Single Nucleotide Polymorphisms in IL17A and IL6 Are Associated with Decreased Risk for Pulmonary Tuberculosis in Southern Brazilian Population

Mycobacterium tuberculosis and host interactions in the manifestation of tuberculosis

The final step of epigenetic processes is changing the gene expression in a new microenvironment in the body, such as neuroendocrine changes, active infections, oncogenes, or chemical agents. The case of tuberculosis (TB) is an outcome of Mycobacterium tuberculosis (M.tb) and host interaction in the manifestation of active and latent TB or clearance. This comprehensive review explains and interprets the epigenetics findings regarding gene expressions on the host-pathogen interactions in the development and progression of tuberculosis. This review introduces novel insights into the complicated host-pathogen interactions, discusses the challengeable results, and shows the gaps in the clear understanding of M.tb behavior. Focusing on the biological phenomena of host-pathogen interactions, the epigenetic changes, and their outcomes provides a promising future for developing effective TB immunotherapies when converting gene expression toward appropriate host immune responses gradually becomes attainable. Overall, this review may shed light on the dark sides of TB pathogenesis as a life-threatening disease. Therefore, it may support effective planning and implementation of epigenetics approaches for introducing proper therapies or effective vaccines.

Immunogenetic Profile Associated with Patients Living with HIV-1 and Epstein-Barr Virus (EBV) in the Brazilian Amazon Region

Viral coinfection among HIV-positive patients, coupled with the development of AIDS, remains a major public health problem. The synergism between the presence of HIV and other viruses has consequences in relation to changes in the severity of the infection, as well as changes in the natural course of both infections. Several polymorphisms present in genes that encode cytokines have a relevant influence on their transcription and consequently on the production of such immunological molecules. The present study evaluated the influence of SNPs located in the promoter regions of genes encoding the cytokines INF-ɣ, TNF, IL-6, IL-4, and IL-2, as well as their respective plasma concentrations, in patients infected with HIV and/or EBV in the state of Pará. Additionally, this study described the epidemiological profile and compared CD4+ and CD8+ T lymphocyte counts among the groups studied. The associative analysis between the SNPs and plasma cytokine concentrations in different groups showed statistical relevance for three polymorphisms: rs2069762 (IL2), where the GG genotype demonstrated higher IL-2 levels in HIV mono-infected individuals; rs2243250 (IL4), where the CT genotype showed higher IL-4 levels in the control group; and rs2069705 (IFNG), where the TT genotype showed higher IFN-γ levels in the coinfected group. Regarding SNP associations with CD4+/CD8+ counts, significant findings were observed in HIV mono-infected individuals: the rs2069705 (IFNG) polymorphism was linked to higher CD4+ counts with the CT genotype, and rs1799964 (TNF) was associated with higher CD8+ counts with the CC genotype. Therefore, this study provides evidence that the rs2069705 (IFNG) SNP is associated with elevated IFN-γ levels, which may have pathogenic consequences, as depletion of this cytokine is concerning for people living with HIV due to its antiviral properties.

Rare Variable M. tuberculosis Antigens induce predominant Th17 responses in human infection

CD4 T cells are essential for immunity to M. tuberculosis (Mtb), and emerging evidence indicates that IL-17-producing Th17 cells contribute to immunity to Mtb. While identifying protective T cell effector functions is important for TB vaccine design, T cell antigen specificity is also likely to be important. To identify antigens that induce protective immunity, we reasoned that as in other pathogens, effective immune recognition drives sequence diversity in individual Mtb antigens. We previously identified Mtb genes under evolutionary diversifying selection pressure whose products we term Rare Variable Mtb Antigens (RVMA). Here, in two distinct human cohorts with recent exposure to TB, we found that RVMA preferentially induce CD4 T cells that express RoRγt and produce IL-17, in contrast to 'classical' Mtb antigens that induce T cells that produce IFNγ. Our results suggest that RVMA can be valuable antigens in vaccines for those already infected with Mtb to amplify existing antigen-specific Th17 responses to prevent TB disease.

Association of Cytokine Gene Polymorphisms and Their Impact on Active and Latent Tuberculosis in Brazil's Amazon Region

Some genetic variations in cytokine genes can alter their expression and influence the evolution of Mycobacterium tuberculosis (Mtb) infection. This study aimed to investigate the association of polymorphisms in cytokine genes and variability in plasma levels of cytokines with the development of tuberculosis (TB) and latent tuberculosis infection (LTBI). Blood samples from 245 patients with TB, 80 with LTBI, and healthy controls (n = 100) were included. Genotyping of the IFNG +874A/T, IL6 -174G/C, IL4 -590C/T, and IL10 -1082A/G polymorphisms was performed by real-time PCR, and cytokine levels were determined by flow cytometry. Higher frequencies of genotypes AA (IFNG +874A/T), GG (IL6 -174G/C), TT (IL4 -590C/T), and GG (IL10 -1082A/G) were associated with an increased risk of TB compared to that of LTBI (p = 0.0027; p = 0.0557; p = 0.0286; p = 0.0361, respectively) and the control (p = <0.0001, p = 0.0021; p = 0.01655; p = 0.0132, respectively). In combination, the A allele for IFNG +874A/T and the T allele for IL4 -590C/T were associated with a higher chance of TB (p = 0.0080; OR = 2.753 and p < 0.0001; OR = 3.273, respectively). The TB group had lower levels of IFN-γ and higher concentrations of IL-6, IL-4, and IL-10. Cytokine levels were different between the genotypes based on the polymorphisms investigated (p < 0.05). The genotype and wild-type allele for IFNG +874A/T and the genotype and polymorphic allele for IL4 -590C/T appear to be more relevant in the context of Mtb infection, which has been associated with the development of TB among individuals infected by the bacillus and with susceptibility to active infection but not with susceptibility to latent infection.

