Identification of haplotype tag SNPs within the entire TLR2 gene and their clinical relevance in patients with major trauma

FURIN, IFNL4, and TLR2 gene polymorphisms in relation to COVID-19 severity: a case-control study in Egyptian patients

BACKGROUND AND AIM

A wide range of clinical manifestations and outcomes, including liver injury, have been reported in COVID-19 patients. We investigated the association of three substantial gene polymorphisms (FURIN, IFNL4, and TLR2) with COVID-19 disease susceptibility and severity to help predict prognosis.

METHODS

150 adult COVID-19-assured cases were categorized as follows: 78 patients with a non-severe presentation, 39 patients with severe disease, and 33 critically ill patients. In addition, 74 healthy controls were included. Clinical and laboratory evaluations were carried out, including complete and differential blood counts, D-dimer, lactate dehydrogenase (LDH), C-reactive protein (CRP), procalcitonin, ferritin, interleukin-6 (Il-6), and liver and kidney functions. FURIN (rs6226), IFNL4 (rs12979860), and TLR2 (rs3804099) genotyping allelic discrimination assays were conducted using real-time PCR.

RESULTS

The FURIN, IFNL4, and TLR2 genotypes and their alleles differed significantly between COVID-19 patients and controls, as well as between patients with severe or critical illness and those with a non-severe presentation. According to a multivariable regression analysis, FURIN (C/T + T/T) and TLR2 (T/C + C/C) mutants were associated with COVID-19 susceptibility, with odds ratios of 3.293 and 2.839, respectively. FURIN C/C and IFNL4 T/T mutants were significantly linked to severe and critical illnesses. Multivariate regression analysis showed that FURIN (G/C + C/C) genotypes and IFNL4 T/T homozygosity were independent risk factors associated with increased mortality.

CONCLUSION

FURIN, IFNL4, and TLR2 gene variants are associated with the risk of COVID-19 occurrence as well as increased severity and poor outcomes in Egyptian patients.

Association of Single Nucleotide Polymorphisms from Angiogenesis-Related Genes, ANGPT2, TLR2 and TLR9, with Spontaneous Preterm Labor

In this study, we hypothesized that the changes localized at angiopoietin-2 (ANGPT2), granulocyte-macrophage colony-stimulating factor (CSF2), fms-related tyrosine kinase 1 (FLT1) and toll-like receptor (TLR) 2, TLR6 and TLR9 genes were associated with spontaneous preterm labor (PTL), as well as with possible genetic alterations on PTL-related coagulation. This case-control genetic association study aimed to identify single nucleotide polymorphisms (SNPs) for the aforementioned genes, which are correlated with genetic risk or protection against PTL in Polish women. The study was conducted in 320 patients treated between 2016 and 2020, including 160 women with PTL and 160 term controls in labor. We found that ANGPT2 rs3020221 AA homozygotes were significantly less common in PTL cases than in controls, especially after adjusting for activated partial thromboplastin time (APTT) and platelet (PLT) parameters. TC heterozygotes for TLR2 rs3804099 were associated with PTL after correcting for anemia, vaginal bleeding, and history of threatened miscarriage or PTL. TC and CC genotypes in TLR9 rs187084 were significantly less common in women with PTL, compared to the controls, after adjusting for bleeding and gestational diabetes. For the first time, it was shown that three polymorphisms-ANGPT2 rs3020221, TLR2 rs3804099 and TLR9 rs187084 -were significantly associated with PTL, adjusted by pregnancy development influencing factors.

The Role of Toll-Like Receptor-2 in Clostridioides difficile Infection: Evidence From a Mouse Model and Clinical Patients

Background

Clostridioides difficile is the leading cause of nosocomial infectious diarrhea. Toll-like receptors (TLRs) are the major components of innate immunity that sense pathogens. The relationship between TLRs and C. difficile infection (CDI) was analyzed in clinical patients and a mouse model.

Materials and Methods

A prospective investigation was conducted in medical wards of Tainan Hospital, Ministry of Health and Welfare, Tainan, Taiwan, from January 2011 to January 2013. Adult patients were followed up for the development of CDI. Single nucleotide polymorphisms (SNPs) of TLR2 and TLR4 were analyzed to assess the relationship between genetic polymorphisms and the development of CDI. A mouse model of CDI was used to investigate the pathogenic role of TLRs in CDI, TLR2 and TLR4 knockout (Tlr2-/- and Tlr4-/-) mice.

Results

In the prospective study, 556 patients were enrolled, and 6.5% (36) of patients, accounting for 3.59 episodes per 1000 patient-days, developed CDI. Of 539 patients with available blood samples, the TLR2 rs3804099 polymorphism was more often noted in those with CDI than in those without CDI (64.5% vs. 46.1%; P = 0.046) but was not significant in multivariate analysis. Because the TLR2 rs3804099 polymorphism was moderately associated with CDI, the role of TLR2 and TLR4 was further evaluated in a mouse model. Both Tlr2-/- and Tlr4-/- mice showed more severe CDI disease than wild-type mice in terms of body weight change and fecal content five days after oral challenge with C. difficile. Furthermore, Tlr2-/- mice suffered from more severe disease than Tlr4-/- mice, as evidenced by stool consistency, cecum weight, and survival rate.

Conclusion

The TLR2 rs3804099 polymorphism is marginally associated with the development of CDI, and the pathogenic role of TLR2 is further supported by a mouse model.

