Low-dose and long-term exposure to 5-aza-cytidine promotes NK-cell ontogeny. (A-B) 5-Aza-cytidine does not significantly alter the expression of KIR2DL1/S1/S4, KIR2DL2/L3/S2, and KIR3DL1 (A), or other inhibitory or activating NK-cell receptors (B), on BM-derived NK cells of huNSG mice. (C) 5-Aza-cytidine induces the expression of BM-residing NK-cell precursors. Frequencies of the indicated NK-cell subpopulations in the BM of 5-aza-cytidine–treated or control huNSG mice (as defined by Freud²² ): preNK (CD34⁺CD117⁺), iNK (CD34⁻CD117^lowCD94⁻), CD94⁺ mNK cells (CD34⁻CD117⁻CD94⁺NKp46⁺), and CD94⁻ mNK cells (CD34⁻CD117⁻CD94⁻NKp46⁺). Data represent 2 independent experiments with a total of 11 huNSG mice and 14 control NSG mice. n.s., not significant.