Increased numbers of CD68 antigen positive dendritic epidermal cells and upregulation of CLA (cutaneous lymphocyte-associated antigen) expression on these cells in various skin diseases

CD68 is a myelomonocytic marker identified in human dermal macrophages. Alt hough the existence of CD68(+) dendritic epidermal cells has been reported, their characteristics have not been well elucidated. Cutaneous lymphocyte- associated antigen (CLA) is a homing receptor of cutaneous inflammatory T c ells. Our recent report suggested that CLA was a homing molecule of CD1a(+) Langerhans cells (LC) in the skin. In the present study we tested whether CD68(+) and CLA(+) dendritic epidermal cells were present in skin specimens of normal skill and diseased skin such as lichen planus (LP), psoriasis vu lgaris (PS), discoid lupus erythematosus (DLE), basal cell epithelioma (BCE ), squamous cell carcinoma (SCC), irritated seborrheic keratosis (iSK), and Bowen's disease (BD). CD68(+) dendritic epidermal cells were identified in normal skin and consisted of half the population of CD1a(+) LC. These data indicate that CD68(+) dendritic epidermal cells constitute a subpopulation of CD1a(+) LC. CLA was expressed on a small percentage of CD68(+) dendriti c epidermal cells in normal skin. A remarkably increased number of CD68(+) dendritic epidermal cells and upregulation of CLA on CD68(+) dendritic epid ermal cells were observed in diseased skin. The percentage of CLA(+) cells among all CD68(+) dendritic epidermal cells was less than that of CLA(+) ce lls among all CD1a(+) LC in diseased skin. The percentage of CLA(+) cells a mong all CD68(+) dendritic dermal cells was much less than that of CLA(+) c ells among all CD1a(+) dendritic dermal cells. In normal skin, the epidermi s showed minimal expression of monocyte chemoattractant protein (MCP)-1 and TGF-beta 2, and no expression of TGF-beta 1. In diseased skin, the epiderm is showed elevated, but still moderate immunoreactivity for MCP-1. Slightly enhanced immunoreactivity for TGF-beta 2, but not for TGF-beta 1, was obse rved in the epidermis of diseased skin. Increased epidermal MCP-1 immunohis tochemical staining was associated with the increased number of CD68(+) den dritic epidermal cells. These data suggest the possibility that MCP-1 secre tion from the epidermis can affect the migration of CD68; Cutaneous lymphoc yte-associated antigen Monocyte chemoattractant protein-1; TAF-beta. (C) 19 98 Elsevier Science Ireland Ltd. All rights reserved.