BM and PB CD56lowCD16low NK-cell recovery after α/β T-cell depleted HSCT. Cells freshly isolated by density gradient centrifugation from BM and PB of pediatric healthy donors and α/β T-cell depleted haplo-HSCT recipients were analyzed through flow cytometry to dissect CD56+CD3− NK cells into 3 subsets based on CD56 and CD16 expression levels, namely CD56highCD16+/−, CD56lowCD16low and CD56lowCD16high NK cell subsets (panel A). Histograms represent the percentage and absolute cell number/μl of total NK cells among lymphocytes and of CD56highCD16+/−, CD56lowCD16low and CD56lowCD16high NK cell subsets in BM (white) and PB (black) (panel B). Error bars represent SEM. BM n = 65; PB n = 62. Unpaired t-test, *p < 0,05; **p < 0,005; ***p < 0,0002; ****p < 0,0001.