The MyD88 rs6853 and TIRAP rs8177374 polymorphic sites are associated with resistance to human pulmonary tuberculosis

Pathogen recognition pathway gene variants and inflammasome sensors gene expression in tuberculosis patients under treatment

BACKGROUND

Several epidemiological studies have suggested that genetic variations in encoding pattern recognition receptors (PRRs) genes such as Toll Like Receptors (TLRs) and their signaling products, may influence the susceptibility, severity and outcome of tuberculosis (TB). After sensing a pathogen, the cell responds producing an inflammatory response, to restrain the pathogen's successful course of infection. Herein we assessed single nucleotide polymorphisms (SNP) and gene expression from pathogen recognition and inflammasome pathways in Brazilian TB patients.

METHODS AND RESULTS

For genetic association analysis we included MYD88 and TLR4, PRRs sensing proteins. Allele distribution for MYD88 rs6853 (A > G) and TLR4 rs7873784 (C > G) presented conserved among the tested samples with statistically differential distribution in TB patients versus controls. However, when testing according to sample ethnicity (African or Caucasian-derived individuals) we identified that the rs6853 G/G genotype was associated with a lower susceptibility to TB in Caucasian population. Meanwhile, the rs7873784 G/G genotype was associated with a higher TB susceptibility in Afro-descendant ethnicity individuals. We also aimed to verify MYD88 and the inflammasome genes NLRP1 and NLRC4 expression in order to connect to active TB and/or clinical aspects.

CONCLUSIONS

We identified that inflammasome gene expression in TB patients under treatment display a similar pattern as in healthy controls, indicating that TB treatment impairs NLRP1 inflammasome activation.

Tirap controls Mycobacterium tuberculosis phagosomal acidification

Progression of tuberculosis is tightly linked to a disordered immune balance, resulting in inability of the host to restrict intracellular bacterial replication and its subsequent dissemination. The immune response is mainly characterized by an orchestrated recruitment of inflammatory cells secreting cytokines. This response results from the activation of innate immunity receptors that trigger downstream intracellular signaling pathways involving adaptor proteins such as the TIR-containing adaptor protein (Tirap). In humans, resistance to tuberculosis is associated with a loss-of-function in Tirap. Here, we explore how genetic deficiency in Tirap impacts resistance to Mycobacterium tuberculosis (Mtb) infection in a mouse model and ex vivo. Interestingly, compared to wild type littermates, Tirap heterozygous mice were more resistant to Mtb infection. Upon investigation at the cellular level, we observed that mycobacteria were not able to replicate in Tirap-deficient macrophages compared to wild type counterparts. We next showed that Mtb infection induced Tirap expression which prevented phagosomal acidification and rupture. We further demonstrate that the Tirap-mediated anti-tuberculosis effect occurs through a Cish-dependent signaling pathway. Our findings provide new molecular evidence about how Mtb manipulates innate immune signaling to enable intracellular replication and survival of the pathogen, thus paving the way for host-directed approaches to treat tuberculosis.

Local Ancestry Adjusted Allelic Association Analysis Robustly Captures Tuberculosis Susceptibility Loci

Pulmonary tuberculosis (TB), caused by Mycobacterium tuberculosis, is a complex disease. The risk of developing active TB is in part determined by host genetic factors. Most genetic studies investigating TB susceptibility fail to replicate association signals particularly across diverse populations. South African populations arose because of multi-wave genetic admixture from the indigenous KhoeSan, Bantu-speaking Africans, Europeans, Southeast Asian-and East Asian populations. This has led to complex genetic admixture with heterogenous patterns of linkage disequilibrium and associated traits. As a result, precise estimation of both global and local ancestry is required to prevent both false positive and false-negative associations. Here, 820 individuals from South Africa were genotyped on the SNP-dense Illumina Multi-Ethnic Genotyping Array (∼1.7M SNPs) followed by local and global ancestry inference using RFMix. Local ancestry adjusted allelic association (LAAA) models were utilized owing to the extensive genetic heterogeneity present in this population. Hence, an interaction term, comprising the identification of the minor allele that corresponds to the ancestry present at the specific locus under investigation, was included as a covariate. One SNP (rs28647531) located on chromosome 4q22 was significantly associated with TB susceptibility and displayed a SNP minor allelic effect (G allele, frequency = 0.204) whilst correcting for local ancestry for Bantu-speaking African ancestry (p-value = 5.518 × 10^-7; OR = 3.065; SE = 0.224). Although no other variants passed the significant threshold, clear differences were observed between the lead variants identified for each ancestry. Furthermore, the LAAA model robustly captured the source of association signals in multi-way admixed individuals from South Africa and allowed the identification of ancestry-specific disease risk alleles associated with TB susceptibility that have previously been missed.

