Impact of interleukin 6 promoter polymorphisms (-174 G > C, -572 G > C and -597 G > A) on plasma IL-6 levels and their influence on the development of DVT: a study from India

Impact of IL-6 and IL-6r variants on HIV-1 susceptibility and progression to AIDS: a case-control study in a Moroccan population

Interleukin-6 (IL-6), a pro-inflammatory cytokine, is an important regulator of the inflammatory immune response. We aimed to assess the association of common single nucleotide polymorphisms (SNPs) in IL-6 (rs1800795 G > C, rs1800797 A > G) and interleukin-6 receptor (IL-6R) (rs2228145 A > C) genes with HIV-1 infection, AIDS progression, and response to treatment. In this case-control study involving 199 individuals living with HIV-1 and 200 HIV-uninfected controls, we conducted genotyping of IL-6/IL-6R SNPs using TaqMan real-time PCR assays. Soluble IL-6 levels were measured using ELISA. No associations were found between the investigated SNPs and HIV infection. However, a significant association was noted between the C-G and G-A haplotypes and susceptibility to HIV-1 infection. Additionally, a significant association was revealed between HIV-1 RNA viral loads and IL-6 SNP G > C in the post-treatment HIV group. Interestingly, we observed a significant association between the investigated SNPs and protection against progression to AIDS, namely the IL-6 G > A SNP in its recessive model and the IL-6R A > C SNP in its codominant and dominant models. Nevertheless, we found no significant differences between IL-6 levels and the different genotypes and alleles of the IL-6 gene either before or after combination antiretroviral therapy. IL-6 promoter haplotypes are associated with susceptibility to HIV-1 infection. Furthermore, IL-6 A > G and IL-6R A > C polymorphisms have been associated with protection against AIDS progression. Interestingly, the IL-6 G > C SNP may affect the response to treatment in people living with HIV-1.

Analysis of the Effects of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C Gene Polymorphisms; IL-6 Levels; and CRP Levels on Chronic Periodontitis in Coronary Artery Disease in Indonesia

Interleukin 6 (IL-6) and C-Reactive Protein (CRP) play an important role in chronic periodontitis with coronary artery disease (CAD). Genetic factors can affect a person's risk of CAD, which affects one-third of the population. This study investigated the role of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms. IL-6 and CRP levels on the severity of periodontitis in CAD in Indonesia were also evaluated. This case-control study was conducted with mild and moderate-severe chronic periodontitis groups. A path analysis test was conducted with Smart PLS with a 95% confidence interval to determine the significant variable for chronic periodontitis. Our study revealed that the effects of IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms on IL-6 levels and CRP levels were not significant. IL-6 and CRP levels were not significantly different between the two groups. We found that IL-6 levels had a significant effect on CRP levels in periodontitis patients with CAD (path coefficient 0.322, p = 0.003). IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C gene polymorphisms had no effect on the severity of chronic periodontitis in CAD patients in the Indonesian population. We also observed no apparent effects of the influence of gene polymorphisms in IL-6 -572 C/G, CRP -757 A/G, and CRP -717 T/C genes. Although the IL-6 and CRP levels were not significantly different between the two groups, IL-6 levels affected CRP levels in periodontitis patients with CAD.

Co-Occurrence of Interleukin-6 Receptor Asp358Ala Variant and High Plasma Levels of IL-6: An Evidence of IL-6 Trans-Signaling Activation in Deep Vein Thrombosis (DVT) Patients

Interleukin-6 (IL-6) is a pleiotropic cytokine involved in several mechanisms, and the alteration of IL-6 signaling leads to the overactivation of various processes including immunity, inflammation, and hemostasis. Although IL-6 increase has been documented in venous thromboembolic diseases, the exact involvement of IL-6 signaling in deep vein thrombosis (DVT) has not been fully understood. Consequently, we investigated the involvement of IL-6 trans-signaling in inflammatory events occurring in DVT, focusing on the role of the interleukin-6 receptor (IL6-R) Asp358Ala variant. The circulating levels of IL-6, soluble IL6-R (sIL6-R), and soluble glycoprotein 130, as well as the Asp358Ala genotyping, were assessed in a consecutive cohort of DVT patients and healthy controls. The results indicated that IL-6 was higher in DVT compared to controls. Moreover, sIL6-R levels were strongly correlated to Asp358Ala variant in both groups, showing a high frequency of this mutation across all samples. Interestingly, our results showed a high frequency of both Asp358Ala mutation and raised IL-6 levels in DVT patients (OR = 21.32; p ≤ 0.01), highlighting that this mutation could explain the association between IL-6 overactivation and DVT outcome. Overall, this study represents a proof of concept for the targeting of IL-6 trans-signaling as a new strategy for the DVT adjuvant therapy.

