Helios^+/− Treg numbers are not affected by antibody blocking with anti– IL-6 or anti–IL-10 in T cell–monocyte co-cultures. Relative change compared with IgG control in (A) total Treg (“Total Tregs”) as well as (B) Helios⁺ (“Helios⁺ Tregs”) and (C) Helios^– (“Helios⁻ Tregs”) Treg numbers in T cell co-cultured with total monocytes or monocyte subsets (CD14⁺CD16⁻ cells without or with CD16+ monocytes) treated with neutralizing antibodies to IL-6 and IL-10 are shown. For comparison, the relative change in Treg numbers after treatment with anti–IL-12 and anti-TNF-α is also shown.