Genetic variants in TNFA, LTA, TLR2 and TLR4 genes and risk of sepsis in patients with severe trauma: nested case-control study in a level-1 trauma centre in SERBIA

INTRODUCTION

Single nucleotide variants (SNVs) represent important genetic risk factors for susceptibility to posttraumatic sepsis and a potential target for immunotherapy. We aimed to evaluate the association between 8 different SNVs within tumor necrosis factor alpha (TNFA), lymphotoxin alpha (LTA) and Toll-like receptor (TLR2 and TLR4) genes and the risk of posttraumatic sepsis.

METHODS

Nested case-control study was conducted in the emergency department of the Clinical Centre of Serbia including 228 traumatized patients (44 with sepsis and 184 without sepsis). To compare the results of trauma subjects with the data from the general population, a control group of 101 healthy persons was included in the study. Genotyping of TNFA (rs1800629 and rs361525), LTA (rs909253), TLR2 (rs3804099, rs4696480 and rs3804100), and TLR4 (rs4986790 and rs4986791) was performed for all patients within all three groups using the real-time PCR method. MutationTaster database and in silico software SIFT were used to predict the variant pathogenic effect.

RESULTS

Carriage of the G allele of the TNFA rs1800629 gene variant (OR 2.1, 95%CI 1.06-4.16) and T allele-carriage of the TLR4 rs4986791 genetic variant (OR 3.02, 95%CI 1.31-6.57) were associated with significantly higher risk of sepsis in trauma patients when compared to the general population prone to sepsis and traumatized patients without developing a sepsis, respectively. Of these two variants, only variant in TLR4 gene (rs4986791) has been labeled as disease causing by both the MutationTaster database and the in-silico software SIFT, which further supports the role of this variant in various pathologies including sepsis. For the remaining six variants no significant association with the susceptibility to sepsis was detected.

CONCLUSIONS

Carriage of the G allele of the TNFA rs1800629 gene variant and T allele-carriage of the TLR4 rs4986791 genetic variant confer significant risk of posttraumatic sepsis. TLR4 gene variants (rs4986790 and rs4986791) has been labelled as disease causing.

The Association of rs1898830 in Toll-Like Receptor 2 with Lipids and Blood Pressure

BACKGROUND AND OBJECTIVE

Toll-like receptors (TLRs) are important components of the innate immune system, involved in establishing immunity to infections. Apart from being implicated in immunity, numerous studies have reported that many TLRs, including TLR2, are involved in the pathogenesis of cardiovascular diseases and their risk factors. Since rs1898830 is associated with TLR2-mediated cellular activation, we aimed to study its association with CVD risk factors, such as lipid levels and hypertension.

METHODS

A cross-sectional study was conducted on 460 individuals free from chronic diseases. Clinical and biological data were collected and DNA was extracted and genotyped using Kompetitive allele specific PCR (KASP™). Multiple logistic regression models, adjusted for six covariates, were used. A power calculation analysis was also performed.

RESULTS

We found that rs1898830 in TLR2 was positively associated with hypertension (OR = 2.18, p = 0.03) and negatively associated with high-density lipoprotein cholesterol (OR = 0.66, p = 0.05). In contrast, no relation was found with total cholesterol and low-density lipoprotein cholesterol.

CONCLUSION

The present results provide additional evidence supporting the implication of TLR2 in CVD risk factors.

The association of inflammasome and TLR2 gene polymorphisms with susceptibility to tuberculosis in the Han Taiwanese population

Pulmonary tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is a global public health concern. Although inflammasome and the toll-like receptor 2 (TLR2) genes play an important role in host defense against Mtb, the associations of polymorphisms in these genes with TB risk are incompletely understood. A total of 230 TB patients and 213 individuals without TB were enrolled in this study. A significant difference in the frequencies of different AIM2 rs2276405 genotypes between the non-TB and TB groups was detected. When the patients were stratified by gender or age, significant differences in genotype frequencies at NLRP3 rs34298354 in men and in non-aged (≤65-year-old) subjects and at IFI16 rs1772408 in women were found. OR analysis showed that the TC rs34298354 genotype in NLRP3 was associated with reduced risk of TB. In women, the AG rs1772408 genotype in IFI16 was associated with decreased TB risk. Haplotype analysis showed that, in comparison with the most common haplotype (T-T) of rs3804099-rs3804100 in the TLR2 gene, the C-T haplotype was associated with an increased risk for TB. Our study indicates that rs34298354 in NLRP3 and rs1772408 in IFI16 protect individuals from TB, and that the less common TLR2 haplotype is associated with increased TB susceptibility.

Association of a single nucleotide polymorphism in the TLR2 gene (rs3804099), but not in the TLR4 gene (rs4986790), with Helicobacter pylori infection and peptic ulcer

BACKGROUND/AIMS

Toll-like receptors (TLRs), particularly TLR2 and TLR4, take part in elicitation of immune responses against Helicobacter pylori (H. pylori). This study aimed to investigate the relationship between single nucleotide polymorphisms (SNP) rs3804099 in the TLR2 gene and rs4986790 in the TLR4 gene with H. pylori infection and peptic ulcer (PU).

MATERIALS AND METHODS

Blood specimens were obtained from 350 individuals, including 100 H. pylori-infected patients with PU, 125 H. pylori-infected asymptomatic subjects (AS), and 125 non-infected healthy subjects (NHS). The DNA was extracted, and the SNPs were determined using ARMS-PCR method.

