T-bet in Tfh cells: Now you see me, now you don't.

In this issue, Fang et al. (https://doi.org/10.1084/jem.20180927) report on a subset of T follicular helper (Tfh) cells that transiently expresses T-bet yet continues to produce IFN-γ at late stages of GC reactions following immunization. They find other genes uniquely expressed in this IFN-γ-producing Tfh subset, such as NKG2D, that can be used to better distinguish these functionally distinct Tfh cells.