Association of genetic polymorphisms in the IL12-IFNG pathway with susceptibility to and prognosis of pulmonary tuberculosis in a Chinese population

The effects of IL-27 and IL-35 gene variation and expression levels on the susceptibility and clinical manifestations of pulmonary tuberculosis

Inflammatory cytokines have crucial roles in the pathogenesis of tuberculosis (TB), and interleukin (IL)-27 and IL-35 have a pro-inflammatory and anti-inflammatory effect on many diseases, including infectious diseases. Therefore, we evaluated the relationship between IL-27 and IL-35 gene polymorphism, expression levels, and pulmonary TB (PTB) susceptibility. Nine single-nucleotide polymorphisms (SNPs) in the IL-27 gene (rs181206, rs153109, and rs17855750) and the IL-35 gene (rs4740, rs428253, rs9807813, rs2243123, rs2243135, and rs568408) were genotyped by the SNPscan technique in 497 patients with PTB and 501 controls. There was no significant difference regarding the genotype and allele frequencies of the above SNPs in the IL-27 and IL-35 genes between patients with PTB and controls. Haplotype analysis showed that the frequency of the GAC haplotype in the IL-35 gene was significantly decreased in patients with PTB when compared to controls (p = 0.036). Stratified analysis suggested that the frequency of the IL-27 rs17855750 GG genotype was significantly increased in patients with PTB with fever. Moreover, the lower frequency of the IL-35 rs568408 GA genotype was associated with drug-induced liver injury in patients with PTB. The IL-35 rs428253 GC genotype, as well as the rs4740 AA genotype and A allele, showed significant relationships with hypoproteinemia in patients with PTB. When compared with controls, the IL-27 level was significantly increased in patients with PTB. Taken together, IL-35 gene variation might contribute to a protective role on the susceptibility to PTB, and IL-27 and IL-35 gene polymorphisms were associated with several clinical manifestations of patients with PTB.

Significance of the chemokine CXCL10 and human beta-defensin-3 as biomarkers of pulmonary tuberculosis

The biomarker significance of IL-35, chemokines (CXCL9 and CXCL10) and human beta-defensins (hBD2 and hBD3) was determined in pulmonary tuberculosis (TB) of 105 Iraqi patients; 37 had active disease, 41 had multi-drug resistant (MDR) PTB and 27 had a relapse of TB. A control sample of 79 healthy persons was also included. Serum levels of markers were assessed using enzyme-linked immunosorbent assay kits. Kruskal-Wallis test together with Dunn-Bonferroni post hoc test revealed significance differences between patients and controls in levels of IL-35, CXCL9, CXCL10 and hBD3, while hBD2 showed no significant difference. Receiver operating characteristic analysis demonstrated that CXCL10 and hBD3 were the most significant markers in predicting TB, particularly active disease. Logistic regression analysis proposed the susceptibility role of CXCL10 in TB. Gender- and age-dependent variations were also observed. Spearman's rank correlation analysis showed different correlations between markers in each group of patients and controls. In conclusion, CXCL10 was up-regulated in serum of TB patients, while hBD3 showed down-regulated level. Both serum proteins are possible candidate biomarkers for evaluation of TB progression, particularly in active disease.

IFN-γ +874 A>T (rs2430561) gene polymorphism and risk of pulmonary tuberculosis: a meta-analysis

INTRODUCTION

The role of interferon gamma (IFN-γ) +874 A>T (rs2430561) gene polymorphism has been evaluated in different ethnicities with pulmonary tuberculosis (PTB) infection, and inconsistent results have been reported. In this study, a meta-analysis was performed to determine the precise association between IFN-γ +874 A>T gene polymorphism and PTB susceptibility.

MATERIAL AND METHODS

A total of 21 studies comprising 4281 confirmed PTB cases and 5186 healthy controls were included in this meta-analysis by searching the PubMed (Medline), EMBASE, and Google Scholar web-databases.

