TLR4 Polymorphisms Research Articles

A Polymorphism in Toll-like Receptor 2 Gene Is Associated with Occurrence of Bacterial Infections in Sickle Cell Disease Patients

Background: Sickle cell disease (SCD) patients (pts) are at increased risk of infection. This susceptibility is partially explained by the loss of spleen function, but other factors such as inflammatory status might also play a role. Despite adequate immunization and antimicrobial prophylaxis, bacterial infection remains a major cause of morbidity and mortality in SCD pts. Toll-like receptors (TLR), transmembrane proteins that recognize a wide range of pathogen molecular patterns, are key receptors in innate immune response. The association among TLR and infections in SCD has scarcely been explored.Objective: To analyze if functional polymorphisms in TLR genes can modulate the susceptibility to bacterial infections in SCD pts.Methods: Case-control retrospective study; 430 SCD pts followed in university hospitals in Brazil (n=196), France (n=180, mainly from Subsaharan Africa and French West Indies) and Senegal (n=54) were included. Sites of bacterial infection were lower respiratory system, abdominal, upper urinary system, bone/joints, central nervous system, blood stream, or any site for tuberculosis. For pts who underwent hematopoietic stem cell transplant (HSCT), only bacterial infections before HSCT were considered. All pts were tested for 7 single nucleotide polymorphisms (SNP) in TLR-1(rs4833095), TLR-2 (rs4696480, rs3804099, rs3804100), TLR-6 (rs5743810) and TLR-10 (rs11466653, rs11096957) using TaqMan 5'-nuclease assay. Univariate analysis was performed with chi-square or Mann-Whitney for categorical and continuous variables respectively. Associations were measured by odds ratio (OR). For SNP associations, significant P-value corrected by Bonferroni (cP) was 0.007; for genetic models, cP was 0.01.Results: Median age of cohort was 30 years (range: 2-70) and 87% were ≥18 years; 57% of pts were female. SCD genotype was SS in 81%, SC in 11%, SB in 7% and other in 1%. Fifty-eight percent received hydroxyurea and 79% received red blood cell transfusions; seven pts underwent HSCT. Eleven pts died during follow-up, mostly from acute chest syndrome and hemorrhagic stroke. All pts had access to immunization against encapsulated bacteria and to penicillin prophylaxis. One hundred ninety-five pts (45%) did not present any bacterial infection, whereas 235 (55%) pts presented at least one episode of bacterial infection, of which 20% had ≥ 3 episodes. Bacterial infections were mainly respiratory (51%), bone/joints (23%) and urinary (20%). In 106 cases, etiological agents were identified; most common agents were Escherichia coli, Streptococcuspneumoniae, Mycobacterium tuberculosis and Salmonella spp. In univariate analysis, there was no association among occurrence of infections and gender, origin and age distribution. Gene analysis: all tested SNPs had a typing rate >90% and minimum allele frequency >1%. The TLR-2 SNP rs4696480 (n=425) showed significant association with infection (p<0.001). Next, we tested genetic models for this association. Distribution of rs4696480 genotypes was: infected - AA=35%, TA=50%, TT=15%; non infected - AA=28%, TA=67%, TT=5%. In the overdominant model, the heterozygous genotype (TA) occurred significantly more in non infected (67%) than in infected pts (50%) compared with TT+AA (OR 0.5, 95%CI 0.34-0.75, P<0.001). Also, in the recessive model, genotype TT occurred significantly more in infected (15%) than in non infected pts (5%) compared with TA+AA (OR 3.18, 95%CI 1.53-6.61, P<0.001). Furthermore, in comparison with an African/African-American population described in the 1000 genomes database (n=661), TA genotype was more frequent in SCD pts, and TT genotype was significantly less frequent. Other TLR SNPs genotype and haplotype analysis did not show any significant association with occurrence of infections.Discussion: In SCD pts, TLR-2 rs4696480 TA genotype might be protective against bacterial infections, whereas TT genotype might increase risk of such infections. Previous reports demonstrated higher secretion of inflammatory factors in cells from AA individuals, lower occurrence and severity of immune diseases in T carriers. TA genotype might stand between deleterious effects of over inflammatory response (AA genotype) and under response (TT genotype) to infectious agents. DisclosuresNo relevant conflicts of interest to declare.

