O'Sullivan S T, Lederer J A, Horgan A F, Chin D H, Mannick J A, Rodrick M L
Department of Surgery, Harvard Medical School, Boston, Massachusetts, USA.
Ann Surg. 1995 Oct;222(4):482-90; discussion 490-2. doi: 10.1097/00000658-199522240-00006.
Patients with serious traumatic injury and major burns and an animal model of burn injury were studied to determine the effect of injury on the production of cytokines typical of the T helper-2 lymphocyte phenotype as opposed to the T helper-1 phenotype and on the production of interleukin-12.
Perturbations of natural and adoptive immunity are related to the increased susceptibility to infection manifested by seriously injured and burn patients. Earlier work has shown that impaired adoptive immunity after injury is characterized by diminished production of interleukin-2 (IL-2), a product of Th lymphocytes. Exposure of naive Th cells to certain antigens and cytokines causes conversion to either the Th-1 or the Th-2 phenotype. Th-1 cells produce IL-2 and interferon-gamma (IFN-tau) and initiate cellular immunity. Th-2 cells secrete interleukin-4 (IL-4) and interleukin-10 (IL-10) and stimulate production of certain antibodies. Conversion to the Th-1 phenotype is facilitated by IL-12, and conversion to the Th-2 phenotype is promoted by IL-4. The authors believed that serious injury might cause conversion of Th cells to the Th-2 as opposed to the Th-1 phenotype rather than generalized Th suppression.
The authors studied circulating peripheral blood mononuclear cells (PBMC) from 16 major burn and 8 trauma patients on 32 occasions early after injury and from 13 age- and sex-matched healthy individuals for cytokine production after phytohemagglutinin stimulation. Also studied was a mouse model of 20% burn injury known to mimic the immune abnormalities seen in humans with burns. Splenocytes from burn mice, 10 to 12 per group, were studied after activation by concanavalin A or by the bacterial antigen Staphylococcus aureus Cowan strain I for cytokine production and cytokine messenger RNA expression as determined by reverse transcriptase polymerase chain reaction. Burn mice were compared with sham-burn controls and attention was focused on day 10 after burn injury, a time when IL-2 production and resistance to infection are highly suppressed. Finally, burn and sham-burn animals, 20 per group, were treated in vivo with IL-12 (25 ng daily for 5 days) and observed for mortality after septic challenge (cecal ligation and puncture [CLP]) performed on day 10 after injury.
Peripheral blood mononuclear cells from burn and trauma patients produced less IFN-tau, the index cytokine of Th-1 cells, than PBMCs from healthy individuals 1 to 14 days after burn injury (SE = 77.6 +/- 16 pg/mL patients vs. 141.3 +/- 35 pg/mL controls, p < 0.05). However, production of IL-4, the index cytokine of Th-2 cells, by patient PBMCs was increased (51.0 +/- 13.0 pg/mL patients vs. 26.9 +/- 2.5 controls, p < 0.05). Splenocytes from mice 10 days after burn injury, when compared with sham-burn controls, showed diminished production of IL-2 (1.04 +/- 0.91 units/mL burns vs. 5.8 +/- 0.55 units/mL controls, p < 0.05) and IFN-tau (1.05 +/- 0.7 units/mL burns vs. 12.0 +/- 8.9 units/mL controls, p < 0.05). However, burn splenocytes produced more IL-4 (2492 +/- 157.0 pg/mL burns vs. 672.0 +/- 22.7 pg/mL controls, p < 0.01) and IL-10 (695.2 +/- 20.8 pg/mL burns vs. 567.0 +/- 16.7 pg/mL controls, p < 0.05). Splenocyte production of IL-12 was also reduced after burn (0.20 +/- 0.035 units/mL) as compared with sham burn (0.46 +/- 0.08 units/mL, p < 0.05). The reduction in IL-2, IFN-tau, and IL-12 production by burn splenocytes was reflected by a tenfold decrease in expression of their respective cytokine mRNAs. In vivo IL-12 treatment of burn animals decreased mortality from CLP on day 10 after injury from 85% to 15% (sham-burn mortality after CLP, 15%, p < 0.05) and increased splenocyte IFN-tau production to supranormal levels.
