TLR9 and pemphigus foliaceus: Since a number of molecules (such as type I IFN, mtDNA, TLR9), which act upstream and downstream of cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING), a pathway involved in the regulation of innate and adaptive immunity, contribute to in the pathogenesis of PF, a likely role of cGAS-STING could be suggested in PF (157).