RESULTS

We observed reduced risk of PTB in allelic contrast (T vs. A: p = 0.001; OR = 0.818, 95% CI: 0.723-0.926), homozygous (TT vs. AA: p = 0.017; OR = 0.715, 95% CI: 0.543-0.941), heterozygous (AT vs. AA: p = 0.002; OR = 0.782, 95% CI: 0.667-0.917), dominant (TT+AT vs. AA: p = 0.002; OR = 0.768, 95% CI: 0.652-0.906), and recessive (TT vs. AA+AT: p = 0.042; OR = 0.802, 95% CI: 0.649-0.992) genetic models. In ethnicity-wise subgroup analysis, reduced risk of PTB was found in the Caucasian population. However, we did not find an association with any of the genetic models in the Asian population.

CONCLUSIONS

In conclusion, the IFN-γ +874 A>T gene polymorphism is significantly associated with reduced risk of PTB, showing a protective effect in the overall and in the Caucasian population. However, this polymorphism is not associated with PTB risk in the Asian population.

Polymorphism in the Promoter Region of the IL18 Gene and the Association With Severity on Paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is an important endemic, systemic disease in Latin America caused by Paracoccidioides spp. This mycosis has been associated with high morbidity and sequels, and its clinical manifestations depend on the virulence of the infecting strain, the degree and type of immune response, infected tissues, and intrinsic characteristics of the host. The T helper(Th)1 and Th17/Th22 cells are related to resistance and control of infection, and a Th2/Th9 response is associated with disease susceptibility. In this study, we focused on interleukin(IL)-12p35 (IL12A), IL-18 (IL18), and IFN-γ receptor 1 (IFNGR1) genetic polymorphisms because their respective roles have been described in human PCM. Real-time PCR was employed to analyze IL12A-504 G/T (rs2243115), IL18-607 C/A (rs1946518), and IFNGR1-611 A/G (rs1327474) single nucleotide polymorphisms (SNP). One hundred forty-nine patients with the acute form (AF), multifocal chronic (MC), or unifocal chronic (UC) forms of PCM and 110 non-PCM individuals as a control group were included. In the unconditional logistic regression analysis adjusted by ethnicity and sex, we observed a high risk of the IL18-607 A-allele for both AF [p = 0.015; OR = 3.10 (95% CI: 1.24–7.77)] and MC groups [p = 0.023; OR = 2.61 (95% CI: 1.14–5.96)] when compared with UC. The IL18-607 A-allele associated risk for the AF and MC groups as well as the protective role of the C-allele in UC are possibly linked to higher levels of IL-18 at different periods of the course of the disease. Therefore, a novel role of IL18-607 C/A SNP is shown in the present study, highlighting its importance in the outcome of PCM.

Can the personalized medicine approach contribute in controlling tuberculosis in general and India in particular?

Poor drug compliance and drug-resistant Mycobacterium tuberculosis are the two principal obstacles in controlling tuberculosis (TB) in endemic regions including India, which has contributed the most to global TB burden. We argue here that a personalized medicine approach, to start with the N-acetyl transferase-2–isoniazid (NAT2–INH) model, could be a step forward in dealing with both these limitations in controlling TB in India.

Interferon-γ and interleukin-12 production in relation to gene polymorphisms in bacillus Calmette-Guérin osteitis

BACKGROUND

Interferon-γ (IFN-γ) and interleukin-12 (IL-12) play a crucial role in the defense against mycobacteria, and in the response to bacillus Calmette-Guérin (BCG) vaccination. We have previously reported clinical and outcome data of 222 BCG osteitis cases diagnosed in 1960-1988 in Finland. The immunological and genetic reports have been based on 132 blood samples obtained in 2007-2008.

METHODS

We compared IFNγ rs2430561 and rs35314021, IL12A rs568408 and rs2243115, and IL12B rs3212227 single-nucleotide polymorphisms (SNP) between 132 BCG osteitis patients and 99 population-based controls. In addition, stimulated production of IFN-γ and IL-12 in cell culture was evaluated in relation to the presence of IFNγ and IL12 wild versus variant genotypes, respectively.

