differentiation–associated protein 5, biopsy samples were collected. In myositis muscle, the increased expression of a given autoantigen had no association with autoantibodies identifying that autoantigen. Inverse correlation with the expression of genes encoding mature muscle proteins and direct correlation with the expression of muscle regeneration markers of autoantigen expression was observed. In cultured human muscle cells, myositis autoantigens were expressed at high levels. Hence, during muscle regeneration, most myositis autoantigens were highly expressed which could relate to the generation of autoimmunity. However, in individual patients with myositis, other factors rather than overexpression of specific autoantigens were likely to direct the development of unique autoantibodies.