Expression of markers characterizing more suppressive Treg. Panel A shows the expression of Helios CD39 and CTLA-4 on CD4+ CD25+ Foxp3+ Treg from an OVC sample. B. Expression of Helios on Treg cells. C. Co-expression of Helios and HLA-DR on Treg (OVC n = 17). D. Percentage of CD39+ Treg, E. Percentage of CD39-HLA-DR Treg (OVC n = 11). F. CTLA-4 expression and G. CD39-CTLA-4 expression on Treg from OVC samples (n = 10).