Haematopoietic stem cell transplantation in the treatment of severe autoimmune disease: results from phase I/II studies, prospective randomized trials and future directions.

Around 700 patients have received an autologous haematopoietic stem cell transplant (HSCT) as treatment for a severe autoimmune disease (AD). The majority of these have been within the context of phase I/II clinical trials and following international guidelines proposed 7 years ago. In general, a positive benefit/risk ratio has led to phase III prospective randomized controlled trials in multiple sclerosis (MS), systemic sclerosis (SSc) and rheumatoid arthritis (RA) in Europe. In the US, similar trials are being planned for SSc, MS and systemic lupus erythematosus (SLE). Transplant related mortality (TRM) has fallen in all disease subgroups since the inception due to more appropriate patient selection, and so far a clear advantage of the more intense myeloablative regimens in terms of remission induction and relapse rate has not emerged. Although each AD has a different profile, over a third of patients have sustained a durable remission, often with no further need for immunosuppressive drugs. In those who relapsed, many responded to agents which pre transplant had been ineffective. The study of immune reconstitution and gene expression pre and post HSCT is being undertaken to further understand the mechanism of autoimmunity.