Variants of Toll-like receptor 6 associated with tuberculosis susceptibility in the Chinese Tibetan population

BACKGROUND

Our investigation attempted to understand the role of innate immunity related genes played in tuberculosis. The relationship between single-nucleotide polymorphisms (SNPs) of three innate immunity-related genes (TLR6, MyD88, and TIRAP) and tuberculosis (TB) risk in two Chinese populations were explored.

METHODS

Totally 1185 Chinese Han, consisting of 580 active TB cases and 605 healthy controls (HCs), and 1216 Chinese Tibetan individuals including 613 TB patients and 603 HCs were enrolled to conduct two case-control studies. TagSNPs of the three genes were selected based on the HapMap database and genotyped by the SNPscan™ Kit. Haploview software 4.2 was applied to perform linkage disequilibrium (LD) analysis and online software SHEsis was used to discover significant haplotype block. RegulomeDB and HaploReg were applied to predict potential functional SNPs of the three genes.

RESULTS

The results showed that minor alleles of rs5743808 and rs5743827 of TLR6 were related with increased TB risk (p = 0.001, OR 95%CI = 1.51 (1.18-1.95) and p = 0.002, OR 95%CI = 1.42 (1.14-1.77)), and significant association was also observed between rs5743827 and TB risk in male subgroup (p = 0.003, OR 95%CI = 1.67 (1.91-2.35)) in the Tibetan population. For the Tibetan population, frequency of haplotype ACGT of rs1039559-rs3775073-rs5743808-rs5743827 of TLR6 was significantly higher in the TB group (p = 0.0008), while haplotype ATAC was significantly higher in the control group (p = 0.0002). The above associations remained after permutation and Bonferroni correction. No significant association was found in the Han population. Probable functions of tagSNPs of TLR6 and some other linked variants were discovered after bioinformatic analysis.

CONCLUSIONS

This study suggested that variants of TLR6 might be associated with TB risk in the Tibetan population, while not in the Han population. The difference between Chinese Han and Tibetan people will provide better understanding of tuberculosis.

Germline Genetic Variants of Viral Entry and Innate Immunity May Influence Susceptibility to SARS-CoV-2 Infection: Toward a Polygenic Risk Score for Risk Stratification

The ongoing COVID-19 pandemic caused by the novel coronavirus, SARS-CoV-2 has affected all aspects of human society with a special focus on healthcare. Although older patients with preexisting chronic illnesses are more prone to develop severe complications, younger, healthy individuals might also exhibit serious manifestations. Previous studies directed to detect genetic susceptibility factors for earlier epidemics have provided evidence of certain protective variations. Following SARS-CoV-2 exposure, viral entry into cells followed by recognition and response by the innate immunity are key determinants of COVID-19 development. In the present review our aim was to conduct a thorough review of the literature on the role of single nucleotide polymorphisms (SNPs) as key agents affecting the viral entry of SARS-CoV-2 and innate immunity. Several SNPs within the scope of our approach were found to alter susceptibility to various bacterial and viral infections. Additionally, a multitude of studies confirmed genetic associations between the analyzed genes and autoimmune diseases, underlining the versatile immune consequences of these variants. Based on confirmed associations it is highly plausible that the SNPs affecting viral entry and innate immunity might confer altered susceptibility to SARS-CoV-2 infection and its complex clinical consequences. Anticipating several COVID-19 genomic susceptibility loci based on the ongoing genome wide association studies, our review also proposes that a well-established polygenic risk score would be able to clinically leverage the acquired knowledge.