Therapeutic Strategies Focused on Cancer-Associated Hypercoagulation for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is associated with chemotherapy resistance and poor prognosis, especially in advanced cases. Although comprehensive genomic analyses have clarified the significance of genomic alterations such as ARID1A and PIK3CA mutations in OCCC, therapeutic strategies based on genomic alterations have not been confirmed. On the other hand, OCCC is clinically characterized by a high incidence of thromboembolism. Moreover, OCCC specifically shows high expression of tissue factor and interleukin-6, which play a critical role in cancer-associated hypercoagulation and may be induced by OCCC-specific genetic alterations or the endometriosis-related tumor microenvironment. In this review, we focused on the association between cancer-associated hypercoagulation and molecular biology in OCCC. Moreover, we reviewed the effectiveness of candidate drugs targeting hypercoagulation, such as tissue factor- or interleukin-6-targeting drugs, anti-inflammatory drugs, anti-hypoxia signaling drugs, anticoagulants, and combined immunotherapy with these drugs for OCCC. This review is expected to contribute to novel basic research and clinical trials for the prevention, early detection, and treatment of OCCC focused on hypercoagulation.

Overactivation of IL6 cis‑signaling in leukocytes is an inflammatory hallmark of deep vein thrombosis

Inflammation is a protective response of the body to various injuries, which is strictly regulated by a variety of factors, including immune cells and soluble mediators. However, dysfunction of this defensive mechanism often results in inflammation‑driven diseases, such as deep vein thrombosis (DVT). The complex relationship between inflammatory cell activity and DVT has not been fully elucidated. The present study aimed to investigate the role of interleukin‑6 (IL6) signaling transduction in DVT. To this aim, the expression levels of transmembrane isoforms of the IL6 receptor (IL6R) and the glycoprotein 130 responsible for the IL6 cis‑signaling were evaluated in the peripheral blood mononuclear cells of patients with DVT and of healthy controls. The results indicated that leukocytes from patients with DVT exhibited overexpression of both IL6R and gp130 membrane isoforms and that these were strongly associated with the occurrence of DVT. Overall, the present findings indicated that IL6 cis‑signaling may have a direct involvement in the leukocyte activation in DVT and may serve as a predictive biomarker of DVT development.

Association of IL-10 (- 1082 A/G) and IL-6 (- 174 G/C) gene polymorphism with type 2 diabetes mellitus in Ethiopia population

BACKGROUND

Interleukin (IL)-6 and IL-10 are the most important cytokine with pro and anti-inflammatory activities, respectively. Dysregulation of IL-6 and IL-10 are associated with increased risk of developing Type 2 Diabetes Mellitus (T2DM). Despite this, a fundamental understanding of both cytokine gene polymorphisms with its expression is critical in understanding of cellular mechanism of insulin resistance as well as T2DM intervention. Therefore, this study aimed to assess IL-6 (- 174 G/C) and IL-10 (- 1082 A/G) gene polymorphism, and its association with T2DM, North West Ethiopia.

METHODS

A comparative cross-sectional study from January to May 2018 was conducted on study participants with T2DM and apparently healthy controls. Deoxyribonucleic acid (DNA) extraction and genotyping was carried out by using amplification refractory mutation system polymerase chain reaction to detect polymorphism of IL-6 and IL-10 gene at the position - 174 and - 1082, respectively. The logistic regression model was fitted to assess the association of between cytokine gene polymorphisms and T2DM. Odds ratio with 95% CI was determined to assess the presence and strength of association between the explanatory variables and outcome variable. A P-value < 0.05 was considered as statistically significant.

