We demonstrate that muscle-infiltrating T cells are predominantly CD4+CD28(null) and CD8+CD28(null) T cells in patients with dermatomyositis and polymyositis.
We investigated expression of costimulatory molecules BB-1, B7-1 (CD80), B7-2 (CD86), and their counter-receptors CD28 and CTLA-4 (CD152) in muscle biopsy specimens of patients with scleroderma-polymyositis overlap syndrome (SSc-PM), primary polymyositis (PM), and other related diseases to examine whether the muscle fibers in patients with SSc-PM behave as antigen-presenting cells (APCs).