Thymoglobulin and Cyclophosphamide as Treatment for Diffuse Cutaneous Systemic Sclerosis

Abstract

To the Editor: Systemic sclerosis (SSc) is an autoimmune disease associated with the development of organ fibrosis and vasculopathy1. Patients with severe, early diffuse cutaneous SSc and significant internal organ involvement have a mortality rate of 50% at 5 years2. There are many aspects of SSc that support the hypothesis that it is an autoimmune disease and might respond to immunosuppressive therapy3,4. Immunosuppressive agents like cyclophosphamide have been investigated as treatment for SSc. Cyclophosphamide can affect immune function by decreasing circulating B and T cells5. A retrospective, open, controlled study of 103 SSc patients with multiple cycles suggested improved survival6. To date, the immunomodulatory effect of thymoglobulin is not fully understood but includes increased T cell clearance from blood, modulation of T cell activation, elimination of cytotoxic T cells, and increased T regulatory cells. In a pilot study, thymoglobulin was studied as single-agent therapy7. Matteson, et al 8 treated 10 patients with Atgam® (antithymocyte globulin) alone, at total dose … Address correspondence to Dr. L. Holmberg, Fred Hutchison Cancer Research Center, 1100 Fairview Ave N., D5-390, PO Box 19024, Seattle, WA 98109-1024. E-mail: lholmber{at}fhcrc.org