TSLP and herpes simplex dermatitis: On the other hand, with regard to bacteria, TSLP has been found to act as a down regulator of antimicrobial peptides, which could explain why the basal levels of this cytokine, that is upregulated in AD affected subjects, leads to severe microbial infections such as eczema herpeticum or the colonization of pre-existing skin lesions [41].