The frequencies of subsets of Tregs within populations of CD4+ CD25+ FoxP3+ T cells, representing induced (Helios+), resting (CD45RA+FoxP3low), activated (CD45RA-FoxP3high) and potentially non-suppressive Tregs (CD45RA-FoxP3low) did not reveal any impact of CMV infection (Figure 1a). Here, CD4 is linked to cytomegalovirus infection.