Clinical and immunological long-term outcomes after autologous hematopoietic stem cell transplantation in systemic sclerosis: a retrospective single-center experience.

Background: Severe forms of systemic sclerosis (SSc) can be treated with autologous hematopoietic stem cell transplantation (aHSCT), but transplant-related mortality (TRM) can be considerable. Objectives: To describe the long-term outcomes after aHSCT with a focus on clinical and immunological parameters. Design: Retrospective single-center cohort study. Methods: The overall survival, course of skin fibrosis and lung function, need for immunosuppressive treatments, and immunophenotyping with flow cytometry of peripheral blood of SSc patients after aHSCT were analyzed. Results: Thirty-three patients were included with a mean follow-up time of 7.0 years (maximum 15.7 years). TRM was 6.1%, and seven deaths occurred during follow-up. Skin fibrosis improved, and lung function (forced vital capacity and diffusion capacity of carbon monoxide) stabilized in the long term. 34.5% never needed immunosuppressive therapy after aHSCT. Of patients who needed immunosuppression, 80% were treatment-free at the time of 15 years after aHSCT. The immunological reset after aHSCT persisted in the long term: Memory B cells declined for 2 years, and T helper cells were reduced for 5 years. Conclusion: aHSCT appears to promote positive long-lasting effects for SSc patients. Long-term data on safety are reassuring, considering that only the most severely affected and refractory SSc patients undergo aHSCT.