RESULTS

The frequency of CT genotype at TLR2 SNP rs3804099 in both the PU and AS groups was significantly higher than in the NHS group (p<0.05). In total H. pylori-infected individuals (PU+AS), the frequency of the CT genotype at rs3804099 was also significantly higher than in the NHS group (p<0.005). The frequency of the CC genotype at rs3804099 in PU+AS was markedly lower than in the NHS group (p=0.066). PU patients carried CT genotype more frequently than total healthy individuals (AS+NHS) (p<0.03). The distribution of the TT genotype was lower, whereas the frequency of the CT genotype was higher in AS individuals infected with CagA+ strains than those infected with CagA- strains (p<0.03). No significant differences were found among the PU, AS, and NHS groups regarding the genetic differences at rs4986790 in the TLR4 gene.

CONCLUSION

These results provide evidence regarding the association of the rs3804099 in the TLR2 gene with H. pylori infection and PU. The rs3804099 may affect vulnerability to H. pylori infection, particularly to CagA+ strains of bacteria.

Melanocortin-1 Receptor Polymorphisms and the Risk of Complicated Sepsis After Trauma: A Candidate Gene Association Study

OBJECTIVE

The aim of the study was to determine if melanocortin-1 receptor (MC1R) single nucleotide polymorphisms (SNPs) are associated with complicated sepsis after trauma.

BACKGROUND

Nosocomial infections are an important cause of morbidity and mortality after trauma. Several SNPs in inflammation-related genes have been associated with sepsis. MC1R is an anti-inflammatory mediator that may be involved in the immune response after trauma.

PATIENTS AND METHODS

We genotyped eight common MC1R SNPs in genomic DNA from subjects enrolled in a previously reported prospective cohort study. Subjects were adult trauma patients admitted to the intensive care unit at a Level 1 trauma center (2003-2005).

RESULTS

A total of 1,246 subjects were included in the analysis. The majority were male (70%), severely injured (81%), and injured by a blunt mechanism (89%). Forty percent developed sepsis, and 23% developed complicated sepsis, which was defined as sepsis with organ dysfunction. In logistic regression analysis, with adjustments for age, sex, body mass index, injury severity score, red blood cell transfusion requirement, and mechanism of injury, the MC1RR163Q variant (rs885479) was associated with a lower risk of developing complicated sepsis (adjusted odds ratio [ORadj] = 0.48, 95% confidence interval [CI]: 0.28-0.81, P = 0.006). In a subgroup of 511 subjects with genome-wide SNP data, the association between the MC1RR163Q variant and complicated sepsis remained significant after adjusting for genetic substructure (by principal components) and the above clinical factors (ORadj = 0.30, 95% CI: 0.13-0.70, P = 0.005).

CONCLUSIONS

MC1RR163Q is associated with a lower risk of complicated sepsis after trauma. Therapeutic targeting of MC1R may be beneficial for trauma patients at risk for complicated sepsis.

Tlr2 on Bone Marrow and Non-Bone Marrow Derived Cells Regulates Inflammation and Organ Injury in Cooperation with Tlr4 During Resuscitated Hemorrhagic Shock

BACKGROUND

Although the role of TLR4 in driving inflammation and organ injury after hemorrhagic shock and resuscitation (H/R) is well established, the role of TLR2-another receptor for damage-associated molecular pattern (DAMP) molecules-is not. In this study, we used a combination of TLR2 and wild type (WT) mice treated with anti-TLR2 and anti-TLR4 neutralizing monoclonal antibodies (mAb) to discern the contribution of TLR2 relative to TLR4 to the systemic inflammatory response in murine H/R.

MATERIAL AND METHODS

WT mice, TLR2, and WT mice receiving an anti-TLR2 or an anti-TLR4 mAB (given as a pretreatment) were sacrificed at 6 or 20 h post-H/R. Bone marrow TLR2/WT chimeric mice were created to assess the importance of immune and nonimmune cell-associated TLR2.

RESULTS

TLR2 mice subjected to H/R exhibited significantly less liver damage and lower markers of systemic inflammation only at 20 h. Bone marrow chimeric mice using combinations of TLR2 mice and WT mice demonstrated that TLR2 on non-bone marrow derived cells played a dominant role in the differences at 20 h. Interestingly, WT mice treated with anti-TLR2 mAB demonstrated a reduction in organ damage and systemic inflammation at both 6 and 20 h following H/R. A combination of anti-TLR2 mAB and anti-TLR4 mAB showed that both receptors drive IP-10 and KC levels and that there is cooperation for increases in IL-6, MIG, and MCP-1 levels between TLR2 and TLR4.

CONCLUSION

These data also support the conclusion that TLR2 and TLR4 act in concert as important receptors in the host immune response to H/R.

Infectious and immunogenetic factors in bipolar disorder

OBJECTIVE

Despite the evidence supporting the association between infection and bipolar disorder (BD), the genetic vulnerability that mediates its effects has yet to be clarified. A genetic origin for the immune imbalance observed in BD, possibly involved in the mechanisms of pathogen escape, has, however, been suggested in recent studies.

METHOD

Here, we present a critical review based on a systematic literature search of articles published until December 2016 on the association between BD and infectious/immunogenetic factors.

