We compared and analyzed the expression of perforin by Tregs among Mild Recovered volunteers between those who had and had not experienced certain symptoms and found higher Perforin+ Treg levels in unstimulated and Pool CoV-2-stimulated PBMC from volunteers who presented with dyspnea during acute COVID-19 than in those who did not (Figure 3D). This evidence concerns the gene PRF1 and COVID-19.