Toll-like receptor 9 polymorphisms and Hepatitis B virus clearance in Moroccan chronic carriers

ObjectivesToll-like receptor 9 (TLR9) plays a crucial role in the innate immune response against viral infections. The failure of this system may result, in an attenuated immune response against HBV. Recent research has focused on the possibility of targeting the defects in TLR9 pathway as a novel approach for anti-HBV treatment. Our study aimed to assess the impact of both TLR9 rs5743836 and rs187084 polymorphisms on spontaneous HBV clearance in Moroccan chronic HBV carriers. MethodsIn this study, 239 individuals chronically infected with HBV (CHB) and 133 subjects who spontaneously resolved the infection (SRB) were genotyped using a Taqman allelic discrimination assay. Results/conclusionRemarkably, we observed a dosage effect of both SNPs on viral loads; with a significant increase of circulating HBV DNA within AA, AG to GG rs5743836 genotypes, whereas the inverse phenomenon was noticed within rs187084 genotypes. There were no consistent association between TLR9 polymorphisms and spontaneous clearance of HBV, however, a significant association was observed between rs187084 AA genotype and HBV progression to advanced liver disease. Further studies on larger populations might be necessary to understand the modulating effect of TLR9 polymorphisms on HBV loads that remain a viral factor of paramount importance to predict HCC development.

Association of TLR8 and TLR9 polymorphisms with tuberculosis in a Chinese Han population: a case-control study

BackgroundToll-like receptor (TLR) single nucleotide polymorphisms (SNPs) have been associated with regulation of TLR expression and development of active tuberculosis (TB). The objectives of this study were to determine whether TLR8 and TLR9 SNPs were associated with the development of latent TB infection (LTBI) and the subsequent pulmonary TB (PTB) in a Chinese Han population.MethodsTwo independent samples were enrolled. The first sample contained 584 TB cases and 608 controls; the second sample included 204 healthy controls, 201 LTBI subjects and 209 bacteria-confirmed active PTB patients. Three SNPs (rs3764880, rs187084 and rs5743836) were genotyped. The associations between the SNPs and risk of LTBI or PTB were investigated using unconditional logistic regression analysis.ResultsThe A-allele of TLR8 rs3764880 SNP was protective against the development of TB in males (A vs G, OR = 0.58, 95%CI = 0.37–0.91). The AA genotype of rs3764880 SNP was found to increase the risk of PTB among females with an OR of 4.81 (1.11–20.85). The G allele of TLR9 SNP rs187084 was found to increase the risk of PTB (G vs A, P = 0.01, OR = 1.48, 95% CI = 1.10–2.00), the significance was also observed under dominant genetic models. The GA-genotype of TLR9 rs187084 SNP was found to increase the risk of PTB with an OR of 1.68 (1.07–2.65), but was found to decrease the risk of MTB infection with an OR = 0.64 (0.41–0.98). TLR9_rs5743836 SNP was excluded from the data analyses, because the minimum allele frequency was< 1%.ConclusionsOur findings in two independent samples indicated that SNPs in TLR8 and TLR9 were associated with the development of TB, and highlight that SNPs may have different effects on disease pathogenesis and progression.

Potential role of Toll-like receptor 2 expression and polymorphisms in colon cancer susceptibility in the Saudi Arabian population.

BackgroundInflammation is a fundamental factor that contributes to the development and progression of several types of cancer including colon cancer. Toll-like receptors (TLRs) and their signaling pathways have been reported to be associated with chronic inflammation and thereby induced cancer. Our aim was to investigate the expression and polymorphisms of TLR2 and their association with colon cancer.MethodsReal-time PCR and immunohistochemistry were used to investigate TLR2 gene expression and to evaluate the potential risk of predisposition to colon cancer caused by three tagging single-nucleotide polymorphisms (SNPs) on TLR2, including rs3804100, rs4696480, and rs3804099. TaqMan assay was conducted on samples from 115 patients with colon cancer and 102 age- and sex-matched normal individuals.ResultsWe found that, TLR2 was highly expressed in epithelial colon cancer cells and both TLR2 mRNA and protein levels, and significantly decreased in tumor tissues compared to normal tissues. Two of three TLR2 SNPs increased the risk of colon cancer. However, TLR2 rs3804099 increased the risk of colon cancer development by more than 3.8- and 5-fold in female patients and patients aged less than 57 years, respectively. The T allele of TLR2 rs3804100 showed a significant association with patients less than 57 years. In silico analysis of the TLR2 nucleotide substitution in SNP rs3804100 and rs3804099 determined that 67% and 70% probability of these single nucleotide variants alter splicing phenotypes, rs3804100 more specifically result on activating an additional splice site. Genotype and allele frequencies of rs4696480 were similar between the overall study populations. Thus, TLR2 rs4696480 appear to be not involved in colon cancer in our study population.ConclusionsThere was a significant link between innate immunity deregulation through disruption of the TLRs and potential development of colon cancer. These SNPs can be used as screening markers for predicting colon cancer risk earlier in life to implement necessary prevention.

