Gene polymorphisms of Toll-like and related recognition receptors in relation to the vaginal carriage of Gardnerella vaginalis and Atopobium vaginae

Influence of connatural factors in shaping vaginal microflora and ensuring its health

Vaginal canal (VC) is exposed to the external environment affected by habitual factors like hygiene and sexual behaviour as well as physiological factors like puberty, menstrual cycle, pregnancy, child birth and menopause. Healthy VC harbours beneficial microflora supported by vaginal epithelium and cervical fluid. Connatural antimicrobial peptide (AMPs) of female reproductive tract (FRT) conjunctly with these beneficial microbes provide protection from a large number of infectious diseases. Such infections may either be caused by native microbes of the VC or transitory microbes like bacteria or virus which are not a part of VC microflora. This review highlight's the role of hormones, enzymes, innate immunological factors, epithelial cells and vaginal mucus that support beneficial microbes over infectious ones thus, helping to maintain homeostasis in VC and further protect the FRT. We also discuss the prospective use of vaginal probiotics and AMPs against pathogens which can serve as a potential cure for vaginal infections.

Genome-wide association study in Estonia reveals importance of vaginal epithelium associated genes in case of recurrent vaginitis

Recurrent vaginitis is a leading reason for visiting a gynaecologist, with bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) being the most common diagnoses. Reasons and mechanisms behind their recurrent nature are poorly understood. We conducted a genome-wide association study (GWAS) to find possible genetic risk factors for recurrent vaginitis using data from a large population-based biobank, the Estonian Biobank. The study included 6870 cases (at least two episodes of vaginitis) and 5945 controls (no vaginitis episodes). GWAS approach included single marker and gene-based analyses, followed by functional annotation of associated variants and candidate gene mapping.In single marker analysis, one statistically significant (P = 7.8 × 10-9) variant rs1036732378 was identified on chromosome 10. The gene-based association analysis identified one gene, KRT6A, that exceeded the recommended significance threshold (P = 2.6 × 10-6). This is a member of the keratin protein family and is expressed during differentiation in epithelial tissues.Functional mapping and annotation of genetic associations by using adjusted significance level identified 22 potential risk loci that may be associated with recurrent vaginitis phenotype. Comparison of our results with previous studies provided nominal support for LBP (associated with immune response to vaginal bacteria) and PRKCH genes (possible role in keratinocyte differentiation and susceptibility to candidiasis).In conclusion, this study is the first highlighting a potential role of the vaginal epithelium in recurrent vaginitis.

Bacterial Vaginosis: Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry No. 015/028, June 2023)

Aim This official guideline was coordinated and published by the DGGG, OEGGG and SGGG with the involvement of additional professional societies. The aim of the guideline is to evaluate the relevant literature and use it to provide a consensus-based overview of the diagnosis and management of bacterial vaginosis. Methods This S2k-guideline was developed by representative members from different medical professional societies on behalf of the guidelines commission of the above-listed societies using a structured consensus process. Recommendations This guideline provides recommendations on the diagnosis, management, counselling, prophylaxis, and other aspects related to bacterial vaginosis.

A review of methods for detecting single-nucleotide polymorphisms in the Toll-like receptor gene family

The Toll-like receptors play an essential role in immunity through targeting the pathogen-associated molecular patterns. Nucleotide variations in TLR genes, especially single-nucleotide polymorphisms, have been shown to alter host immune susceptibility to several infections and diseases. Since TLR genes' polymorphisms can be a promising biomarker, ongoing investigations aim to develop, optimize and validate SNP detection methods. This review discusses various TLR SNP detection methods, either used extensively or occasionally, but having a vast potential in high-throughput settings. Methods such as PCR-restriction fragment length polymorphism, TaqMan^® assay, direct sequencing and matrix-assisted laser desorption ionization - time of flight mass spectroscopy MS are frequently used methods whereas Illumina GoldenGate^® assay, reverse hybridization technology, PCR-confronting two-pair primers, KBiosciences KASPar^® SNP assay, SNP stream^®, PCR-fluorescence hybridization and SNaPshot^® are powerful but sporadically used methods. We suggest that, for individual laboratories, the detection method of choice depends on a combination of factors such as throughput volume, reproducibility, feasibility and cost-effectiveness.

