Decrease of circulating dendritic cells in burn patients.

Burn injury is associated with immune suppression and the subsequent development of sepsis. Severe burn injury is associated with depressed immune response, including a functional impairment of Th1 lymphocytes and natural killer cells and a decrease in interferon-a production. Dendritic cells (DCs) are potent antigen-presenting cells and play a key role in T cell activation; they are essential in coordinating the host response to pathogens. Using three-colour flow cytometry, we determined the percentage of lineage-negative LIN-DR+ DCs in burn patients and healthy subjects. The percentages of DCs were lower in the circulation of septic than in nonseptic patients and healthy subjects at all times examined (14 days) after burn injury. In contrast, the DC percentage in nonseptic patients was low at day 1, increased from day 3 to day 10, and reverted to normal levels at day 14. The data from the present study suggest that the DC percentage decreased early after burn injury. In addition, in the presence of severe sepsis, the DC percentage remained lower until day 14. This DC reduction may contribute to the immunosuppression observed after burn injury.