CYTOKINE RESPONSE TO BURN INJURY - RELATIONSHIP WITH PROTEIN-METABOLISM

Plasma levels of interleukin 1beta (IL-1beta), tumor necrosis factor a lpha (TNFalpha), interleukin 6 (IL-6), and markers of protein Metaboli sm were determined in 12 burn patients throughout the healing period ( day 2 to 21 post-injury) to determine the pattern of variations in pla sma cytokine concentration. To establish the relationship between cyto kine production and the nutritional status a wide range of severity st andpoints (burn surface area ranging from 9% to 82%) was chosen. Inter leukin 6 levels were increased in all patients throughout the study pe riod; maximum concentrations (615 +/- 198 pg/mL) were reached on day 4 and correlated (p < 0.01) with the extent of burn injury. Tumor necro sis factor alpha levels were also elevated; they were significantly hi gher on day 7 in the patients who developed sepsis than in the other p atients (67 +/- 21 pg/mL vs. 20 +/- 7 pg/mL; p < 0.05) but did not cor relate with the extent of burn injury. Interleukin 1beta was rarely de tected. Cortisolemia on day 7 was inversely correlated with levels of TNFalpha but not with those of IL-6. Interleukin 6 levels correlated p ositively with protein turnover (phenylalaninemia) and catabolism (3-m ethylhistidine/creatinine ratio) and negatively with levels of fibrone ctin and transthyretin. Our data indicate that the systemic cytokine r esponse to burn injury is mainly represented by IL-6. These data also support the hypothesis that IL-6 is a key mediator of the variations i n protein metabolism following burn injury.