DM is regarded as a CD4+ T-cell–driven disease, and CD4+ T cells might participate in the occurrence and development of DM in the following ways: mediating the growth, proliferation, classification, and transformation of B cells, indirectly participating in the production of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), and the differentiation of T helper (Th) cells (17–21). This evidence concerns the gene CD4 and myositis disease.