The composition of T-cell subsets are altered in the burn wound early after injury

Background Burn-induced inflammation leads to impaired immune responses resulting in increased morbidity and mortality. T-cells are central in the immune response and circulating CD4 and CD8 T-cells have been used to evaluate immune status; however, the role of these T-cell subsets in the burn wound is unknown. Methods Male C57BU6 mice were subjected to a major 3rd degree scald burn or sham treatment. Twenty-four hours later, full thickness skin samples from sham mice and the burn wounds were collected and single cells were isolated and analyzed for alpha beta TCR, gamma delta TCR, CD3, CD4, CD8 and CD69 expressions by flow cytometry. Results The burn wound contained significantly greater numbers of T-cells than skin from sham mice, due to a profound infiltration of alpha beta T-cells. These infiltrating alpha beta T-cells were primarily suppressor T-cells with a CD8(+) or CD8(-)CD4(-) phenotype. The 15-fold increase in CD8(+) T-cells caused a decrease in the CD4:CD8 ratio from 0.7 in sham skin to 0.3 in the burn wound. In contrast, the majority of the gamma delta T-cells in sham skin were CD4(-)CD8(-), which decreased 9-fold in the burn wound. CD69 expression was suppressed on burn wound ctI3 T-cells, but increased on gamma delta T-cells in the burn wound. Conclusions The infiltrating burn wound alpha beta T-cells likely act to quell inflammation. In contrast wound gamma delta T-cells were activated with elevated CD4 and CD69 expression. Thus, these two distinct T cell subsets likely differentially regulate the burn wound inflammatory response.