Although statistical significance was not reached, the IL-2 expansion regimen favored the release of IFN-γ (Fig. 5B), a cytokine associated with favorable polarization of anti-AF immunity (6), as well as other effector cytokines and chemokines linked to innate immune cell recruitment (i.e., CCL3, CCL4, and GM-CSF; Fig. 5C). Here, CCL4 is linked to atrial fibrillation.