Autologous hematopoietic stem cell transplantation in multiple sclerosis: 20 years of experience.

Intense immunosuppression followed by autologous hematopoietic stem cell transplantation (AHSCT) has been widely used in the last 20 years for the treatment of aggressive forms of autoimmune disorders, especially multiple sclerosis (MS). All clinical studies, although small and uncontrolled, demonstrate a great efficacy of this procedure in halting inflammation and disease activity, even in those patients affected by "malignant forms" of MS. The long-term follow-up has also revealed the possible maintenance of positive results in the course of time, and this evidence is supported by immunological data that suggest the possibility of a resetting of the immune system after AHSCT. The safety of AHSCT has improved in the last years, but the transplant related mortality is still nowadays of about 1-2 %, pointing out that a careful selection of patients to submit to AHSCT is mandatory. The long clinical experience allowed to identify the ideal candidate: a young patient, with a short disease duration, with recurring and disabling relapses and the presence of inflammatory activity on brain magnetic resonance scans, unresponsive to approved therapies. A large, randomized clinical study comparing AHSCT with the best approved therapies is still necessary to confirm the role of transplantation in MS treatment.