Association between TLR4 A299G polymorphism and pneumonia risk: a meta-analysis

Single Nucleotide Polymorphisms of Toll-like Receptor 4 in Hepatocellular Carcinoma-A Single-Center Study

Hepatocellular carcinoma (HCC) is the most common primary liver tumor leading to significant morbidity and mortality; its exact genetic background is largely unrecognized. Toll-like receptor-4 (TLR4) reacts with lipopolysaccharides, molecules found in the outer membrane of Gram-negative bacteria. In damaged liver, TLR4 expression is upregulated, leading to hepatic inflammation and injury. We tried to investigate the role of the two most common single-nucleotide polymorphisms (SNPs) of TLR4 in HCC-genesis. Aged > 18 years old, cirrhotic patients were included in this study. Exclusion criteria were non-HCC tumors and HIV co-infection. TLR4 SNPs association with HCC occurrence was the primary endpoint, and associations with all-cause and liver-related mortality, as well as time durations between diagnosis of cirrhosis and HCC development or death and diagnosis of HCC and death were secondary endpoints. A total of 52 out of 260 included patients had or developed HCC. TLR4 SNPs showed no correlation with primary or secondary endpoints, except for the shorter duration between HCC development and death in patients with TLR4 mutations. Overall, TLR4 SNPs showed no correlation with carcinogenesis or deaths in patients with liver cirrhosis; patients with TLR4 SNPs that developed HCC had lower survival rates, a finding that should be further evaluated.

TLR4 rs4986790 polymorphism confers risk to Helicobacter pylori infection in Zhejiang, China and its enlightenment to nursing care

PURPOSE

Previous literatures on the association between TLR4 gene rs4986790 polymorphism and Helicobacter pylori infection risk reported conflict results. We conducted a case-control study and meta-analysis to investigate whether TLR4 gene rs4986790 polymorphism confers risk to Helicobacter pylori infection.

PATIENTS AND METHODS

254 patients with Helicobacter pylori positive and 235 patients with Helicobacter pylori negative were enrolled. PubMed, Embase, CNKI (Chinese national knowledge internet) were carefully searched and reviewed. Odds ratio (OR) together with 95% confidence interval (CI) were applied to calculate the association power.

RESULTS

GG genotype of TLR4 gene rs4986790 polymorphism contributes increased risk to the population of Zhejiang, China (p = 0.019). Meta-analysis found that the positive findings came from Asian population by allele contrast (p = 0.006), homozygote comparison (p = 0.006) and recessive genetic model (p = 0.001).

CONCLUSION

TLR4 gene rs4986790 polymorphism is associated with Helicobacter pylori infection risk for population of Zhejiang, China. Combined with individual gene polymorphism, the accuracy of risk assessment of Helicobacter pylori infection can be improved and individualized health education can be provided for patients with Helicobacter pylori infection by nurses.

Associations of TLR4 and IL-8 genes polymorphisms with age-related macular degeneration (AMD): a systematic review and meta-analysis

BACKGROUND

The results of different studies have indicated the possible associations of TLR4 and IL-8 genes polymorphisms with Age-related Macular Degeneration (AMD). A meta-analysis study was designed to evaluate the possible associations of TLR4 (rs4986790/c.896A>G and rs4986791/ c.1196 C > T) and IL-8 (rs4073/c.251A>T and rs2227306/c.781 C > T) genes polymorphisms with AMD.

METHOD

A systematic literature search was carried out in PubMed, Embase, Web of Science, and Scopus databases to identify relevant publications. Pooled Odds Ratio (OR) with 95% Confidence Interval (CI) was used to evaluate the power of association.

RESULTS

A total of 12 case-control studies with 4804 AMD patients and 4422 healthy controls were included in this meta-analysis. The analysis of genotypic and allelic models demonstrated significant associations between IL-8 c.781 C > T (CC vs. TT+TC: OR = 0.62 [0.48-0.81], P < .01; CC vs. TC: OR = 0.65 [0.48-0.89], P < .01; TT vs. CC: OR = 1.64 [1.04-2.57], P = .03; and C vs. T: OR = 0.71 [0.65-0.79], P < .01) and risk of AMD, which all of them passed Bonferroni correction for multiple testing (P-value≤0.01), except for TT vs. CC model. In addition, we found associations under the genotypic model of TLR4 c.896A>G (AA vs. AG+GG: OR = 0.73 [0.55-0.97], P = .03; and AA vs. AG: OR = 0.71 [0.53-0.95], P = .02) although after Bonferroni correction (P'-value<0.02) none of these associations remained significant. However, the data from this meta-analysis declined the associations of TLR4 c.1196 C > T and IL-8 c.251A>T polymorphisms with AMD.