Effects of Lipopolysaccharide-Binding Protein (LBP) Single Nucleotide Polymorphism (SNP) in Infections, Inflammatory Diseases, Metabolic Disorders and Cancers

Inflammation, which is induced by the immune response, is recognized as the driving factor in many diseases, including infections and inflammatory diseases, metabolic disorders and cancers. Genetic variations in pivotal genes associated with the immune response, particularly single nucleotide polymorphisms (SNPs), may account for predisposition and clinical outcome of diseases. Lipopolysaccharide (LPS)-binding protein (LBP) functions as an enhancer of the host response to LPS, the main component of the outer membrane of gram-native bacteria. Given the crucial role of LBP in inflammation, we will review the impact of SNPs in the LBP gene on infections and inflammatory diseases, metabolic disorders and cancers.

Toll-like receptor variants and cervical Atopobium vaginae infection in women with pelvic inflammatory disease

PROBLEM

Toll-like (TLR) receptor genetic variants have been implicated in bacterial vaginosis (BV). We determined whether TLR variants are associated with fastidious BV-associated microbes that are linked with infertility following pelvic inflammatory disease (PID).

METHOD OF STUDY

Sneathia spp., Atopobium vaginae, BVAB1, and Ureaplasma urealyticum were measured in 250 women from the PID Evaluation and Clinical Health (PEACH) study. Relative risk (RR) and 95% confidence intervals (CI) were calculated adjusting for chlamydia and gonorrhea. Principal component analysis was used to adjust for population stratification. A false discovery rate q-value of 0.05 was significant.

RESULTS

TLR2-1733C>A (P = .003) and TLR2-616A>G (P = .004) were associated with cervical A. vaginae. TLR2-1733C>A and TLR6-438C>T were associated with A. vaginae detection in the endometrium, but this was not significant after adjustment for multiple comparisons (FDR q-value = 0.06).

CONCLUSION

Host gene variants in TLR2 signaling pathways were modestly associated with cervical A. vaginae in women with clinical PID.

The Role of Skin and Orogenital Microbiota in Protective Immunity and Chronic Immune-Mediated Inflammatory Disease

The skin and orogenital mucosae, which constitute complex protective barriers against infection and injuries, are not only the first to come into contact with pathogens but are also colonized by a set of microorganisms that are essential to maintain a healthy physiological environment. Using 16S ribosomal RNA metagenomic sequencing, scientists recognized that the microorganism colonization has greater diversity and variability than previously assumed. These microorganisms, such as commensal bacteria, affect the host’s immune response against pathogens and modulate chronic inflammatory responses. Previously, a single pathogen was thought to cause a single disease, but current evidence suggests that dysbiosis of the tissue microbiota may underlie the disease status. Dysbiosis results in aberrant immune responses at the surface and furthermore, affects the systemic immune response. Hence, understanding the initial interaction between the barrier surface immune system and local microorganisms is important for understanding the overall systemic effects of the immune response. In this review, we describe current evidence for the basis of the interactions between pathogens, microbiota, and immune cells on surface barriers and offer explanations for how these interactions may lead to chronic inflammatory disorders.

The Vaginal Microbiome: Current Understanding and Future Directions

This article summarizes the highlights of the expert technical consultation on bacterial vaginosis (BV), sponsored by the National Institute of Allergy and Infectious Disease and held in Washington, DC, on 8-9 April 2015. Many issues touched on in this article are discussed in much greater detail in the 6 preceding articles in this supplement to The Journal of Infectious Diseases There was a consensus among the meeting attendees concerning the most important research issues in the field: the pathogenesis of the syndrome, way to optimize treatment, and the relative roles of sexual transmission and endogenous infection in BV epidemiology. This article concludes with a listing of BV and genitourinary tract research priorities that were discussed and agreed on by attendees. The most important of these included better characterization of vaginal microbiome community state subtypes, application of advanced "-omic" technologies to improve understanding of BV pathogenesis, further investigation of the relationships between the male and female genitourinary tract microbiomes, and the development of new drugs for BV treatment.

TLR2 2258 G>A single nucleotide polymorphism and the risk of congenital infection with human cytomegalovirus

BACKGROUND

Human cytomegalovirus (HCMV) is responsible for the most common intrauterine infections, which may be acquired congenitally from infected pregnant woman to fetus. The research was aimed to estimate the role of three single nucleotide polymorphisms (SNPs) located in TLR2 gene, and the common contribution of TLR2, and previously studied TLR4 and TLR9 SNPs, to the occurrence of congenital HCMV infection in fetuses and newborns.

