Genetic polymorphisms in sepsis

To Determine the Genotyping of Fc-gamma Receptor FCGR2A Polymorphism as Genetic Susceptibility to Neonatal Sepsis: A Study from a Tertiary Center of North India

Background

Neonatal sepsis term is an infection of newborns <28 days of age. It is a common cause of death in developing countries. The receptor-gamma receptor FCGR2A has been shown to be associated with neonatal sepsis. It is an activating receptor found in many cell types such as monocytes, neutrophils, macrophages, platelets, and others. The receptor has a polymorphism (single-nucleotide polymorphism rs1801274) in its gene (FCGR2A) that encodes either a histidine (H) or arginine (R) at amino acid position 131. There are many studies showing the impact of these FCGR2A polymorphisms on sepsis. Our study aims to determine the prevalence of Fc-gamma receptor FCGR2A (rs1801274) polymorphism in neonatal sepsis and control in Eastern UP populations.

Patients and Methods

We conducted a cross-sectional descriptive study of 590 patients (310 healthy individuals and 280 sepsis patients) to determine polymorphisms in the CD32A coding region in neonates. All individuals were genotyped for a variant at position 131 of the FcγRIIA gene.

Discussion

In our study, the prevalence of FcγRIIa polymorphism is more in neonates with sepsis than in noninfected neonates. It was observed that the heterozygous allele (AG) were significantly increased in septic neonates when compared to the normal.

Conclusion

Our data indicate that FcγRIIA genotyping can be used as a marker of genetic susceptibility to sepsis.

Association between the Lymphotoxin-α A252g Gene Polymorphism and the Risk of Sepsis and Mortality: A Meta-Analysis

Background

The association between the lymphotoxin-α (LTA) A252G polymorphism and sepsis risk has been extensively studied, but the results have been controversial. This study is aimed at investigating the overall association between the LTA A252G polymorphism and the risk of sepsis/septic shock and sepsis-related mortality.

Methods

We searched the PubMed and EMBASE databases to identify studies that investigated the association between the LTA A252G polymorphism and risks of sepsis, septic shock, and mortality. The relevant data were extracted, and statistical analyses were performed using the Revman 5.0 and STATA 12 software.

Results

A total of 32 publications were included in the meta-analysis. The results demonstrated that the LTA A252G polymorphism showed no significant association with sepsis risk (GG+GA vs. AA: OR = 0.92, 95%CI = 0.79–1.07, p = 0.27) or with sepsis shock risk (GG+GA vs. AA: OR = 1.01, 95%CI = 0.84–1.22, p = 0.91). However, in the subgroup analyzed by ethnicity, the LTA A252G polymorphism significantly decreased sepsis risk in the Asian population for the recessive model [GG vs. GA+AA: OR = 0.82, 95%CI = 0.68–0.99, p = 0.04] but not in the Caucasian population. Moreover, comparisons between sepsis patients who survived and those who did not suggested that the LTA A252G polymorphism decreases the risk of mortality [GG+GA vs. AA: OR = 0.57, 95%CI = 0.41–0.80, p < 0.01].

Conclusion

Our results suggested that the A252G polymorphism in the LTA gene decreased the risk of sepsis in Asians and may reduce mortality in septic individuals.

Polygenic Risk Score for Early Prediction of Sepsis Risk in the Polytrauma Screening Cohort

BACKGROUND

Increasing genetic variants associated with sepsis have been identified by candidate-gene and genome-wide association studies, but single variants conferred minimal alterations in risk prediction. Our aim is to evaluate whether a weighted genetic risk score (wGRS) that aggregates information from multiple variants could improve risk discrimination of traumatic sepsis.

METHODS

Sixty-four genetic variants potential relating to sepsis were genotyped in Chinese trauma cohort. Genetic variants with mean decrease accuracy (MDA) > 1.0 by random forest algorithms were selected to construct the multilocus wGRS. The area under the curve (AUC) and net reclassification improvement (NRI) were adopted to evaluate the discriminatory and reclassification ability of weighted genetic risk score (wGRS).

RESULTS

Seventeen variants were extracted to construct the wGRS in 883 trauma patients. The wGRS was significantly associated with sepsis after trauma (OR = 2.19, 95% CI = 1.53-3.15, P = 2.01 × 10-5) after being adjusted by age, sex, and ISS. Patients with higher wGRS have an increasing incidence of traumatic sepsis (P trend = 6.81 × 10-8), higher SOFA (P trend = 5.00 × 10-3), and APACHE II score (P trend = 1.00 × 10-3). The AUC of the risk prediction model incorporating wGRS into the clinical variables was 0.768 (95% CI = 0.739-0.796), with an increase of 3.40% (P = 8.00 × 10-4) vs. clinical factor-only model. Furthermore, the NRI increased 25.18% (95% CI = 17.84-32.51%) (P = 6.00 × 10-5).

