Safety and Long-term Efficacy of Autologous Hematopoietic Cell Transplantation for Patients with Systemic Sclerosis

Eleni Gavriilaki^1,2*Despina Mallouri³Ioannis Batsis²Zoi Bousiou²Anna Vardi²Nikolaos Spyridis²Georgios Karavalakis²Alkistis Kyra Panteliadou²Panagiotis Dolgyras²Christos Varelas²Vlasios I Alevizopoulos^1*Panagiotis G. Asteris⁴Panayiotis Vlachoyiannopoulos⁵Damianos Sotiropoulos²Ioanna Sakellari²

• ¹2nd Propedeutic Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
• ²Hematology Department – BMT Unit, G. Papanikolaou General Hospital, Thessaloniki, Greece
• ³Hematology Department, German Oncology Center, Agios Athanasios, Limassol, Cyprus
• ⁴Computational Mechanics Laboratory, School of Pedagogical and Technological Education, Athens; Greece, Athens, Greece
• ⁵Department of Pathophysiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece

Autologous hematopoietic cell transplantation (HCT) has been introduced in patients with severe systemic sclerosis (SSc). We aimed to assess the safety and long-term efficacy of HCT modality for severe SSc, refractory to conventional therapy, in 17 patients who were referred to our JACIE-accredited Unit from 2005 to 2024. Peripheral blood stem cells were collected using cyclophosphamide and GCSF. An immunoablative conditioning regimen of cyclophosphamide and anti-thymocyte globulin was administered. Disease assessments were done before and after mobilization treatment and post-transplant, focusing on skin sclerosis, pulmonary function, cardiac involvement, gastrointestinal manifestations, the necessity for additional immunosuppressive therapy and their overall well -being. Before transplantation, 13/17 (76%) of the patients had diffuse skin involvement with a mean mRSS of 31 (2-49), 2/17 (12%) pulmonary hypertension and 14/17 (82%) gastrointestinal manifestations. The median follow-up period was 9.1 (0. 5 -14. 3) years. Improvement of skin sclerosis was observed, with a decrease in mRSS before transplantation from 31 (2-49) to 7 (2-22) post-HCT. Lung function remained stable in 8/15 (53%), improved in 5/15 (33%) and deteriorated in 2/15 (13%). Gastrointestinal manifestations were improved in 12/14 (86%) while all patients (16/16, 100%) reported a great impact on their quality of life. Ten out of the 16 (63%) patients were free of immunosuppressive drugs after the HCT. Overall survival was 16/17 (94.2%). Concerning TRM, there was one (1/17, 5.8%) death early post-transplant. In this specific cohort, autologous HCT led to improvements in the outcomes assessed, regarding selected patients with severe SSc refractory to immunosuppressive medications.