Abstract: Objective To study the characteristics of dendritic cell (DC) phenotype in the skin lesions of mycosis fungoides (MF) and its clinical significance. Methods Immunohistochemistry technique with some monoclonal antibodies against surface molecules on DCs was used. Results There were lots of immature DCs and mature DCs in both epidermis and upper dermis of patch/plaque stage lesions, mainly CD1a⁺, CD1c⁺, Lag⁺/Langerin⁺ immature DCs and CD83⁺/DC-Lamp⁺ mature DCs. In the dermis of tumor stage lesions, there were lots of CD1a⁺ CD1c⁺ immature DCs and CD83⁺/DC-Lamp⁺ mature DCs, too. However Lag⁺/Langerin⁺ cells were shown more in the epidermis and upper dermis, less in the lower dermis, with increasing number of CD1a⁺, CD1c⁺ cells in the lower dermis. Conclusions There is migration of epidermal Langerhans'cells in patch/plaque stage of MF lesions, which might take part in anti-tumor immune reactions. Meanwhile, the large amount of CD1a⁺DCs in the dermis of tumor stage lesions might play a role in the relevant immune tolerance.

Key words: Mycosis fungoides, Dendritic cells, Phenotype