RESULTS

We provide evidence suggesting that infectious insults could act as triggers of maladaptive immune responses in BD and that immunogenetic vulnerability may amplify the effects of such environmental risk factors, increasing susceptibility to subsequent environmental encounters. Quality of evidence was generally impaired by scarce attempt of replication, small sample sizes and lack of high-quality environmental measures.

CONCLUSION

Infection has emerged as a potential preventable cause of morbidity in BD, urging the need to better investigate components of the host-pathogen interaction in patients and at-risk subjects, and thus opening the way to novel therapeutic opportunities.

A case-control study of innate immunity pathway gene polymorphisms in Puerto Ricans reveals association of toll-like receptor 2 +596 variant with asthma

BACKGROUND

For many years, African Dust Storms (ADE) has been thought to be associated with high prevalence of asthma in Puerto Rico (PR). Endotoxins (ENX) have been associated with ADE particulate matter (PM) and are known to promote pro-inflammatory responses in lung cells of susceptible individuals through the Toll-like receptor (TLR2/4) signaling pathways. Genetic variants are plausible contributors to such susceptibility. Therefore, we have evaluated a series of nine single nucleotide polymorphisms (SNPs) in TLR genes, which have been correlated positive and negatively to asthma prevalence and/or risk, in the Puerto Rican asthmatic population.

METHODS

The following SNPs were evaluated in 62 asthmatics and 61 controls through Taqman® Real Time PCR Assay: TLR4 (+896A/G, +1196C/T, -6687A/G); TLR2 (+596C/T, -16934 T/A, +399A/G, +1349C/T) and CD14 (-159C/T, +1188C/G). Genotypes were assessed for asthma association employing an odds ratio (OR) analysis.

RESULTS

Minor allele frequencies (n = 123) were determined for those variants as 0.07, 0.06, 0.35, 0.35, 0.37, 0.29, 0.04, 0.35 and 0.11, respectively. Two (+596C/T, +399A/G) TLR2 SNPs showed to be more represented in the asthmatic group by 89 % and 65 %, respectively. TLR4 SNP +896A/G analysis revealed only 1 G/G genotype (2 %) on the asthmatic group. The CD14 SNPs were similarly represented in the Puerto Rican population. Only the TLR2 +596 SNP was found to be significantly associated to asthma (OR = 3.24 for CT, 2.71 for TT) and particularly to females.

CONCLUSIONS

The identification of TLR SNPs will reveal potential candidates for gene-environment interactions in Puerto Ricans. As far as we know this is the first study to evaluate this type of TLR gene polymorphisms in Puerto Rican asthmatics, contributing to the current knowledge in the Hispanic population.

Combined effect of TLR2 gene polymorphism and early life stress on the age at onset of bipolar disorders

Gene-environment interactions may play an important role in modulating the impact of early-life stressful events on the clinical course of bipolar disorder (BD), particularly associated to early age at onset. Immune dysfunction is thought to be an important mechanism linking childhood trauma with early-onset BD, thus the genetic diversity of immune-related loci may account for an important part of the interindividual susceptibility to this severe subform. Here we investigated the potential interaction between genetic variants of Toll-like receptors 2 (TLR2) and 4 (TLR4), major innate immune response molecules to pathogens, and the childhood trauma questionnaire (CTQ) in age at onset of BD. We recruited 531 BD patients (type I and II or not otherwise specified), genotyped for the TLR2 rs4696480 and rs3804099 and TLR4 rs1927914 and rs11536891 single-nucleotide polymorphisms and recorded for history of childhood trauma using the CTQ. TLR2 and TLR4 risk genotype carrier state and history of childhood emotional, physical and sexual abuses were evaluated in relation to age at onset as defined by the age at first manic or depressive episode. We observed a combined effect of TLR2 rs3804099 TT genotype and reported sexual abuse on determining an earlier age at onset of BD by means of a Kaplan-Meier survival curve (p = 0.002; corrected p = 0.02). Regression analysis, however, was non-significant for the TLR2-CTQ sexual abuse interaction term. The negative effects of childhood sexual abuse on age at onset of BD may be amplified in TLR2 rs3804099 risk genotype carriers through immune-mediated pathways. Clinical characteristics of illness severity, immune phenotypes and history of early life infectious insults should be included in future studies involving large patient cohorts.

Cross-sectional analysis of Toll-like receptor variants and bacterial vaginosis in African-American women with pelvic inflammatory disease

OBJECTIVE

Bacterial vaginosis (BV) is a common condition associated with serious complications including pelvic inflammatory disease (PID). However, the pathogenesis of BV is poorly understood. Toll-like receptors (TLR) are responsible for microbial recognition and elimination through inflammatory responses. TLR variants have been implicated in infectious and inflammatory diseases and may be involved in BV pathogenesis. We conducted a cross-sectional study to determine if TLR variants are associated with BV.

METHODS

Logistic regression was used to test associations between 14 variants assayed in 6 genes (TLR1, TLR2, TLR4, TLR6, TIRAP and MyD88) and BV/intermediate flora among 192 African-American women with clinical PID from the PID Evaluation and Clinical Health (PEACH) Study. Additionally, we examined associations between variants and endometrial BV-associated anaerobes. To account for multiple comparisons a permutated p<0.003 was used to determine statistical significance.

