Autologous stem cell transplantation for systemic sclerosis

Systemic sclerosis (SSc) is a generalised autoimmune disease, of yet unknown origin, with two major clinical subsets: the limited (lcSSc) and the diffuse cutaneous (dcSSc) forms, which can be distinguished by the extent of skin involvement, the autoantibody profile and the pattern of organ involvement. With an incidence of 1/105, SSc affects around 250,000 people in Europe and is responsible for significant morbidity with a 5-year mortality rate of at least 30% of all patients. In patients with rapidly progressive dcSSc, the 5-year mortality is estimated to be 40-50%. Hematopoietic stem cell transplantation (HSCT), mostly autologous but also allogeneic in some specific cases, has been employed worldwide since 1996 as a new therapeutic strategy in patients with a poor prognosis. In 2007, 150 HSCT procedures have been reported in the EBMT data base. We review herein both the short and the long-term reports from the various European and North American phase I-II studies, which have shown that autologous HSCT in selected patients with severe dcSSc results in sustained improvement of skin thickening and stabilisation of organ function up to seven years after transplantation. Based on these promising results, ongoing phase III trials have been designed in parrallel, both in Europe (ASTIS) and in North America (SCOTT) aiming to analyse the respective benefits from autologous HSCT respectively without or with high dose irradiation. This review reports the current data concerning the effects of HSCT on survival, skin, and major organ function in patients with severe dcSSc.