Expression of the canonical TR transcription factor forkhead box P3 (FOXP3) was reduced in CVID patients with autoimmunity compared to those without (39), and the suppressive activity of TR cells in CVID with autoimmunity was also reduced, with the degree of dysfunction correlating with the extent of FOXP3 downregulation (41). This evidence concerns the gene FOXP3 and common variable immunodeficiency.