CONCLUSION

The current meta-analysis study suggested that IL-8 c.781 C > T polymorphism is associated with susceptibility to AMD.

Consensus Document on Community-Acquired Pneumonia in Children. SENP-SEPAR-SEIP

Community-acquired pneumonia (CAP) is a prevalent disease among children and is frequently associated with both diagnostic and therapeutic uncertainties. Consensus has been reached between SEPAR, SENP and SEIP, and their conclusions are as follows.

Correlation between TICAM1 gene polymorphisms and community-acquired pneumonia in children

This study aims to explore the relationship between single nucleotide polymorphisms (SNPs) of the TICAM1 gene and community-acquired pneumonia (CAP) in Chinese children. The polymorphisms of eight tag SNP (TagSNP) locus of TICAM1 were detected using the improved multiplex ligation detection reaction (iMLDR) assay in 375 children with CAP (average age, 37.8 ± 21.6 months) and 306 healthy children (average age, 38.5 ± 23.8 months). The correlation between polymorphisms of these TagSNPs and the risk, severity, sepsis, and CRP level of childhood CAP were evaluated using logistic regression analysis. The CC genotype of rs11466711T/C locus of TICAM1 is correlated with childhood CAP susceptibility, which significantly reduced the risk of childhood CAP (P < .05), The AA genotype of the rs6510826G/A locus and haplotype CCCA were associated with CRP level in childhood CAP, which significantly increased the risk of CRP increase (P < .05 and P < .01, respectively), The AA genotype of rs35747610G/A site is associated with sepsis in childhood CAP, significantly reduced risk of sepsis (P < .05). While the haplotype CCCG of this locus led to a significant reduction in the risks of childhood CAP, severe pneumonia and pneumonia sepsis (all P < .05). TICAM1 has multiple functional variants closely related to the development and progression of childhood CAP, and these variations may have a synergistic effect on the development of childhood CAP.

Toll-like receptor 4: A promising therapeutic target for pneumonia caused by Gram-negative bacteria

Gram‐negative bacteria (GNB) emerge as important pathogens causing pulmonary infection, which can develop into sepsis due to bacterial resistance to antibiotics. GNB pneumonia poses a huge social and economic burden all over the world. During GNB infection in the lung, Toll‐like receptor 4 (TLR4) can form a complex with MD2 and CD14 after recognizing lipopolysaccharide of GNB, initiate the MyD88‐ and TRIF‐dependent signalling pathways and stimulate host non‐specific immune response. In this review, we summarize recent progress in our understanding of the role of TLR4 in GNB pneumonia. The latest experimental results, especially in TLR4 knockout animals, suggest a promising potential of targeting TLR4 signalling pathway for the treatment of GNB pneumonia. Furthermore, we highlight the benefits of Traditional Chinese Medicine as novel candidates for the therapy of GNB pneumonia due to the modulation of TLR4 signalling pathway. Finally, we discuss the promise and challenge in the development of TLR4‐based drugs for GNB pneumonia.

Genetic dissection of host immune response in pneumonia development and progression

The role of host genetic variation in pneumonia development and outcome is poorly understood. We studied common polymorphisms in the genes of proinflammatory cytokines (IL6 rs1800795, IL8 rs4073, IL1B rs16944), anti-inflammatory cytokines (IL10 rs1800896, IL4 rs2243250, IL13 rs20541) and toll-like receptors (TLR2 rs5743708 and rs4696480, TLR4 rs4986791, TLR9 rs352139, rs5743836 and rs187084) in patients with community-acquired pneumonia (CAP) (390 cases, 203 controls) and nosocomial pneumonia (355 cases, 216 controls). Experimental data were included in a series of 11 meta-analyses and eight subset analyses related to pneumonia susceptibility and outcome. TLR2 rs5743708 minor genotype appeared to be associated with CAP/Legionnaires’ disease/pneumococcal disease. In CAP patients, the IL6 rs1800795-C allele was associated with severe sepsis/septic shock/severe systemic inflammatory response, while the IL10 rs1800896-A allele protected against the development of these critical conditions. To contribute to deciphering of the above results, we performed an in silico analysis and a qualitative synthesis of literature data addressing basal and stimulated genotype-specific expression level. This data together with database information on transcription factors’ affinity changes caused by SNPs in putative promoter regions, the results of linkage disequilibrium analysis along with SNPs functional annotations supported assumptions about the complexity underlying the revealed associations.