The association of IL-17A rs2275913 single nucleotide polymorphism with anti-tuberculous drug resistance in patients with pulmonary tuberculosis

BACKGROUND

Drug-resistant  Tuberculosis (DR-TB) is a global health burden with high morbidity and mortality in developing countries including Egypt. The susceptibility to infection with DR-TB strains may be genetically determined. Several interleukin gene polymorphisms were investigated as risk factors for tuberculosis infection but focusing on their association with DR-TB was limited. Therefore, the objective of this study is to assess the association of IL 17 - 197 G > A (rs2275913) single nucleotide polymorphism (SNP) with susceptibility to DR-TB strains in comparison to drug-sensitive tuberculosis (DS-TB) strains in Egyptian patients with pulmonary TB. This cross-sectional study was conducted on 80 patients with DR-TB strains and 80 with DS-TB strains as a control group. Both age and sex were comparable among the study's groups. IL-17 - 197 G > A (rs2275913) SNP was genotyped by real-time PCR, and IL-17 serum concentration was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The GA and AA genotype frequencies of IL 17 - 197 G > A (rs2275913) SNP were significantly higher in patients with DR-TB strains than those with DS-TB strains (p < 0.001). The frequency of the A allele was significantly (p < 0.001) higher in patients with DR-TB group (32.5%) compared to the control group (13.8%). Substantial higher serum levels of IL-17 were detected in the DR-TB group with significant association with AA and AG genotypes.

CONCLUSION

Polymorphism in IL-17 -197 G > A (rs2275913) resulted in higher serum levels of IL-17 and Egyptian patients with such polymorphism are three times at risk of infection with DR-TB strains than patients with wild type.

Interleukin 4 gene polymorphisms and the risk of tuberculosis: A meta-analysis

BACKGROUND

Interleukin-4 (IL-4) is implicated in the progression of tuberculosis (TB); however, these results remain controversial.

OBJECTIVES

This meta-analysis examined the relationship between IL and 4 polymorphisms (-589C/T, +4221C > A, and -33C/T) and the risk of TB.

METHODS

A retrospective database analysis was conducted using the CNKI and PubMed databases. Using fixed- and random-effects models, we calculated the combined odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We identified 14 articles related to this topic, and theresultsshowed that the IL-4 -589C/T polymorphism didnotinfluencethe risk of TB. However,in subgroupanalyses we found that the IL-4 -589C/T polymorphism was associated with the risk of TB inCaucasians (recessive modelOR = 2.54, 95% CI = 1.30-4.96). In our study, the IL-4--33C/T polymorphism was not associated with the risk of TB. The IL-4 + 4221C > A polymorphism was associated with the risk of TB (recessive model: OR = 1.40, 95% CI = 1.07-1.83).

CONCLUSION

This meta-analysis showed that the IL-4 -589C/T polymorphism was associated with TB risk in Caucasian populations, and the IL-4 + 4221C > A polymorphism is associated with TB risk.

Research progress on genetic control of host susceptibility to tuberculosis

The "Lübeck disaster", twins studies, adoptees studies, and other epidemiological observational studies have shown that host genetic factors play a significant role in determining the host susceptibility to Mycobacterium tuberculosis infection and pathogenesis of tuberculosis. From linkage analyses to genome-wide association studies, it has been discovered that human leucocyte antigen (HLA) genes as well as non-HLA genes (such as SLC11A1, VDR, ASAP1 as well as genes encoding cytokines and pattern recognition receptors) are associated with tuberculosis susceptibility. To provide ideas for subsequent studies about risk prediction of MTB infection and the diagnosis and treatment of tuberculosis, we review the research progress on tuberculosis susceptibility related genes in recent years, focusing on the correlation of HLA genes and non-HLA genes with the pathogenesis of tuberculosis. We also report the results of an enrichment analysis of the genes mentioned in the article. Most of these genes appear to be involved in the regulation of immune system and inflammation， and are also closely related to autoimmune diseases.

It Takes a Village: The Multifaceted Immune Response to Mycobacterium tuberculosis Infection and Vaccine-Induced Immunity

Despite co-evolving with humans for centuries and being intensely studied for decades, the immune correlates of protection against Mycobacterium tuberculosis (Mtb) have yet to be fully defined. This lapse in understanding is a major lag in the pipeline for evaluating and advancing efficacious vaccine candidates. While CD4+ T helper 1 (TH1) pro-inflammatory responses have a significant role in controlling Mtb infection, the historically narrow focus on this cell population may have eclipsed the characterization of other requisite arms of the immune system. Over the last decade, the tuberculosis (TB) research community has intentionally and intensely increased the breadth of investigation of other immune players. Here, we review mechanistic preclinical studies as well as clinical anecdotes that suggest the degree to which different cell types, such as NK cells, CD8+ T cells, γ δ T cells, and B cells, influence infection or disease prevention. Additionally, we categorically outline the observed role each major cell type plays in vaccine-induced immunity, including Mycobacterium bovis bacillus Calmette-Guérin (BCG). Novel vaccine candidates advancing through either the preclinical or clinical pipeline leverage different platforms (e.g., protein + adjuvant, vector-based, nucleic acid-based) to purposefully elicit complex immune responses, and we review those design rationales and results to date. The better we as a community understand the essential composition, magnitude, timing, and trafficking of immune responses against Mtb, the closer we are to reducing the severe disease burden and toll on human health inflicted by TB globally.

