Both allogeneic and autologous bone marrow transplantation (BMT) have shown to modify and in some instances reverse a variety of animal models of autoimmune disease. This has prompted many investigators to propose the use of peripheral blood stem cell transplantation (PBSCT) for the treatment of autoimmune disease including scleroderma. Unfortunately, this approach risks infusing untreated autoreactive lymphocyte clones after the immunoablative preparative regimen. We have previously demonstrated that high-dose cyclophosphamide without BMT can induce durable and complete remissions in another autoimmune disease, severe aplastic anemia. Recent data with high dose cyclophosphamide show that it can induce complete remissions in other autoimmune hematologic disorders. The objective of this study is to determine whether high dose cyclophosphamide can induce a durable remission in scleroderma patients with life-threatening disease, and to determine toxicity of high dose cyclophosphamide in high risk scleroderma patients.