The Roles of Inflammasomes in Host Defense against Mycobacterium tuberculosis

Mycobacterium tuberculosis (MTB) infection is characterized by granulomatous lung lesions and systemic inflammatory responses during active disease. Inflammasome activation is involved in regulation of inflammation. Inflammasomes are multiprotein complexes serving a platform for activation of caspase-1, which cleaves the proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-18 into their active forms. These cytokines play an essential role in MTB control. MTB infection triggers activation of the nucleotide-binding domain, leucine-rich-repeat containing family, pyrin domain-containing 3 (NLRP3) and absent in melanoma 2 (AIM2) inflammasomes in vitro, but only AIM2 and apoptosis-associated speck-like protein containing a caspase-activation recruitment domain (ASC), rather than NLRP3 or caspase-1, favor host survival and restriction of mycobacterial replication in vivo. Interferons (IFNs) inhibits MTB-induced inflammasome activation and IL-1 signaling. In this review, we focus on activation and regulation of the NLRP3 and AIM2 inflammasomes after exposure to MTB, as well as the effect of inflammasome activation on host defense against the infection.

Is there an Inflammation Role for MYD88 in Rheumatoid Arthritis?

Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease with strong genetic influence, especially upon immune response components. Several cytokines from the toll-like receptors activation pathway display recognized role for RA establishment. However, few studies have verified the role of key mediators such as MYD88 gene and its genetic variants. In the present study, we aim to evaluate the rs6853 functional single-nucleotide variation (SNV) role in RA etiopathogenesis, clinical severity status, and its impact in MYD88 mRNA levels and IL-lβ protein levels. For the association study, a total of 423 RA patients and 346 health individuals, enrolled as control, from Northeast and Southeast Brazil were genotyped using specific Taqman probe. For the gene expression assays, we performed a MYD88 rs6853 genotype-guided monocyte cell culture divided into non-stimulated and lypopolysaccharides (LPS)-stimulated cells from healthy individuals. MYD88 gene expression was measured using primer specifics while IL-1β levels were evaluated by ELISA. We observed that A allele and AA genotype were associated to an increased risk to RA development (OR = 1.60; 95% CI 1.24-2.08; p = 0.0004/OR = 2.83; 95% CI 1.25-6.41; p = 0.0152). The AA genotype exhibited lower MYD88 mRNA levels than GG genotype in non-stimulated monocyte cell culture (FC - 3.83; p = 0.003). Additionally, we verified an increase of IL-1β levels when AA genotype non-stimulated monocytes were compared to AA genotype LPS-stimulates (p = 0.021). In summary, MYD88 rs6853 polymorphism associated to RA development in our Brazilian cohort and showed influence upon MYD88 mRNA levels' expression and IL-lβ production.

Paradoxical Roles of the MAL/Tirap Adaptor in Pathologies

Toll-like receptors (TLRs) are at the forefront of pathogen recognition ensuring host fitness and eliciting protective cellular and humoral responses. Signaling pathways downstream of TLRs are tightly regulated for preventing collateral damage and loss of tolerance toward commensals. To trigger effective intracellular signaling, these receptors require the involvement of adaptor proteins. Among these, Toll/Interleukin-1 receptor domain containing adaptor protein (Tirap or MAL) plays an important role in establishing immune responses. Loss of function of MAL was associated with either disease susceptibility or resistance. These opposite effects reveal paradoxical functions of MAL and their importance in containing infectious or non-infectious diseases. In this review, we summarize the current knowledge on the signaling pathways involving MAL in different pathologies and their impact on inducing protective or non-protective responses.