Immune and inflammation-related gene polymorphisms and susceptibility to tuberculosis in Southern Xinjiang population: A case-control analysis

Genetic and immune factors play an important role in tuberculosis. Under different ethnicities and genetic backgrounds, different immune and inflammation-related gene polymorphisms may confer different susceptibility to tuberculosis. This study investigated the relationship between immune and inflammation-related gene polymorphism and susceptibility to tuberculosis in Xinjiang Uyghur population, China. In this case-control study, we enrolled 507 pulmonary tuberculosis patients and 454 healthy controls from Southern Xinjiang. single nucleotide polymorphism (SNP) genotyping was performed. The 12 SNPs of nine immune and inflammation-related genes (including TNF rs361525, IL6 rs2066992 and rs1524107, IL17A rs3748067, IL17F rs763780, VDR rs731236, rs2228570 and rs1544410, IFNGR1 rs1327474, P2RX7 rs3751143, CTAGE1 rs4331426 and Toll-like receptor 4 (TLR4) rs4986790) and their relationship with tuberculosis were evaluated. The T allele and TT genotype of IL-6 rs2066992 and rs1524107 increased the risk of active tuberculosis. The C allele of IFNGR1 rs1327474 was related to the reduced risk of tuberculosis in the Xinjiang Uyghur population. The G allele and AG/GG genotypes of TLR4 rs4986790 were associated with an increased risk of tuberculosis (p < .05). Furthermore, haplotype analysis found that the haplotype TT of interleukin (IL)-6 was a risk factor, whereas the CG type was a protective factor for active tuberculosis in the Xinjiang Uyghur population. There were three immune and inflammation-related genes (IL-6, IFNGR1 and TLR4) and a total of four SNPs (rs2066992, rs1524107, rs1327474 and rs4986790) related to the susceptibility of the Uyghur population to tuberculosis. Our findings may provide evidence for further understanding the mechanism of tuberculosis susceptibility in the Xinjiang Uyghur population.

Association of IL-4 rs2243250 polymorphism with susceptibility to tuberculosis: A meta-analysis involving 6794 subjects

BACKGROUND

Interleukin-4 (lL-4) is a critical negative cytokine in tuberculosis (TB) immune process, acting through modulating macrophages activation and Th1/Th2 balance. rs2243250 has been demonstrated to be associated with enhanced promoter strength in IL-4 expression. We performed a meta-analysis to assess the association between IL-4 rs2243250 polymorphism and TB risk.

METHODS

We identified relevant studies by a comprehensive search of PubMed, Web of Science, and Embase databases, published up to February 10, 2021. The pooled odds ratios (ORs) and its 95% confidential intervals (95%CIs) were used to evaluate the associations under five genetic models. All statistical analyses were conducted with STATA 12.0 software.

RESULTS

Totally 11 qualified studies involving 3097 TB cases and 3697 controls were enrolled in this meta-analysis. Overall, we didn't detect any significant association between IL-4 rs2243250 polymorphism and TB risk (T vs. C: OR = 1.05, 95% CI = 0.85-1.30, p = 0; 65; TT + TC vs. CC: OR = 1.05, 95% CI = 0.73-1.50, p = 0.81; TT vs. TC + CC: OR = 1.10, 95% CI = 0.81-1.50, p = 0.54; TT vs. CC: OR = 1.17, 95% CI = 0.71-1.94, p = 0.54; TC vs. CC: OR = 1.03, 95% CI = 0.73-1.45, p = 0.88). Significant heterogeneity was identified in analyses under all genetic models. However, in the subgroup of European population, the recessive model provided an OR of 2.54 (1.30-4.96), with no significant between-study heterogeneity.

CONCLUSION

In conclusion, our meta-analysis indicated that IL-4 rs2243250 may increase TB risk in European population in recessive genetic model. Further research is needed to clarify the cause of ethnic difference in genetic association study.

Associations of six common functional polymorphisms in interleukins with tuberculosis: evidence from a meta-analysis

BACKGROUND

Associations of polymorphisms in interleukin-6 (IL-6), IL-8 and IL-10 with tuberculosis (TB) susceptibility were already reported by many publications. The aim of this meta-analysis was to more precisely clarify associations between polymorphisms in IL-6/IL-8/IL-10 and TB by combing the results of all relevant publications.

METHODS

Eligible publications were searched from PubMed, Embase, Web of Science and CNKI. We used Review Manager to combine the results of individual studies.

RESULTS

A total of 47 publications were included in this study. IL-6 rs1800795 (1750 cases and 2335 controls, dominant, recessive and allele comparisons), IL-8 rs4073 (1125 cases and 1188 controls, dominant, recessive and allele comparisons), IL-10 rs1800871 (5528 cases and 7671 controls, dominant, recessive and allele comparisons), IL-10 rs1800872 (5269 cases and 7013 controls, dominant and allele comparisons) and IL-10 rs1800896 (7564 cases and 8952 controls, recessive comparison) polymorphisms were all significantly associated with TB in overall combined analyses. In subgroup analyses, we found that the positive results were mainly driven by the pulmonary tuberculosis and Asian subgroups.

CONCLUSIONS

Collectively, this meta-analysis proved that IL-6 rs1800795, IL-8 rs4073, IL-10 rs1800871, IL-10 rs1800872 and IL-10 rs1800896 may confer susceptibility to TB.

RNA Sensing of Mycobacterium tuberculosis and Its Impact on TB Vaccination Strategies

Tuberculosis (TB) is still an important global threat and although the causing organism has been discovered long ago, effective prevention strategies are lacking. Mycobacterium tuberculosis (MTB) is a unique pathogen with a complex host interaction. Understanding the immune responses upon infection with MTB is crucial for the development of new vaccination strategies and therapeutic targets for TB. Recently, it has been proposed that sensing bacterial nucleic acid in antigen-presenting cells via intracellular pattern recognition receptors (PRRs) is a central mechanism for initiating an effective host immune response. Here, we summarize key findings of the impact of mycobacterial RNA sensing for innate and adaptive host immunity after MTB infection, with emphasis on endosomal toll-like receptors (TLRs) and cytosolic sensors such as NLRP3 and RLRs, modulating T-cell differentiation through IL-12, IL-21, and type I interferons. Ultimately, these immunological pathways may impact immune memory and TB vaccine efficacy. The novel findings described here may change our current understanding of the host response to MTB and potentially impact clinical research, as well as future vaccination design. In this review, the current state of the art is summarized, and an outlook is given on how progress can be made.