The regulatory role of Toll-like receptors after ischemic stroke: neurosteroids as TLR modulators with the focus on TLR2/4.

Ischemic stroke is the most common cerebrovascular disease and considered as a worldwide leading cause of death. After cerebral ischemia, different pathophysiological processes including neuroinflammation, invasion and aggregation of inflammatory cells and up-regulation of cytokines occur simultaneously. In this respect, Toll-like receptors (TLRs) are the first identified important mediators for the activation of the innate immune system and are widely expressed in glial cells and neurons following brain trauma. TLRs are also able to interact with endogenous and exogenous molecules released during ischemia and can increase tissue damage. Particularly, TLR2 and TLR4 activate different downstream inflammatory signaling pathways. In addition, TLR signaling can alternatively play a role for endogenous neuroprotection. In this review, the gene and protein structures, common genetic polymorphisms of TLR2 and TLR4, TLR-related molecular pathways and their putative role after ischemic stroke are delineated. Furthermore, the relationship between neurosteroids and TLRs as neuroprotective mechanism is highlighted in the context of brain ischemia.

TLR4 Polymorphisms and Expression in Solid Cancers.

Toll-like receptors (TLRs) are a type of pattern-recognition receptor (PRR) that are part of the innate immune system known to recognize pathogen-associated molecular patterns and thereby play a crucial role in host immune response. Among the various known TLRs, TLR4 is one of the most extensively studied PRRs expressed by immune, certain nonimmune, and tumor cells. When TLR4 binds with the bacterial lipopolysaccharide, it induces production of proinflammatory cytokines, chemokines, and effector molecules as part of the immune response. Continuous exposure to pathogens and TLR4 signaling results in chronic inflammation that may further lead to malignant transformation. TLR4 is a highly polymorphic gene, and genetic variations are known to influence host immune response, leading to dysregulation of signaling pathway, which may affect an individual's susceptibility to various diseases, including cancer. Furthermore, TLR4 expression in different tumor types may also serve as a marker for tumor proliferation, differentiation, metastasis, prognosis, and patient survival. This review aims to summarize various reports related to TLR4 polymorphisms and expression patterns and their influences on different cancer types with a special focus on solid tumors.

Significance of CCL2 (−2518A/G), CCR2 (190G/A) and TLR4 polymorphisms (896 A/G and 1196C/T) in tuberculosis risk in Indian population

Tuberculosis remains one of the major health burden worldwide; with substantial mortality in Indian population. Several host gene polymorphisms have been studied wherein association between variations in host genes and susceptibility or resistance to tuberculosis have been reported. In the present study, we aimed at investigating the effect of polymorphisms of CCL2, CCR2 and TLR4 genes on risk of acquiring tuberculosis in Indian population. The CCL2 (−2518A/G) and TLR4 (D299G or 896A/G & T399I or 1196C/T) gene polymorphisms were studied by PCR-RFLP method, while the CCR2 (V64I or 190G/A) gene polymorphism was done by ARMS-PCR method. Our findings revealed that the frequencies of the risk alleles ‘G’ and ‘T’ of TLR4 896 A/G and 1196C/T polymorphisms were significantly (p = 0.05) higher in TB cases than in healthy controls with higher odds (OR = 1.73 and 1.78 respectively). The risk allele ‘A’ of the CCR2 190G/A gene polymorphism showed a trend towards increased frequencies of ‘GA’ and ‘AA’ genotypes in TB patients as compared to healthy subjects with higher odds (2.06) of developing TB when in homozygous (AA) condition. Our findings indicate that the presence of variant alleles of genes CCR2 (190 G to A) and TLR4 (896A/G & 1196C/T) make Indian population vulnerable towards developing tuberculosis. Further, analysis with larger sample sizes is required to support our findings, which may allow application of these biomarkers for better management of tuberculosis in Indian population.

