Role of cytokines in epidermal Langerhans cell migration

In the epidermal compartment of skin, keratinocytes (KC), Langerhans cells (LC), and their soluble products, i.e. cytokines, constitute a unique immunologic microenvironment. KC participate in cutaneous immune responses by producing various cytokines, LC, a member of the dendritic cell(DC) family, represent the professional antigen-presenting cells in the epidermis. Although it has been demonstrated that migration of LC from skin to lymph nodes is a critical step for the antigen presentation, molecular mechanisms for such an event remain unclear. Recent studies suggest that cytokines are able to modulate LC/DC migration. There is accumulating evidence that proinflammatory cytokines including interleukin (IL)-1 and tumor necrosis factor cu promote LC emigration from the skin, whereas the anti-inflammatory cytokine IL-10 is a counter-regulator. LC/DC express chemokine receptors, Chemokines generated from lymphatic endothelial cells and lymph node cells play a role in the directional migration of LC/DC into lymph nodes, This article reviews current studies on the role of cytokines in LC/DC migration.