Immunosuppression following excision of burn eschar and syngeneic grafting in major thermal trauma.

Recent reports have suggested that very early excision (less than 24 hours post-burn) and primary closure of burn wounds might circumvent the immunosuppression which follows severe thermal trauma. The total body surface are (TBSA) involved in burn injuries of human subjects at risk for significant post-burn immunosuppression is large enough to require grafting. In the present study cell-mediated immunity was measured via one-way allogeneic mixed lymphocyte reactions (MLR) in mice subjected to full-thickness scald wounds over 25-30 percent TBSA followed by escharectomy and syngeneic full-thickness skin grafting. A significant decrease in the proliferative capability of T-cells could be demonstrated on days five and seven post-treatment in unburned grafted animals (day five, 30.7 percent; day seven, 24.8 percent) over untreated normals. T-cells from animals burned but not excised also showed significant hyporesponsiveness (day five, 33.2 percent; day seven, 26.1 percent normal MLR). Animals undergoing both burning and excision showed even more profound immunosuppression (day five, 18.3 percent to 23.7 percent; day seven, 7.4 percent to 11.6 percent normal MLR). Surgical incision without excising the skin did not suppress cell-mediated immunity (day five, 90.8 percent; day seven, 90.4 percent normal MLR). When T-cells from treated animals of each group (with the exception of the incision control group) were added to normal MLR cultures, significant (greater than 50 percent) cell-mediated suppression by suppressor T-cells could be demonstrated. This study showed that the trauma of excision and grafting alone results in depression of cell-mediated immunity. These data call into question the ability of very early excision and grafting to alter the immunosuppression which follows severe thermal trauma.