Serious injury induced diminished production of IL-1 2 and a shift to the Th-2 phenotype with increased production of IL-4 and IL-10, cytokines known to inhibit Th-1 function. The ability of exogenous IL-12 to restore Th-1 cytokine production and resistance to infection suggests a therapeutic role for IL-12 in the immune dysfunction seen after major injury.
研究严重创伤性损伤患者、大面积烧伤患者以及烧伤损伤动物模型，以确定损伤对典型的辅助性T细胞2淋巴细胞表型（与辅助性T细胞1表型相对）细胞因子产生的影响，以及对白细胞介素-12产生的影响。
自然免疫和过继免疫的紊乱与严重受伤和烧伤患者表现出的感染易感性增加有关。早期研究表明，损伤后过继免疫受损的特征是辅助性T淋巴细胞产物白细胞介素-2（IL-2）产生减少。未致敏的辅助性T细胞暴露于某些抗原和细胞因子会导致其转化为辅助性T细胞1或辅助性T细胞2表型。辅助性T细胞1产生IL-2和干扰素-γ（IFN-τ）并启动细胞免疫。辅助性T细胞2分泌白细胞介素-4（IL-4）和白细胞介素-10（IL-10）并刺激某些抗体的产生。IL-12促进向辅助性T细胞1表型的转化，IL-4促进向辅助性T细胞2表型的转化。作者认为，严重损伤可能导致辅助性T细胞转化为辅助性T细胞2而非辅助性T细胞1表型，而不是全身性辅助性T细胞抑制。
作者研究了16例大面积烧伤患者和8例创伤患者在受伤后早期32次采血时循环外周血单个核细胞（PBMC），以及13名年龄和性别匹配的健康个体在植物血凝素刺激后细胞因子的产生情况。还研究了已知可模拟人类烧伤免疫异常的20%烧伤损伤小鼠模型。每组10至12只烧伤小鼠的脾细胞在经刀豆蛋白A或细菌抗原金黄色葡萄球菌考恩I株激活后，用于检测细胞因子产生及通过逆转录聚合酶链反应测定细胞因子信使核糖核酸表达。将烧伤小鼠与假烧伤对照组进行比较，并将重点放在烧伤损伤后第10天，此时IL-2产生和抗感染能力受到高度抑制。最后，每组20只烧伤和假烧伤动物在体内用IL-12（每天25 ng，共5天）治疗，并观察在受伤后第10天进行脓毒症激发（盲肠结扎和穿刺[CLP]）后的死亡率。
烧伤和创伤患者的外周血单个核细胞在烧伤后1至14天产生的IFN-τ（辅助性T细胞1的指标性细胞因子）比健康个体的PBMC少（患者组SE = 77.6±16 pg/mL，对照组141.3±35 pg/mL，p<0.05）。然而，患者PBMC产生的IL-4（辅助性T细胞2的指标性细胞因子）增加（患者组51.0±13.0 pg/mL，对照组26.9±2.5 pg/mL，p<0.05）。与假烧伤对照组相比，烧伤后10天小鼠的脾细胞显示IL-2产生减少（烧伤组1.04±0.91单位/mL，对照组5.8±0.55单位/mL，p<0.05）和IFN-τ减少（烧伤组1.05±0.7单位/mL，对照组12.0±8.9单位/mL，p<0.05）。然而，烧伤脾细胞产生更多的IL-4（烧伤组2492±157.0 pg/mL，对照组672.0±22.7 pg/mL，p<0.01）和IL-10（烧伤组695.2±20.8 pg/mL，对照组567.0±16.7 pg/mL，p<0.05）。与假烧伤相比，烧伤后脾细胞IL-12的产生也减少（0.20±0.035单位/mL）（假烧伤组0.46±0.08单位/mL，p<0.05）。烧伤脾细胞IL-2、IFN-τ和IL-12产生的减少反映在其各自细胞因子信使核糖核酸表达下降了10倍。对烧伤动物进行体内IL-12治疗可使受伤后第10天CLP的死亡率从85%降至15%（CLP后假烧伤死亡率为15%，p<0.05），并使脾细胞IFN-τ产生增加至超正常水平。
严重损伤导致IL-12产生减少，并向辅助性T细胞2表型转变，IL-4和IL-10产生增加，已知这些细胞因子会抑制辅助性T细胞1功能。外源性IL-12恢复辅助性T细胞1细胞因子产生和抗感染能力的能力表明，IL-12在严重损伤后出现的免疫功能障碍中具有治疗作用。