RESULTS

African-American women with PID carrying the AA genotype for TLR2 SNP rs1898830 had a threefold increased rate of BV/intermediate flora (OR 2.9, 95% CI 1.2 to 7.3). This was not significant after accounting for multiple comparisons (p=0.0201). TLR2 variants rs1898830, rs11938228 and rs3804099 were associated with increased endometrial anaerobic gram-negative rods (p=0.0107, p=0.0076 p=0.0121), anaerobic non-pigmented Gram-negative rods (p=0.0231, p=0.0083, p=0.0044), and anaerobic Gram-positive cocci (p=0.0596, p=0.0640, p=0.1459).

CONCLUSIONS

Among African-American women with PID, we observed trends between TLR2 variants, BV/intermediate flora, and BV-associated microbes. This provides some insight into BV pathogenesis. As not all BV-associated microbes may lead to pathology, future studies should focus on associations between TLR variants and individual BV-associated microbes.

Association between toll-like receptor 2 gene diversity and early-onset bipolar disorder

BACKGROUND

Toll-like receptor 2 (TLR2) molecules play a pivotal role in innate immune responses by their ability to recognize and sense a wide repertoire of infectious and endogenous cellular structural elements. Here we evaluated whether genetic variants in TLR2 influence the age of the disease onset in bipolar disorder (BD).

METHODS

DNAs from 571 BD patients 229 early-onset (EO-BD) and 342 late-onset (LO-BD) and 199 healthy controls (HC) were analyzed for the following TLR2 polymorphisms: the 5'-UTR -196 to -174 insertion/deletion (ins/del), the intron 1 rs4696480 A/T, and the exon 3 rs3804099 C/T and rs3804100 C/T. PHASE software was used for haplotype reconstruction. Genetic associations were examined using a chi-square test.

RESULTS

We found that the TLR2 rs3804099 TT was significantly more prevalent in EO-BD than in LO-BD patients (corrected p (pc)=0.024). After excluding family history of psychiatric disorders, we also found that the TLR2 rs4696480 TT genotype was significantly more prevalent in EO-BD as compared to LO-BD and controls (pc=0.002 and 0.002). Homozygous state for the insTTT haplotype, carrying the above mentioned risk genotypes, was significantly more frequent in EO-BD than in LO-BD patients (pc=0.007) and in EO-BD without family history of psychiatric disorders as compared to (i) those with positive history (pc=0.03), (ii) with LO-BD without family history (pc=0.001) and (iii) with HC (pc=0.009).

LIMITATIONS

Confirmation by replication in independent BD cohorts is warranted.

CONCLUSIONS

Our data suggest the potential role of TLR2 genetic variants in the pathogen-mediated susceptibility to BD.

Risk factors of fecal toxigenic or non-toxigenic Clostridium difficile colonization: impact of Toll-like receptor polymorphisms and prior antibiotic exposure

BACKGROUND

This study is to investigate the significance and risk factors of fecal toxigenic (tCdC) or non-toxigenic Clostridium difficile colonization (ntCdC) among hospitalized patients.

METHODS

Adults admitted to medical wards in a district hospital between January 2011 and June 2012 were enrolled, and those with a history of colectomy, C. difficile fecal colonization or infection or receipt of either metronidazole or oral vancomycin within 3 months, were excluded. Stools collected within 48 hours after admission and every week during hospitalization were cultured for C. difficile.

FINDINGS

Among the 441 enrolled patients, 84 (20.0%) had CdC at initial screening, including 58 (13.2%) with tCdC and 26 (6.8%) with ntCdC. Among patients with initial negative fecal screening for CdC, it took an average of 70.6 days or 66.5 days to develop tCdC or ntCdC during the study period. Finally 78 (17.7%) had tCdC and 34 (7.7%) had ntCdC. During the follow-up period, the patients with tCdC had a higher risk of CDAD (11/79, 14.1%) than those without CdC (3/328, 0.9%) and those with ntCdC (0/34, 0%) (P<0.001). In multivariate analysis, the TLR4 rs1927914 polymorphism (GG genotype) (odds ratio [OR] 4.4, 95% confidence interval [CI] 1.6-11.8, P = 0.003) and recent cefepime therapy (OR 5.3, 95% CI 2.1-13.2, P<0.001) were independently associated with tCdC, whereas recent cefuroxime (OR 11.7, 95% CI 2.3-60.2, P = 0.003) and glycopeptide therapy (OR 10.9, CI: 2.1-57.2, P = 0.005) associated with ntCdC.

CONCLUSION

The incidence of CDAD is highest in patients with tCdC and lowest in patients with ntCdC, and the TLR4 rs1927914 polymorphism GG genotype and recent cefepime therapy were independently associated with tCdC.

Association between genetic polymorphisms of Toll-like receptor 2 (TLR2) and schizophrenia in the Korean population