Single nucleotide polymorphisms of TLR-2, TLR-3, TLR-4 and susceptibility to inflammatory diseases of the respiratory tract

The aim of the research is to establish an association between Arg753Gln polymorphism of TLR-2 gene, Leu412Phe of TLR-3 gene, Asp299Gly of TLR-4 gene and susceptibility to inflammatory diseases of the upper and lower respiratory tract and the complicated forms of АRI development. Materials and methods . 98 healthy subjects distributed according to the genotype of TLR-2, TLR-3, TLR-4 were enrolled in the study of association between Arg753Gln polymorphism of TLR-2, Leu412Phe of TLR-3 and Asp299Gly of TLR-4 genes and inflammatory diseases of the upper and lower respiratory tract. The polymorphic site of TLR-2 Arg753Gln, TLR-3 Leu412Phe and TLR-4 Asp299Gly genotyping was performed by polymerase chain reaction using oligonucleotide primers. The relative risk of the disease and complications development was estimated using the odds ratio with 95 % confidence interval. The statistical significance of differences in qualitative characteristics was evaluated using Fischer's exact test. Results. It has been revealed that individuals with polymorphic TLR-2, TLR-3 and TLR-4 genes have an increased susceptibility to АRI with frequent episodes during the year that are complicated by lower respiratory tract inflammation as well as chronic inflammatory diseases of the upper respiratory tract. It has been shown that the risk of bronchitis and pneumonia development in АRIs is higher in subjects with polymorphic genotypes of TLR-2, TLR-3 and TLR-4 as compared to the carriers of normal alleles distribution: 2.9 times with Leu/Phe genotype of TLR-3, 20.0 times with Phe/Phe of TLR-3 and 12.8 times with combinations of polymorphic genotypes of TLR-2, TLR-3, TLR-4. Conclusions. The results of the study indicate that the presence of single-nucleotide polymorphisms TLR-2 Arg753Gln, TLR-3 Leu412Phe and TLR-4 Asp299Gly is the marker of high susceptibility to respiratory diseases. Individuals with polymorphic status of TLR-2, TLR-3 and TLR-4 genotypes have an increased susceptibility to inflammatory diseases of the upper and lower respiratory tract with АRI frequency of 4 or more episodes during the year.

Association of Toll-like receptor 4 polymorphism with hepatitis E virus-infected Indian patients.

Hepatitis E infection caused by hepatitis E virus (HEV), a major public health concern in developing countries, is responsible for sporadic and epidemic acute viral hepatitis in adults. Pathogenesis of hepatitis E infection is poorly understood. Toll-like receptors (TLRs) are the key players of innate immunity recognize pathogen-associated molecular patterns (PAMPs). Previously, we found higher TLR4 expression (at protein and gene level) with impaired cytokine response upon stimulus of PBMCs with LPS in HEV-infected patients. In view of the earlier observations of the association of polymorphisms in TLR4 genes (A299G, C399T) with liver diseases, we investigated TLR4 polymorphisms in HEV-infected patients. We observed the significant association of TLR4-399CC and CT alleles with hepatitis E (both subclinical and acute patients). Carrier frequency of TLR4-399 CT was lower in patients' categories in comparison with the controls. Higher frequency of allele TLR4-399C significantly correlated with disease progression. Acute hepatitis E patients showed the higher frequency of CG and TA haplotypes, while the rare haplotype (TG) was more frequent in controls. The other single nucleotide polymorphism (SNP) at TLR4-299 (A>G) did not show any difference. We report here for the first time the association of TLR4 polymorphism with hepatitis E and suggest that TLR 4 hyporesponsiveness during HEV infection might be related to its polymorphism.

Association between TLR4 polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and virulence factors in uropathogenic Escherichia coli.

