In contrast, a study by Zong [42] demonstrated IL-15 expression in PM muscle by CD163+ macrophages and myoblasts, but not by fully differentiated myotubes, whereas Sugiura [41] reported expression of IL-15 predominantly in the cytoplasm of muscle cells and to lesser extents by infiltrating mononuclear cells derived from PM patients. The gene discussed is CD163; the disease is polymyositis.