Immunological dysregulation has been suggested to be involved in the pathogenesis of schizophrenia. Accumulating evidences further implicate that activated inflammatory processes may be particularly relevant for the precipitation of negative and cognitive symptoms of schizophrenia. Toll-like receptor 2 (TLR2) plays an important role in innate immunity by sensing a variety of pathogens and inducing an acquired immunity. In the present study, we investigated whether the coding region of single nucleotide polymorphisms (SNPs) of the TLR2 gene was associated with schizophrenia as well as with clinical symptoms in schizophrenia patients. The study population consisted of 286 Korean schizophrenia patients and 305 Korean control subjects. The assessment of the Scale for the Assessment of Negative Symptoms was used to evaluate the negative symptoms of schizophrenia; the operational criteria checklist was used to measure general psychopathology. We selected two cSNPs [rs3804099 (Asn199Asn) and rs3804100 (Ser450Ser)] considering their heterozygosity and minor allele frequency. SNP genotyping was conducted using direct sequencing. We did not find any significant associations between SNPs and schizophrenia in the genotype and allelic frequencies. On the other hand, in the analysis of cognitive symptoms, rs3804099 showed significant differences in schizophrenia patients with poor concentration in the dominant model (TC/CC vs. TT, p=0.0099). Also, rs3804100 showed a significant association with poor concentration in the co-dominant (TC vs. TT, p=0.014) and the dominant models (TC/CC vs. TT, p=0.0035). We obtained no significant support for the association of the TLR2 gene with susceptibility to schizophrenia in the Korean population. However, our results provide possibility that C allele of rs3804099 and rs3804100 may be associated with poor concentration in schizophrenia patients. Further studies with larger samples are required to confirm our results.

The -144C/A polymorphism in the promoter of HSP90beta is associated with multiple organ dysfunction scores

Introduction

Variations in genetic background are the leading cause of differential susceptibility to traumatic infection. Heat shock protein 90 (HSP90), a broadly distributed and conserved molecule, regulates inflammation under stressful and traumatic conditions. However, the relationships between HSP90 genetic polymorphisms, post-traumatic inflammatory responses and organ function remain unknown.

Methods

A total of 286 healthy volunteers and patients with severe trauma took part in a single nucleotide polymorphism (SNP)-based analysis of the HSP90beta gene and a clinical association analysis. HSP90beta and TNF-alpha levels were determined using quantitative PCR and western blot. The transcriptional activity of the HSP90beta promoter was assayed using the Dual-Luciferase Reporter Assay System.

Results

The minor allele frequencies for the SNP located at −144 bp relative to the HSP90beta transcriptional start site were 28.47% and 28.52% in the normal and trauma populations, respectively; no significant differences were found between these two distributions. However, the results showed that a promoter containing the -144A allele had a higher transcriptional activity than did a promoter containing the wild-type -144C allele. Furthermore, the -144A promoter induced high expression of HSP90beta and low expression of the inflammatory factor TNF-alpha in a lipopolysaccharide-induced inflammatory model. A clinical association analysis showed that the multiple organ dysfunction scores for -144AA genotype carriers were significantly lower than those of -144CC carriers following trauma. No significant correlations were found between the presence of the two alleles and the incidence of sepsis.

Conclusions

These results indicate that differences in expression caused by the -144 polymorphism in the HSP90beta promoter are associated with cellular inflammatory responses and the severity of organ injury. These findings will aid in risk assessment and early prevention of complications for patients with severe trauma.

Racial variation in toll-like receptor variants among women with pelvic inflammatory disease

BACKGROUND

Racial disparities exist in gynecological diseases. Variations in Toll-like receptor (TLR) genes may alter signaling following microbial recognition.

METHODS

We explored genotypic differences in 6 functional variants in 4 TLR genes (TLR1, TLR2, TLR4, TLR6) and the adaptor molecule TIRAP between 205 African American women and 51 white women with clinically suspected pelvic inflammatory disease (PID). A permutated P < .007 was used to assess significance. Associations between race and endometritis and/or upper genital tract infection (UGTI) were explored. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The TT genotype for TLR1 rs5743618, the GG genotype for TLR1 rs4833095, the CC genotype for TLR2 rs3804099, the TLR6 rs5743810 T allele, and the CC genotype for TIRAP rs8177374 significantly differed between races (P < .007). African American race was associated with endometritis and/or UGTI (OR, 4.2 [95% CI, 2.0-8.7]; P = .01). Among African Americans, the TLR6 rs5743810 T allele significantly decreased endometritis and/or UGTI (OR, 0.4 [95% CI, .2-.9]; P = .04). Additionally, rs5743618, rs4833095, and rs8177374 increased endometritis and/or UGTI, albeit not significantly.

CONCLUSIONS

Among women with PID, TLR variants that increase inflammation are associated with African American race and may mediate the relationship between race and endometritis and/or UGTI.

Association of Toll-like receptor 2 polymorphisms with papillary thyroid cancer and clinicopathologic features in a Korean population

Toll-like receptors (TLRs) single nucleotide polymorphisms (SNPs) were analyzed in patients with papillary thyroid cancer (PTC; n = 133) and their clinicopathologic features and age-matched controls (n = 321) using direct sequencing. PTC patients were divided into subgroups according to size, number, location, extrathyroidal invasion and lymph node metastasis. The two SNPs of TLR2 gene were not associated with the development of PTC. In clinical analysis, two SNPs were associated with location of cancer (rs3804099, P = 0.032, OR, 0.52; 95% CI, 0.28-0.96 in log-additive model; rs3804100, P = 0.039, OR, 0.46, 95% CI, 0.22-0.96 in codominant1 model; P = 0.018, OR, 0.42, 95% CI, 0.21-0.87 in dominant model; P = 0.011, OR, 0.46, 95% CI, 0.25-0.85 in log-additive model). The allele frequencies of two SNPs also showed significant associations with location of cancer (rs3804099, P = 0.046, OR, 0.57, 95% CI, 0.33-0.99 and rs3804100, P = 0.019, OR = 0.52, 95% CI = 0.30-0.90). However, two SNPs were not associated with the clinicopathologic features of PTC. It is suggested that TLR2 polymorphisms may contribute to the clinicopathologic features of PTC, especially the PTC in both lobes.

