CSA-treated NK cells have higher cytotoxicity, in part due to the reduction in KIR-expressing cells. Cytotoxicity against (A) K562 cells or (B) Raji cells after 7 days of culture. The results for individual donors (n = 11, - - - -) and average cytotoxicity (▬) (E/T = 5:1) are shown. Statistics were calculated using the Wilcoxon signed rank test. (C) Cytotoxicity of NK cells (cultured with vehicle or CSA) against KIR-L–expressing LCLs (HLA-B Bw4 and HLA-C C1/C2). The average cytotoxicity of 4 donors plus and minus the SE is shown (E/T = 5:1). Statistics calculated using the Wilcoxon signed rank test. (D) FACS histograms for granzyme B (left), perforin (middle), and FasL (right) for cells cultured with CSA (heavy line, open histogram) or vehicle (EtOH, dotted line, closed histogram). Isotype controls are shown in dashed line and open histogram. Granzyme B and perforin were detected using intracellular staining, while surface staining was used for FasL. Results are representative of samples from 4 donors.