CONCLUSION

Our finding indicated that genetic variants could enhance the predictive power of the risk model for sepsis and highlighted the application among trauma patients, suggesting that the sepsis risk assessment model will be a promising screening and prediction tool for the high-risk population.

Sepsis in the era of data-driven medicine: personalizing risks, diagnoses, treatments and prognoses

Sepsis is a series of clinical syndromes caused by the immunological response to infection. The clinical evidence for sepsis could typically attribute to bacterial infection or bacterial endotoxins, but infections due to viruses, fungi or parasites could also lead to sepsis. Regardless of the etiology, rapid clinical deterioration, prolonged stay in intensive care units and high risk for mortality correlate with the incidence of sepsis. Despite its prevalence and morbidity, improvement in sepsis outcomes has remained limited. In this comprehensive review, we summarize the current landscape of risk estimation, diagnosis, treatment and prognosis strategies in the setting of sepsis and discuss future challenges. We argue that the advent of modern technologies such as in-depth molecular profiling, biomedical big data and machine intelligence methods will augment the treatment and prevention of sepsis. The volume, variety, veracity and velocity of heterogeneous data generated as part of healthcare delivery and recent advances in biotechnology-driven therapeutics and companion diagnostics may provide a new wave of approaches to identify the most at-risk sepsis patients and reduce the symptom burden in patients within shorter turnaround times. Developing novel therapies by leveraging modern drug discovery strategies including computational drug repositioning, cell and gene-therapy, clustered regularly interspaced short palindromic repeats -based genetic editing systems, immunotherapy, microbiome restoration, nanomaterial-based therapy and phage therapy may help to develop treatments to target sepsis. We also provide empirical evidence for potential new sepsis targets including FER and STARD3NL. Implementing data-driven methods that use real-time collection and analysis of clinical variables to trace, track and treat sepsis-related adverse outcomes will be key. Understanding the root and route of sepsis and its comorbid conditions that complicate treatment outcomes and lead to organ dysfunction may help to facilitate identification of most at-risk patients and prevent further deterioration. To conclude, leveraging the advances in precision medicine, biomedical data science and translational bioinformatics approaches may help to develop better strategies to diagnose and treat sepsis in the next decade.

Host genetic variants in sepsis risk: a field synopsis and meta-analysis

Background

Published data revealed that host genetic variants have a substantial influence on sepsis susceptibility. However, the results have been inconsistent. We aimed to systematically review the published studies and quantitatively evaluate the effects of these variants on the risk of sepsis.

Methods

We searched the PubMed, EMBASE, Medline, Web of Knowledge, and HuGE databases to identify studies that investigated the associations between genetic variants and sepsis risk. Then, we conducted meta-analyses of the associations for genetic variants with at least three study populations and applied the Venice criteria to assess the association result credibility.

Results

A literature search identified 349 eligible articles that investigated 405 variants of 172 distinct genes. We performed 204 primary and 185 subgroup meta-analyses for 76 variants of 44 genes. The results showed that 29 variants of 23 genes were significantly associated with the risk of sepsis, including 8 variants of pattern recognition receptors (PRRs), 14 variants of cytokines, one variant of an immune-related gene and 6 variants of other genes. Furthermore, the cumulative epidemiological evidence of a significant association between each variant and the risk of sepsis was classified as strong or moderate for 18 variants. For the 329 variants with fewer than three study populations, 63 variants of 48 genes have been reported to be significantly associated with the risk of sepsis in a systematic review.

Conclusion

We identified several genetic variants that could influence the susceptibility to sepsis by systematic review and meta-analysis. This study provides a comprehensive overview of the genetic architecture of variants involved in sepsis susceptibility and novel insight that may affect personalized targeted treatment in the future clinical management of sepsis.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2313-0) contains supplementary material, which is available to authorized users.