Escherichia coli is the main etiological agent of urinary tract infections. Its virulence factors are important during the initial interaction stage with the host as they enable colonization of urinary tract tissues. The genetic markers evidencing susceptibility to develop recurrent infections have been previously described. Toll-like receptors are critical sensors of microbial attacks, and they are also effectors of the individual's innate defense for elimination of pathogens. The aim of this study was to evaluate the association between functional polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and susceptibility to develop urinary tract infections as well as E. coli virulence factors. This study includes 100 samples from patients diagnosed with UTI and 100 samples from uninfected subjects. A conventional urine culture was performed and the isolates were identified by using the Vitek automated system. TLR4 gene polymorphisms were identified by the PCR-RFLP technique. The hlyA, fimH, papC, iutA and cnf1 virulence factors as well as the E. coli phylogenetic group were assessed by PCR. In this study, it was observed that the presence of the - 2570 polymorphism represents a risk of UTI (p < 0.01), whereas - 2081 confers protection (p < 0.01). The 896A>G and 1196C>T polymorphisms were associated with the E. coli virulence factors fimH and hlyA, respectively (p < 0.05). The B2 group was the most frequent in clinical isolates (51%), and it displayed more virulence factors regarding other phylogenetic groups (p ≤ 0.05). An interesting finding was that strains considered as commensals, belonging to groups A and B1, can cause UTI and present virulence factors. Polymorphisms occurring in the TLR4 promoter region are correlated with susceptibility or risk of UTI, whereas structural polymorphisms are associated with the recognition of virulence factors displayed by E. coli.

The Relationship of the TLR9 and TLR2 Genetic Polymorphisms with Cervical Cancer Risk: a Meta-Analysis of Case-Control Studies.

This meta-analysis aimed to assess the association of common TLR9 and TLR2 gene polymorphisms (TLR9 1486T/C, TLR9 G2848A, and TLR2-196 to -174 del/ins) with cervical cancer risk. Studies were searched in Scopus, Pubmed, Embase, and CNKI until December 2017. Both fixed-effects and random-effects models were applied to combine odds ratio (OR) and 95% confidence intervals (95% CI). A total of 11 studies including 7856 participants were identified. The pooled estimation revealed an increased risk of cervical cancer in Caucasian subjects carrying the C allele of the TLR9 1486T/C polymorphism (OR = 1.46, 95% CI: 1.11-1.92, p = 0.007), while there was a decreased risk in Mixed subjects carrying the C allele (OR = 0.35, 95% CI: 0.15-0.82, p = 0.016). Concerning the TLR9 G2848A polymorphism, the A allele was associated with an increased risk of cervical cancer in Caucasians (OR = 1.19, 95% CI: 1.02-1.40, p = 0.030), whereas Asian and Mixed subjects showed no significant associations. No significant associations were demonstrated between the TLR2-196 to -174 del/ins polymorphism and cervical cancer. Our findings suggest that the TLR9 1486T/C and G2848A polymorphisms contribute to cervical cancer risk, but there is no association of the TLR2-196 to -174 del/ins polymorphism with cervical cancer.

Role of variants rs5030717 and rs5030718 of TLR4 in the risk prediction of nephropathy, hypertension and dyslipidaemia in type 2 diabetes mellitus

ABSTRACTBackground: Type 2 diabetes mellitus describes a metabolic disorder characterised by prolonged elevated blood glucose that brings a risk of developing microvascular and macrovascular disease. Several factors, such as dysregulation of the Toll-like receptor 4 (TLR-4), are reputed to contribute to the multiple pathophysiological disturbances responsible for impaired glucose homeostasis. We hypothesised that variants rs5030717 and rs5030718 of TLR4 are associated with diabetic nephropathy, hypertension and dyslipidaemia.Material & methods: We recruited 370 diabetics (122 with nephropathy, 119 with hypertension and 129 with dyslipidaemia) and 120 ethnicity matched healthy controls. TLR4 polymorphisms were evaluated using polymerase chain reaction followed by restriction fragment length polymorphism analysis. The genotyping data were compared between cases and controls using chi-square test and logistic regression analysis.Results: Although there was no overall difference in the genotype frequencies of TLR4 rs5030717 in diabetes v controls, the genotype frequencies of diabetic dyslipidaemia cases compared with controls were different (p = 0.001). Overall, the rs5030718 GA and GG genotype frequencies in the entire diabetes cohort were different from those of the controls (p = 0.037), and the frequencies of diabetic nephropathy cases (p = 0.03) and diabetic dyslipidaemia cases were different (p = 0.001) compared with controls. There were no links with diabetic hypertension.Conclusion: TLR4 polymorphisms rs5030717 and rs5030718 may be useful in predicting those type 2 diabetics who are at risk of hypertension, nephropathy and/or dyslipidaemia.