Lack of association between polymorphism of IL-2 -330T/G and pulmonary tuberculosis among Caucasians

This meta-analysis was conducted to assess the consistency and strength of the relationship between polymorphism of IL-2 -330T/G and susceptibility to pulmonary tuberculosis (TB). PubMed, Web of Knowledge and CNKI were searched to find eligible studies about the relationship between IL-2 -330T/G polymorphism and susceptibility to pulmonary TB. A total of eight studies comprising 971 cases and 1519 controls were grouped together for the purpose of elucidating the relationship between polymorphism of IL-2 -330T/G and pulmonary TB susceptibility. The allele model (G vs. T: odds ratio (OR) = 1.34; 95% confidence interval (CI) 1.05–1.71, P_het = 0.001) and the recessive model (GG+GT vs. TT: OR = 1.60; 95% CI 1.08–2.38, P_het = 0.0001) showed an increased risk of development of pulmonary TB. However, the homozygous model (GG vs. TT: OR = 1.74; 95% CI 0.98–3.09, P_het = 0.0005) and the dominant model (GG vs. TT + TG: OR = 1.30; 95% CI = 0.80-2.14, P_het =  0.001) failed to show an increased incidence of pulmonary TB. When analysis was stratified by ethnicity, no obvious associations were identified in the Caucasian subgroup under all four genetic models. Additionally, heterogeneity disappeared in the analysis of Caucasian subgroup. Our combined data suggested that there was no association between IL-2 -330T/G polymorphism and pulmonary TB among Caucasians.

Low Prevalence of Latent Tuberculosis Infection among Contacts of Smear-Positive Adults in Brazil

This follow-up cross-sectional study aimed to analyze the prevalence rate and risk factors related to latent tuberculosis infection (LTBI) and active tuberculosis (TB) in children aged < 15 years in contact with adults with smear-positive pulmonary TB (PTB) in a Brazilian municipality. Data were collected from interviews, clinical evaluations, chest X-rays, tuberculin skin tests, and interferon gamma release assays. The median time elapsed between diagnosis of the index case (IC) and inclusion in the study was 2.5 years (interquartile range [IQR] = 1.5-4.4) and 7.4 years (IQR = 3.8-9.7) when we reassessed the development (or not) of active TB. The median age at the time of exposure to the IC was 6.6 years (IQR = 3.3-9.4) and 14.1 years (IQR = 8.9-17.7) at the last follow-up. Of the 99 children and adolescents in contact with smear-positive PTB, 21.2% (95% CI = 14.0-29.9) were diagnosed with LTBI, and none developed active TB. There was no statistically significant difference between the LTBI and non-LTBI groups regarding demographic, socioeconomic, and epidemiological characteristics. Unlike national and international scenarios, we found a lower frequency of LTBI and no active TB among our studied patients. For better understanding of these findings, further studies might add, among other factors, host and Mycobacterium tuberculosis genetic features.

Polymorphisms in TLR4 and TNFA and Risk of Mycobacterium tuberculosis Infection and Development of Active Disease in Contacts of Tuberculosis Cases in Brazil: A Prospective Cohort Study

BACKGROUND

The role of genetic polymorphisms in latent tuberculosis (TB) infection and progression to active TB is not fully understood.

METHODS

We tested the single-nucleotide polymorphisms (SNPs) rs5743708 (TLR2), rs4986791 (TLR4), rs361525 (TNFA), rs2430561 (IFNG) rs1143627 (IL1B) as risk factors for tuberculin skin test (TST) conversion or development of active TB in contacts of active TB cases. Contacts of microbiologically confirmed pulmonary TB cases were initially screened for longitudinal evaluation up to 24 months, with clinical examination and serial TST, between 1998 and 2004 at a referral center in Brazil. Data and biospecimens were collected from 526 individuals who were contacts of 177 active TB index cases. TST conversion was defined as induration ≥5 mm after a negative TST result (0 mm) at baseline or month 4 visit. Independent associations were tested using logistic regression models.

RESULTS

Among the 526 contacts, 60 had TST conversion and 44 developed active TB during follow-up. Multivariable regression analysis demonstrated that male sex (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.1-4.6), as well as SNPs in TLR4 genes (OR: 62.8, 95% CI: 7.5-525.3) and TNFA (OR: 4.2, 95% CI: 1.9-9.5) were independently associated with TST conversion. Moreover, a positive TST at baseline (OR: 4.7, 95% CI: 2.3-9.7) and SNPs in TLR4 (OR: 6.5, 95% CI: 1.1-36.7) and TNFA (OR: 12.4, 95% CI:5.1-30.1) were independently associated with incident TB.

CONCLUSIONS

SNPs in TLR4 and TNFA predicted both TST conversion and active TB among contacts of TB cases in Brazil.

Study of association of the rs2275913 IL-17A single nucleotide polymorphism and susceptibility to cutaneous leishmaniasis caused by Leishmania braziliensis

Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is the most spread clinical form of leishmaniasis in Brazil. However, only a few part of the people infected develop clinically perceptive disease, suggesting the influence of human genetic components in the CL pathogeny. The rs2275913 SNP is the nucleotide variant of the IL17A gene. The A allele is associated with a vast number of infectious and non-infectious diseases. Here, we investigated the association of the rs2275913 SNP (G/A) from IL-17A and two forms of susceptibility to CL in Brazil by case-control study. Furthermore, we evaluated the functional relevance of this SNP during the immune response of the host and analyzed its impact in the parasite elimination. Weak associations of A allele with susceptibility to L. braziliensis infection or to symptomatic CL were observed, and a tendency of A allele carriers to be more susceptible to infection and cutaneous disease. Functional analysis of the Th17 cell phenotypes revealed lower frequencies of CD4+ IL-17+ cells in samples of infected people with AA/AG genotypes. Furthermore, people carrying the A allele maintain higher parasite loads, reinforcing the genetic susceptibility findings. This study adds knowledge about the influence of a significant genetic variation on IL-17 promoter on CL pathogenesis, and may contribute to enhance the knowledge about the role of IL-17 in the L. braziliensis infections.

