TLR2 and allergic disease: Therefore, we suggest that the dual TLR2/7 ligands CL413 (with the caveat of its high IFN-α induction in vivo) and especially CL531, due to its reduced ability to activate mast cells in vitro and capacity to suppress allergen-specific IgE production in vivo (together with a lower capacity than CL413 to induce IFN-α), are promising adjuvant candidates to further improve the treatment of allergic diseases.