Interleukin-10 promoter gene polymorphisms and susceptibility to tuberculosis: a meta-analysis

Transcriptional analysis of human peripheral blood mononuclear cells stimulated by Mycobacterium tuberculosis antigen

Background

Mycobacterium tuberculosis antigen (Mtb-Ag) is a polypeptide component with a molecular weight of 10-14 kDa that is obtained from the supernatant of the H37Ra strain after heat treatment. It stimulates the activation and proliferation of γδT cells in the blood to produce an immune response against tuberculosis. Mtb-Ag is therefore crucial for classifying and detecting the central genes and key pathways involved in TB initiation and progression.

Methods

In this study, we performed high-throughput RNA sequencing of peripheral blood mononuclear cells (PBMC) from Mtb-Ag-stimulated and control samples to identify differentially expressed genes and used them for gene ontology (GO) and a Kyoto Encyclopedia of Genomes (KEGG) enrichment analysis. Meanwhile, we used PPI protein interaction network and Cytoscape analysis to identify key genes and qRT-PCR to verify differential gene expression. Single-gene enrichment analysis (GSEA) was used further to elucidate the potential biological functions of key genes. Analysis of immune cell infiltration and correlation of key genes with immune cells after Mtb-Ag-stimulated using R language.

Results

We identified 597 differentially expressed genes in Mtb-Ag stimulated PBMCs. KEGG and GSEA enrichment analyzed the cellular pathways related to immune function, and DEGs were found to be primarily involved in the TNF signaling pathway, the IL-17 signaling pathway, the JAK-STAT signaling pathway, cytokine-cytokine receptor interactions, and the NF-κB signaling pathway. Wayne analysis using GSEA, KEGG, and the protein-protein interaction (PPI) network showed that 34 genes, including PTGS2, IL-1β, IL-6, TNF and IFN-γ et al., were co-expressed in the five pathways and all were up-regulated by Mtb-Ag stimulation. Twenty-four DEGs were identified using qRT-PCR, including fourteen up-regulated genes (SERPINB7, IL20, IFNG, CSF2, PTGS2, TNF-α, IL36G, IL6, IL10, IL1A, CXCL1, CXCL8, IL4, and CXCL3) and ten down-regulated genes (RTN1, CSF1R CD14, C5AR1, CXCL16, PLXNB2, OLIG1, EEPD1, ENG, and CCR1). These findings were consistent with the RNA-Seq results.

Conclusion

The transcriptomic features associated with Mtb-Ag provide the scientific basis for exploring the intracellular immune mechanisms against Mtb. However, more studies on these DEGs in pathways associated with Mtb-Ag stimulation are needed to elucidate the underlying pathologic mechanisms of Mtb-Ag during Mtb infection.

IL-10 Overexpression After BCG Vaccination Does Not Impair Control of Mycobacterium tuberculosis Infection

Control of tuberculosis depends on the rapid expression of protective CD4+ T-cell responses in the Mycobacterium tuberculosis (Mtb)-infected lungs. We have recently shown that the immunomodulatory cytokine IL-10 acts intrinsically in CD4+ T cells and impairs their parenchymal migratory capacity, thereby preventing control of Mtb infection. Herein, we show that IL-10 overexpression does not impact the protection conferred by the established memory CD4+ T-cell response, as BCG-vaccinated mice overexpressing IL-10 only during Mtb infection display an accelerated, BCG-induced, Ag85b-specific CD4+ T-cell response and control Mtb infection. However, IL-10 inhibits the migration of recently activated ESAT-6-specific CD4+ T cells into the lung parenchyma and impairs the development of ectopic lymphoid structures associated with reduced expression of the chemokine receptors CXCR5 and CCR7. Together, our data support a role for BCG vaccination in preventing the immunosuppressive effects of IL-10 in the fast progression of Mtb infection and may provide valuable insights on the mechanisms contributing to the variable efficacy of BCG vaccination.