CTLA-4 Genetic Variants Predict Survival in Patients with Sepsis

Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is a coinhibitory checkpoint protein expressed on the surface of T cells. A recent study by our working group revealed that the rs231775 single nucleotide polymorphism (SNP) in the CTLA-4 gene was associated with the survival of patients with sepsis and served as an independent prognostic variable. To further investigate the impact of CTLA-4 genetic variants on sepsis survival, we examined the effect of two functional SNPs, CTLA-4 rs733618 and CTLA-4 rs3087243, and inferred haplotypes, on the survival of 644 prospectively enrolled septic patients. Kaplan⁻Meier survival analysis revealed significantly lower 90-day mortality for rs3087243 G allele carriers (n = 502) than for AA-homozygous (n = 142) patients (27.3% vs. 40.8%, p = 0.0024). Likewise, lower 90-day mortality was observed for TAA haplotype-negative patients (n = 197; compound rs733618 T/rs231775 A/rs3087243 A) than for patients carrying the TAA haplotype (n = 447; 24.4% vs. 32.9%, p = 0.0265). Carrying the rs3087243 G allele hazard ratio (HR): 0.667; 95% confidence interval (CI): 0.489⁻0.909; p = 0.0103) or not carrying the TAA haplotype (HR: 0.685; 95% CI: 0.491⁻0.956; p = 0.0262) remained significant covariates for 90-day survival in the multivariate Cox regression analysis and thus served as independent prognostic variables. In conclusion, our findings underscore the significance of CTLA-4 genetic variants as predictors of survival of patients with sepsis.

Association of HLA-G 3'UTR polymorphisms and haplotypes with severe sepsis in a Brazilian population

BACKGROUND

The human leukocyte antigen G (HLA-G) is a molecule involved in immune system modulation, acting in the maintenance of a state of immune tolerance. Some polymorphisms in the HLA-G gene 3' untranslated region (3'UTR) were associated to distinct levels of HLA-G expression and to sepsis development. In the present study, haplotypes and polymorphisms of the HLA-G 3'UTR were analyzed in Brazilian septic patients.

METHODS

The HLA-G 3'UTR was amplified by PCR, sequenced and eight polymorphisms were genotyped (the 14bp insertion/deletion, +3003T/C, +3010C/G, +3027A/C, +3035C/T, +3142G/C, +3187A/G and+3196C/G) in DNA samples from septic patients (with severe sepsis or septic shock) and controls. The haplotypes were inferred and association tests were performed through Chi square test and binary logistic regression.

RESULTS

The+3027AC genotype was associated asa risk factor to sepsis development (OR 3.17, P_Bonferroni 0.048). Further, the presence of the UTR-7 haplotype (OR 2.97, P_Bonferroni 0.018), and of 14bp-Ins_+3142G_+3187A haplotype (OR 2.39, P_Bonferroni 0.045) were associated with sepsis, conferring susceptibility.

CONCLUSION

Our data confirm an important role of HLA-G 3'UTR polymorphisms in the development of severe forms of sepsis (severe sepsis and septic shock). The genotyping of HLA-G genetic variants and haplotypes could be useful as a prediction tool of increased risk to severe sepsis.

Association study of MCP-1 promoter polymorphisms with the susceptibility and progression of sepsis

Previous studies have indicated that the monocyte chemo-attractant protein 1 (MCP-1), also referred to as C-C motif chemokine ligand 2 (CCL2), plays a significant role in the pathogenesis of sepsis, and this study investigated the clinical relevance of two MCP-1 gene polymorphisms on sepsis onset and progression. The Multiplex SNaPshot genotyping method was used to detect MCP-1 gene polymorphisms in the Chinese Han population (403 sepsis patients and 400 controls). MCP-1 mRNA expression levels were measured using real-time quantitative PCR, and enzyme-linked immunosorbent assays were used to analyze MCP-1, tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and interleukin-1 beta (IL-1β) plasma concentrations. The rs1024611 polymorphism analysis showed lower frequencies of minor homozygous genotype (AA) and allele (A) in sepsis patients compared to the healthy controls (19.4% vs. 31.5%, P = 0.0001 and 45.9% vs. 54.8%, P = 0.0004, respectively). And the frequencies of GG genotype and G allele were lower in sepsis patients compared to the controls (19.6% vs. 31.3%, P = 0.0002 and 46.0% vs. 54.5%, P = 0.0007, respectively). The rs1024611 AG/GG and rs2857656 GC/CC genotypes were both overrepresented in patients with severe sepsis (both P = 0.0005) and septic shock (P = 0.010 and P = 0.015, respectively) compared to the patients with mild sepsis. Moreover, among sepsis patients, the rs1024611 AG/GG and rs2857656 GC/CC carriers exhibited significant increases in expression levels of MCP-1 (P = 0.025), TNF-α (P = 0.034) and IL-6 (P = 0.043) compared with the rs1024611 AA or rs2857656 GG carriers. This study provides valuable clinical evidence that the MCP-1/CCL2 polymorphisms rs1024611 and rs2857656 are associated with sepsis susceptibility and development. We conclude that MCP-1/CCL2 plays a significant role in the pathogenesis of sepsis, which has potentially important therapeutic implications.