Enhancing the immune stimulatory effects of cetuximab therapy through TLR3 signalling in Epstein-Barr virus (EBV) positive nasopharyngeal carcinoma

ABSTRACT Cetuximab immunotherapy targeting the epidermal growth factor receptor (EGFR) has been used to treat nasopharyngeal cancer (NPC) with some success. Therefore, combining an immune adjuvant to boost the immune microenvironment may improve its clinical efficacy. Herein, we investigate the immune-stimulatory effects of Poly-ICLC (a TLR3 agonist) in enhancing cetuximab-based immunotherapy and correlate these responses with FcɣRIIIa (V158F) or TLR3 single nucleotide polymorphisms (SNPs- L412F and C829T) expressed on immune effector cells. We observed high levels of TLR3 mRNA in NPC cells; and both TLR3 and EGFR expression were unaffected by Poly-ICLC treatment. Cetuximab plus Poly-ICLC significantly enhanced NK-mediated ADCC through up-regulation of CD107a and Granzyme B expression. This effect was independent of FcɣRIIIa-V158F and TLR3-L412F or TLR3-C829T polymorphisms expressed on NK cells. Additionally, IFN-ɣ expression and secretion were doubled following cetuximab plus poly-ICLC treatment; compared to either treatment alone. This effect was independent of TLR3 polymorphisms. Consequentially, adaptive immune responses were also seen with increased DC maturation (CD83), co-stimulatory molecules expression (CD80 and CD86) and increased frequency of EGFR-specific CD8 + T cells following Poly-ICLC treatment. The percentage of CD80+ CD83+ and CD83+ CD86+ DC was highest in the Poly-ICLC plus cetuximab group, compared to either treatment alone. These results demonstrate the effectiveness of Poly-ICLC in enhancing both cetuximab-mediated innate and adaptive anti-tumor immunity against NPC, which is independent of FcɣRIIIa-158, TLR3-L412F or TLR3-C829T polymorphisms. Additionally, Poly-ICLC does not downregulate EGFR expression on NPC cells and hence, will not dampen cetuximab anti-tumor activity.

Maternal exposure to farming environment protects offspring against allergic diseases by modulating the neonatal TLR-Tregs-Th axis

BackgroundAs the development of urbanization in China, the morbidity of allergic disease rise up prominently even in children, which may be partially associated with the excessively clean environment. It has been reported that common microorganism in rural environment shows protective effects on allergic disease by modulating TLRs-Tregs/Th cell axis. But the mechanism of this protection still needs to be elucidated in detail. We investigated the effects of maternal exposure to farming environment on the neonatal innate immune system, especially on the TLR-Treg-Th (Th1, Th2, Th9, and Th17) axis, in the Jilin province of China.MethodsEighty-four non-farming and 42 farming pregnant women were recruited. Endotoxins and glucans in dust from the living rooms of the pregnant mothers were measured. Cord blood mononuclear cells were challenged with phytohemagglutinin, lipopolysaccharide, or peptidoglycan. Proliferative response of lymphocyte was measured by 3H-TdR incorporation methods, CD4 + CD25 + FOXP3 + T cells percentage was assessed with flow cytometry, Tregs specific genes (FOXP3, LAG3, GITR, CTLA-4 and TGF-β) and TLR2, TLR4 genes expression were detected by RT-PCR, specific cytokines of Th1, Th2, Th9, Th17 and Tregs were measured with flow cytometer, suppressive capacity of Tregs was tested by culturing with effector cells in vitro, and TLR2/4 gene polymorphism was detected.ResultsHigher endotoxin content was observed in the living rooms of the farming mothers. Compared with that in the non-farming group, in farming neonatal CBMCs, lymphocyte proliferation declined; the IFN-γ/IL-13 ratio increased; and the quantity of Tregs and gene expression of FOXP3, GITR, CTLA4 and TLR2 increased significantly (P < 0.05). Isolated Tregs suppressed the proliferation of effector T cells and IL-13 production more strongly in vitro (P = 0.04, 0.03, respectively), and the TLR2 polymorphism affected FOXP3 expression and IFN-γ and IL-13 production.ConclusionsMaternal exposure to farming affected the quantity and function of neonatal Tregs upon stimulation with PPG and LPS, which partly contributed to reducing the risk for allergic diseases in the offspring. The results of our study will lay the theoretical foundation for allergic disease prevention in early life.

