(2) Myositis-specific antibodies are absent (3); (3) The condition is often associated with other autoimmune diseases such as arthritis, systemic sclerosis, etc (8); (4) The muscle biopsy exhibits inflammatory cell foci dominated by CD20+ and CD68+ cells (5); (5) Other infections, heredity, or other pathogenic mechanisms have been excluded. This evidence concerns the gene CD68 and systemic sclerosis.