Overexpression of NLRP 3, NLRC 4 and AIM 2 inflammasomes and their priming‐associated molecules ( TLR 2, TLR 4, Dectin‐1, Dectin‐2 and NF κB) in Malassezia folliculitis

The activation of NLRP 3, NLRC 4 and AIM 2 inflammasomes is pivotal for innate immunity against some pathogenic fungi, but their role in the pathogenesis of Malassezia folliculitis ( MF ) remains unclear. The objective of the study was to determine the expression of 4 canonical inflammasomes ( NLRP 1, NLRP 3, NLRC 4 and AIM 2) and their priming‐associated molecules ( TLR 2, TLR 4, Dectin‐1, Dectin‐2 and NF κB) in MF lesion. Expression of NLRP 1, NLRP 3, NLRC 4, AIM 2, caspase‐1, IL ‐1β, TLR 2, TLR 4, Dectin‐1, Dectin‐2 and NF κB was detected by immunohistochemistry in skin lesion of 23 MF patients and normal skin of 12 healthy subjects. Furthermore, NLRP 1, NLRP 3, NLRC 4, AIM 2, caspase‐1 and IL ‐1β mRNA was measured by quantitative real‐time PCR ( qRT ‐ PCR ) in 12 MF cases and 10 controls. Immunohistochemical analysis revealed that NLRP 3, NLRC 4, AIM 2, Casp‐1, IL ‐1β, TLR 2, TLR 4, Dectin‐1, Dectin‐2 and NF κB expression was up‐regulated in the epidermis and dermal inflammatory cells of MF lesion compared with control skin ( P < .01‐.05), but NLRP 1 expression was not different between both groups ( P > .05). qRT ‐ PCR showed that levels of NLRP 3, Casp‐1 and IL ‐1β mRNA were significantly increased ( P < .01‐.05), whereas those of NLRP 1, NLRC 4 and AIM 2 mRNA were slightly augmented compared to control skin ( P > .05). Our observation suggests that simultaneous activation of NLRP 3, NLRC 4 and AIM 2 inflammasomes may play an important role in the pathogenesis of MF.