Early IL-10 promotes vasculature-associated CD4+ T cells unable to control Mycobacterium tuberculosis infection

Cytokine-producing CD4⁺ T cells play a crucial role in the control of Mycobacterium tuberculosis infection; however, there is a delayed appearance of effector T cells in the lungs following aerosol infection. The immunomodulatory cytokine IL-10 antagonizes control of M. tuberculosis infection through mechanisms associated with reduced CD4⁺ T cell responses. Here, we show that IL-10 overexpression only before the onset of the T cell response impaired control of M. tuberculosis growth; during chronic infection, IL-10 overexpression reduced the CD4⁺ T cell response without affecting the outcome of infection. IL-10 overexpression early during infection did not, we found, significantly impair the kinetics of CD4⁺ T cell priming and effector differentiation. However, CD4⁺ T cells primed and differentiated in an IL-10–enriched environment displayed reduced expression of CXCR3 and, because they did not migrate into the lung parenchyma, their ability to control infection was limited. Importantly, these CD4⁺ T cells maintained their vasculature phenotype and were unable to control infection, even after adoptive transfer into low IL-10 settings. Together our data support a model wherein, during M. tuberculosis infection, IL-10 acts intrinsically on T cells, impairing their parenchymal migratory capacity and ability to engage with infected phagocytic cells, thereby impeding control of infection.

Cumulative Evidence for Association between IL-10 Polymorphisms and Kawasaki Disease Susceptibility: A Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis was carried out to evaluate the associations between IL-10 polymorphisms and Kawasaki disease (KD) risk.

METHODS

A comprehensive literature search was performed using PubMed, EMBASE, China National Knowledge Infrastructure and SciELO for all relevant studies evaluating IL-10 polymorphism and susceptibility to KD. The associations were measured by odds ratios (ORs) and its corresponding 95% confidence intervals (CIs).

RESULTS

A total of 13 studies including four studies on -1082 A > G, four studies on -819 T > C and five studies on -592 A > C polymorphism were selected. Pooled data revealed that IL-10 -592 A > C polymorphism was significantly associated with an increased risk of KD (C vs. A: OR = 0.402, 95% CI 0.194-0.832, p = 0.014). However, IL-10 -1082 A > G and -819 T > C polymorphisms were not significantly associated with risk of KD under all five genetic models.

CONCLUSIONS

Our results revealed that IL-10 -592 A > C polymorphism was associated with risk of KD, while IL-10 -1082 A > G and -819 T > C polymorphisms were not involved in the development of KD.

Genetic Polymorphism of Tumor Necrosis Factor-Alpha, Interferon-Gamma and Interleukin-10 and Association With Risk of Mycobacterium Tuberculosis Infection

BACKGROUND

Mycobacterium tuberculosis has become the leading cause of morbidity and death in humans worldwide. Thus, genetic variability of the host plays a major role in human susceptibility to the pathogen, among others. Therefore, the objective of this finding was to assess the association of genetic polymorphisms of cytokines with tuberculosis infection.

METHOD

A cross-sectional study was conducted between January and May 2018. Five ml of whole blood was collected and extracted the genomic DNA through simple salting out method. The patterns of genetic polymorphism were determined by amplification refractory method PCR using specific primers. Finally, the PCR run on electrophoresis of agarose gel and the band was visualized under UV light. A logistical regression model has been adapted to assess the association of genetic polymorphisms with tubercular infection. In order to determine the association between the explanatory and outcome variable, the odds ratio with 95% CI was calculated. P < 0.05 is a statistically significant value.

RESULT

In present study, the frequency of TNF-α -308 G allele and GG genotype OR (95% CI)= 0.20 (0.11-0.37), and OR (95% CI)= 0.29 (0.18-0.46)), respectively) and IFN-γ +874 A allele and AA genotype OR (95% CI)= 3.80 (2.11-6.86) and (OR (95% CI)= 1.61(1.13-2.28), respectively) were significantly associated with tuberculosis incidence. In contrast, there is no significant correlation between IL-10 -1082 A and AA of allele and genotype, respectively in tuberculosis patients (p > 0.05) was evident.

CONCLUSION

From our finding, the genetic variability of TNF-α -308 A and IFN-γ +874 alleles are the potent host genetic risk factors associated with tuberculosis infection.