Association of TNF rs668920841 and INRA111 polymorphisms with caprine brucellosis: A case-control study of candidate genes involved in innate immunity

Caprine brucellosis is an infectious, contagious zoonotic disease caused by Brucella melitensis. Multiple factors, including host genetics, can influence the outcome of the exposure to Brucella; and it is expected that genetic variants that affect the host innate immune response could have a key role in Brucella infection and pathogenesis. In this study, we evaluated if polymorphisms in innate immunity-related genes are associated with results of Brucella infection in goats. Nine polymorphisms within interferon gamma (IFNG), tumor necrosis factor (TNF), MyD88 innate immune signal transduction adaptor (MYD88), interleukin 10 (IL10) and IL-10 receptor subunit alpha (IL10RA) genes and two molecular markers (BMS2753 and INRA111) were resolved by PCR-capillary electrophoresis in samples from 81 seronegative and 61 seropositive goats for brucellosis. A heterozygous genotype at INRA111, a microsatellite near the VRK serine/threonine kinase 2 (VRK2) gene, was associated with absence of Brucella-specific antibodies in goats naturally exposed to the pathogen (P = .004). Conversely, variants in the TNF gene (rs668920841) and near the IFN gamma receptor 1 (IFNGR1) gene (microsatellite BMS2753) were significantly associated with presence of Brucella-specific antibodies at allelic (P = .042 and P = .046) and genotypic level (P = .012 and P = .041, respectively). Moreover, an in silico analysis predicted a functional role of the insertion-deletion polymorphism rs668920841 on the transcriptional regulation of the caprine TNF gene. Altogether, these results contribute to the identification of genetic factors that have a putative effect on the resistance / susceptibility phenotype of goats to Brucella infection.

MAL adaptor (TIRAP) S180L polymorphism and severity of disease among tuberculosis patients

OBJECTIVE

Though several genetic variants have been recognized to be associated with susceptibility to Tuberculosis (TB) infection and disease, a recent observation on the association of TIRAP C975T (S180L) variants with TB disease severity in mice model prompted us to assess their relevance in humans. In addition, TIRAP variants have also been reported to be associated with varied circulating Interferon-gamma induced protein (IP-10) levels. We investigated the association of TIRAP variants with severity of TB disease and IP-10 production in humans, which may be useful in predicting poor clinical outcome.

METHODS

Culture positive symptomatic adult pulmonary TB (PTB) patients enrolled between August 2014 and October 2017 were included in this investigation. Allelic discrimination PCR and conventional IP-10 quantification methods were employed for genotyping and IP-10 measurement followed by statistical investigations to analyse patients' variables.

RESULTS

Among 211 participants, C/C allele was identified in 70% (n = 147); 26% (n = 55) and 4% (n = 9) had C/T and T/T alleles respectively. There was no significant association between TIRAP variants and smear grade, chest-X-ray score, symptom severity score and circulating IP-10 levels. However, significant association was observed between i) circulating IP-10 levels and time to Mycobacterium Growth Indicator Tube (MGIT) culture conversion (p =0.032); ii) smear grade among active TB patients and circulating IP-10 levels (p =0 .032).

CONCLUSIONS

Although mice experiments showed promising results with more severe disease in C/C and T/T individuals, we did not observe any such association in humans.

Polymorphisms in the myeloid differentiation primary response 88 pathway do not explain low expression levels in sudden infant death syndrome

AIM

The aim of this study was to investigate if a range of known rare and common genetic variants in the Toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88) pathway were present or overrepresented in sudden infant death syndrome (SIDS) compared to controls.

METHODS

Genetic variations in the genes encoding TLR4, MyD88 and Interleukin-1 receptor-associated kinase 4 were analysed. The subjects investigated included 158 SIDS cases with a median age of 15.25 weeks (2-47 weeks), 80 cases of infectious death with a median age of 24.9 weeks (0-285 weeks) and 199 adult controls with a median age of 50 years (11-86 years). The cases were collected in the years 1988-2017, and the autopsies were performed at the Department of Forensic Sciences at Oslo University Hospital, Oslo, Norway.

