Figure 2.

The impact of ecto-CRT on the activation and cytotoxic potential of natural killer cells in acute myeloid leukemia patients. (A, B) The percentage of IFN-γ-and degranulating (CD107a⁺/GZMB⁺) CD45⁺CD3⁻CD56⁺ natural killer (NK) cells upon PMA + Ionomycin or K562 cell line stimulation in 17 CRT^Lo and 18 CRT^Hi acute myeloid leukemia (AML) patients prior to the induction chemotherapy (A) or in 12 CRT^Lo and 12 CRT^Hi AML patiens after the restoration of normal hematopoiesis (B). Patient samples were analyzed by flow cytometry. Box plots: lower quartile, median, upper quartile; whiskers, minimum, maximum; ns: not significant. (C) Cytotoxic potential of NK cells isolated from AML patients before the initiation of chemotherapy (Prior, n=10) versus upon the restoration of normal hematopoiesis (Recovery, n=10). Purified NK cells were tested for their ability to kill target K562 cell line at two different effector:target cell ratios (5:1 and 10:1) and the viability of K562 cells was determined by flow cytometry after 4 hours (h). (D, E) Cytotoxic potential of NK cells isolated from five CRT^Hi and 5 CRT^Lo AML patients before the initiation of chemotherapy (D) or upon the restoration of normal hematopoiesis (E). Purified NK cells were tested for their ability to kill target K562 cell line at effector:target cell ratio 5:1 and the percentage of dead (AnnV⁺DAPI⁺) K562 cells was determined by flow cytometry after 4 h. The representative dot plots of NK cell cytotoxicity assay showing the viability of target K562 cells in CRT^Hi versus CRT^Lo AML patients before the initiation of chemotherapy (D) or upon the restoration of normal hematopoiesis (E) are shown. Box plots: lower quartile, median, upper quartile; whiskers, minimum, maximum; ns: not significant. CRT: calreticulin.