The diminished postoperative capacity of blood leukocytes to produce IL-6 is associated with high concentrations of IL-6 in the circulation

Immune capacity determines outcome following surgery or trauma: a systematic review and meta-analysis

Purpose

Immunological functions are altered following physical injury. The magnitude of the immunological response is dependent on the initial injury. However, variability in the immune response exists within and between patients where only some patients are at risk of developing complications such as systemic inflammatory response syndrome after injury. This systematic review and meta-analysis assessed whether lipopolysaccharide (LPS) induced cytokine production capacity of leucocytes can be used as a functional test to predict the risk of developing complications after injury.

Methods

Medline, Embase and Web of Science were systematically searched to identify articles that investigated the association between LPS induced cytokine production capacity in leucocytes and any clinical outcome after surgery or trauma. Where sufficient information was supplied, a meta-analysis was performed to determine the overall clinical outcomes.

Results

A total of 25 articles out of 6765 abstracts identified through the literature search were included in this review. Most articles described a positive association between cytokine production capacity and the development of inflammatory complications (n = 15/25). Coincidingly, the meta-analysis demonstrated that TNFα (Hedges g: 0.63, 95% CI 0.23, 1.03), IL-6 (Hedges g: 0.76, 95% CI 0.41, 1.11) and IL-8 (Hedges g: 0.93, 95% CI 0.46, 1.39) production capacity was significantly higher, one day after injury, in patients who developed inflammatory complications compared to patients who did not following trauma or surgical intervention. No significant difference was observed for IL-1β.

Conclusion

The associations of elevated LPS-induced cytokine production capacity with the risk of developing inflammatory complications are consistent with previous theories that proposed excessive inflammation is accompanied by anti-inflammatory mechanisms that results in a period of immunosuppression and increased risk of secondary complications. However, immunological biomarkers for risk stratification is still a developing field of research where further investigations and validations are required.

Electronic supplementary material

The online version of this article (10.1007/s00068-019-01271-6) contains supplementary material, which is available to authorized users.

The interleukin-6 (IL6)-174 G/C promoter genotype is associated with the presence of septic shock and the ex vivo secretion of IL6

Septic shock is associated with a high mortality and an excessive activation of immune cascades. Interleukin (IL)-6 has been found to be a key cytokine in the pathogenesis of severe sepsis, but the importance of a regulatory polymorphism within the IL6 promoter has been controversial in these patients. The aim of the study was therefore to systematically investigate the IL6-174 G/C promoter genotype with regard to the presence of shock in patients with sepsis, the IL6 serum levels, and the ex vivo secretion of IL6, respectively. Overall, 112 consecutive subjects with severe sepsis and septic shock according to consensus criteria were enrolled. The ex vivo secretion of IL6 after stimulation with lipopolysaccharide (LPS) in a whole blood assay and the IL6 serum concentrations were determined after admission of the patients. Among the 112 subjects with severe sepsis, 85 patients fulfilled the criteria of septic shock. In these patients, the frequency of the mutated C-allele of the IL6 promoter polymorphism was significantly (P = 0.04) higher compared to that in individuals without shock. IL6 serum concentrations were highest in patients with the GG genotype (mean 2209 pg mL(-1)), followed by CG genotype (mean 1113 pg mL(-1)), and lowest in individuals with the CC genotype (mean 256 pg mL(-1)). Interestingly, a significantly (P = 0.005) higher ex vivo secretion of IL6 is detected in heterozygote individuals (535 pg mL(-1)) and patients with the IL6 CC genotype (555 pg mL(-1)) compared to patients with the -174 GG genotype (276 pg mL(-1)). In conclusion, the IL6-174 G/C promoter genotype is associated with shock in patients with sepsis. Functionally, the mutated C-allele is correlated with low IL6 serum concentrations, but a high ex vivo secretion after LPS stimulation. These results further indicate a complex regulation of the expression of IL6 during infection and have implications for the design of immune intervention trials.

