Promise and Challenges of Human Regulatory T Cells in the Clinic

Abstract

Regulation of immune reactions is critical in ealth and disease. Nowhere is this clearer than folowing allogeneic hematopoietic cell transplantation HCT). Here the beneficial effects of graft-versusumor reactions are clearly demonstrated, as well as he detrimental morbidity and mortality of unconrolled graft-versus-host disease (GVHD). Control of mmune reactions is complex and involves many facors including blood flow, micro-environmental interctions, cytokines, chemokines and both pro-inflamatory and anti-inflammatory molecules. In addition t has become well recognized that specialized popuations of cells, termed regulatory T cells, are critically nvolved in controlling immune reactions. Although he field of regulatory T cell biology has been exlored for many years, the more recent identification f specific populations of cells capable of regulating mmune responses with defined phenotype has opened ur re-examination of the potential impact of these ellular populations on immune function. To date, a umber of different cell populations have been charcterized with defined ability to regulate immune rections, which include two major cell populations, amely those of CD4 CD25 regulatory T cells Treg) [1] and abTCR NK-T cells which express an nvariant T cell receptor and are CD1 reactive [2]. hese cellular populations have generated enormous nterest in the field of HCT since animal models have emonstrated the potential benefit of regulatory T ell biology.