RESULTS

The distributions of IFNγ rs2430561, IFNγ rs35314021, IL12A rs568408, IL12A rs2243115 and IL12B rs3212227 SNP did not differ between BCG osteitis patients and Finnish population-based controls. For IFNγ rs2430561, IFNγ rs35314021 and IL12A rs2243115, the negative result was confirmed by comparing the minor allele frequencies (MAF) in BCG osteitis cases with those in the publicly available genome aggregation database, including data for 3,472 Finnish persons. Instead, for IL12A rs568408 and IL12B rs3212227, the comparison of MAF in BCG osteitis cases with those in population-based and in aggregation-based controls gave conflicting results. The presence of the wild versus variant genotype had no significant association with IL-12 or IFN-γ production in BCG-stimulated cell cultures.

CONCLUSION

IFNγ gene polymorphisms did not show any association with BCG osteitis after newborn vaccination.

Association of interleukin-27 gene polymorphisms with susceptibility to HIV infection and disease progression

Interleukin‐27 (IL‐27) gene polymorphisms are linked to infectious disease susceptibility and IL‐27 plasma level is associated with HIV infection. Therefore, we aimed to investigate the association between IL‐27 polymorphisms and susceptibility to HIV infection and disease progression. A total of 300 patients with HIV infection (48 long‐term nonprogressors and 252 typical progressors) and 300 healthy controls were genotyped for three IL‐27 polymorphisms, rs17855750, rs181206, rs40837 which were performed by using multiple single nucleotide primer extension technique. Significant association was found between IL‐27 rs40837 polymorphisms with susceptibility to HIV infection (AG vs AA: adjusted OR = 1.60, 95% CI, 1.11‐2.30, P = 0.012; AG+GG vs AA: adjusted OR = 1.44, 95% CI, 1.02‐2.03, P = 0.038) and disease progression (LTNP: AG vs AA: adjusted OR = 2.33, 95% CI, 1.13‐4.80, P = 0.021; TP: AG vs AA: adjusted OR = 1.50, 95% CI, 1.04‐2.24, P = 0.030). Serum IL‐27 levels were significantly lower in cases compared to controls (P < 0.001). There were lower serum IL‐27 levels in TPs than in LTNPs (P < 0.001). We further found that LTNPs with rs40837 AG or GG genotype had lower serum IL‐27 levels than with AA genotype (P < 0.05). The CD4⁺T counts in cases were significantly lower than controls (P < 0.001). In contrast, individuals with rs40837 AG genotype had lower CD4⁺T counts than with AA genotype in cases (P < 0.05). In addition, CD4⁺T counts in TPs were significantly lower than LTNPs (P < 0.001). IL‐27 rs40837 polymorphism might influence the susceptibility to HIV infection and disease progression probably by regulating the level of serum IL‐27 or the quantity of CD4⁺T.

IL1R1 and IL1R2 polymorphisms were associated with tuberculosis risk: A pilot study

BACKGROUND

Interleukin (IL)-1 has been reported to be involved in the development of tuberculosis (TB). IL1R1 and IL1R2 encode a cytokine receptor that belongs to the IL-1 receptor family. However, few studies have reported on the polymorphisms of IL1R1 and IL1R2 in TB patients.

METHODS

We investigated nine single-nucleotide polymorphisms (SNPs) in IL1R1 and IL1R2 in 300 TB patients and 300 controls, aiming to evaluate their association with TB risk. Odds ratios and 95% confidence intervals were calculated using unconditional logistic regression after adjusting for age and gender.

RESULTS

On comparing the allele frequencies of candidate SNPs, we found that the minor allele 'A' of rs4851527 in IL1R2 was associated with a decreased risk of TB, whereas the minor alleles of rs10490571, rs956730 and rs3917225 in IL1R1 were associated with an increased risk of TB (p < 0.05). In the genetic model analysis, we found that the allele 'A' of rs4851527 was correlated with a decreased risk of TB in a log-additive model, whereas the minor alleles of rs719250, rs3218977, rs10490571, rs956730 and rs3917225 were correlated with an increased risk of TB in dominant and log-additive models (p < 0.05). Additionally, we found three haplotypes that were associated with an increased risk of TB: TGCT and TGTT haplotypes constructed by rs11674595, rs4851527, rs719250 and rs3218896, as well as GA haplotype constructed by rs3218977 and rs2072472 (p < 0.05).