RESULT

Participants carrying the GG genotype of IL-6 (- 174) (OR (95% CI) = 4.61 (2.07-10.54) was a high likelihood of having T2DM compared to those carrying the CC and AA genotypes. AA and AG genotypes of IL-10 (- 1082) were at lower odd of developing T2DM compared to those carrying the GG genotype. In addition, individuals carrying the G allele of IL-6 (- 174) have 2.82-fold odds of developing T2DM compared to individuals carrying the C allele (OR (95% CI) =2.81 (1.78-4.50)).

CONCLUSION

Our study revealed that genetic polymorphisms of IL-6 (- 174) GG genotype is the potential host genetic risk factors to T2DM. While, IL-10 (- 1082) AA genotype is negatively associated with T2DM. Therefore, IL-6 (- 174) and IL-10 (- 1082) genetic variation may be considered as a biomarker for early screening and diagnosis of T2DM.

Pharmacogenetics-Based Preliminary Algorithm to Predict the Incidence of Infection in Patients Receiving Cytotoxic Chemotherapy for Hematological Malignancies: A Discovery Cohort

Introduction: Infections in hematological cancer patients are common and usually life-threatening; avoiding them could decrease morbidity, mortality, and cost. Genes associated with antineoplastics’ pharmacokinetics or with the immune/inflammatory response could explain variability in infection occurrence.

Objective: To build a pharmacogenetic-based algorithm to predict the incidence of infections in patients undergoing cytotoxic chemotherapy.

Methods: Prospective cohort study in adult patients receiving cytotoxic chemotherapy to treat leukemia, lymphoma, or myeloma in two hospitals in Santiago, Chile. We constructed the predictive model using logistic regression. We assessed thirteen genetic polymorphisms (including nine pharmacokinetic—related genes and four inflammatory response-related genes) and sociodemographic/clinical variables to be incorporated into the model. The model’s calibration and discrimination were used to compare models; they were assessed by the Hosmer-Lemeshow goodness-of-fit test and area under the ROC curve, respectively, in association with Pseudo-R².

Results: We analyzed 203 chemotherapy cycles in 50 patients (47.8 ± 16.1 years; 56% women), including 13 (26%) with acute lymphoblastic and 12 (24%) with myeloblastic leukemia.

Pharmacokinetics-related polymorphisms incorporated into the model were CYP3A4 rs2242480C>T and OAT4 rs11231809T>A. Immune/inflammatory response-related polymorphisms were TLR2 rs4696480T>A and IL-6 rs1800796C>G. Clinical/demographic variables incorporated into the model were chemotherapy type and cycle, diagnosis, days in neutropenia, age, and sex. The Pseudo-R² was 0.56, the p-value of the Hosmer-Lemeshow test was 0.98, showing good goodness-of-fit, and the area under the ROC curve was 0.93, showing good diagnostic accuracy.

Conclusions: Genetics can help to predict infections in patients undergoing chemotherapy. This algorithm should be validated and could be used to save lives, decrease economic costs, and optimize limited health resources.

Association of NFκβ, TNFα, IL-6, IL-1β, and LPL Polymorphisms with Type 2 Diabetes Mellitus and Biochemical Parameters in a Mexican Population

Chronic low-grade inflammation is strongly related to the etiology of diabetes mellitus type 2 (T2DM), and the expression of inflammatory cytokines may be modulated by polymorphisms located in the regulatory regions of the NFκβ, IL-1β, IL-6, TNFα, and LPL genes. We considered it particularly important to investigate the relationship of gene polymorphisms involved in chronic inflammation with the risk of T2DM or uncontrolled biochemical parameters.

METHODS

We included 199 individuals with a T2DM diagnosis and 213 individuals without a T2DM diagnosis. Restriction fragment length polymorphism (RFLP) analyses were used to assess polymorphisms.

