Expression of Elafin in the Epidermis of Cutaneous Fungal Infection

Kim, Chong Hyeok; Song, Hae Jun

Abstract

BACKGROUND
Elafin is a serine proteinase inhibitor first discovered in keratinocytes from hyperproliferative human epidermis. In addition to the proteinase inhibiting domain, elafin contains multiple transglutaminase substrate domains which enable cross-linking to extracellular and cell envelope proteins. Several characteristics of elafin suggest potential anti-microbial activity. Elafin is absent in normal skin at protein level, but is induced in inflammatory and infectious dermatoses which threat the epidermal integrity by vesicopustule formation and neutrophilic cell infiltration. Cutaneous fungal infection is one of the well-known examples of diseases characterized by such condition. The purpose of this study was to check out the possibility that elafin may be involved in the pathomechanism of fungal infection.
METHODS
The biopsy samples taken from 10 cases of superficial fungal infections, 10 cases of deep and systemic mycoses, 2 cases of slide culture specimens of Candida species, were used for the immunohistochemical tissue staining for elafin expression. Polyclonal anti-elafin was used in 1:300 dilution. As control, biopsy smaples of normal skin, ichthyosis, psoriasis were used for the staining for elafin expression.
RESULTS
In the normal and ichthyotic epidermis, elafin expression was virtually negative. In superficial mycoses except candidiasis, elafin was expressed in the spinous layer of infected epidermis, and fungal structures in the stratum corneum were stained with elafin antisera. In the cases of dermatophytosis of ichthyosis patients, while fungal hyphae were stained with elafin antisera, epidermal cell did not express elafin. In candidial esophagitis, elafin was expressed in the esophgeal mucosa, but spores were not stained with elafin anti-sera. In slide culture of Candida species, spores were not stained with elafin antisera, also. In cases of systemic and deep mycoses, fungal hyphae and spores were stained with elafin antisera and epidermis adjacent to severe dermal inflammatory reaction showed elafin expression.
CONCLUSION
Elafin may have certain role in systemic and cutaneous fungal infection to contribute to high resistance of the epidermis against proteolysis and fungal infections, and it is shown that elafin or elafin-like protein may also be produced and utilized by fungi themselves.