CONCLUSIONS

Our data shed new light on the association between genetic polymorphisms of IL1R1 and IL1R2 and TB susceptibility in the Chinese Han population.

Genetic polymorphisms of the P2X7 gene associated with susceptibility to and prognosis of pulmonary tuberculosis

In this population-based case control study, we recruited 1601 pulmonary tuberculosis cases and 1526 healthy controls, aiming to investigate the association of genetic polymorphisms of the P2X7 gene with the susceptibility to and prognosis of pulmonary tuberculosis in a Chinese Han population. Five single-nucleotide polymorphisms (SNPs) in the P2X7 gene were genotyped. The odds ratio (OR) or relative risk (RR) together with 95% confidence interval (CI) were used to estimated the effect of genetic polymorphisms on the disease. After correction for multiple comparisons, the SNP rs1718119 remained significant. The allele A of rs1718119 was related to a reduced risk for all active tuberculosis (OR for each additional allele A: 0.81, 95% CI: 0.69-0.94) and sputum smear-positive cases (OR for each additional allele A: 0.78, 95% CI: 0.66-0.93). The effects of these genetic variations were more evident among smokers. Survival analysis showed a weak association between rs7958311 and treatment outcome, where each additional allele A of the SNP rs7958311 contributed to a 59% increase in the probability of a successful treatment outcome (adjusted RR: 1.59, 95% CI: 1.05-2.40, P=0.028); but it wasn't significant after the Bonferroni correction. We demonstrated that genetic variations of the P2X7 gene might be involved in the risk and prognosis of human tuberculosis.

A single nucleotide polymorphism in the interferon-γ gene (IFNG +874 T/A) is associated with susceptibility to tuberculosis

Interferon-γ (Interferon gamma, IFNG) is an important cytokine involved in providing resistance to mycobacterial diseases. Common variants of IFNG, such as IFNG +874 T/A(rs2430561), may be related to tuberculosis susceptibility, but this association has not been consistently observed. We performed an updated meta-analysis to evaluate the association between the IFNG +874 T/A (rs2430561) polymorphism and tuberculosis susceptibility. PubMed and SinoMed databases were searched up to October 2016, and odds ratios (OR) and 95% confidence intervals (CI) were used to assess the association strength. Based on search criteria for manuscripts reporting tuberculosis susceptibility and its relationship with the IFNG +874 T/A(rs2430561)polymorphism, 42 case-control studies from 39 different articles were retrieved. Significantly positive, decreased, and protective associations were found between the IFNG +874 T/A(rs2430561)polymorphism and tuberculosis risk in five genetic models. Moreover, in the stratified subgroup analysis, a protective relationship was detected in four different ethnicities and sources of the control groups. Furthermore, the IFNG +874 T/A(rs2430561)polymorphism played an important role in protecting individuals from both pulmonary tuberculosis and extra-pulmonary tuberculosis. Our meta-analysis suggests that the IFNG +874 T/A(rs2430561)polymorphism is potentially associated with tuberculosis susceptibility and may be used as a predictive biomarker. Further studies with larger sample sizes and consideration of gene-environment interactions should be conducted to elucidate the role of IFNG +874 T/A(rs2430561) polymorphism in tuberculosis susceptibility.

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.

Temporal Expression of Peripheral Blood Leukocyte Biomarkers in a Macaca fascicularis Infection Model of Tuberculosis; Comparison with Human Datasets and Analysis with Parametric/Non-parametric Tools for Improved Diagnostic Biomarker Identification

