Our data show that GVHD patient cells stimulated with anti‐CD3/anti‐CD28 and cultured with SLP76pTYR showed significantly reduced production of IFN‐γ and TNF‐α from CD8+ T cells compared to patient cells cultured in the presence of vehicle alone (control) (Figure 8E,F). This evidence concerns the gene CD28 and graft versus host disease.