FOXP3 and atrial fibrillation: In addition, the decrease in the frequency of Nrp-1−Rorgt−Foxp3+ T cells in the PPs in GF-AF mice (SupplementalFigure 4A) may also be involved in the induction of the antigen-specific IgA response, because Foxp3+ T cells induce GC and IgA responses by generating GC Tfh cells (27) and their depletion causes the loss of specific IgA responses (46).