Toll-like receptor (TLR2 and TLR4) polymorphisms and chronic obstructive pulmonary disease

Toll-like receptors (TLRs) participate in the defence against bacterial infections that are common in patients with Chronic Obstructive Pulmonary Disease (COPD). We studied all tagging SNPs in TLR2 and TLR4 and their associations with the level and change over time of both FEV(1) and sputum inflammatory cells in moderate-to-severe COPD. Nine TLR2 SNPs and 17 TLR4 SNPs were genotyped in 110 COPD patients. Associations of SNPs with lung function and inflammatory cells in induced sputum were analyzed cross-sectionally with linear regression and longitudinally with linear mixed-effect models. Two SNPs in TLR2 (rs1898830 and rs11938228) were associated with a lower level of FEV(1) and accelerated decline of FEV(1) and higher numbers of sputum inflammatory cells. None of the TLR4 SNPs was associated with FEV(1) level. Eleven out of 17 SNPs were associated with FEV(1) decline, including rs12377632 and rs10759931, which were additionally associated with higher numbers of sputum inflammatory cells at baseline and with increase over time. This is the first longitudinal study showing that tagging SNPs in TLR2 and TLR4 are associated with the level and decline of lung function as well as with inflammatory cell numbers in induced sputum in COPD patients, suggesting a role in the severity and progression of COPD.

Genetic predisposition to respiratory infection and sepsis

Genetic variations, in part, determine individual susceptibility to sepsis and pneumonia. Advances in genetic sequence analysis as well as high throughput platform analysis of gene expression has allowed for a better understanding of immunopathogenesis during sepsis. Differences in genes can also modulate immune and inflammatory response during sepsis thereby translating to differences in clinical outcomes. An increasing number of candidate genes have been implicated to play a role in sepsis susceptibility, most of which are controversial with few exceptions. This does not refute the significance of genetic polymorphisms in sepsis, but rather highlights the difficulties and pitfalls related to genetic association studies. These difficulties include differences in study design such as heterogeneous patient cohorts and differences in pathogenic organisms, linkage disequilibrium, and lack of power for detailed haplotype analysis or examination of gene-gene interactions. There is extensive diversity in the pathways of inflammation and immune response during sepsis making it even harder to prove the functional and clinical significance of one single genetic polymorphism which could be easily masqueraded or compensated by other upstream or downstream events of the pathway involved. The majority of studies have analysed candidate genes in isolation from other possible polymorphisms. It is likely that susceptibility to sepsis is the result of polymorphisms from multiple genes rather than one single mutation. Future studies should aim for multi-centered collaborative approach looking at genome wide association or gene profiling to provide a more complete appraisal of the key genetic players in determining genetic susceptibility to sepsis. This review paper will summarise the prominent candidate gene polymorphisms with known functional changes or those with haplotype data. In addition, a summary of the expanding research in the field of epigenetics and post-sepsis immunosuppression will be discussed.

Clinical relevance of single nucleotide polymorphisms within the entire NLRP3 gene in patients with major blunt trauma

INTRODUCTION

The nucleotide-binding oligomerization domain-like receptor (NLR) family has been recognized as comprising intracellular pattern recognition receptors in which NLRP3 (NLR family, pyrin domain containing 3) plays an important role in the initiation of host immune inflammatory responses. The genetic variants have been recognized to be critical determinants of interindividual differences in both inflammatory responses and clinical outcomes in critical illness. However, little is known about the clinical relevance of NLRP3 gene polymorphisms in critical illness.

METHODS

A total of 718 patients with major blunt trauma were included in this study. Six tag SNPs (tSNPs) were selected from the entire NLRP3 gene through construction of haplotype bins, and they were genotyped using a pyrosequencing method. They were analyzed in relation to sepsis morbidity rate, multiple organ dysfunction (MOD) scores and IL-1β production. Moreover, the functionality of the rs2027432 polymorphism was assessed by the observation of its effect on transcriptional activities.

RESULTS

Among the six tSNPs genotyped in this study, two of them (rs2027432 and rs12048215) were significantly associated with sepsis morbidity rate and MOD scores. A significant association was also observed between these two polymorphisms and IL-1β production by peripheral leukocytes in response to ex vivo lipopolysaccharide stimulation. However, no combined effects were found between these two polymorphisms. In addition, the rs2027432 polymorphism could significantly enhance the promoter activities of the NLRP3 gene.

CONCLUSIONS

rs2027432 and rs12048215 polymorphisms might be used as relevant risk estimates for the development of sepsis and MOD syndrome in patients with major trauma, in which rs2027432 might be a functional SNP.

Association of Toll-like receptor 2 polymorphisms with National Institute of Health Stroke Scale scores of ischemic stroke patients

Toll-like receptor 2 (TLR2) has been shown to have an important role in the postischemic inflammatory response and to contribute to ischemic brain damage. In this study, we investigated whether coding region single nucleotide polymorphisms (SNPs) of the TLR2 gene were associated with ischemic stroke (IS) and with clinical phenotypes in IS patients. We genotyped two SNPs (rs3804099 [Asn199Asn] and rs3804100 [Ser450Ser]) using direct sequencing in 202 IS patients and 291 control subjects. No SNPs of the TLR2 gene were found to be associated with IS. However, in analysis of clinical phenotypes, we found that rs3804099 was associated with the National Institute of Health Stroke Scale (NIHSS) scores of IS patients in codominant (TC vs. TT, p = 0.0005; CC vs. TT, p = 0.0007) and dominant models (TC/CC vs. TT, p = 0.0001). Also, rs3804100 revealed significant association in codominant (TC vs. TT, p = 0.0002; CC vs. TT, p = 0.008) and dominant models (TC/CC vs. TT, p < 0.0001). In allele frequency analysis, we also found that the C alleles of rs3804099 and rs3804100 were associated with higher NIHSS scores (p = 0.0003 in rs3804099; p = 0.0001 in rs3804100). Our results suggest that TLR2 may be related to severe IS.

