Background
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a TNF family member, which has been closely associated with regulation of the immune response and pathogenesis of autoimmune diseases. The expression of TRAIL was found in CD8 T cells that had undergone oligoclonal expansion in the lungs of patients with systemic sclerosis (scleroderma) and were able to stimulate collagen production in lung fibroblasts in vitro. Among the family members, TRAIL displays highest homology to Fas ligand, the receptor of which may mediate not only cell apoptosis but also the proliferation of normal human fibroblasts.