TOLL-LIKE RECEPTORS (TLR) 2 AND 4 EXPRESSION OF KERATINOCYTES FROM PATIENTS WITH LOCALIZED AND DISSEMINATED DERMATOPHYTOSIS

There are few studies on the role of innate immune response indermatophytosis. An investigation was conducted to define the involvement ofToll-Like Receptors (TLRs) 2 and 4 in localized (LD) and disseminated (DD)dermatophytosis due to T. rubrum. Fifteen newly diagnosed patients,eight patients with LD and seven with DD, defined by involvement of at least threebody segments were used in this study. Controls comprised twenty skin samples fromhealthy individuals undergoing plastic surgery. TLR2 and TLR4 were quantified in skinlesions by immunohistochemistry. A reduced expression of TLR4 in the lower and upperepidermis of both LD and DD patients was found compared to controls; TLR2 expressionwas preserved in the upper and lower epidermis of all three groups. As TLR4 signalinginduces the production of inflammatory cytokines and neutrophils recruitment, itsreduced expression likely contributed to the lack of resolution of the infection andthe consequent chronic nature of the dermatophytosis. As TLR2 expression acts tolimit the inflammatory process and preserves the epidermal structure, its preservedexpression may also contribute to the persistent infection and limited inflammationthat are characteristic of dermatophytic infections.