Association of the TNF-α-308, TNF-α-238 gene polymorphisms with risk of bone-joint and spinal tuberculosis: a meta-analysis

The aim of the present study was to investigate the association of TNF-α-308 and TNF-α-238 gene polymorphisms with the risk of bone-joint and spinal tuberculosis (TB) by meta-analysis. By searching PubMed, Web of Science, Wanfang databases, CNKI, Medline, and Cochrane Library, the published articles about studies of the association of the TNF-α-308, TNF-α-238 gene polymorphisms with risk of bone-joint and spinal tuberculosis were collected by two reviewers. Begg’s and Egger’s tests were performed to assess publication bias. Stata 12.0 software was used for data analysis. The symmetry of the funnel plot indicated no significant publication bias in the Begg’s test (A: P=1.00, B: P=0.764), and the results of the Egger’s test showed no evidence of publication bias (A: P=0.954, B: P=0.626). Seven studies assessed the relationship between TNF-α-308 gene polymorphisms and risk of bone-joint and spinal tuberculosis risk. The heterogeneity (I²) of GG vs. AA or AG was 0% and there was no heterogeneity (χ² = 0.06 and P=0.944) in a fixed-effects model. There was also a lack of association between TNF-α-308 polymorphism and bone-joint and spinal tuberculosis risk under the recessive model. The remaining models of the TNF-α-308 genotype and further studies of TNF-α-238 did not show a noteworthy association. Overall, there was no significant association between TNF-α-308, TNF-α-238 gene polymorphisms and bone-joint and spinal tuberculosis risk. Our study suggests that tumor necrosis factor α (TNF-α) gene polymorphisms may not contribute to bone-joint and spinal tuberculosis based on the current evidence.

Association between CLEC4E gene polymorphism of mincle and pulmonary tuberculosis infection in a northern Chinese population

BACKGROUND

Pulmonary tuberculosis caused by an intracellular pathogen, Mycobacterium tuberculosis continues to exist as a hazardous disease to human life globally. Genetic polymorphisms regulate resistance and susceptibility to tuberculosis. The C-type lectin receptor of family 4 member E (CLEC4E) confers protection against tuberculosis in laboratory animals but its function in influencing exposure or resistance to pulmonary tuberculosis (PTB) in humans remains obscure.

AIM

We conducted this research to analyze the effects or concomitance of CLEC4E gene variations with susceptibility to pulmonary tuberculosis in a northern Chinese population.

METHOD

In this study, 202 participants with pulmonary tuberculosis and 214 controls without PTB were enrolled. Two single nucleotide polymorphisms (SNPs) for CLEC4E on chromosome 12 were selected with a minor allele frequency of >0.05. All the SNPs were genotyped using high resolution melting analysis-PCR.

RESULTS

We estimated and compared two SNPs, rs10841845 and rs10841847. From our study findings, CLEC4E rs10841845 conferred protection against the development of pulmonary TB with a P value of <0.05 and odds ratio of <1 for all models of genetic inheritance. CLEC4E rs10841847 genotypes in co-dominant, Recessive, Dominant models and alleles had a significant statistical difference between patients and controls associated with resistance against the development of PTB (P<0.05 and OR<1).

CONCLUSION

Our findings suggest that variations at rs10841845 and rs10841847 of CLEC4E genes are associated with increased individual protection against PTB.

Association of interleukin-17 gene polymorphisms and susceptibility to brucellosis in Hamadan, western Iran

IL-17is one of the most important inflammatory cytokines that stimulate immunity responses in humans infected with Brucella species, acting as a regulator that reduces release of γ-IFN, thus increasing resistance to brucellosis. Gene polymorphisms in the regulatory regions of cytokine-encoding genes affect the amountsof cytokines produced and play a fundamental role in infectious diseases. The aim of this study was to determine the association between IL-17 gene polymorphisms and susceptibility to brucellosis. In this case-control study, 86 patients with brucellosis and 86 healthy persons in Hamadan, western Iran, from September 2014 to September 2016, were included. IL-17 genetic variants at positions rs4711998 A/G, rs8193036 C/T, rs3819024 A/G, rs2275913 A/G, rs3819025 A/G, rs8193038 A/G, rs3804513 A/T, rs1974226 A/G and rs3748067 A/G were analyzed by restriction fragment length polymorphism-PCR. Serum IL-17 titers were measured by sandwich ELISA. GG genotypes at positions rs4711998 and rs3748067 were present significantly more frequently in patients with brucellosis than in controls (P < 0.05). The AA genotype at positions rs4711998, rs2275913 and rs3748067 and GG genotype at position rs19744226 were present significantly more frequently in controls than in the patient group. These results suggest that the AA genotype at positions rs3748067, rs3819025 and rs4711998 and GG genotype at position rs3819024 are likely protective factors against brucellosis, whereas the GG genotype at positions rs3748067, rs3819025 and rs4711998 and AA genotype at position rs3819024 may be risk factors against the disease. No significant relationships were found between serum IL-17 titers and genotypes of the single-nucleotide polymorphisms.

Genetic Polymorphisms of IL1B, IL6, and TNFα in a Chinese Han Population with Pulmonary Tuberculosis

Background

The factors that predispose to pulmonary tuberculosis (PTB) are not fully understood. Previous studies have shown that cytokine gene polymorphisms were associated with PTB.

Objectives

In this study, we have investigated the relationship between ILB, IL6, and TNFα polymorphisms and a predisposition to Mycobacterium tuberculosis (MTB) infection and PTB.

Methods

A total of 209 cases of PTB, 201 subjects with latent TB infection (LTBI), and 204 healthy controls (HCS) were included in this study. Logistic regression analyses under allelic, homozygous, and heterozygous models were used to calculate P values, odds ratios (ORs), and 95% confidence intervals (CIs) for assessing the association between single nucleotide polymorphisms (SNPs) and disease risk, adjusting for sex and age. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR) method.

Results

When comparing PTB patients with LTBI subjects, significant associations with disease development were observed for SNPs of IL6 and TNFα. When comparing LTBI subjects with HCS, IL1B polymorphisms were significantly associated with LIBI. Haplotype analyses suggested that the CGG haplotype of IL1B was associated with an increased risk of PTB (P = 0.039, OR = 1.34, 95% CI: 1.01–1.76), while the TTGCG haplotype of TNFα was a protective factor against PTB (P = 0.039, OR = 0.66, 95% CI: 0.44–0.98).

