FOXP3 and HIV-1 infection: During acute HIV-1 infection, the frequency of Foxp3+Helios+CD45RA+ Treg cells was inversely correlated with the frequency of intermediate CD14++CD16+ monocytes, whereas it was positively correlated with the PD-1 density on intermediate CD14++CD16+ monocytes (Fig. 3a and Fig. 3b).