The Immune Response of a Burn Injury Compared to an Excisional Injury in a Murine Model

Cutaneous injury triggers a significant immune response. Cells of the innate and adaptive systems are recruited to coordinate repair, prevent infection and limit damage. It remains unclear if different aetiologies of injury influences the characteristics of the immune response as well as the long-term impact post injury. A murine model was used to characterise the immune response. A 8% TBSA full thickness dorsal burn or excision injury was used. At days 1,3,7,14,28 and 84 post injury mice were euthanased; whole blood was collected for haematology and cytokine profiling, and inguinal lymph nodes were harvested for immune cell populations including dendritic and T cells. Both the innate and adaptive immune responses differed between the two aetiologies. The burn injury generated a rapid and greater acute cytokine response displaying both Th1 and Th2 cytokine profiles resulting in changes to the innate cells, with a drive towards monocyte to macrophage differentiation following burn injury. The dendritic cell profile differed between the two injury groups, with reduced dendritic cell maturation that persisted to day 84 post-injury. The cytokine and dendritic cell profiles appeared to impact the adaptive response, with reduced T cell activation after burn injury which was sustained to the later time points. The data suggests there are significant differences in the immune response, which is dependent on injury aetiology. The burn injury had sustained an immunological change that was not apparent following excisional injury. This may explain in part the long-term implications of burn injury, such as increased incidence of infection and malignancy, and provides a basis for further investigation to guide clinical intervention after burn injury.