Fig. 3.

Residual NK cells in NBAS patients are functionally impaired upon activation by K562 cells. A Scheme of the experimental setup. B NK cell degranulation, indicated by the percentage of CD107a⁺ cells of CD56⁺ NK cells, was measured by flow cytometry after 4-h co-culture of NBAS patients’ or healthy controls’ NK cells with K562 target cells. Baseline CD107a⁺ in the absence of K562 cells was subtracted. Combined data, comparing the mean of six patients to that of healthy controls, and representative FACS contour plots of one patient and healthy control combination are depicted (limits were set according to CD107a expression in the absence of K562 cells and distinguishing CD56^bright and CD56^dim NK cell subsets). C Intracellular protein expression of perforin and granzyme B in NK cells, which had not been co-cultured with K562 target cells, was measured by flow cytometry (geometric mean fluorescence intensity, gMFI). Isotype control staining was subtracted. Combined data, comparing the mean of five patients to that of healthy controls, and representative FACS histograms of one patient (red line) and healthy control (blue line) combination are depicted