CD4 and atrial fibrillation: Finally, when comparing the frequency ratio of IFN-γ-secreting CD4+ T cells to IL-10-secreting CD4+ T cells in AF mothers to that of NAF mothers at all follow-up points, we found that the ratio in AF mothers was significantly higher than that in NAF mothers (p = 0.002, p = 0.046, p = 0.001, p = 0.005) before antiviral intervention, one month after antiviral intervention, at delivery, and at 15–18 weeks postpartum.