Immune suppression while awaiting surgery and following it: dissociations between plasma cytokine levels, their induced production, and NK cell cytotoxicity

Surgery may render patients susceptible to life-threatening complications, including infections and later metastases. Suppression of cell mediated immunity (CMI) and perturbations in the cytokine network were implicated in these outcomes. The current study assessed the effects of various surgeries on a wide array of immune indices, and compared patients' pre-operative immune status to that of control subjects. A total of 81 subjects (controls, moderate and major surgeries) provided up to five daily blood samples. Whole blood procedures were conducted within hours of blood withdrawal, assessing NK cell number and cytotoxicity, and plasma cytokine levels and induced production (IFNgamma, IL-6, IL-10, and IL-12). Our findings indicate that surgery reduced NK cell numbers/ml blood, and independently suppressed NK activity per NK cell and per ml blood. Among other perturbations in the cytokine network, pro-CMI cytokine production (IL-12 and IFNgamma) was reduced by surgery. Surprisingly, plasma levels of IFNgamma and IL-6 increased following surgery, while their in vitro induced production showed opposite effects. Patients awaiting surgery exhibited impaired IL-12 induced production and NK activity/ml, and reduced IFNgamma plasma levels. No significant associations were found between NK cytotoxicity and Th1 cytokines, although these indices showed high correlations with other variables. Overall, our findings indicate that patients exhibit impaired immune functions even before operation, which seem to contribute to the evident post-operative immune suppression. In the peri-operative context, induced cytokine production and plasma cytokines levels reflect different processes. Last, we suggest that peri-operative suppression of NK activity is mediated by neuroendocrine responses rather than Th1 cytokines.

Interleukin-6-gene C/G 174 polymorphism in nonagenarian and octogenarian subjects in the BELFAST study. Reciprocal effects on IL-6, soluble IL-6 receptor and for IL-10 in serum and monocyte supernatants

In this study, we have assessed any change in the frequency of the GG homozygotes of the 174 IL-6 polymorphism with increasing age, arguing that if IL-6 tracks with functional disability and age-related diseases, then there may be attrition or reduction in the frequency of homozgyous subjects, who produce higher levels of IL-6 in serum, in older survivors in a population. We have tested this hypothesis in a large group of free-living, mentally competent, nonagenarian and octogenarian subjects from the Belfast Elderly Longitudinal Ageing Study-BELFAST study and found that the frequency of GG homozygotes with IL-6-174C/G polymorphism decreases with age by about 10%, compared with young controls. In addition we find that CC homozygotes have higher serum levels of IL-6 levels compared with GG (P=0.055), with reciprocal and significant changes in the anti-inflammatory IL-10 (P=0.05). Both IL-6 and IL-10 were spontaneously produced from separated mononuclear cell monolayers in elderly subjects, with significantly higher levels of secreted IL-10 supernatant levels (P=0.05) at 20 h, for G allele subjects carrying the IL-6-174C/G polymorphism. In conclusion, in the BELFAST study, there appears to be a reduction in the frequency of GG homozygotes in the octo/nonagenarian age group and a higher serum IL-6 level associated with CC homozygotes with reciprocal changes for the anti-inflammatory cytokine IL-10.

Linkage disequilibrium between tumor necrosis factor (TNF)-alpha-308 G/A promoter and TNF-beta NcoI polymorphisms: Association with TNF-alpha response of granulocytes to endotoxin stimulation

OBJECTIVE

Controversial data have been reported on the association between the tumor necrosis factor (TNF)-alpha-308 G[U279C]A promoter polymorphism or the TNF-alpha I polymorphism with TNF-alpha plasma concentrations. The purpose of this study was to evaluate whether there is a linkage disequilibrium between the two polymorphisms. Moreover, the influence of these polymorphisms on the TNF-alpha synthesis of activated granulocytes was studied.

DESIGN

Analysis of TNF-alpha concentrations of human whole blood after endotoxin stimulation.

SETTING

Medical research laboratory.

