Hematopoietic stem cell transplantation for multiple sclerosis: current status and future challenges

This article reviews recent advances in clinical trials of hematopoietic stem cell transplantation as a therapy for multiple sclerosis, and progress in exploring the potential for neural repair of hematopoietic-derived precursors.

Important recent findings are that hematopoietic stem cell transplantation can completely suppress the inflammatory component of multiple sclerosis, hematopoietic stem cells can migrate into the central nervous systems of rodents and humans, and can differentiate into cells expressing neural and glial markers. Hematopoietic stem cells also have neural and myelin repair potential. The heterogeneity of transplant regimens, the selection of patients at different stages of disease in clinical trials, and the limited duration of follow-up all currently preclude the evaluation of the long-term clinical benefits of hematopoietic stem cell transplantation for multiple sclerosis.

Hematopoietic stem cell transplantation is an experimental treatment that shows strong effects on the inflammatory component of multiple sclerosis. On the basis of experience acquired from initial pilot studies, controlled clinical trials are now being designed to verify long-term clinical efficacy. Selecting patients at high risk in the earlier stages of the disease that is dominated by inflammation, and monitoring objectively disease activity by magnetic resonance imaging will be critically important in these studies. Recent advances on the migratory potential and on the differentiation plasticity of hematopoietic stem cells have opened new opportunities for remyelination and axonal repair strategies for multiple sclerosis.