Conclusion

Our study demonstrated that IL1B variants were related to LTBI and IL6 and TNFα variants were associated with PTB.

Bacterial pathogenesis and interleukin-17: interconnecting mechanisms of immune regulation, host genetics, and microbial virulence that influence severity of infection

Interleukin-17 (IL-17) is a pro-inflammatory cytokine involved in the control of many different disorders, including autoimmune, oncogenic, and diverse infectious diseases. In the context of infectious diseases, IL-17 protects the host against various classes of microorganisms but, intriguingly, can also exacerbate the severity of some infections. The regulation of IL-17 expression stems, in part, from the activity of Interleukin-23 (IL-23), which drives the maturation of different classes of IL-17-producing cells that can alter the course of infection. In this review, we analyze IL-17/IL-23 signalling in bacterial infection, and examine the interconnecting mechanisms that link immune regulation, host genetics, and microbial virulence in the context of bacterial pathogenesis. We consider the roles of IL-17 in both acute and chronic bacterial infections, with a focus on mouse models of human bacterial disease that involve infection of mucosal surfaces in the lungs, urogenital, and gastrointestinal tracts. Polymorphisms in IL-17-encoding genes in humans, which have been associated with heightened host susceptibility to some bacterial pathogens, are discussed. Finally, we examine the implications of IL-17 biology in infectious diseases for the development of novel therapeutic strategies targeted at preventing bacterial infection.

Association of IL4, IL6, and IL10 polymorphisms with pulmonary tuberculosis in a Tibetan Chinese population

Background

Pulmonary tuberculosis (PTB) is an infectious disease with a high incidence worldwide. Genes encoding cytokines IL4, IL6, and IL10 are highly polymorphic and can influence the susceptibility to PTB.

Results

We found correlations between one SNP in IL6 (rs2069837 p = 6.63E-11), seven SNPs in IL10 (rs1554286 p = 6.87E-20, rs1518111 p = 6.11E-11, rs3021094 p = 6.75E-29, rs3790622 p = 2.40E-06, rs3024490 p = 6.73E-11, rs1800872 p = 6.18E-11, rs1800871 p = 6.73E-11) and incidences of PTB. The SNPs rs2069837, rs1554286, rs1518111, rs3024490, rs1800872, and rs1800871 increased PTB risk by 1.95-fold, 2.34-fold, 1.84-fold, 1.84-fold, 1.84-fold and 1.84-fold, respectively. The SNPs rs3021094 and rs3790622 decreased PTB risk by 0.33-fold and 0.38-fold, respectively. We also found two linkage disequilibrium blocks in the studied IL SNPs. The IL4 haplotype TCCCGGA (OR = 1.33, p = 0.014) increased PTB risk, the IL10 haplotypes ATGGATA (OR = 0.39, p = 4.84E-06) provided a protective effect and decreased PTB risk.

Materials and Methods

For this study, we recruited 467 subjects with PTB and 503 healthy subjects from a Tibetan population living in Lhasa and nearby, China. Association analyses of sixteen single-nucleotide polymorphisms (SNPs) in IL4, IL6, and IL10 were performed.

Conclusions

Our findings demonstrate an association between polymorphisms in IL6 and IL10 and risk of PTB.

The crucial roles of Th17-related cytokines/signal pathways in M. tuberculosis infection

Interleukin-17 (IL-17), IL-21, IL-22 and IL-23 can be grouped as T helper 17 (Th17)-related cytokines because they are either produced by Th17/Th22 cells or involved in their development. Here, we review Th17-related cytokines/Th17-like cells, networks/signals and their roles in immune responses or immunity against Mycobacterium tuberculosis (Mtb) infection. Published studies suggest that Th17-related cytokine pathways may be manipulated by Mtb microorganisms for their survival benefits in primary tuberculosis (TB). In addition, there is evidence that immune responses of the signal transducer and activator of transcription 3 (STAT3) signal pathway and Th17-like T-cell subsets are dysregulated or destroyed in patients with TB. Furthermore, Mtb infection can impact upstream cytokines in the STAT3 pathway of Th17-like responses. Based on these findings, we discuss the need for future studies and the rationale for targeting Th17-related cytokines/signals as a potential adjunctive treatment.

Association between the IL-6 gene polymorphism and tuberculosis risk: a meta-analysis

Background

The gene polymorphism of interleukin-6 (IL-6) has been shown to be implicated in tuberculosis susceptibility in many studies, but with conflicting results. This study aimed to provide more accurate estimation of the relationship between IL-6 gene polymorphism and tuberculosis risk through a meta-analysis.

Method

A literature search was performed in PubMed, EMBASE, and other databases. Data were retrieved, and pooled odds ratio (OR) with 95% CI were calculated. Statistical analyses were performed by using STATA 12.0.

Results

Twelve publications with 2635 cases and 3049 controls were included. The pooled analysis demonstrated significant evidence of association between IL-6 (-174G/C) and low risk of tuberculosis in dominant model (CC+GC vs GG: OR =0.693, 95% CI 0.581-0.826, p<0.001). Subgroup analysis got similar results for IL-6 (-174G/C) in Asians and Latinos, but the significance did not exist in Caucasians. IL-6 (-572C/G) polymorphism was also associated with low risk of tuberculosis in dominant model (CC+GC vs GG: OR =0.719, 95% CI 0.577-0.896, p=0.003). No publication bias was detected in either of the polymorphisms.

Conclusion

In summary, IL-6 -572 C/G polymorphism may be associated with a decreased risk of tuberculosis, and C allele is the protective factor against tuberculosis for IL-6 -174G/C among Asians and Latinos, but not in Caucasian population.

Interleukin 17A gene polymorphism rs2275913 is associated with osteitis after the Bacillus Calmette-Guérin vaccination

AIM

Interleukin-17 (IL-17) appears to promote the host's defence against mycobacterial infections. This study evaluated the association between IL17A gene polymorphism and the risk of Bacillus Calmette-Guérin (BCG) osteitis after newborn vaccination and between IL17A gene polymorphism and IL-17A concentrations in serum.

