To investigate the changes of serum tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and T lymphocyte subsets in severe burn patients with stress induced and to explore the effect of intensive insulin therapy on inflammatory response and immune function in severe burn patients.

Fifty-six patients with severe burn from March 2012 to December 2015 in the Department of Burns, Third Affiliated Hospital of Inner Mongolia Medical University were enrolled. They were divided into intensive insulin therapy group and conventional therapy group according to the random digital table method, 28 cases in each group. Continuous intravenous pump of insulin (50 IU of insulin added to 50 mL of 0.9% sodium chloride solution) was used to guide therapy based on patients′ glucose measurements. The blood glucose levels in intensive insulin therapy group, were controlled at 4.4-7.0 mmol/L and conventional therapy group were controlled at 7.0-10.0 mmol/L. The levels of serum TNF-α, IL-6 and peripheral blood CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺ were measured at 3rd, 7th, 14th and 21st day after treatment. The number of positive infection of blood, urine, sputum culture and wound culture in 21 days of treatment were recorded and the infection rate was calculated. The data were analyzed by analysis of variance of repeated measurement, t test and chi-square test.

After treatment, the levels of TNF-α and IL-6 in both groups gradually decreased, the differences were statistically significant (with P values below 0.05). The levels of TNF-α in the intensive insulin therapy group were (841.40 ± 340.87), (588.99 ± 238.61), (518.23±227.41) pg/mL respectively on the 7th, 14th and 21st day after treatment, lower than those in the conventional therapy group (1068.19 ± 452.38), (739.81±283.31), (662.91±250.77) pg/mL respectively, the differences were statistically significant (t=2.12, 2.16, 2.26; P=0.039, 0.036, 0.028). The levels of IL-6 in the intensive insulin therapy group were (754.88 ± 325.72), (242.53 ± 117.16), (242.53±117.16) pg/mL respectively on the 7th, 14th and 21st day after treatment, lower than those in the conventional therapy group (990.01±443.83), (424.81±161.02), (310.38±119.54) pg/mL respectively, the differences were statistically significant (t=2.26, 2.24, 2.15; P=0.028, 0.029, 0.036). After treatment, the percentages of CD3⁺, CD4⁺, CD8⁺ cells and CD4⁺/CD8⁺ in the peripheral blood of the two groups increased, with differences statistical significance(with P values below 0.05). The percentages of CD3⁺, CD4⁺ and CD8⁺ cells in both groups were compared at various time points, the differences were statistically significant(with P values below 0.05). On the 14th and 21st day after treatment, the ratios of CD4⁺ and CD8⁺ were 1.27 ± 0.37, 1.31 ± 0.37, respectively higher than those of the conventional therapy group 1.08 ± 0.31, 1.12 ± 0.32, the differences were statistically significant(t=2.03, 2.08; P=0.047, 0.043). The infection rate in intensive insulin therapy group was 14.3% (4/28), which was significantly lower than that in conventional therapy group 39.3%(11/28), the difference was statistically significant (χ²=4.46, P<0.05).

Intensive insulin therapy can better inhibit the inflammatory response in the patients with severe burn, improve the immune function of the patients and reduce the infection rate.