OBJECTIVETo observe the changes in serum contents of interleukin-6 (IL-6) and interleukin-10 (IL-10) in patients with severe burn injury, and to investigate their relation with occurrence of sepsis and prognosis of patients.

METHODSOne-hundred and sixty adult patients admitted into our hospital (1.0 ± 6.0) h after injury during March 2007 to March 2011 with massive and severe burns were enrolled in the investigation. Patients were divided into non-sepsis group (NS, n = 112), sepsis-survival group (SS, n = 36), and sepsis-deceased group (SD, n = 12) based on the occurrence of sepsis and death. Sepsis occurred on post burn day (PBD) 9 ± 5 in patients in the latter two groups. Patients died on PBD 18 ± 4 in SD group. Twenty healthy adult volunteers were chosen as healthy control group (HC). The age of subjects for observation among four groups, and total burn area and full-thickness burn area of patients among NS, SS, and SD groups were compared. Serum was isolated from blood samples collected from each patient every day from day of admission till PBD 20 to determine the contents of IL-6 and IL-10 by ELISA, and the same determinations were done in HC group. Data of trial subjects were processed with one-way analysis of variance. Data of IL-6 and IL-10 contents were processed with analysis of variance of repeated measure data and SNK method (q test).

RESULTS(1) There was no significant statistical difference among four groups in age (F = 2.090, P > 0.05). Total burn areas of patients in SS and SD groups were significantly larger than that in NS group (q test, with P values both below 0.05), and total burn area of patients in SD group was obviously larger than that in SS group (q test, P < 0.05). Full-thickness burn areas of patients in SS and SD groups were significantly larger than that in NS group (q test, with P values both below 0.05). (2) Serum contents of IL-6 of patients in NS, SS, and SD groups from PBD 1 to 20 were obviously higher than that of volunteers in HC group. There was no significant statistical difference among NS, SS, and SD groups in serum contents of IL-6 from PBD 1 to 7 (with F value from 0.188 to 2.897, P values all above 0.05). Serum content of IL-6 of patients in NS group decreased from PBD 4. Serum content of IL-6 of patients in SS group decreased gradually from PBD 13, but that in SD group increased continuously at the same time points. Serum contents of IL-6 of patients in NS group [(262 ± 25) pg/mL on PBD 8] were lower than those in SS group [(287 ± 38) pg/mL on PBD 8, q test, P < 0.05] and SD group [(299 ± 22) pg/mL on PBD 8, q test, P < 0.05] from PBD 8. Serum contents of IL-6 of patients in SS group [(300 ± 33) pg/mL on PBD 13] were obviously lower than those in SD group [(338 ± 22) pg/mL on PBD 13, q test, P < 0.05] from PBD 13. (3) Serum contents of IL-10 of patients in NS, SS, and SD groups were higher than that in HC group at each time point. There was no significant statistical difference among NS, SS, and SD groups in serum contents of IL-6 from PBD 1 to 5 (with F values from 1.802 to 2.538, P values all above 0.05). Serum content of IL-10 of patients in NS group was obviously lower than that of patients in SD group from PBD 6 (q test, P values all below 0.05). On PBD 8, serum content of IL-10 of patients in SS group [(54 ± 19) pg/mL] was obviously lower than that in SD group [(91 ± 23) pg/mL, q test, P < 0.05]. The sum of sensitivity (83.33%, 10/12) and specificity (91.67%, 33/36) minus 1 was maximum when the critical value of IL-10 content was set at 77 pg/mL based on the comparison between SS group and SD group in serum content of IL-10 on PBD 8.

CONCLUSIONSThe occurrence and outcome of sepsis is related to burn area and depth when the patients are in similar age. Serum contents of IL-6 and IL-10 play important roles in the pathogenesis of sepsis after burn. IL-6 content in early stage shall not be used in predicting the prognosis of patients with sepsis. IL-10 continuously higher than 77 pg/mL in early stage forecasts unfavorable prognosis of patient.