Why is regulatory T-cell reconstitution important to prevent GvHD in allo-HSCT?

During the 46th Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT), the GvHD Hub spoke to Barbara Fazekas de St Groth, University of Sydney, Sydney, AU, about the function of regulatory T-cells. We asked, Why is regulatory T-cell reconstitution important to prevent GvHD in allo-HSCT?

Using murine models, Barbara Fazekas de St Groth has investigated how regulatory T cells work and discovered that they act by regulating dendritic cell (DC) costimulation. This appears to be true under normal conditions, not just during an inflammatory reaction. If the number of regulatory T cells is insufficient to control DCs, costimulation increases and results in lymphopenia-induced proliferation.