Interleukin-2 and interleukin-6 in relation to burn wound size in the acute phase of thermal injury.

Thermal injury induces significant physiologic responses of acute inflammation, acute phase reaction and cell repair and growth, mediated by interleukins, cytokines and growth factors. To determine the relative role of interleukin-2 (IL-2) and interleukin-6 (IL-6) in the acute phase of thermal injury, 60 patients (47 men and 13 women, with average age of 37 years [1.5 to 70.0 years]) were analyzed within the first 36 hours and at five to seven days postoperatively. The patient population was categorized by percent burn (2 or 3, or both, degrees): less than 20 percent, n = 22; 20 to 40 percent, n = 18, and greater than 40 percent, n = 20. The average percent burn was 32 percent (range 4 to 95 percent). The mechanism of injury was by flame (25 instances), explosion and flame (19 instances), scald (12 instances), electric (three instances) or chemical (one instance). Twelve patients had an associated inhalation injury; 14 patients had sepsis syndrome. The overall mortality rate was 13 percent. Within 36 hours of onset of injury, IL-6 and IL-2 levels increased in proportion to the severity of the burn wound size. IL-2 levels were significantly elevated in the 20 to 40 percent burn group as compared with the greater than 40 percent group and patients in a control group (p < 0.0001). IL-6 levels increased with burn wound size and were significant only in the greater than 40 percent group (p < 0.0007). Any physiologic modulation of the thermal injury by biologic modifiers must be adapted to the extent of burn wound size and phase of injury: acute, recovery or reparative for optimal benefit and results.