Innate immunity gene expression changes in critically ill patients with sepsis and disease-related malnutrition

The aim of this study was an attempt to determine whether the expression of genes involved in innate antibacterial response (TL R2, NOD 1, TRAF6, HMGB 1 and Hsp70) in peripheral blood leukocytes in critically ill patients, may undergo significant changes depending on the severity of the infection and the degree of malnutrition. The study was performed in a group of 128 patients with infections treated in the intensive care and surgical ward. In 103/80.5% of patients, infections had a severe course (sepsis, severe sepsis, septic shock, mechanical ventilation of the lungs). Clinical monitoring included diagnosis of severe infection (according to the criteria of the ACC P/SCC M), assessment of severity of the patient condition and risk of death (APACHE II and SAPS II), nutritional assessment (NRS 2002 and SGA scales) and the observation of the early results of treatment. Gene expression at the mRNA level was analyzed by real-time PCR. The results of the present study indicate that in critically ill patients treated in the IC U there are significant disturbances in the expression of genes associated with innate antimicrobial immunity, which may have a significant impact on the clinical outcome. The expression of these genes varies depending on the severity of the patient condition, severity of infection and nutritional status. Expression disorders of genes belonging to innate antimicrobial immunity should be diagnosed as early as possible, monitored during the treatment and taken into account during early therapeutic treatment (including early nutrition to support the functions of immune cells).

Association of tumor necrosis factor α -308G/A and interleukin-6 -174G/C gene polymorphism with pneumonia-induced sepsis

PURPOSE

Sepsis is a lethal outcome of the inflammation and coagulation process. Human interleukin (IL)-6 and tumor necrosis factor (TNF) α are well-known inflammation factors closely associated with sepsis. In the present study, we aim to investigate the association of promoter-region polymorphisms IL-6 (-174G/C) rs1800795 and TNF-α (-308G/A) rs1800629 with pneumonia-induced sepsis.

MATERIALS AND METHODS

A total of 277 Chinese patients with severe pneumonia-induced sepsis were recruited into this study. All study participants were admitted to the intensive care unit until discharge or death in the First Affiliated Hospital of Zhengzhou University from July 2010 to July 2014. The patients were classified as severely septic, septic shock, and mortality. Clinical data and demographic information were recorded. TaqMan genotyping was performed to detect single nucleotide polymorphism distribution.

RESULTS

The genotype results demonstrated that carriers of the TNF-α rs1800629 A allele had a 4.28-fold higher risk for septic shock (adjusted odds ratio [OR], 4.28; 95% confidence interval [CI], 2.24-8.18; P < .01) compared with severe sepsis, and carriers of the IL-6 rs1800795 C allele had a 2.42-fold higher risk for septic shock (OR, 2.42; 95% CI, 1.08-5.45; P < .01) compared with severe sepsis. No significant difference of SNP distribution was found between the survivors and the nonsurvivors. After the results were adjusted for age and the outcomes of blood cultures, a multivariate logistic regression analysis showed similar results. Individuals with the TNF-α 308 rs1800629 A allele (adjusted OR, 2.96; 95% CI, 1.30-7.87) or the IL-6 rs1800795 C allele (adjusted OR, 1.87; 95% CI, 1.03-3.61) had a higher prevalence of septic shock. However, these SNP distribution differences were not associated with mortality.

CONCLUSIONS

In intensive care unit patients, the TNF-α -308A allele and the IL-6 rs1800795 allele variants were susceptibility risk factors for septic shock induced by pneumonia.

Severe septic patients with mitochondrial DNA haplogroup JT show higher survival rates: a prospective, multicenter, observational study

Objective

In a previous cohort study (n=96), we found an association between mitochondrial (mt) DNA haplogroup JT and increased survival of severe septic patients, after controlling for age and serum lactic acid levels. The aim of this research was to increase the predictive accuracy and to control for more confounder variables in a larger cohort (n=196) of severe septic patients, to confirm whether mtDNA haplogroup JT influences short and medium-term survival in these patients.