Interleukin 10 gene promoter polymorphisms (rs1800896, rs1800871 and rs1800872) and haplotypes are associated with the activity of systemic lupus erythematosus and IL10 levels in an Iranian population

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with unknown aetiology. According to the role of interleukin 10 (IL10) in SLE pathogenesis, the genetic alterations in its promoter region could be associated with elevated IL10 levels and exacerbated disease. Here, we investigated the association of genotype and haplotype frequencies of three IL10 gene promoter polymorphisms with susceptibility to SLE, IL10 plasma levels and disease activity of patients in an Iranian population. A total of 116 SLE patients and 131 healthy subjects were enrolled. The PCR-RFLP technique was used to detect IL10 promoter genotypes at the positions of -1082 (G/A), -819 (C/T) and -592 (C/A) in association with IL10 plasma levels and SLEDAI scores. The GG genotype of -1082 polymorphism was associated with the increased risk of SLE [OR = 2.65, 95% CI (1.21-5.82), p-value = 0.046]. The CC genotype in -819 region was associated with SLE susceptibility [OR = 3.38, 95% CI (1.26-9.07), p-value = 0.034] and C allele was introduced as risk allele [OR = 1.86, 95% CI (1.15-3.01), p-value = 0.009] in this region. IL10 plasma levels were overexpressed in CC genotype carriers of -592 SNP and decreased in AA genotype carriers of -1082. IL10 was also increased in SLE patients with CGT (-592/-1082/-819) haplotype. The SLEDAI score was higher among CC genotype carriers at the position of -592 and TT genotype carriers at the region of -819. SLEDAI was also elevated among patients with CGC (-592/-1082/-819) and CAC (p = 0.011) haplotypes. The present study suggests that the IL10 -819(C/T), -1082(G/A) and -592(C/A) polymorphisms and the haplotypes are associated with SLE susceptibility, increased disease activity and elevated IL10 levels. While this is the first time to report such an association in an Iranian population, further studies are needed to confirm these findings.

The role of three interleukin 10 gene polymorphisms (- 1082 A > G, - 819 C > T, - 592 A > C) in the risk of chronic and aggressive periodontitis: a meta-analysis and trial sequential analysis

Background

Periodontitis is a major oral health problem and it is considered as one of the reasons for tooth loss in developing and developed nations. The objective of the current review was to investigate the association between IL10 polymorphisms − 1082 A > G (rs1800896), -819C > T (rs1800871), − 592 A > C (rs1800872) and the risk of either chronic periodontitis or aggressive periodontitis.

Methods

This is a meta- analysis study, following the preferred reporting items for systematic reviews and meta- analyses (PRISMA). Relevant studies were searched in the health related electronic databases. Methodological quality of the included studies were assessed using the Newcastle-Ottawa Scale. For individual studies, odds ratio (OR) and its 95%confidence interval (CI) were calculated to assess the strength of association between IL10 polymorphisms (− 1082 A > G, -819C > T, − 592 A > C) and the risk of periodontitis. For pooling of the estimates across studies included, the summary OR and its 95% CIs were calculated with random-effects model. The pooled estimates were done under four genetic models such as the allelic contrast model, the recessive model, the dominant model and the additive model. Trial sequential analysis (TSA) was done for estimation of the required information size for this meta-analysis study.

Results

Sixteen studies were identified for this review. The included studies were assessed to be of moderate to good methodological quality. A significant association between polymorphism of IL10–1082 A > G polymorphism and the risk of chronic periodontitis in the non-Asian populations was observed only in the recessive model (OR,1.42; 95% CI:1.11, 1.8,I²: 43%). The significant associations between − 592 A > C polymorphism and the risk of aggressive periodontitis in the non-Asian populations were observed in particular genetic models such as allele contrast (OR, 4.34; 95%CI:1.87,10.07,I²: 65%) and recessive models (OR, 2.1; 95% CI:1.16, 3.82,I²: 0%). The TSA plot revealed that the required information size for evidence of effect was sufficient to draw a conclusion.

Conclusions

This meta-analysis suggested that the IL10–1082 A > G polymorphism was associated with chronic periodontitis CP risk in non-Asians. Thus, in order to further establish the associations between IL10 (− 819 C > T, − 592 A > C) in Asian populations, future studies should include larger sample sizes with multi-ethnic groups.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0637-9) contains supplementary material, which is available to authorized users.