A temporal study of gene expression in peripheral blood leukocytes (PBLs) from a Mycobacterium tuberculosis primary, pulmonary challenge model Macaca fascicularis has been conducted. PBL samples were taken prior to challenge and at one, two, four and six weeks post-challenge and labelled, purified RNAs hybridised to Operon Human Genome AROS V4.0 slides. Data analyses revealed a large number of differentially regulated gene entities, which exhibited temporal profiles of expression across the time course study. Further data refinements identified groups of key markers showing group-specific expression patterns, with a substantial reprogramming event evident at the four to six week interval. Selected statistically-significant gene entities from this study and other immune and apoptotic markers were validated using qPCR, which confirmed many of the results obtained using microarray hybridisation. These showed evidence of a step-change in gene expression from an ‘early’ FOS-associated response, to a ‘late’ predominantly type I interferon-driven response, with coincident reduction of expression of other markers. Loss of T-cell-associate marker expression was observed in responsive animals, with concordant elevation of markers which may be associated with a myeloid suppressor cell phenotype e.g. CD163. The animals in the study were of different lineages and these Chinese and Mauritian cynomolgous macaque lines showed clear evidence of differing susceptibilities to Tuberculosis challenge. We determined a number of key differences in response profiles between the groups, particularly in expression of T-cell and apoptotic makers, amongst others. These have provided interesting insights into innate susceptibility related to different host `phenotypes. Using a combination of parametric and non-parametric artificial neural network analyses we have identified key genes and regulatory pathways which may be important in early and adaptive responses to TB. Using comparisons between data outputs of each analytical pipeline and comparisons with previously published Human TB datasets, we have delineated a subset of gene entities which may be of use for biomarker diagnostic test development.

Polymorphisms of IFN-γ (+874A/T) and IL-12 (+1188A/C) in tuberculosis patients and their household contacts in Hyderabad, India

Several cytokine gene variants have shown to be associated with host susceptibility to infectious diseases including tuberculosis (TB). High rates of transmission were identified within household members of TB patients. In this study, we examined whether single nucleotide polymorphisms of IFN-γ +874A/T and IL-12 +1188A/C affect susceptibility to TB. Genomic DNA from patients with active disease, their household contacts HHC and healthy controls HC was genotyped for IFN-γ +874A/T and IL-12 +1188A/C SNPs by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). IFN-γ +874 AA and AT genotypes were significantly with different frequencies in patients and total HHC as compared to HC (p<0.0001). In patients IL-12 +1188 AC and CC genotypes were associated with TB (p<0.003, p<0.008). In total HHC AC, CC genotypes and both alleles (A&C) were significantly different as compared to HC (p<0.004, p<0.001, p<0.034) and the same result was obtained when HHC were stratified into related (p<0.02, p<0.001) and unrelated (p<0.009, p<0.017) individuals. Allelic frequencies, however, were significant only in related contacts (p<0.021). Generalized multifactor dimensionality reduction method (GMDR) testing revealed high risk combinations of several genotypes in IFN-γ & IL-12 genes. Our findings suggest an important role of genetic variations of IFN-γ and IL-12 for susceptibility to TB.

Association between IFN-γ +874A/T and IFN-γR1 (-611A/G, +189T/G, and +95C/T) Gene Polymorphisms and Chronic Periodontitis in a Sample of Iranian Population

Background. Interferon gamma (IFN-γ) is an immune regulatory cytokine that acts through its receptor and plays important role in progression of inflammatory disease such as chronic periodontitis (CP). The purpose of this study was to determine the differences in the distribution of IFN-γ (+874A/T) and IFN-γR1 (-611A/G, +189T/G, and +95C/T) gene polymorphisms among CP and healthy individuals and to investigate relationships between these polymorphisms and susceptibility to CP. Materials and Methods. 310 individuals were enrolled in the study including 210 CP patients and 100 healthy controls. Single nucleotide polymorphisms at IFN-γ (+874A/T) and IFN-γR1 (-611A/G, +189T/G, and +95C/T) were analyzed by ARMS-PCR and PCR-RFLP methods. Results. The significant difference was found in genotype and allele frequency of IFN-γ (+874A/T) gene polymorphism in chronic periodontitis patients and healthy controls. The distribution of genotypes and allele frequencies for IFN-γR1 (-611A/G, +189T/G, and +95C/T) were similar among the groups and no differences in the frequencies of alleles or genotypes of IFN-γR1 genetic polymorphisms variants between case and control groups were detected. Conclusion. The finding of this study showed that IFN-γ +874A/T gene polymorphism may affect susceptibility to CP, whereas IFN-γR1 genetic polymorphisms at -611A/G, +189T/G, and +95C/T were not associated with this disease.

