Human OX40 tunes the function of regulatory T cells in tumor and nontumor areas of hepatitis C virus-infected liver tissue.

International audience; Regulatory T cells (Tregs) can be considered as a mixed population of distinct subsets, endowed with a diverse extent and quality of adaptation to microenvironmental signals. Here, we uncovered an opposite distribution of Treg expansion, phenotype, and plasticity in different microenvironments in the same organ (liver) derived from patients with chronic hepatitis C: On the one side, cirrhotic and tumor fragments were moderately and highly infiltrated by Tregs, respectively, expressing OX40 and a T-bet high IFN-c – " T-helper (Th)1-suppressing " phenotype; on the other side, noncirrhotic liver specimens contained low frequencies of Tregs that expressed low levels of O…