AmpliSeq transcriptome analysis of human alveolar and monocyte-derived macrophages over time in response to Mycobacterium tuberculosis infection

Human alveolar macrophages (HAM) are primary bacterial niche and immune response cells during Mycobacterium tuberculosis (M.tb) infection, and human blood monocyte-derived macrophages (MDM) are a model for investigating M.tb-macrophage interactions. Here, we use a targeted RNA-Seq method to measure transcriptome-wide changes in RNA expression patterns of freshly obtained HAM (used within 6 h) and 6 day cultured MDM upon M.tb infection over time (2, 24 and 72 h), in both uninfected and infected cells from three donors each. The Ion AmpliSeq™ Transcriptome Human Gene Expression Kit (AmpliSeq) uses primers targeting 18,574 mRNAs and 2,228 non-coding RNAs (ncRNAs) for a total of 20,802 transcripts. AmpliSeqTM yields highly precise and reproducible gene expression profiles (R2 >0.99). Taking advantage of AmpliSeq's reproducibility, we establish well-defined quantitative RNA expression patterns of HAM versus MDM, including significant M.tb-inducible genes, in networks and pathways that differ in part between MDM and HAM. A similar number of expressed genes are detected at all time-points between uninfected MDM and HAM, in common pathways including inflammatory and immune functions, but canonical pathway differences also exist. In particular, at 2 h, multiple genes relevant to the immune response are preferentially expressed in either uninfected HAM or MDM, while the HAM RNA profiles approximate MDM profiles over time in culture, highlighting the unique RNA expression profile of freshly obtained HAM. MDM demonstrate a greater transcriptional response than HAM upon M.tb infection, with 2 to >10 times more genes up- or down-regulated. The results identify key genes involved in cellular responses to M.tb in two different human macrophage types. Follow-up bioinformatics analysis indicates that approximately 30% of response genes have expression quantitative trait loci (eQTLs in GTEx), common DNA variants that can influence host gene expression susceptibility or resistance to M.tb, illustrated with the TREM1 gene cluster and IL-10.

Antimycobacterial effect of IFNG (interferon gamma)-induced autophagy depends on HMOX1 (heme oxygenase 1)-mediated increase in intracellular calcium levels and modulation of PPP3/calcineurin-TFEB (transcription factor EB) axis

IFNG (interferon gamma)-induced autophagy plays an important role in the elimination of intracellular pathogens, such as Mycobacterium tuberculosis (Mtb). However, the signaling cascade that leads to the increase in autophagy flux in response to IFNG is poorly defined. Here, we demonstrate that HMOX1 (heme oxygenase 1)-generated carbon monoxide (CO) is required for the induction of autophagy and killing of Mtb residing in macrophages in response to immunomodulation by IFNG. Interestingly, IFNG exposure of macrophages induces an increase in intracellular calcium levels that is dependent on HMOX1 generated CO. Chelation of intracellular calcium inhibits IFNG-mediated autophagy and mycobacterial clearance from macrophages. Moreover, we show that IFNG-mediated increase in intracellular calcium leads to activation of the phosphatase calcineurin (PPP3), which dephosphorylates the TFEB (transcription factor EB) to induce autophagy. PPP3-mediated activation and nuclear translocation of TFEB are critical in IFNG-mediated mycobacterial trafficking and survival inside the infected macrophages. These findings establish that IFNG utilizes the PPP3-TFEB signaling axis for inducing autophagy and regulating mycobacterial growth. We believe this signaling axis could act as a therapeutic target for suppression of growth of intracellular pathogens.

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.

Identification of compounds that decrease numbers of Mycobacteria in human macrophages in the presence of serum amyloid P

Mϕs are a heterogeneous population of cells and include classically activated Mϕs (M1) and alternatively activated Mϕs (M2). Mϕs can change from M1 to M2 and vice versa in response to environmental stimuli. Serum amyloid P (SAP) is a constitutive plasma protein that polarizes Mϕs to an M2 phenotype, and part of this effect is mediated through FcγRI receptors. In an effort to find ways to alter Mϕs phenotypes, we screened for compounds that can block the SAP-FcγRI interaction. From a screen of 3000 compounds, we found 12 compounds that reduced the ability of fluorescently labeled human SAP to bind cells expressing human FcγRI. Based on cell surface marker expression, 8 of the compounds inhibited the effect of SAP on skewing human Mϕs to an M2 phenotype and in the presence of SAP polarized Mϕs to an M1 phenotype. In diseases, such as tuberculosis, M1s are more effective at killing bacteria than M2s. SAP potentiated the numbers of the mycobacterial strains Mycobacterium smegmatis and Mycobacterium tuberculosis in Mϕs. When added along with SAP, 2 of the compounds reduced intracellular Mycobacterium numbers. Together, these results indicate that the blocking of SAP effects on Mϕs can skew these cells toward an M1 phenotype, and this may be useful in treating diseases, such as tuberculosis.