Relationship between γ-interferon gene polymorphisms and susceptibility to brucellosis infection

Interferon-gamma (IFN-γ) is a pro-inflammatory cytokine that plays a pivotal role in the defense mechanism against Brucella infection. It was hypothesized that the IFN-γ in (+874 A/T in intron 1) TT and +5644 T/A, TT genotypes, which are reportedly associated with high IFN production, are associated with susceptibility to brucellosis in Iranian subjects. Genotyping of these IFN-γ variants by an allele-specific polymerase chain reaction method was performed in 281 subjects, comprising 153 patients with active brucellosis and 128 healthy controls. It was found that the +874 minor allele (A) and homozygote genotype (AA) were significantly more frequently present in brucellosis patients than in controls (OR = 2.588; 95% CI, 1.313-5.104; P = 0.006 for the AA genotype; OR = 1.575; 95% CI, 1.124-2.216; P = 0.010 for the A allele). However, the allelic and genotypic distribution of the IFN-γ polymorphism at position UTR5644 A>T did not differ significantly between patients and controls (P > 0.05). The distribution of haplotypes in this study suggests that the T/A haplotype (+874/UTR5644), which was present more frequently in controls than in patients, may protect subjects against Brucella infection. It is suggested that IFN-γ +874 AA genotype and A allele are risk factors for developing brucellosis infection in Iranian subjects.

Genetic polymorphisms of IFNG and IFNGR1 in association with the risk of pulmonary tuberculosis

OBJECTIVE

Genetic host factors play an important role in controlling individual's susceptibility to the pathogen. This study aims to explore the single and joint effect of genetic polymorphisms of interferon-gamma (IFNG) and its receptor (IFNGR1) in association with the pulmonary tuberculosis in a Chinese Han population.

METHODS

This population-based case control study consisted of 1434 pulmonary tuberculosis patients and 1412 healthy controls. Six tag SNPs in IFNG/IFNGR1 were genotyped using TaqMan allelic discrimination technology. The logistic regression model was carried out to analyze the associations between the genotypes and haplotypes and the risk of tuberculosis by calculating the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

After the Bonferroni correction for multiple comparisons, three SNPs (rs2234711, rs1327475 and rs7749390) in IFNGR1 gene were observed to be significantly associated with the altered risks of tuberculosis. For the SNP rs2234711, individuals carrying C allele (vs. T) showed a decreased risk, with the adjusted OR(95% CI) of 0.82(0.76-0.91). The additive model revealed that each additional allele contributed about 14% decreased risk (OR: 0.86, 95% CI: 0.77-0.95). Moreover, we observed a strong linkage disequilibrium between rs2234711 and rs3799488. Compared with the common rs2234711C-rs3799488C haplotype, the haplotype rs2234711T-rs3799488C contributed to a significant increase in the risk of tuberculosis (adjusted OR: 1.24, 95% CI: 1.09-1.41).

CONCLUSIONS

Our results suggest that genetic polymorphisms in IFNGR1 gene are involved in the risk of tuberculosis in the Chinese population. Future studies should include a comprehensive sequencing analysis to identify the specific causative sequence variants underlying the observed associations.

Detection of Mycobacterium avium subspecies paratuberculosis in patients with Crohn's disease is unrelated to the presence of single nucleotide polymorphisms rs2241880 (ATG16L1) and rs10045431 (IL12B)

Mycobacterium avium subspecies paratuberculosis (MAP) has been controversially linked with Crohn's disease (CD). Detection of MAP in CD has been highly variable, and one explanation might be the genetic heterogeneity of this syndrome. Many of the single nucleotide polymorphisms (SNPs) linked with CD are contained within genes that are associated with bacterial handling in general, and some are specifically implicated in susceptibility to mycobacterial disease. We tested a cohort of IBD patients (n = 149) to determine whether the presence of MAP was associated with a selection of these SNPs. Blood samples from CD patients (n = 84), ulcerative colitis (UC, n = 65) patients and healthy controls (n = 55) were examined for the presence of MAP and SNPs in ATG16L1, IL12B, NOD2/CARD15, NKx2-3, IL23R and IRGM. Statistical analysis was then used to determine whether there was any association between the presence of MAP and these SNPs. MAP, rs2241880 (ATG16L1) and rs10045431 (IL12B) were found to be significantly associated with CD. The presence of MAP was not related to the status of the SNPs in ATG16L1 or IL12B. We have found no evidence for the contribution of these SNPs to the presence of MAP in CD patients.

