RESUMO
BACKGROUND: Urushiol is a widely known potent allergen that causes severe contact dermatitis through the epidermis or blood vessels. The role of antigen presenting cells (APC) in allergic contact dermatitis (ACD) is well known, but the role of APC in systemic contact dermatitis (SCD) is not yet fully evaluated. OBJECTIVE: The aim of this study is to observe the changes of APC in thenormal and SCD skin and to discuss their possible roles in the disease process. METHODS: Immunohistochemical differences of the Langerhans cells (LC) and dermal dendritic cells (DDC) were investigated in cases of the normal and SCD skin (Ed note: keep uniformity as above). Immunohistochemical staining with anti-CD1a, S-100 protein, HLA-DR, and factor XIIIa antibodies were performed. The number of CD1a, S-100 protein, and HLA-DR positive cells per mm2 of the epidermis was counted. The number of HLA-DR and Factor XIIIa-positive DDC per mm2 was also evaluated. RESULTS: The LC positive for CD1a and S-100 in the epidermis were slightly higher in SCD, but their difference was not statistically significant. HLA-DR and Factor XIIIa-positive DDC in the dermis weresignificantly increased in the skin of SCD than normal. HLA-DR positive LC in the epidermis was also increased. CONCLUSION: Our results suggest that DDC plays a more important role than that of epidermal LC in urushiol-induced SCD. Increased HLA-DR-positive LC in the epidermis suggests that antigen delivery through the blood also affects the epidermal Langerhans cell beside the dermal dendritic cells.