The Role of Host Genetics (and Genomics) in Tuberculosis

Familial risk of tuberculosis (TB) has been recognized for centuries. Largely through studies of mono- and dizygotic twin concordance rates, studies of families with Mendelian susceptibility to mycobacterial disease, and candidate gene studies performed in the 20th century, it was recognized that susceptibility to TB disease has a substantial host genetic component. Limitations in candidate gene studies and early linkage studies made the robust identification of specific loci associated with disease challenging, and few loci have been convincingly associated across multiple populations. Genome-wide and transcriptome-wide association studies, based on microarray (commonly known as genechip) technologies, conducted in the past decade have helped shed some light on pathogenesis but only a handful of new pathways have been identified. This apparent paradox, of high heritability but few replicable associations, has spurred a new wave of collaborative global studies. This review aims to comprehensively review the heritability of TB, critically review the host genetic and transcriptomic correlates of disease, and highlight current studies and future prospects in the study of host genomics in TB. An implicit goal of elucidating host genetic correlates of susceptibility to Mycobacterium tuberculosis infection or TB disease is to identify pathophysiological features amenable to translation to new preventive, diagnostic, or therapeutic interventions. The translation of genomic insights into new clinical tools is therefore also discussed.

Opposing roles of IL-10 in acute bacterial infection

Interleukin-10 (IL-10) is recognized as an anti-inflammatory cytokine that downmodulates inflammatory immune responses at multiple levels. In innate cells, production of this cytokine is usually triggered after pathogen recognition receptor (PRR) engagement by pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patters (DAMPs), as well as by other soluble factors. Importantly, IL-10 is frequently secreted during acute bacterial infections and has been described to play a key role in infection resolution, although its effects can significantly vary depending on the infecting bacterium. While the production of IL-10 might favor host survival in some cases, it may also result harmful for the host in other circumstances, as it can prevent appropriate bacterial clearance. In this review we discuss the role of IL-10 in bacterial clearance and propose that this cytokine is required to recover from infection caused by extracellular or highly pro-inflammatory bacteria. Altogether, we propose that IL-10 drives excessive suppression of the immune response upon infection with intracellular bacteria or in non-inflammatory bacterial infections, which ultimately favors bacterial persistence and dissemination within the host. Thus, the nature of the bacterium causing infection is an important factor that needs to be taken into account when considering new immunotherapies that consist on the modulation of inflammation, such as IL-10. Indeed, induction of this cytokine may significantly improve the host's immune response to certain bacteria when antibiotics are not completely effective.

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

In Mycobacterium tuberculosis (MTB) infection, the complex interaction of host immune system and the mycobacteria is associated with levels of cytokines production that play a major role in determining the outcome of the disease. Several single-nucleotide polymorphisms (SNPs) in cytokine genes have been associated with tuberculosis (TB) outcome. The aim of this study was to evaluate the association between previously reported SNPs IL2–330 T>G (rs2069762); IL4–590 C>T (rs2243250); IL6–174 G>C (rs1800795); IL10–592 A>C (rs1800872); IL10–1082 G>A (rs1800896); IL17A -692 C>T (rs8193036); IL17A -197 G>A (rs2275913); TNF -238 G>A (rs361525); TNF -308 G>A (rs1800629) and IFNG +874 T>A (rs2430561) and pulmonary TB (PTB) susceptibility. We conducted a case-control study in individuals from Southern Brazil who were recruited between February 2012 and October 2013 in a high incidence TB city. We performed a multiplex genotyping assay in 191 patients with PTB and 175 healthy subjects. Our results suggest a decreased risk for PTB development associated with the IL17A -197A allele (OR = 0.29; p = 0.04), AA genotype (OR = 0.12; p = 0.04) and A carrier (AG/AA) (OR = 0.29; p = 0.004) and IL6 -174C carrier (CC/CG) (OR = 0.46; p = 0.04). We could not properly analyze IL17A -692 C>T (rs8193036) and IFNG +874T>A due to genotypic inconsistencies and found no evidence of association for the IL2, IL4, IL10 and TNF polymorphisms and PTB. In conclusion, our results show a protective effect of IL17 and IL6 polymorphisms on PTB outcome in Southern Brazilian population.