Levels of interleukin-(IL)-12p40 are markedly increased in Brucellosis among patients with specific IL-12B genotypes

Brucellosis remains a major zoonosis worldwide. Brucella antigens induce the production of T-helper 1 (Th1) cytokines such as interleukin-12 (IL-12) in humans. We aimed to investigate the association of two single nucleotide polymorphisms (SNPs) in the gene encoding the IL-12p40 cytokine (IL-12B) with brucellosis and to examine the functionality of these SNPs through measuring serum levels of IL-12p40. We genotyped IL-12B gene rs3212227, A>C; rs6887695 G>C polymorphisms in a case-control study on a total of 281 subjects including 153 patients with active brucellosis and 128 healthy controls, using RFLP and serum IL-12p40 levels, were assessed by ELISA. The rs3212227 minor allele (C) and homozygote genotype (CC) were more frequent in controls compared with patients with brucellosis (P = 0.006, OR = 0.608, 95%CI = 0.429-0.861 for the C allele; P = 0.024, OR = 0.443, 95% CI: 0.218-0.900 for the CC genotype). Comparison of IL-12B genotypes and serum levels of the IL-12p40 revealed that rs3212227 AA genotype, with higher frequency in patients than in controls, was associated with increased levels of the cytokine (P = 0.0001). Furthermore, the distribution of haplotype and genotype combinations in our study suggested that rs3212227C/rs6887695C haplotype or CC/GC or CC/CC genotype combinations may protect controls against Brucella infection by contributing to a functional downregulation of the serum IL-12p40 production in vivo, as shown by ELISA (P < 0.05). Overall, our study demonstrated that rs3212227 A variant was associated with higher levels of serum IL-12p40 and could possibly contribute to an inherited predisposition to brucellosis.

Personalized medicine approach in mycobacterial disease

Mycobacterial diseases are a group of illnesses that cause a considerable number of deaths throughout the world, regardless of years of public health control efforts. Personalized medicine is a new but rapidly advancing field of healthcare. Personalized medicine in the field of mycobacteriology may be applied in the different levels of management such as prevention, diagnosis, treatment and prognosis. A genetic predisposition and a protein dysfunction study are recommended to tailor an individual approach in mycobacterial diseases.

Effect of IL12A and IL12B polymorphisms on the risk of Chlamydia trachomatis-induced tubal factor infertility and disease severity

BACKGROUND

Interleukin-12 (IL-12) and related cytokines induce activation and differentiation of T cells. Our aim was to investigate the associations between genetic differences in IL-12-family cytokines and the pathogenesis of chlamydial disease.

METHODS

The final study population consisted of 100 women with Chlamydia trachomatis-induced tubal factor infertility (TFI) and 125 pregnant women as controls. Three single nucleotide polymorphisms (SNPs) of IL12A and seven SNPs of IL12B genes were determined from isolated DNA using the Sequenom system with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.

RESULTS

We found that the IL12B SNP rs3212227 was associated with both susceptibility and severity of TFI. The minor allele C was rare and only one CC homozygote was found among the controls. AC heterozygotes were more common among TFI cases than among controls (P = 0.009) and were associated with increased risk of TFI [odds ratios (OR) = 2.44, 95% confidence intervals (CI) = 1.23-4.87]. Carrying the minor allele C was also associated with disease severity (P for trend = 0.008) and moderate (OR = 2.51, 95% CI = 1.06-5.95) and severe tubal damage (OR = 2.73, 95% CI = 1.15-6.52).

CONCLUSIONS

The results suggest that variation in the IL12B gene partly explains inter-individual differences in disease susceptibility and severity.

Fine mapping of genetic polymorphisms of pulmonary tuberculosis within chromosome 18q11.2 in the Chinese population: a case-control study

BACKGROUND

Recently, one genome-wide association study identified a susceptibility locus of rs4331426 on chromosome 18q11.2 for tuberculosis in the African population. To validate the significance of this susceptibility locus in other areas, we conducted a case-control study in the Chinese population.

