Degranulation and cytotoxicity by T-cell and NK cell subsets from patients with perforin, Munc13-4, syntaxin-11, and Munc18-2 deficiencies. (A-B) Freshly isolated, resting or (C) IL-2–stimulated PBMCs from healthy adult volunteers or patients with biallelic mutations in FHL-associated genes were incubated alone or mixed with target cells and mAbs, as indicated, at 37°C. Thereafter, cells were surface stained with fluorochrome-conjugated antibodies to CD3, CD4, CD8, CD56, CD57, and CD107a. (A) Contour plots of CD57 versus CD107a staining on CD8⁺ T-cell subsets after 2 hours of the indicated target cell stimulations. Plots of representative donors and patients are shown. Numbers indicate percentages of degranulating CD57⁻ and CD57⁺ cells. (B-C) Induced CD107a surface (ΔCD107a⁺) expression on freshly isolated (B) or IL-2–stimulated (C) CD8⁺CD57⁺ T-cell and CD3⁻CD56⁺ NK cell subsets after 2 hours of target cell stimulations, as indicated. For healthy donors, bars indicate the mean ± SD of 34 donors. For patients, which are color-coded according to age at onset, boxes indicate values for each patient and are linked with lines.