The -137G/C single nucleotide polymorphism in IL-18 gene promoter contributes to tuberculosis susceptibility in Chinese Han population

BACKGROUND

Interleukin (IL) -18 is crucial to host defense against mycobacterial infections. Recent studies have indicated IL-18 gene polymorphisms are associated with susceptibility to several clinical diseases.

OBJECTIVE

The aim of this study is to investigate the association of IL-18 (-137G/C and -607C/A) gene promoter single nucleotide polymorphisms (SNPs) with susceptibility to tuberculosis (TB), and the effects of those SNPs to its protein producing capacity in Chinese Han population.

METHODS

407 TB patients (including 113 children and 294 adults) and 469 healthy volunteers (including 167 children and 302 adults) from Chinese Han population were enrolled. The IL-18 gene promoter polymorphisms at positions of -137 and -607 were determined by sequence specific primer-polymerase chain reaction (SSP-PCR). The IL-18 levels in the supernatants of PBMCs from 46 healthy volunteers were measured by ELISA.

RESULTS

The gene distribution of IL-18 -137G/C and -607C/A showed none difference between adult and pediatric population. The frequency of IL-18 -137GG genotype was significantly higher in total TB group than that in total healthy control group (79.1% V 69.3%, P<0.01), while the frequencies of GC genotype and C allele were conversely lower (19.2% V 27.9%, P<0.01; 11.3% V 16.7%, P<0.01 respectively). The difference of the -137CC genotype distribution between patients and controls was not observed. At the -607C/A polymorphic site, patient and control groups had a very similar gene distribution. Isolated PBMCs with IL-18 -137GC/CC genotype were able to produce a higher level of IL-18 than those with IL-18 -137GG genotype, either spontaneously or in response to PMA plus calcimycin A23187.

CONCLUSION

IL-18 -137G/C polymorphism contributed to TB susceptibility in Chinese Han population. Allele G might be a predisposing gene of TB, while allele C probably plays a role in preventing mycobacterium tuberculosis infection by promoting more vigorous protein expression.

B. Durães S, C. Cardoso C, Nunes Sarno E, G. Pacheco A, C. F. Lana F, Ozório Moraes M. Association of IL10 Polymorphisms and Leprosy: A Meta-Analysis

Leprosy is a chronic infectious disease that depends on the interplay of several factors. Single nucleotide polymorphisms (SNPs) in host immune related genes have been consistently suggested as participants in susceptibility towards disease. Interleukin-10 (IL-10) is a crucial immunomodulatory cytokine in mycobacterial pathogenesis and especially the -819C>T SNP (rs1800871) has been tested in several case-control studies indicating association with leprosy risk, although a recent consensus estimate is still missing. In this study, we evaluated the association of the -819C>T SNP and leprosy in two new Brazilian family-based populations. Then, we performed meta-analysis for this polymorphism summarizing published studies including these Brazilian family-based groups. Finally, we also retrieved published studies for other distal and proximal IL10 polymorphisms: -3575 T>A (rs1800890), -2849 G>A (rs6703630), -2763 C>A (rs6693899), -1082 G>A (rs1800896) and -592 C>A (rs1800872). Results from meta-analysis supported a significant susceptibility association for the -819T allele, with pooled Odds Ratio of 1.22 (CI = 1.11–1.34) and P-value = 3x10^–5 confirming previous data. This result remained unaltered after inclusion of the Brazilian family-based groups (OR = 1.2, CI = 1.10–1.31, P-value = 2x10^–5). Also, meta-analysis confirmed association of -592 A allele and leprosy outcome (OR = 1.24, CI = 1.03–1.50, P-value = 0.02). In support of this, linkage disequilibrium analysis in 1000 genomes AFR, EUR, ASN and AMR populations pointed to r² = 1.0 between the -592C>A and -819C>T SNPs. We found no evidence of association for the other IL10 polymorphisms analyzed for leprosy outcome. Our results reinforce the role of the -819C>T as a tag SNP (rs1800871) and its association with leprosy susceptibility.