Changes in the inositol lipid signal system and effects on the secretion of TNF-α by macrophages in severely scalded mice

AIM

In order to study the mechanism of abnormal macrophage (Mϕ) function in pro-inflammatory cytokine changes after burn, the inositol lipid signal system and its role in tumour necrosis factor-alpha (TNF-α) secretion by peritoneal Mϕs was observed in severely scalded mice.

METHODS

Eighteen percent total body surface area (TBSA) full-thickness scalded mice were used as animal model in this experiment. Peritoneal Mϕs stimulated by lipopolysaccharide in vitro were collected at different time intervals (0, 2, 6, 12, 24 and 48 after burn hour (PBH)), The activities of phosphatidylinositol-phospholipase C (PI-PLC), inositol-1, 4,5, -triphosphate (IP(3)), protein kinase C (PKC), diacylglycerol (DAG) and TNF-α and the level of Ca(2+) concentration in peritoneal Mϕs were measured, and the effects of specific PKC inhibitor H-7 and calmodulin antagonist W-7 on the production of TNF-α were also observed.

RESULTS

After scald, increased activities of TNF-α and PLC of Mϕ were observed and peaked at 12 PBH. The activities of DAG and IP(3) and the concentration of Ca(2+) were markedly increased and reached their peaks at 24 PBH simultaneously. Membrane PKC activity was up-regulated after scald and showed a positive correlation with the change of DAG (r=0.83, P<0.05). There was also positive correlation between IP(3) and Ca(2+) activity (r=0.946, P<0.01). When 12 PBH was chosen as the time point for in vitro intervention with the pre-treatment by H-7, both membrane PKC and TNF-α activity decreased significantly. There was no obvious change of TNF-α activity with the application of W-7.

CONCLUSIONS

These results indicated that the abnormal activity of TNF-α of Mϕs might be regulated by the inositol lipid signal system following severe burn. The DAG-PKC signal pathway showed closer relationship than IP(3)-Ca(2+) in TNF-α production and could be the optimal target in the prevention and treatment of the systemic inflammatory response syndrome.

Mold allergen sensitization in adult asthma according to integrin β3 polymorphisms and Toll-like receptor 2/+596 genotype

BACKGROUND

Integrin β3 (ITGB3) and Toll-like receptor 2 (TLR2) are candidate genes for asthma and sensitization to mold allergens. Integrin β3 forms a complex with TLR2, and this biological interaction is required for the response of monocytes to TLR2 agonists such as fungal glucan.

OBJECTIVE

To study whether genetic interaction between single nucleotide polymorphisms (SNPs) in genes encoding the TLR2-ITGB3 complex enhances susceptibility to mold sensitization.

METHODS

Association analysis was conducted in 1243 adults (524 with asthma) who participated in the follow-up of the Epidemiological Study on the Genetics and Environment of Asthma. Allergic sensitization to mold allergens was determined by skin prick testing. Association of mold sensitization with 14 ITGB3 SNPs was tested under an additive genetic model. Interaction between ITGB3 SNPs and TLR2/+596, which was previously shown to be associated with asthma, was studied.

RESULTS

A positive skin prick test to mold was found in 115 subjects with asthma (22.0%) and in 61 subjects without asthma (8.5%). The ITGB3 rs2056131 A allele was associated with mold sensitization in subjects with asthma with an odds ratio (95% CI) of 0.60 (0.43-0.83; P = .001). Ten other ITGB3 SNPs were significantly associated with mold sensitization in TLR2/+596TT subjects with asthma (P = .03-.002), whereas much weaker associations were found in carriers of the TLR2/+596 C allele (P = .60-.04). Interaction between TLR2/+596 and these ITGB3 SNPs was statistically significant (P interaction = .05-.001).

CONCLUSION

TLR2/+596 genotype may influence the association between ITGB3 SNPs and mold sensitization in adults with asthma.

Genetic polymorphisms and posttraumatic complications

Major trauma is the leading cause of death in young adults. Despite advances in prehospital system and treatment in hospital, mortality rates have not improved significantly over the past decades. Victims of severe injuries who survive the initial hours have great risk for additional life-threatening complicaitons, including uncontrollable infection (sepsis) and multiple organ dysfunction syndrome (MODS). Single nucleotide polymorphisms (SNPs) have been shown to affect susceptibility to the course of numerous diseases. Accumulating evidence suggests that genetic backgrounds also play important roles in posttraumatic complications. Genetic polymorphisms may become powerful biomarkers for diagnosis and prognosis of trauma-induced complications. Recent advances in studies on associations between genetic polymorphisms and sepsis or MODS have led to better understanding of posttraumatic complications. Here we summarise recent findings on genetic variations in molecules of the innate immune system and other systems as well as their connection with susceptibility to posttraumatic complications.