It is now apparent that distinct functional Tfh subpopulations hold the potential to produce specific combinations of cytokines.2,9,96,101–104 Indeed, Tfh subpopulations have been described both in humans and mice, and these may play distinct roles in mediating humoral responses in allergy and asthma and lead to specific protection following vaccination and infection.94,102,105,106 In a key study, Eisenbarth and colleagues demonstrated that IL-13-producing Tfh (Tfh13) cells co-express Bcl6 and GATA3 in mice and humans with IgE antibodies against allergens. This evidence concerns the gene BCL6 and infection.