Apoptotic cells are present in ischemic zones of deep partial-thickness burns

Deep partial-thickness burns exhibit ambiguous behavior, either spontaneously healing or evolving into full-thickness burns. The aim of this study was to investigate these lesions for the presence of apoptotic cells and to compare their rate with that of superficial and full-thickness burns. We used colocalization of DNA fragments (ie, terminal deoxynucleotidyl transferase Biotin-dUTP nick end labeling) and Fas ligand CD95 antibodies to calculate the apoptotic rate of superficial, deep partial-thickness and full-thickness burns in 45 patients after the thermal injury. Biopsies were collected mainly during the acute postburn phase (first week of hospitalization). Deep partial-thickness burns presented apoptotic cells, both in the dermis and in cutaneous adnexa, and showed a higher apoptotic rate than superficial and full-thickness burns (44.5% in deep partial thickness, interquartile range 6.3-90.5%; 5.6% in superficial partial thickness, interquartile range: 0-13%; 0% for full-thickness burn; P = .000243). A significant greater apoptotic rate was present in cells of deep partial-thickness burns when compared with superficial and full thickness. These data would suggest that deep burns sustain an ischemic damage that forces cells to undergo apoptosis and could represent the biologic basis for their clinical evolution into full-thickness burns. Further correlation studies are now required to confirm this hypothesis.