The skin is an important component of the immune system conforming a particular microenviroment referred to as the skill immune system (SIS). The SIS includes immunocompetent cells such as Langerhans cells, keratinocytes, dermal cells and cutaneous-specifie T cells, the dermal perivascular unit, and epidermal and dermal humoral constituent that involve interacting; cytokines and chemokines. The perivascular unit embraces the high endothelial venules (HEV), T cells, mast cells and dermal dendrocytes." The Langerhans cells, which are members of the dendritic cell family, are the professional omnipresent antigen-presenting cell (APC) of the epidermis, In contrast, keratinocytes become active immunocompetent cell solely after a cutaneous stimulus.