Phospho-NF-κB p65 expression in iNKT cells in subjects who received a 1.44 μg/kg/h regadenoson infusion for 24 hours with a 6-hour observation period when no drug was infused. (A-B) Phospho-NF-κB p65 expression in iNKT cells in a participant examined during pVOC (stage 3). (A) Flow cytometry and iNKT cell gates in serial blood samples taken at the indicated times. Regadenoson was infused starting at time 0 and ending at 24 hours. (B) Phospho-NF-κB p65 expression in iNKT cells compared with CD3⁺ non-iNKT cells from a pVOC patient. Solid peak represents phospho-NF-κB p65 in iNKT cells before regadenoson. Dashed peak represents phospho-NFκB expression in CD3⁺ non-iNKT cells, and the shaded area is phospho-NF-κB p65 expression in iNKT at time points after regadenoson infusion. NF-κB activation gate is defined as increased expression of phospho-NF-κB p65 relative to CD3⁺ non-iNKT cells. Percent iNKT cells in the activation gate at time points after regadenoson infusion is reported. (C) Percent change in iNKT cell phospho-NF-κB p65 before and after a 24-hour infusion of regadenoson in patients in steady state (stage 2, hatched box) and pVOC (stage 3, dark gray box). (D) Phospho-NF-κB p65 expression in iNKT cells from African-American controls (white box), steady-state patients (stage 2, hatched box), and pVOC participants before and immediately after a 24-hour regadenoson infusion (stage 3, dark gray boxes).