Abrogation of degranulation and cytotoxicity by resting PBLs from FHL4 patients. (A) Resting PBLs from healthy adult and infant donors plus FHL2, FHL3, and FHL4 patients were evaluated for cytotoxicity toward K562 cells in 4-hour ⁵¹Cr release assays. Lytic units were calculated from specific lysis values. (B) Resting PBLs from adult and infant donors were stained with anti-CD3 and -CD56 mAbs and analyzed by flow cytometry. The percentage of indicated lymphocyte subsets was determined. Bars indicate the mean (±SD) of 7 donors. (C-E) Resting PBLs were incubated alone or with target cells as indicated for 2 hours at 37°C. Thereafter, cells were stained with fluorochrome-conjugated anti-CD3, anti-CD56, and anti-CD107a mAbs. (C) Lymphocytes were gated on forward scatter/side scatter plots, followed by gating on CD3 versus CD56 plots. Profiles show CD56 versus CD107a mAb staining of CD3⁻CD56⁺ NK cells. (D) Induced CD107a surface expression on CD3⁻CD56⁺ NK cells after indicated stimulation was plotted. Lines represent mean values. (E) Induced CD107a surface expression on lymphocytes after indicated stimulation was plotted. Lines represent mean values. (F) Resting PBLs from healthy adults or infant donors were stained with anti-CD3, anti-CD4, anti-CD8, anti-CD14, anti-CD62L, and anti-CCR7 mAbs. Values represent the mean (±SD) percentage of indicated CD3⁺CD14⁻ T-cell subsets.