Furthermore, infusion of enriched donor NK cells into transplant recipients reduced the incidence of GVHD (87), and NK cells activated ex vivo with IL-12, IL-15, and IL-18 (which induces a more memory-like phenotype as discussed below) helped prevent GVHD in a mouse model of HLA-mismatched SCT (88). This evidence concerns the gene IL18 and graft versus host disease.