Page 158 - Haematologica August 2018

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A. Roberto et al.
uCD56dim NK cells are not NK cell precursors and express low levels of NKp46
Ontogenetically, human NK cell precursors have been divided into three main differentiation stages on the basis of their different expression of several surface markers, including CD34, CD117 and CD127. These precursors give rise first to cCD56bright (stage 4) and then to terminally differ-
entiated cCD56dim (stage 5) NK cell subsets that are charac- terized by a CD34neg/CD117neg/CD127neg phenotype and express aNKRs (i.e., NKG2D and natural cytotoxicity recep- tors [NCRs]).29,30 Our data showed that uCD56dim NK cells from both healthy donors and hHSCT patients are NKG2Dpos and NKp30pos, but do not express CD34, CD117 and CD127, thus proving that they are NK cells in later
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Figure 3. Phenotype of NK cell subsets in healthy donors and haploidentical HSCT patients. (A) Representative example of flow cytometry dot plots from a healthy donors (HDs) and a patient after three weeks from haploidentical HSCT (hHSCT) showing the surface expression of CD117, CD34, CD127 and NKG2D on cCD56bright (blue), cCD56dim (black) and uCD56dim (red) NK cells. The phenotypes of these representative NK cell subsets are overlaid with those of their viable lymphocytes (gray background) used as positive controls. (B) Summary statistical graph showing the expression of CD34, CD117 and CD127 on cCD56bright (blue), cCD56dim (black) and uCD56dim (red) from three HSC HDs and their recipients at three and five weeks after hHSCT. (C) Summary statistical graph showing the expression of NKG2D, Granzyme-B, Perforin, NKp30, NKp46 on cCD56bright (blue), cCD56dim (black) and uCD56dim (red) from HSC HDs and their recipients after three and four weeks from hHSCT. *P<0.05
haematologica | 2018; 103(8)