Cytokine alterations in lichen sclerosus: an immunohistochemical study

Abstract

Although the histology of lichen sclerosus is characteristic, the precise nature of the inflammatory changes and the signals provoking them is uncertain. To delineate the inflammatory changes in lichen sclerosus more accurately by studying cytokine changes. An immunohistochemical study of 12 specimens of genital lichen sclerosus and one specimen of extragenital lichen sclerosus was undertaken using monoclonal antibodies to interferon (IFN)-gamma, IFN-gamma receptor, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, IL-2 receptor (CD25), intercellular adhesion molecule-1 (ICAM-1) and its ligand CD11a. Control specimens were seven specimens of normal vulva obtained during gynaecological procedures, three specimens of normal skin, adjacent uninvolved thigh from three of the patients with lichen sclerosus, five specimens of nonvulval psoriasis, four specimens of nonvulval lichen planus and two specimens from chronic wounds. The lichen sclerosus specimens demonstrated slightly increased staining for IFN-gamma within the epidermis compared with the normal vulva and nonvulval skin. There was increased dermal staining for IFN-gamma both within the pale zone of the upper dermis and within the inflammatory zone below this. We confirmed our previous demonstration that in lichen sclerosus HLA-DR immunostaining is increased in association with vascular endothelium, the inflammatory cell infiltrate and around the keratinocytes. The areas of the epidermis with the strongest immunostaining for HLA-DR generally also had the strongest staining for IFN-gamma. In the lichen sclerosus specimens the zone of inflammation also demonstrated increased immunostaining for TNF-alpha, IL-1alpha, IFN-gamma receptor, CD25, CD11a and ICAM-1 while the zone of sclerosus demonstrated a smaller increase in immunostaining for IFN-gamma receptor, TNF-alpha, CD11a and ICAM-1, and the epidermis demonstrated increased staining for ICAM-1. The increased staining for IFN-gamma, TNF-alpha, IL-1alpha, IFN-gamma receptor, CD25, CD11a and ICAM-1 suggest that the cytokine response in lichen sclerosus shares characteristics of the cytokine response in lichen planus and chronic wounds.