The effect of dermatophytes on cytokine production by human keratinocytes

Dermatophytosis (tinea) is a common disease in superficial mycoses and is generally confined to the stratum corneum in the epidermis and cutaneous appendages. The mechanisms by which dermatophytes cause dermatophytosis, however, are poorly understood. In this study, we evaluated the effect of Trichophyton mentagrophytes, T. tonsurans and T. rubrum on cytokine production by normal human epidermal keratinocytes (NHEKs). After 3-24 h of co-culture of NHEKs with each of the dermatophytes, cytokines in the supernatant were measured by enzyme-linked immunosorbent assay. Promoter activity of IL-8 was measured by chloramphenicol acetyl transferase (CAT) assay. IL-8 and GRO-alpha levels were higher in supernatants co-cultured with T. mentagrophytes isolates from animal than in those with T. mentagrophytes isolates from human, and with T. tonsurans and T. rubrum isolates. CAT expression for IL-8 promoter activity was higher in cell lysates stimulated with T. mentagrophytes isolates from animal than in those with T. mentagrophytes isolates from human, and with T. tonsurans and T. rubrum isolates. These findings suggest that dermatophytes directly induce production of cytokines at the transcriptional level by human keratinocytes, and that there are differences in their ability to induce cytokine production between the dermatophytes.