Methods

We conducted a prospective, multicenter, observational study in six Spanish Intensive Care Units. We determined 30-day and 6-month survival and mtDNA haplogroup in this second cohort of 196 patients and in the global cohort (first and second cohorts combined) with 292 severe septic patients. Multiple logistic regression and Cox regression analyses were used to test for the association of mtDNA haplogroups JT with survival at 30-days and 6-months, controlling for age, sex, serum interleukin-6 levels and SOFA score.

Results

Logistic and Cox regression analyses showed no differences in 30-day and 6-month survival between patients with mtDNA haplogroup JT and other haplogroups in the first cohort (n=96). In the second cohort (n=196), these analyses showed a trend to higher 30-day and 6-month survival in those with haplogroup JT. In the global cohort (n=292), logistic and Cox regression analyses showed higher 30-day and 6-month survival for haplogroup JT. There were no significant differences between J and T sub-haplogroups in 30-day and 6-month survival.

Conclusions

The global cohort study (first and second cohorts combined), the largest to date reporting on mtDNA haplogroups in septic patients, confirmed that haplogroup JT patients showed increased 30-day and 6-month survival. This finding may be due to single nucleotide polymorphism defining the whole haplogroup JT and not separately for J or T sub-haplogroups.

Association between CD14 promoter -159C/T polymorphism and the risk of sepsis and mortality: a systematic review and meta-analysis

Background

Recent studies on the association between CD14-159C/T polymorphism and sepsis showed inconclusive results. Accordingly, we conducted a comprehensive literature search and a meta-analysis to determine whether the CD14-159C/T polymorphism conferred susceptibility to sepsis or was associated with increased risk of death from sepsis.

Methodology

Data were collected from the following electronic databases: PubMed, Embase, Medline, Web of Knowledge, and HuGE Navigator, with the last report up to June 15, 2012. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association. We summarized the data on the association between CD14-159C/T polymorphism and sepsis in the overall population and subgroup by ethnicity and sepsis subtype.

Principal Findings

A total of 16 studies on sepsis morbidity (1369 cases and 2382 controls) and 4 studies on sepsis mortality (731 sepsis patients) met the inclusion criteria for meta-analysis. Overall analysis showed no strong evidences of association with sepsis susceptibility under any genetic model. However, slight associations were found in Asian populations (dominant model: OR = 1.38, 95%CI = 0.96–1.98, P = 0.08) and septic shock patients (dominant model: OR = 1.72, 95%CI 1.05–2.83, P = 0.03; allelic model: OR = 1.52, 95%CI 1.09–2.12, P = 0.01) in the stratified analysis. Moreover, there was borderline association between CD14-159C/T and sepsis mortality under the dominant genetic model (OR = 1.44, 95%CI = 0.98–2.11, P = 0.06).

Conclusions/Significance

This meta-analysis suggests that the CD14-159C/T polymorphism may not be a significant susceptibility factor in the risk of sepsis and mortality. Only weak associations were observed in Asian populations and septic shock patients. More studies based on larger sample sizes and homogeneous sepsis patients are needed to confirm these findings.

Participation of 47C>T SNP (Ala-9Val polymorphism) of the SOD2 gene in the intracellular environment of human peripheral blood mononuclear cells with and without lipopolysaccharides

The outcome of sepsis occurs due to influence of environmental and genetic factors besides genes variants whose expression support its outcome or not. Oxidative stress is associated to the pathogenicity of sepsis, occurring when there is a reactive species overproduction associated with inflammation. The aim of this study was to characterize the cellular redox status of human peripheral blood mononuclear cells (PBMCs) with either -9Ala (AA) or -9Val (VV) SOD2 genotypes and evaluate their response to oxidative stress induced by lipopolysaccharide (LPS). The PBMCs were isolated from the blood of 30 healthy human volunteers (15 volunteers for each allele) and the following assays were performed: antioxidant enzyme activities (superoxide dismutase; catalase; glutathione peroxidase), total radical-trapping antioxidant parameter, non-enzymatic antioxidant capacity (total antioxidant reactivity), and quantification of conjugated dienes (lipid peroxidation). At basal conditions (i.e., not stimulated by LPS), cells from 47C allele carriers showed higher activities of CAT and SOD, as well as higher TAR compared to 47T allele. However, when 47CC cells were challenged with LPS, we observed a higher shift toward a pro-oxidant state compared to 47TT cells. The CAT activity and lipid peroxidation were increased in cells with both alleles, but SOD activity increased significantly only in 47TT cells. These results demonstrate that SOD2 polymorphisms are associated with different cellular redox environments at both basal and LPS-stimulated states, and identification of this polymorphism may be important for a better understanding of pro-inflammatory conditions.