Autologous Haematopoietic Stem Cell Transplantation (HSCT) has been standard of care for several decades for haematological malignancies. In the last 20 years there has been increasing interest in re-purposing HSCT to treat severe autoimmune diseases. In this context, HSCT is used as a form of high dose immunosuppression, with re-infusion of the patients own haematopoietic stem cells as a safe way of delivering chemotherapy with minimal periods of neutropenia. It is hypothesized that the reinfused stem cells may reconstitute a tolerant immune system and the chemotherapy will eradicate the auto-reactive immune clone.
There is now compelling data to suggest that this hypothesis may be correct. Numerous groups, along with our own, have demonstrated increased thymic output post HSCT along with changes in both T regulatory cells and T cell receptor chains suggesting a more tolerant immune environment post HSCT. This talk will focus on the compelling clinical data from recent Phase III trials and some insights into the mechanism of these clinical outcomes.Â