ROS production in Vδ2⁺ T cells in differentially stimulated cultures and expression of Fas/Fas-L in ZOL-stimulated Vδ2⁺ vs CD3⁺ cells. (A) ROS produced in Vδ2⁺ T cells on days 0, 3, 6, and 9 in IL-2/IL-15, IL-2/IL-15/PMA, and IL-2/IL-15/ZOL-stimulated PBMCs (n = 3), respectively. Half of the medium was changed on days 3 and 6 and supplemented with IL-2/IL-15, as indicated by arrows. (B) Expression of AICD-mediating death receptor Fas (CD95) and its ligand Fas-L (CD95L) are specifically and significantly higher expressed in ZOL-activated Vδ2⁺ cells from patients with HH (n = 3) than Vδ2⁺ cells from HDs (n = 3) and the respective CD3⁺ compartments in HH and HD. The population designated as CD3⁺ includes all T cells except Vδ2⁺ cells, that is, αβ⁺, Vδ1⁺, and Vδ1^–/Vδ2^– T cells. (C) 7-AAD was used to distinguish viable from apoptotic/dead cells (for gating strategy, see supplemental Figure 5). Fas is expressed by all ZOL-stimulated Vδ2⁺ cells that is, in live and apoptotic condition in HH and HD; Fas-L is only detected in apoptotic gates and significantly higher expressed by ZOL-stimulated Vδ2⁺ cells from individuals with HH than HDs. MFI of Fas and Fas-L are comparably high for living Vδ2⁺ cells but significantly higher for apoptotic Vδ2⁺ cells of HH vs HD PBMCs. (D) Percentage of apoptotic Vδ2⁺ cells is significantly higher in ZOL-stimulated PBMCs HH (n = 4) compared with HDs (n = 3). ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001; MFI, mean fluorescence intensity; ns, not significant; PMA, phorbol 12-myristate 13-acetate.