RESULTS

The results showed that none of the genetic variants selected from the MyD88 pathway were associated with neither SIDS nor infectious death. Most of the rare genetic variants were homozygote for the common allele in all groups, while the rest revealed allelic variation.

CONCLUSION

The genetic variations investigated in this study did not appear to be involved in the pathogenesis of SIDS.

Association of the TLR1 variant rs5743557 with susceptibility to tuberculosis

Background

Toll-like receptor 1 (TLR1) and TLR6 play important roles in the innate immune response against Mycobacterium tuberculosis (M.TB) via interactions with TIR domain-containing adaptor protein (TIRAP) and myeloid differentiation primary response 88 (MYD88). The aim of this study was to investigate the relationship of TLR1, TLR6, MYD88 and TIRAP polymorphisms with susceptibility to latent tuberculosis infection (LTBI) and tuberculosis (TB).

Methods

In total, 204 uninfected healthy controls (HC), 201 individuals with LTBI and 209 TB patients were enrolled. Two interferon-γ release assays were used to differentiate individuals with LTBI from uninfected controls. TagSNPs of the four genes were genotyped by the SNPscan^TM Kit. The Haploview 4.2 and SHEsis software packages were combined to perform linkage disequilibrium (LD) and haplotype analyses. Multifactor dimensionality reduction (MDR) software was used to investigate gene-gene interaction. The Stata 12.0 software was used to perform meta-analysis of the relationship between rs5743557 and TB susceptibility.

Results

The AA genotype of rs5743557 was associated with reduced TB risk (P=0.006) and the AA/GA genotypes of TLR1 rs5743604 were associated with increased TB risk (P=0.017) when the LTBI group was compared with the TB group. The frequency of TLR1 haplotype rs4833095-rs5743604 CG was significantly higher in the LTBI group than in the TB group (P=0.019877). However, only the relationship between rs5743557 and TB susceptibility remained significant after 1000-fold permutation testing (P=0.023). The meta-analysis suggested that rs5743557_A was associated with decreased TB risk in the Chinese adult population (P<0.001, OR 0.80, 95% CI: 0.72-0.88). No significant gene-gene interactions were found.

Conclusions

The results of our study suggest that the tagSNP rs5743557 of TLR1 is associated with the risk of TB.

Association of an IRF3 putative functional uORF variant with resistance to Brucella infection: A candidate gene based analysis of InDel polymorphisms in goats

Brucellosis is an important zoonotic disease caused by infection with Brucella spp. It generates major economic losses in livestock production worldwide. Goats are the principal hosts of B. melitensis, the main infection agent of caprine and human brucellosis. The selection of resistance-related genes is considered one of the best long-term means to improve control to bacterial infection in domestic ruminants. We performed a candidate gene association study to test if six short insertion/deletion polymorphisms (InDels) at bacterial-infection related genes influence the resistance to Brucella infection in female creole goats. InDels (IRF3-540: rs660531540, FKBP5-294: rs448529294, TIRAP-561: rs657494561, PTPRT-588: rs667380588, KALRN-989: rs667660989 and RAB5a-016: rs661537016) were resolved by PCR-capillary electrophoresis in samples from 64 cases and 64 controls for brucellosis. Allelic frequencies were significantly different between cases and controls at IRF3-540 and KALRN-989 (p = 0.001 and 0.005). Indeed, the minor alleles (a and k) at InDels IRF3-540 and KALRN-989 were more frequent among controls than cases, providing evidence that these alleles confer protection against Brucella infection. Moreover, IRF3-540 a-containing genotypes (Aa and aa) were associated with absence of Brucella-specific antibodies in goats (p = 0.003; OR = 3.52; 95% CI = 1.55-7.96), and more specifically, a-allele was associated with resistance to Brucella infection in a dose-dependent manner. Also, we observed that the IRF3-540 deletion (a-allele) extends a conserved upstream ORF by 75 nucleotides to the main ORF, and thus it may decrease gene expression by reducing translation efficiency from the main ORF. These results suggest a potential functional role of IRF3-540 deletion in genetic resistance to Brucella infection in goats.