METHODS

IL17A rs2275913 gene polymorphisms and serum IL-17A concentrations were studied in 132 adults aged 21-49 years from across Finland, who had BCG osteitis in infancy after a newborn BCG vaccination. The subjects were recruited in 2007-2008, and their whole-blood samples were sent to the National Institute for Health and Welfare, Turku, Finland. Their genotypes and minor allele frequencies were compared with 405 population-based unvaccinated controls aged two to three months from a prospective birth cohort study.

RESULTS

The genotypes and allele frequencies of IL17A rs2275913 differed significantly between the former BCG osteitis patients and controls. The genotype was variant in 75.8% of cases and 64.0% of controls (p = 0.012), and the minor allele frequency was 50.0% in the cases and 41.6% of the controls (p = 0.009). Serum IL-17 concentrations did not differ significantly between the cases with wild or variant genotypes.

CONCLUSION

IL17A rs2275913 gene polymorphism was associated with a risk of BCG osteitis after vaccination.

Interleukin-17 limits hypoxia-inducible factor 1α and development of hypoxic granulomas during tuberculosis

Mycobacterium tuberculosis (Mtb) is a global health threat, compounded by the emergence of drug-resistant strains. A hallmark of pulmonary tuberculosis (TB) is the formation of hypoxic necrotic granulomas, which upon disintegration, release infectious Mtb. Furthermore, hypoxic necrotic granulomas are associated with increased disease severity and provide a niche for drug-resistant Mtb. However, the host immune responses that promote the development of hypoxic TB granulomas are not well described. Using a necrotic Mtb mouse model, we show that loss of Mtb virulence factors, such as phenolic glycolipids, decreases the production of the proinflammatory cytokine IL-17 (also referred to as IL-17A). IL-17 production negatively regulates the development of hypoxic TB granulomas by limiting the expression of the transcription factor hypoxia-inducible factor 1α (HIF1α). In human TB patients, HIF1α mRNA expression is increased. Through genotyping and association analyses in human samples, we identified a link between the single nucleotide polymorphism rs2275913 in the IL-17 promoter (-197G/G), which is associated with decreased IL-17 production upon stimulation with Mtb cell wall. Together, our data highlight a potentially novel role for IL-17 in limiting the development of hypoxic necrotic granulomas and reducing disease severity in TB.

Interleukin-17 A and F gene polymorphisms affect the risk of tuberculosis: An updated meta-analysis

BACKGROUND

Cytokines are fundamental elements in mediating and stimulating the immune response against tuberculosis (TB). Growing evidence indicated that polymorphisms in the interleukin-17 (IL-17) A and F genes are implicated in TB.

OBJECTIVES

This meta-analysis was aimed to re-evaluate and update the relationship between IL-17A rs2275913 G/A and IL17F rs763780 T/C polymorphisms and TB risk.

METHODS

Using inclusive searches of the PubMed, MEDLINE, EMBASE, Web of Science and Elsevier Science Direct, we identified outcome data from all articles estimating the association between IL-17 A and F polymorphisms and TB risk.

RESULTS

A total of 15 studies comprising 7130 patients and 7540 controls were included. Our pooled analysis demonstrated that the IL-17A rs2275913 G/A SNP was not associated with the risk of TB in overall, or in Asians and Caucasians, but it conferred resistance to TB in Latin Americans using allele (OR=0.53), codominant (OR=0.53 and 0.38), dominant (OR=0.49) and recessive (OR=0.46) inheritance models. For IL-17F rs763780 T/C, the pooled evidence indicated that this variation was a risk factor for TB in allele (C vs T) and dominant (TC+CC vs TT) models in overall (OR of 1.35) and among Asians (OR=1.40), but not in Caucasians.

CONCLUSION

In summary, our meta-analysis suggested that the IL-17A rs2275913 was a protective factor against TB, but -17F rs763780 T/C was a risk factor for TB.

Haplotype of the Interleukin 17A gene is associated with osteitis after Bacillus Calmette-Guerin vaccination

Bacillus Calmette-Guerin (BCG) osteitis was more common in Finland than elsewhere at the time when universal BCG vaccinations were given to Finnish newborns. There is evidence that IL-17 plays a role in the defense against tuberculosis. The aim of this study was to evaluate the associations of IL17A rs4711998, IL17A rs8193036 and IL17A rs2275913 single-nucleotide polymorphisms (SNPs) with the risk of BCG osteitis after newborn vaccination. IL17A rs4711998, rs8193036 and rs2275913 SNPs were determined in 131 adults had presented with BCG osteitis after newborn BCG vaccination. We analyzed, using the HaploView and PLINK programs, whether allele or haplotype frequencies of these SNPs differ between the former BCG osteitis patients and Finnish population controls. Of the three IL17A SNPs studied, rs4711998 associated nominally with BCG osteitis; minor allele frequency was 0.215 in 130 BCG osteitis cases and 0.298 in 99 controls (p = 0.034). Frequency of the second common haplotype (GTA) differed significantly between BCG osteitis cases and controls (0.296 vs. 0.184, p = 0.040 after multi-testing correction). The GTA haplotype of the IL17A SNPs rs4711998, rs8193036 and rs2275913 was associated with osteitis after BCG vaccination.

Interleukin-17F and interleukin-6 gene polymorphisms in Asian Indian patients with Takayasu arteritis

OBJECTIVES

To assess genetic association between single nucleotide polymorphisms (SNPs) in genes encoding T-helper cytokines and Takayasu Arteritis (TA) susceptibility in Asian Indian population.

METHODS

In Phase-1, the genomic DNA of 120 TA patients and 119 healthy controls were genotyped for SNPs rs1800795 (interleukin (IL)-6), rs763780 (IL-17F), rs1800871, rs1800872, rs1800896 (IL-10) and rs1800468, rs1800469, rs1800470 (transforming growth factor-β). Allele frequencies between cases and controls were compared using chi-squared test and also reassessed empirically (p_e) by 10,000 permutations. In Phase-2, additional 98 TA patients and 101 controls were genotyped for replicating the significant associations noted in Phase-1 of the study.