PATIENTS

Healthy human volunteers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Healthy human volunteers were genotyped for both TNF polymorphisms by means of polymerase chain reaction. TNF-alpha plasma concentrations were determined with chemiluminescence after incubation of whole blood with endotoxin. A strong (p <.0001) linkage disequilibrium was found for the TNF-beta I and the TNF-alpha-308 genetic polymorphisms. Almost all individuals homozygous for the TNF-B2 allele of the TNF-beta I polymorphism were also TNF-alpha-308 G homozygotes. Carriers of the TNF-alpha-308 genotype AG had a significantly higher TNF-alpha production capacity than G homozygotes. The TNF-beta I genotype TNF-B1/TNF-B2 was associated with significantly higher TNF-alpha concentrations than the genotype TNF-B2/TNF-B2. Individuals homozygous for the TNF-B2 and the TNF-alpha-308 G alleles had a significantly reduced TNF-alpha response compared with individuals heterozygous for both TNF polymorphisms.

CONCLUSIONS

A linkage disequilibrium between the two TNF polymorphisms was found. This study revealed a significant association between genotype and phenotype for both TNF polymorphisms. Heterozygosity for both TNF polymorphisms is associated with an increased TNF-alpha response.

Association of a TNFbeta gene polymorphism with complications after major abdominal operations

In injured patients, it has been shown that a polymorphism of the tumor necrosis factor-beta (TNFbeta) gene is related to the development of sepsis. We investigated the relation of TNFbeta gene polymorphism with the development of severe complications after elective major abdominal operations, and with production of TNFalpha perioperatively. In the present investigation, the Ncol polymorphism was studied in genomic DNA isolated from the blood of 172 patients. Preoperatively and postoperatively, lipopolysaccharide (LPS)-stimulated production of TNFalpha in the patients' whole blood was tested in vitro. Genotypes and TNFalpha production were related to the occurrence of severe complications. Postoperatively, 15% (n = 26) of the patients developed severe complications. The overall mortality was 2% (n = 3). The homozygous TNFB2 genotype was found in 54% of the patients, the homozygous TNFB1 genotype was found in 14% of the patients, and the heterozygous genotype was found in 32% of the patients. In patients with complications, the B2B2 genotype was much more frequent (21/26, 81%) than in those without complications (72/146, 49%; P < 0.003). The development of complications was associated with a lower capacity to produce TNFalpha 3 and 7 days after the operation. In patients without complications, the TNFbeta polymorphism was not related to different levels of TNFalpha production. These data indicate an association between TNFbeta polymorphism and postoperative complications and they suggest the B2/B2 genotype as a high risk factor for the development of sepsis after elective operative trauma.

Preservation of splenic immune functions by female sex hormones after trauma-hemorrhage

OBJECTIVES

Immune functions are markedly depressed in males but not in proestrus females after trauma-hemorrhage. Nonetheless, it is unclear what role sex steroids play in the maintenance of immune function in females after trauma-hemorrhage.

DESIGN

Prospective, controlled animal study.

SETTING

University research laboratory.

SUBJECTS

Eight-week-old female CBA/J mice.

INTERVENTIONS

Mice underwent sham-ovariectomy or ovariectomy. Two weeks thereafter, ovariectomized and proestrus sham-ovariectomized mice were subjected to laparotomy (i.e., soft tissue trauma) and hemorrhagic shock (35 +/- 5 mm Hg for 90 mins, resuscitated) or sham operation. Splenocyte proliferation and interleukin-2, interleukin-3, and interferon-gamma release were determined at 2 hrs after trauma-hemorrhage.

MEASUREMENTS AND MAIN RESULTS

These immune functional capacities were maintained in proestrus sham-ovariectomized mice after trauma-hemorrhage, whereas they were suppressed in ovariectomized mice subjected to trauma-hemorrhage. 17beta-Estradiol in vitro had no effect on splenocyte functions in proestrus sham-ovariectomized females; however, addition of 17beta-estradiol to splenocytes from ovariectomized females subjected to trauma-hemorrhage normalized immune functional capacities.

CONCLUSIONS

These findings suggest that elevated circulating 17beta-estradiol in proestrus females plays a direct role in the maintenance of immunocompetence after trauma-hemorrhage.