RESULTS

We found a risk association between T2DM and uncontrolled biochemical parameters in a Mexican population for the genotypes del/del of NFκβ, -174 and -572 of IL-6, C/C of IL-1β, -308 and -238 of TNFα, and T/T of LPL. In subjects without diabetes (controls), we found an association between the G/C genotype of the -572 polymorphism and the G/C and C/C genotypes of the -597 polymorphism of IL-6 with the risk of glucose levels > 131 mg/dL. Genotype C/C of polymorphism -174 of the IL-6 gene was associated with high triglyceride levels, and levels > 5.8% of HbA1c were associated with the G/A genotype of TNFα -308.

CONCLUSION

Here, we describe for the first time the relationship of T2DM risk and uncontrolled biochemical parameters with polymorphisms in the NFκβ, IL-6, TNFα, IL-1β, and LPL genes in a Mexican population. We also showed that for the population included in this study, there is an additive effect of the polymorphisms of the studied genes that considerably increases the risk of developing T2DM.We also showed that there are interactions between genes related to chronic inflammation that affect the risk of T2DM.

A linear prognostic score based on the ratio of interleukin-6 to interleukin-10 predicts outcomes in COVID-19

BACKGROUND

Prognostic tools are required to guide clinical decision-making in COVID-19.

METHODS

We studied the relationship between the ratio of interleukin (IL)-6 to IL-10 and clinical outcome in 80 patients hospitalized for COVID-19, and created a simple 5-point linear score predictor of clinical outcome, the Dublin-Boston score. Clinical outcome was analysed as a three-level ordinal variable ("Improved", "Unchanged", or "Declined"). For both IL-6:IL-10 ratio and IL-6 alone, we associated clinical outcome with a) baseline biomarker levels, b) change in biomarker level from day 0 to day 2, c) change in biomarker from day 0 to day 4, and d) slope of biomarker change throughout the study. The associations between ordinal clinical outcome and each of the different predictors were performed with proportional odds logistic regression. Associations were run both "unadjusted" and adjusted for age and sex. Nested cross-validation was used to identify the model for incorporation into the Dublin-Boston score.

FINDINGS

The 4-day change in IL-6:IL-10 ratio was chosen to derive the Dublin-Boston score. Each 1 point increase in the score was associated with a 5.6 times increased odds for a more severe outcome (OR 5.62, 95% CI -3.22-9.81, P = 1.2 × 10^-9). Both the Dublin-Boston score and the 4-day change in IL-6:IL-10 significantly outperformed IL-6 alone in predicting clinical outcome at day 7.

INTERPRETATION

The Dublin-Boston score is easily calculated and can be applied to a spectrum of hospitalized COVID-19 patients. More informed prognosis could help determine when to escalate care, institute or remove mechanical ventilation, or drive considerations for therapies.

FUNDING

Funding was received from the Elaine Galwey Research Fellowship, American Thoracic Society, National Institutes of Health and the Parker B Francis Research Opportunity Award.

IL-6 -572C>G and CARD8 304T>A Genetic Polymorphisms are Associated with the Absolute Neutrophil Count in Patients with Hematological Malignancies Under Chemotherapy: An Application of Multilevel Models to a Preliminary Pharmacogenetic Study

Purpose

Neutropenia is a common event in patients undergoing cytotoxic chemotherapy for the treatment of a hematological malignancy. Some polymorphisms, as IL-6 -572C>G (rs1800796), IL-1β -31 G>A (rs1143627), and CARD8 304T>A (rs2043211), in genes related to the inflammatory process, could affect the level of absolute neutrophil count (ANC) after chemotherapy. Since an efficient inflammatory process enhances neutrophil survival, we hypothesize that these polymorphisms are associated with ANC.

Patients and Methods

We carried out a prospective cohort study in two hospitals in Santiago, Chile. The patients included were adults diagnosed with acute myeloblastic leukemia, acute lymphoblastic leukemia, or non-Hodgkin's lymphoma, undergoing cytotoxic chemotherapy. We use a multilevel linear regression model to test our hypothesis. The best model was selected using the Akaike's information criterion (AIC).

Results

We analyzed 1726 hemograms and ANCs from 172 hospitalizations from 32 patients. The results show that CC and CG genotypes of IL-6 -572 C>G polymorphism are associated with higher ANCs compared with the GG genotype (Ln (ANC) ~ 0.81 IC95% 0.02-1.55). Similarly, TT and AT genotypes of CARD8 304T>A polymorphism were related to higher ANCs compared with AA (Ln (ANC) ~ 0.95 IC95% 0.02-1.82). IL-1β genetic polymorphism had no statistically significant association with ANC.

