Non-pharmacologic strategies in hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) may be performed to treat a variety of malignant and non-malignant disorders by eradicating tumor, replacing a non-functioning with a normal immune system, or replenishing a deficient enzyme. While HSCT may provide cure for many patients, barriers such as acute and chronic graft-versus-host disease (a/cGVHD) and graft failure continue to challenge clinicians with considerable potential for morbidity and mortality. A thorough understanding of each disease process is essential to the development of both pharmacologic and non-pharmacologic therapies in this setting; unfortunately, acute and chronic GVHD, are distinct, complex entities, and medications used to prevent and treat them cause significant toxicities and leave patients at high risk for overwhelming infections. Standard pharmacologic therapies that are currently in use are limited in that they have the potential to cause significant toxicity without completely curing the disease. Novel, non-pharmacologic therapies for the prevention and treatment of acute and chronic GVHD must continue to be developed and studied in randomized trials. Given that the potential mechanisms of action of the non-pharmacologic therapies discussed herein attempt to modulate the cellular milieu that supports the development of GVHD, a brief discussion of GVHD and its pathophysiology is warranted; detailed discussions are provided by Cutler et al. and Bolanos-Meade elsewhere in the current issue. We will therefore focus on two non-pharmacological innovative forms of therapy, and potentially, prevention of GVHD.