Progress of research on toll-like receptors family gene polymorphism and susceptibility to tuberculosis

Tuberculosis is a chronic infectious disease caused by Mycobacterium (M.) tuberculosis. Innate immunity plays an important role in the response to M. tuberculosis. Toll-like receptors (TLRs) are important pattern recognition receptors in innate immunity. TLRs serve as switches that play decisive roles in identifying pathogens-related components. Previous studies found that TLR1, TLR2, TLR4, TLR9 were essential to promote the development of innate immune responses. The SNPs of rs4833095, rs5743618, rs3923647 of TLR1, rs57473708, rs3804099 of TLR2 and rs352139, rs5743836 of TLR9 were closely related to the susceptibility of tuberculosis in some populations. And there appeared certain relationship between the polymorphisms of TLR3, TLR6, TLR7, TLR8, TLR10 and the susceptibility of tuberculosis. The normal function of TLRs ensures the body's normal immune response to M. tuberculosis. The diversity of TLRs genes allows different individuals to respond differently to the same pathogen. Studies targeting on the relationship between single nucleotide polymorphism in TLRs and susceptibility to tuberculosis can predict the susceptibility to tuberculosis in some populations, as well as discover new drugs targets.

The Possible Role of Gene Variant Coding Nonfunctional Toll-Like Receptor 2 in the Pathogenesis of Mastocytosis

Background: Data on the genetic predisposition to mastocytosis are scarce. The aim of this work was to study the association of single nucleotide polymorphisms of Toll-like receptor (TLR)-2, TLR-4, and TLR-9 genes in Polish patients with mastocytosis. Objectives: The study comprised 137 patients with mastocytosis (102 cutaneous [60 children and 42 adults] and 35 systemic cases); 171 disease-free individuals were used as controls. Method: The frequency of polymorphisms R753Q (rs5743708) of TLR-2, 896 A>G (rs496790) of TLR-4, and –1237C>T (rs5743836) of TLR-9 genes were determined with the use of the amplification refractory mutation system polymerase chain reaction method. Results: It was found that the R753Q TLR-2 gene polymorphism was significantly more frequent in patients with mastocytosis in comparison to healthy controls (p = 0.037) and in the group of SM versus controls (p = 0.0076). The presence in the genotype 753Q variant of TLR-2 gene increased the risk of mastocytosis more than 2-fold (OR 2.51; p = 0.04), and the risk of SM more than 4-fold (OR 4.22; p = 0.01). TLR-4 and TLR-9 polymorphisms were not associated with mastocytosis. Conclusions: Our results suggest that the R753Q polymorphism of the TLR-2 gene may be involved in the pathogenesis of mastocytosis.

Evaluation of the detection of Toll-like receptors (TLRs) in cancer development and progression in patients with colorectal cancer.

BackgroundToll-like receptors (TLRs) play essential role in innate and acquired immunity, are expressed in various cell types, and are associated with altered susceptibility to many diseases, and cancers. The aim of this study was to investigate TLR2 (-196 to-174del), TLR4 (Asp299Gly and Thr399Ile) and TLR9 (T1237C and T1486C) gene polymorphisms at risk of colorectal cancer (CRC) development and progression.MethodsPeripheral blood was obtained from 397 patients with adjuvant (stage II/III, n = 202) and metastatic (n = 195) CRC. Moreover, blood samples from 50 healthy volunteers and 40 patients with adenomatous polyps were also included as control groups. DNA from patients and controls was analyzed using PCR and PCR-RFLP for genotyping functional polymorphism within TLR2, TLR4 and TLR9 genotypes.ResultsTLR2–196 to-174del/del genotype was detected in 76.6% of the patients and was significantly higher that the controls groups (p<0.001). TLR4 Asp299Gly, TLR4 Thr399Ile, TLR9 T1237C and T1486C homozygous genotypes were detected in 70.5%, 70.5%, 61.5% and 61.5% of the patients respectively, and were also significantly higher than that in the control groups (p<0.001). All polymorphisms detected were also significantly associated with the metastatic disease (p<0.001) leading to shorter overall survival (p<0.001); whereas, TLR4 Asp299Gly and Thr399Ile polymorphisms were significantly associated with KRAS mutations.ConclusionsThe detection of higher frequencies of the TLR2, TLR4 and/or TLR9 polymorphisms in CRC patients compared with the control groups highlight the role of these polymorphism in CRC development and cancer progression.

