It has been reported that EBV infection induces the expansion of NKG2A+/KIR-/CD56dim NK cells [44],so the NK cells associated with ANKL in the current study may have originated from earlier stage NK cells, as their immunophenotype was NKG2A+/KIR-/CD56bright[45], which favors an EBV origin. Here, KIR3DL1 is linked to aggressive NK-cell leukemia.