Allergen-specific immunotherapy modulates the balance of circulating Tfh and Tfr cells.

Abstract Follicular helper T cells (Tfh cells) are a CD4 T cell subset essential for germinal center formation and B cell responses, although their role in allergy and allergen-specific immunotherapy (AIT) is unclear. Here, we show that AIT-treated patients have a higher ratio of regulatory Tfh cells (Tfr) to follicular T cells (Tfh) and hypothesize an IL-2 dependent mechanism.