The relative number of CD4+CD25+ regulatory T cells and Foxp3-expressing Tregs in patients with PBC was significantly reduced compared to that in healthy controls, and the CD8+/Foxp3+ Treg ratio was markedly higher in late-stage patients with PBC than in those with chronic hepatitis C and autoimmune hepatitis (117). Here, FOXP3 is linked to chronic hepatitis C virus infection.