MyD88 in Mycobacterium tuberculosis infection

MyD88 adaptor protein mediates numerous biologically important signal transduction pathways in innate immunity. MyD88 signaling fosters bacterial containment and is necessary to raise an adequate innate and acquired immune response to Mycobacterium tuberculosis (Mtb). The phagosome is a crucial cellular location not only for Mtb replication, but it is also where components of the Myddosome and inflammasome are recruited. Besides its function as a TLR-adaptor protein, MyD88 may help stabilizing cytosolic receptors that are recruited to the phagosome. MyD88 plays a critical role not only in the generation of an inflammatory response, but also in inducing regulatory signals to prevent excessive inflammation and cellular damage in the lung.

The -938C>A Polymorphism in MYD88 Is Associated with Susceptibility to Tuberculosis: A Pilot Study

Introduction. Tuberculosis (TB) is a major disease worldwide, caused by Mycobacterium tuberculosis (MTB) infection. The Toll-Like Receptor (TLR) pathway plays a crucial role in the recognition of MTB. Aim. The present study aimed to investigate the involvement of myeloid differentiation primary response protein 88 (MYD88) gene polymorphisms in TB. Materials and Methods. A total of 103 TB cases and 92 control subjects were genotyped for the MYD88 -938C>A (rs4988453) and 1944C>G (rs4988457) polymorphisms. Results. The MYD88 -938CA and -938AA genotypes were associated with an increased risk for tuberculosis with odds ratio (OR) of 5.71 (95% confidence intervals [CIs] 2.89–11.28, p = 0.01). Conclusions. The MYD88 -938C>A genetic polymorphism is associated with increased susceptibility to TB and may serve as a marker to screen individuals who are at risk.

Impaired toll like receptor 9 response in pulmonary tuberculosis

BACKGROUND & AIM

Innate immune responses are important in susceptibility to pulmonary tuberculosis (TB). In order to test the hypothesis that Toll-like receptor (TLR) 2 function would be abnormal in patients with active pulmonary TB we compared the cytokine responses of peripheral blood mononuclear cells (PBMC) to innate immune ligands in a case-control study.

METHODS

PBMC from 19 untreated pulmonary TB patients, 17 healthy controls, and 11 treated pulmonary TB patients, were cultured for 24h with TLR 2 ligand (PAM-CSK) and other TLR ligands (muramyl dipeptide, flagellin, lipopolysaccharide (LPS), CpG oligodeoxynucleotide (CpG-ODN)). Interleukin-8 (IL-8) was estimated in the supernatant by ELISA. Messenger RNA expression for inflammatory cytokines was quantitated using real time PCR.

RESULTS

The important findings were (1) reduced PBMC secretion of IL-8 in response to all ligands in active TB; (2) normal to increased PBMC secretion of IL-8 in response to all ligands except CpG ODN (TLR 9 ligand) in TB patients who had recovered; (3) absence of difference in mRNA expression for a consortium of inflammatory pathway genes between healthy controls, active pulmonary tuberculosis and treated pulmonary tuberculosis patients.

CONCLUSION

There was a generalized post-translational suppression of the IL-8 response to innate immune ligands in active TB. There appears to be a defect of TLR 9 signaling in patients with tuberculosis, the nature of which needs to be further explored.

A Common Variant in the Adaptor Mal Regulates Interferon Gamma Signaling

Humans that are heterozygous for the common S180L polymorphism in the Toll-like receptor (TLR) adaptor Mal (encoded by TIRAP) are protected from a number of infectious diseases, including tuberculosis (TB), whereas those homozygous for the allele are at increased risk. The reason for this difference in susceptibility is not clear. We report that Mal has a TLR-independent role in interferon-gamma (IFN-γ) receptor signaling. Mal-dependent IFN-γ receptor (IFNGR) signaling led to mitogen-activated protein kinase (MAPK) p38 phosphorylation and autophagy. IFN-γ signaling via Mal was required for phagosome maturation and killing of intracellular Mycobacterium tuberculosis (Mtb). The S180L polymorphism, and its murine equivalent S200L, reduced the affinity of Mal for the IFNGR, thereby compromising IFNGR signaling in macrophages and impairing responses to TB. Our findings highlight a role for Mal outside the TLR system and imply that genetic variation in TIRAP may be linked to other IFN-γ-related diseases including autoimmunity and cancer.

