IL4 and food allergy: Although the absolute number of IL-4–producing TFR cells is < 15% of IL-4–producing TFH cells, these TFR cells still contribute to IgE response, which suggests either that the food allergy IgE response is highly sensitive to IL-4 levels produced by follicular T cells or that TFR-derived IL-4 plays an outsized role in the IgE response.