METHODS

The present study consisted of 578 cases and 756 controls. The SNP rs4331426 and other six tag SNPs in the 100 Kbp up and down stream of rs4331426 on chromosome 18q11.2 were genotyped by using the Taqman-based allelic discrimination system.

RESULTS

As compared with the findings from the African population, genetic variation of the SNP rs4331426 was rare among the Chinese. No significant differences were observed in genotypes or allele frequencies of the tag SNPs between cases and controls either before or after adjusting for age, sex, education, smoking, and drinking history. However, we observed strong linkage disequilibrium of SNPs. Constructed haplotypes within this block were linked the altered risks of tuberculosis. For example, in comparison with the common haplotype AA(rs8087945-rs12456774), haplotypes AG(rs8087945-rs12456774) and GA(rs8087945-rs12456774) were associated with a decreased risk of tuberculosis, with the adjusted odds ratio(95% confidence interval) of 0.34(0.27-0.42) and 0.22(0.16-0.29), respectively.

CONCLUSIONS

Susceptibility locus of rs4331426 discovered in the African population could not be validated in the Chinese population. None of genetic polymorphisms we genotyped were related to tuberculosis in the single-point analysis. However, haplotypes on chromosome 18q11.2 might contribute to an individual's susceptibility. More work is necessary to identify the true causative variants of tuberculosis.

Toll-like receptor 4 promotes tubular inflammation in diabetic nephropathy

Inflammation contributes to the tubulointerstitial lesions of diabetic nephropathy. Toll-like receptors (TLRs) modulate immune responses and inflammatory diseases, but their role in diabetic nephropathy is not well understood. In this study, we found increased expression of TLR4 but not of TLR2 in the renal tubules of human kidneys with diabetic nephropathy compared with expression of TLR4 and TLR2 in normal kidney and in kidney disease from other causes. The intensity of tubular TLR4 expression correlated directly with interstitial macrophage infiltration and hemoglobin A1c level and inversely with estimated glomerular filtration rate. The tubules also upregulated the endogenous TLR4 ligand high-mobility group box 1 in diabetic nephropathy. In vitro, high glucose induced TLR4 expression via protein kinase C activation in a time- and dose-dependent manner, resulting in upregulation of IL-6 and chemokine (C-C motif) ligand 2 (CCL-2) expression via IκB/NF-κB activation in human proximal tubular epithelial cells. Silencing of TLR4 with small interfering RNA attenuated high glucose-induced IκB/NF-κB activation, inhibited the downstream synthesis of IL-6 and CCL-2, and impaired the ability of conditioned media from high glucose-treated proximal tubule cells to induce transmigration of mononuclear cells. We observed similar effects using a TLR4-neutralizing antibody. Finally, streptozotocin-induced diabetic and uninephrectomized TLR4-deficient mice had significantly less albuminuria, renal dysfunction, renal cortical NF-κB activation, tubular CCL-2 expression, and interstitial macrophage infiltration than wild-type animals. Taken together, these data suggest that a TLR4-mediated pathway may promote tubulointerstitial inflammation in diabetic nephropathy.

The +874T/A polymorphism in the interferon-γ gene and tuberculosis risk: an update by meta-analysis

The +874T/A polymorphism in the interferon-γ (IFN-γ) gene has been extensively examined for association to tuberculosis (TB); however, results of different studies have been inconsistent. The aim of this study was to comprehensively analyze the genetic risk of the +874T/A polymorphism in IFN-γ gene for TB by meta-analysis. A total of 4553 cases and 4631 controls in 21 case-control studies were included in this meta-analysis. The results indicated that the variant T allele carriers had a 27% decreased risk of TB, when compared with the homozygote AA (odds ratio [OR] = 0.73, 95% confidence interval [CI] = 0.61-0.87 for TT + TA versus AA). In the subgroup analysis by ethnicity, significant decreased risks were associated with T allele carriers in Asians (OR= 0.71, 95% CI = 0.52-0.97, p = 0.03) but not in Caucasians (OR = 0.87, 95% CI = 0.65-1.17, p = 0.37). Our results suggest that the IFN-γ +874T/A polymorphism contributes to susceptibility to TB.