Evaluation of TLR2, TLR4, and TOLLIP polymorphisms for their role in tuberculosis susceptibility.

Previous studies indicated that single-nucleotide polymorphisms (SNPs) of genes coding for toll-like receptors (TLRs) and toll-interacting protein (TOLLIP) may be involved in the pathogenesis of pulmonary tuberculosis (PTB). This study was designed to investigate potential associations between the polymorphisms in TLR2, TLR4, and TOLLIP and susceptibility to latent tuberculosis infection (LTBI) or subsequent PTB in a Chinese Han population. A total of 209 PTB and 201 LTBI patients and 204 healthy control subjects (HCS) were enrolled in our study. We performed a logistic regression including sex and age as covariates to test the effect of genotype. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR). Eleven markers in TLR2, TLR4, and TOLLIP were assessed. No significant association between polymorphisms of TLR2 and TLR4 with PTB or LTBI was detected. For TOLLIP, rs5743899 (p=0.005, OR=1.83, 95% CI: 1.20-2.80) CC genotype were risk factors for PTB progression. Moreover, rs5743867 under addictive (p=0.005, OR=1.54, 95% CI: 1.14-2.07) and recessive model (p=0.004, OR=1.86, 95% CI: 1.22-2.83) were also risk factors for PTB susceptibility. Our results indicate that polymorphisms in TOLLIP affected the risk of PTB disease.

Association of the TLR4 and NOD2 Polymorphisms with Childhood Acute Lymphoblastic Leukemia

Association of the TLR4 and NOD2 Polymorphisms with Childhood Acute Lymphoblastic Leukemia

Toll-like receptor 2, 4 and 9 polymorphisms and their association with ICU-acquired infections in Central Greece

PurposeTo test the potential of four common Toll-like receptor (TLR) polymorphisms to predispose to specific intensive care unit (ICU)-acquired infections and affect outcomes in a Greek ICU. Materials and methodsThe incidence of TLR2-Arg753Gln, TLR4-Asp299Gly, TLR4-Thr399Ile and TLR9-T1237C polymorphisms, and their association with ICU-acquired infections and patients' clinical outcomes were prospectively evaluated The examined genetic polymorphisms were assessed by real-time Polymerase-Chain-Reaction (PCR). ResultsDuring a 15-month period, 224 patients were enrolled and genotyped. The prevalence of genetic polymorphisms for TLR4-Asp299Gly, TLR4-Thr399Ile, mixed TLR4-Asp299Gly/Thr399Ile, TLR9-T1237C and TLR2-Arg753Gln was 14.4%, 14.7%, 11.2%, 24.5% and 2.2%, respectively.TLR4 polymorphisms were associated with increased susceptibility towards specific ICU-acquired infections, i.e. Gram-negative central-nervous-system infections (CNSI), ventilator-associated pneumonia (VAP) and urinary-tract infections (UTI), principally due to multi-drug resistant (MDR) Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumonia, respectively (all P < 0.05). TLR9-T1237C polymorphism was associated with lower incidence and fewer relapses of CNSIs and UTIs when compared to mixed TLR4-Asp299Gly/Thr399Ile polymorphism group (P ≤ 0.039).ICU-stay was significantly prolonged in TLR4 polymorphisms (P ≤ 0.0416). ConclusionsCommon TLR-signaling polymorphisms might be implicated in the clinical phenotype of ICU-acquired infections in Central Greece. The possible impact of TLR4 polymorphisms on enhanced susceptibility towards Gram-negative MDR-infections in defined critical-disease states warrants further investigation.Trial Registration Clinical Trials.gov identifier: NCT00932243