Innate Immune Signalling Genetics of Pain, Cognitive Dysfunction and Sickness Symptoms in Cancer Pain Patients Treated with Transdermal Fentanyl

Common adverse symptoms of cancer and chemotherapy are a major health burden; chief among these is pain, with opioids including transdermal fentanyl the mainstay of treatment. Innate immune activation has been implicated generally in pain, opioid analgesia, cognitive dysfunction, and sickness type symptoms reported by cancer patients. We aimed to determine if genetic polymorphisms in neuroimmune activation pathways alter the serum fentanyl concentration-response relationships for pain control, cognitive dysfunction, and other adverse symptoms, in cancer pain patients. Cancer pain patients (468) receiving transdermal fentanyl were genotyped for 31 single nucleotide polymorphisms in 19 genes: CASP1, BDNF, CRP, LY96, IL6, IL1B, TGFB1, TNF, IL10, IL2, TLR2, TLR4, MYD88, IL6R, OPRM1, ARRB2, COMT, STAT6 and ABCB1. Lasso and backward stepwise generalised linear regression were used to identify non-genetic and genetic predictors, respectively, of pain control (average Brief Pain Inventory < 4), cognitive dysfunction (Mini-Mental State Examination ≤ 23), sickness response and opioid adverse event complaint. Serum fentanyl concentrations did not predict between-patient variability in these outcomes, nor did genetic factors predict pain control, sickness response or opioid adverse event complaint. Carriers of the MYD88 rs6853 variant were half as likely to have cognitive dysfunction (11/111) than wild-type patients (69/325), with a relative risk of 0.45 (95% CI: 0.27 to 0.76) when accounting for major non-genetic predictors (age, Karnofsky functional score). This supports the involvement of innate immune signalling in cognitive dysfunction, and identifies MyD88 signalling pathways as a potential focus for predicting and reducing the burden of cognitive dysfunction in cancer pain patients.

TIRAP C539T polymorphism contributes to tuberculosis susceptibility: evidence from a meta-analysis

BACKGROUND

Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP), an important adaptor protein downstream of the Toll-like receptor (TLR) 2 and 4 pathways, is highly involved in the activation and coordination of the anti-mycobacterial immune response. We performed a meta-analysis to assess the association between TIRAP C539T polymorphism and tuberculosis (TB) risk.

METHODS

A systematic literature search for relevant studies up to February 27, 2014 was conducted in PUBMED, EMBASE, Web of science, CNKI, VIP, and Wanfang database. The association between gene and disease was assessed using odds ratios (ORs) with 95% confidence intervals (95%CIs) based on five genetic models.

RESULTS

A total of 16 qualified studies were enrolled in this meta-analysis. The results of pooling all studies detected statistically resistance of TIRAP C539T mutants to TB risk (T vs. C: OR 0.80, 95%CI 0.65-0.97; TC vs. CC: OR 0.71, 95%CI 0.55-0.92; TT+TC vs. CC: OR 0.74, 95% CI 0.58-0.94). Further subgroup analyses by ethnicity also demonstrated reduced risk of TB in European population (T vs. C: OR 0.71, 95%CI 0.52-0.95; TC vs. CC: OR 0.56, 95%CI 0.35-0.91; TT+TC vs. CC: OR 0.61, 95%CI 0.40-0.92), whereas no such effects were observed in other ethnicities.

CONCLUSION

This present meta-analysis suggests TIRAP C539T polymorphism is significantly correlated with reduced risk of TB infection, with stronger effect in European. Additional well-designed, larger-scale epidemiological studies among different ethnicities are needed.