Figure 2.

In KIR-mismatched haplo-HSCT, the late appearance of alloreactive (KIR⁺) NK cells (6–8 weeks after transplant) may result in a delayed anti-leukemia and antiviral infection effect. In order to prevent these risks, a promising approach has been proposed consisting in the infusion of manipulated NK cells at short time intervals after HSCT. In particular, trogocytosis could be used as a tool to rapidly and transiently modify the migratory properties of donor-derived alloreactive NK cells by inducing CCR7 expression on their surface. These alloreactive NK cells, infused during the time required for the maturation of NK cells from HSC, may play a relevant role in preventing leukemic relapse (GvL activity), GvH/HvG reactions (by killing patient’s DCs/Tcells), and in controlling infections. After this period, mature alloreactive NK cells generated from HSC acquire CCR7 directly (in vivo) from patient’s CCR7⁺ cells, including mDC and T cell blasts.