Redirecting KIR⁺ alloreactive NK cells to lymph nodes to clear recipient DCs and prevent GVHD. (A) KIR⁺ alloreactive NK cells isolated from an allogeneic donor may be exploited in different adoptive immunotherapy protocols in leukemia patients because of their ability to kill host leukemia cells, DCs, and T cells. Remarkably, attempts to clear recipient DCs to prevent or treat GVHD may be hampered by the fact that KIR⁺ NK cells do not express CCR7, a chemokine receptor required for response to CCL19 and CCL21 and migration to lymph nodes (particularly rich of mature DCs). (B) Importantly, KIR⁺ NK cells have been shown to rapidly take up CCR7 on in vitro interaction with CCR7⁺ cells and acquire the capability of migrating to lymph nodes. (C) As shown in this figure, this property may be exploited to confer alloreactive NK cells the ability of targeting DCs present in secondary lymphoid organs, thus preventing the induction of allogeneic T-cell responses and GVHD.