To monitor the fate of donor naïve T cells during GVHD development, purified B6 WT or CD73 KO CD25−CD62Lhigh naïve T cells were transferred into BDF1 recipients i.v. The prevalence and absolute number of CD73 KO donor CD4+ or CD8+ T cells in recipient spleens were identical to those of WT donor CD4+ or CD8+ T cells 5 and 7 days after T cell transfer (Figure 2A, B). The gene discussed is NT5E; the disease is graft versus host disease.