EARLY BUT NOT LATE BURN WOUND EXCISION PARTIALLY RESTORES VIRAL-SPECIFIC T-LYMPHOCYTE CYTOTOXICITY

Objective: Early burn wound excision restores immunocompetence and imp roves patient survival, but the exact mechanisms have not yet been def ined, Burn injury impairs cytotoxic T lymphocyte (CTL) activity as a f unction of burn size, increasing the risk of infection, The purpose of this study was to determine if early wound excision improved viral-sp ecific CTL function. Methods: Anesthetized C57BL/6 mice (n = 20) recei ved 0%, 20%, or 40% total body surface area full-thickness contact bur ns and were inoculated 3 days later with intraperitoneal lymphocytic c horiomeningitis virus, Eight days after infection, or 11 days after bu rn, CTL effectors (E) were harvested and tested against infected, radi olabeled L-D-b targets (T) in a Cr-51-release assay, at varied E:T rat ios, Dilution curves of CTL activity were compared by analysis of vari ance, In the second experiment, mice n = 18) underwent a 30% burn that was totally excised and grafted on postburn days (PBDs) 0, 3, and 7, Control groups included sham burn and no excision of a 30% burn. In th e third experiment, mice (n = 22) received a 30% burn that was partial ly, completely, or not excised on PBD 3, Control groups included sham burn with and without excision, All groups were infected with intraper itoneal lymphocytic choriomeningitis virus on PBD 3, Viral-specific CT L activity was determined on PBD 11. Results: Both 20% and 40% burn in jury impaired viral-specific CTL function, Wound excision on PBDs 0 an d 3, but not on PBD 7, partially restored CTL function, Total excision of the 30% burn improved CTL activity to a greater extent than did pa rtial excision. Conclusion: Burn injury inhibits viral-specific CTL ac tivity, Early, complete mound excision augments CTL function. Improved CTL activity after burn may reduce the risk of infection, providing a n immunologic rationale for expeditious wound excision.