RESULTS

All 8 SNPs in Phase 1 were in Hardy-Weinberg proportions. The G allele at rs763780 (IL-17F) was significantly associated with TA (p=0.014). We also found that rs1800795 (IL-6) was associated with tuberculosis (p=0.001) under a dominant model. In Phase-2 replication part of the study, the rs763780 showed a trend towards association with TA (p=0.08), and the magnitude and direction of the odds ratio (OR) also were consistent with results of Phase-1. In the combined analysis, protective association of the G allele of rs763780 with TA was again significant [OR (95% CI)=0.44 (0.25-0.77); p=0.0029]. The G allele was also significantly associated (p<0.05) with underlying tuberculosis (TB) and occurrence of syncope in TA.

CONCLUSION

G allele of rs763780 in IL-17F gene was protectively associated against susceptibility to TA. GG genotypes of rs1800795 in IL-6 was also associated with occurrence of tuberculosis in our patients with TA.

Interactions between Type 1 Interferons and the Th17 Response in Tuberculosis: Lessons Learned from Autoimmune Diseases

The classical paradigm of tuberculosis (TB) immunity, with a central protective role for Th1 responses and IFN-γ-stimulated cellular responses, has been challenged by unsatisfactory results of vaccine strategies aimed at enhancing Th1 immunity. Moreover, preclinical TB models have shown that increasing IFN-γ responses in the lungs is more damaging to the host than to the pathogen. Type 1 interferon signaling and altered Th17 responses have also been associated with active TB, but their functional roles in TB pathogenesis remain to be established. These two host responses have been studied in more detail in autoimmune diseases (AID) and show functional interactions that are of potential interest in TB immunity. In this review, we first identify the role of type 1 interferons and Th17 immunity in TB, followed by an overview of interactions between these responses observed in systemic AID. We discuss (i) the effects of GM-CSF-secreting Th17.1 cells and type 1 interferons on CCR2⁺ monocytes; (ii) convergence of IL-17 and type 1 interferon signaling on stimulating B-cell activating factor production and the central role of neutrophils in this process; and (iii) synergy between IL-17 and type 1 interferons in the generation and function of tertiary lymphoid structures and the associated follicular helper T-cell responses. Evaluation of these autoimmune-related pathways in TB pathogenesis provides a new perspective on recent developments in TB research.

The IL-17A rs2275913 single nucleotide polymorphism is associated with protection to tuberculosis but related to higher disease severity in Argentina

Mycobacterium tuberculosis (Mtb) causes nearly 10 millions of new tuberculosis disease cases annually. However, most individuals exposed to Mtb do not develop tuberculosis, suggesting the influence of a human genetic component. Here, we investigated the association of the rs2275913 SNP (G → A) from IL-17A and tuberculosis in Argentina by a case-control study. Furthermore, we evaluated in vitro the functional relevance of this SNP during the immune response of the host against Mtb and analyzed its impact on clinical parameters of the disease. We found an association between the AA genotype and tuberculosis resistance. Additionally, within the healthy donors population, AA cells stimulated with a Mtb lysate (Mtb-Ag) produced the highest amounts of IL-17A and IFN-γ, which further support the genetic evidence found. In contrast, within the tuberculosis patients population, AA Mtb-Ag stimulated cells showed the lowest immunological parameters and we evidenced an association between the AA genotype and clinical parameters of disease severity, such as severe radiological lesions and higher bacilli burden in sputum. Overall, our findings demonstrated that the AA genotype from the IL-17A rs2275913 SNP is positively associated with protection to active tuberculosis but related to higher disease severity in the Argentinean population.

Comparison of single nucleotide polymorphisms [SNP] at TNF-α promoter region with TNF receptor 2 (TNFR2) in susceptibility to pulmonary tuberculosis; using PCR-RFLP technique

Since apoptosis and survival of the immune cells are crucially important in prevention or predisposition of individual from/to infections, especially in intracellular ones, the current study was performed to assess the correlation of host genetic polymorphisms with susceptibility to TB. For this reason, we investigated the difference of the single nucleotide polymorphisms [SNPs] in tumor necrosis factors [TNF-α] genes at (-238, -308, -857 and -863 position) and tumor necrosis factors receptors two [TNFR2] at (T 587 G position) between patients [n=151] and control [n=83]. The genotyping was studied by using PCR-RFLP which had high sensitivity in detecting compared with other techniques. The results showed a strong correlation between two polymorphisms in different loci of TNF-α gene including TNF-α T-857 C and A 238 G. But no association were found in TNFR2 genes with susceptibility to TB. And we found no correlation between TNFR2 and TNF-α gene polymorphisms. Therefore, the TNF-α T 857 C and A 238 G SNPs could be promising marker for identifying risk populations.

Polymorphisms in Beta-2 Adrenergic Receptor Gene and Association with Tuberculosis

PURPOSE

Genetic susceptibility for tuberculosis in human has been previously demonstrated. Polymorphisms in genes involved in immune responses may alter the susceptibility of individuals to tuberculosis. Polymorphisms of beta-2 adrenergic receptor (ADRB2) gene can be possibly an important risk factor in tuberculosis. In this study, the association between rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene and tuberculosis was evaluated.

METHODS

Genotype distributions of the rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene in 106 patients with pulmonary tuberculosis and 88 healthy subjects were studied by PCR-RFLP method in an Iranian population.

RESULTS

The frequency of rs1042713*G and rs1042714*G alleles in ADRB2 gene in tuberculosis patients was significantly different from healthy controls [odds ratio (OR) 0.176, 95% confidence interval (CI) 0.065-0.48, P value <0.001 and OR 0.45, 95% CI 0.247-0.825, P value = 0.009, respectively]. There were no significant differences in haplotype analysis between the patients and control subjects.

CONCLUSION

The association was reported between rs1042713 and rs1042714 polymorphisms in ADRB2 gene and tuberculosis for the first time. rs1042713*G and rs1042714*G polymorphisms in ADRB2 gene makes people more susceptible to develop the disease.