Conclusion

IL-6 rs1800796 -572C>G and CARD8 rs2043211 304T>A polymorphisms are associated with the absolute neutrophil count in patients undergoing cytotoxic chemotherapy for treatment of hematological malignancies. Our findings might be useful to improve the safety of chemotherapy through predictive ANC models.

IL (Interleukin)-6 Contributes to Deep Vein Thrombosis and Is Negatively Regulated by miR-338-5p

Supplemental Digital Content is available in the text.

Objective:

Deep venous thrombosis (DVT), one of the most common venous thromboembolic disorders, is closely linked with pulmonary embolism and post-thrombotic syndrome, both of which have a high mortality. However, the factors that trigger DVT formation are still largely unknown. Elevated expression of IL (interleukin)-6—an important inflammatory cytokine—has been linked with DVT formation. However, the molecular mechanisms leading to the elevated IL-6 in DVT remain unclear. Here, we proposed that epigenetic modification of IL-6 at the post-transcriptional level may be a crucial trigger for IL-6 upregulation in DVT.

Approach and Results:

To explore the association between microRNAs and IL-6 in DVT, we performed microRNA microarray analysis and experiments both in vitro and in vivo. Microarray and quantitative real-time polymerase chain reaction results showed that IL-6 expression was increased while miR-338-5p level was decreased substantially in peripheral blood mononuclear cells of patients with DVT, and there was significant negative correlation between miR-338-5p and IL-6. Experiments in vitro showed that overexpressed miR-338-5p reduced IL-6 expression, while miR-338-5p knockdown increased IL-6 expression. Moreover, our in vivo study found that mice with anti–IL-6 antibody or agomiR-338-5p delivery resulted in decreased IL-6 expression and alleviated DVT formation, whereas antagomiR-338-5p acted inversely. Most of miR-338-5p was found located in cytoplasm by fluorescence in situ hybridization. Dual-luciferase reporter assay identified direct binding between miR-338-5p and IL-6.

Conclusions:

Our results suggest that decreased miR-338-5p promotes DVT formation by increasing IL-6 expression.

Influence of Interleukin-6 (IL-6) Promoter Gene Polymorphisms (-174G>C, -572G>C, and -597G>A) on IL-6 Plasma Levels and Their Impact in the Development of Acute Ischemic Stroke in Young Indians

This study aimed to determine whether there is an influence of interleukin 6 (IL-6) gene promoter polymorphisms on IL-6 plasma levels and its role in the development of ischemic stroke in young Indians. One hundred young patients with ischemic stroke (age ≥ 45 years) and equal number of age- and sex-matched controls were genotyped for 174G>C, -572G>C, and -597G>A promoter polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. Plasma IL-6 levels were measured by enzyme-linked immunosorbent assay. Plasma IL-6 levels were significantly higher in patients as compared to controls (patients: 28.61 ± 8.61 pg/mL, controls: 7.60 ± 4.10 pg/mL, P = .001). Both -174G>C (allelic χ2/P value: 4.79/.028, genotypic χ2/P value: 5.3/.021) and -572G>C (allelic χ2/P value: 9.63/.00113 Genotypic χ2/P value: 74/.0002) polymorphisms exhibited genotypic as well as allelic significant association with the disease phenotype. Comparison was made between patients and controls for all 3 polymorphisms using a recessive model with respect to plasma IL-6 levels; no polymorphism showed any significant correlative association with the increased IL-6 levels (P = .31, .51, .32). Interleukin 6 is an inflammatory marker that is considerably influenced by nongenetic factors and is not a good candidate gene for studying genetic components associated with ischemic stroke. It seems that the variability in IL-6 levels is an integrated effect of nongenetic influences and the inflammatory events that follow ischemic stroke instead of being its cause. It is suggested that there is no direct association between -174G>C, -572G>C, and -597G>A polymorphisms and elevated IL-6 levels in the development of ischemic stroke.