Aggressive MS and Autologous HSCT: A review on behalf of the Autoimmune Diseases Working Party of the European Society for Blood and Marrow Transplantation.

Multiple sclerosis (MS) presents a spectrum of disease activities, making prognostication and treatment challenging. Our focus on aggressive MS (AMS), a subset lacking a universally accepted definition, aims to clarify its identification and management. Here we critically dissect the different criteria for defining AMS based on the latest research and consensus, the early prognostic factors which can unambiguously identify aggressive variants early in the disease course and the available high-efficacy therapies, with a special focus on autologous haematopoietic stem cell transplantation (AHSCT), which is considered a standard of care for relapsing-remitting MS refractory to disease-modifying treatments. The review explores the potential of tailoring AHSCT protocols to individual risk and disease activity profiles, suggesting a personalized approach that could optimize treatment efficacy and safety. While awaiting the results of ongoing randomized clinical trials, AHSCT should be considered for patients with poor prognostic factors early in the disease course, in case of suboptimal response to disease-modifying therapies, but also in naïve patients with AMS experiencing rapid disability accrual.