I think estrogen might be something they're looking at re: T Reg Cells.
Here's a dry abstract
on the topic.
Estrogen (E2)-induced immunomodulation involves dual effects on antigen-presenting cells (APC) and CD4(+)CD25(+) regulatory T cells (Treg) but not a direct effect on effector T cells.
That study builds on earlier research--Cutting edge: estrogen drives expansion of the CD4+CD25+ regulatory T cell compartment.
I hope we hear more about estrogen.
I'm fearful it's going to go undercover rapidly since they they're still trying to find funding for the Phase II estriol trial (with Copaxone no less).