Skin dendritic cells in burn patients.

The body's immunological response to burn injury has been a subject of great inquiry in recent years. Burn injury disturbs the immune system, resulting in a progressive suppression of the immune response that is thought to contribute to the development of sepsis. Dendritic cells (DCs) are potent antigen-presenting cells that possess the ability to stimulate naïve T cells.DCs are derived from bone marrow progenitors and circulate in the blood as immature precursors prior to migration into peripheral tissues. Within different tissues, DCs differentiate and become active in the taking up and processing of antigens, and their subsequent presentation on the cell surface is linked to major histocompatibility molecules. Upon appropriate stimulation, DCs undergo further maturation and migrate to secondary lymphoid tissues, where they present antigen to T cells and induce an immune response. The purpose of this study was to determine the effects of burn injury on skin DCs in terms of percentage, HLA-DR, and Toll-like receptor-4 (TLR-4) expression. The skin DCs were isolated from burned skin and non-burned skin in the same patient at 7 days post-injury, and skin DCs were isolated from unburned healthy individuals as control. DCs from burned skin notably express low levels of HLA-DR and TLR-4 soon after cell isolation. In the post-burn period the ability of skin DCs to respond to bacterial stimuli is impaired. These changes in DC behaviour might contribute to the impaired host defences against bacteria during burn sepsis.