METHODS

The study was performed in 20 Polish fetuses and newborns, congenitally infected with HCMV, and in 31 uninfected controls, as well as with participation of pregnant women, the mothers of 16 infected and 14 uninfected offsprings. Genotypes in TLR2 SNPs were determined, using self-designed nested PCR-RFLP assays, and confirmed by sequencing. The genotypes were tested for Hardy-Weinberg (H-W) equilibrium, and for their relationship with the development of congenital cytomegaly, using a logistic regression model. The common influence of TLR2, TLR4 and TLR9 SNPs on the occurrence of congenital disease was estimated by multiple-SNP analysis.

RESULTS

Distribution of the genotypes and alleles in TLR2 1350 T>C and 2029 C>T SNPs was similar between the studied groups of fetuses and neonates. In case of 2258 G>A polymorphism, the GA heterozygotic status was significantly more frequent in the infected cases than among the uninfected individuals (25.0% vs. 3.2%, respectively), and increased the risk of HCMV infection (OR 10.00, 95% CI 1.07-93.44; P ≤ 0.050). Similarly, the A allele within 2258 G>A polymorphism was significantly more frequent among the infected offsprings than in the uninfected ones (12.5% vs. 1.6%; P ≤ 0.050). Complex AA variants for both TLR2 2258 and TLR9 2848 G>A polymorphisms, were estimated to be at increased risk of congenital HCMV infection (OR 11.58, 95% CI 1.19-112.59; P ≤ 0.050). Additionally, significant relationships were observed between the occurrence of complex AA or GA variants for both TLR2 and TLR9 SNPs and the increased viral loads, determined in fetal amniotic fluids and in maternal blood or urine specimens (P ≤ 0.050).

CONCLUSIONS

Among various TLR2, TLR4 and TLR9 polymorphisms, TLR2 2258 G>A SNP seems to be an important factor associated with increased risk of congenital HCMV infection in Polish fetuses and neonates.

Genetic variations of NOD2 and MD2 genes in hepatitis B virus infection

OBJECTIVES

Nucleotide oligomerization domain 2 (NOD2) and myeloid differentiation protein 2 (MD-2) have crucial roles in the innate immune system. NOD2 is a member of the NOD-like receptor (NLR) family of pattern recognition receptors (PRRs), while MD-2 is a co-receptor for Toll-like receptor 4 (TLR4), which comprises another group of PRRs. Genetic variations in the NOD2 and MD-2 genes may be susceptibility factors to viral pathogens including hepatitis B virus (HBV). We investigated whether polymorphisms at NOD2 (rs2066845 and rs2066844) or at MD-2 (rs6472812 and rs11466004) were associated with susceptibility to HBV infection and advancement to related liver complications in a Saudi Arabian population. Methods: A total of 786 HBV-infected patients and 600 healthy uninfected controls were analyzed in the present study. HBV-infected patients were categorized into three groups based on the clinical stage of the infection: inactive HBV carriers, active HBV carriers, and patients with liver cirrhosis + hepatocellular carcinoma (HCC). Results: All four SNPs were significantly associated with susceptibility to HBV infection although none of the SNPs tested in NOD2 and MD-2 were significantly associated with persistence of HBV infection. We found that HBV-infected patients that were homozygous CC for rs2066845 in the NOD2 gene were at a significantly increased risk of progression to HBV-related liver complications (Odds Ratio = 7.443 and P = 0.044). Furthermore, haplotype analysis found that the rs2066844-rs2066845 C-G and T-G haplotypes at the NOD2 gene and four rs6472812-rs11466004 haplotypes (G-C, G-T, A-C, and A-T) at the MD-2 gene were significantly associated with HBV infection in the affected cohort compared to those found in our control group. Conclusion: We found that the single nucleotide polymorphisms rs2066844 and rs2066845 at NOD2 and rs6472812 and rs11466004 at MD-2 were associated with susceptibility to HBV infection in a Saudi population.

The Interplay of Host Immunity, Environment and the Risk of Bacterial Vaginosis and Associated Reproductive Health Outcomes

Bacterial vaginosis (BV) is one of the most common causes of vaginal symptoms in US women, but its causal mechanism has not yet been defined. BV is more prevalent in women who are immunosuppressed, and several risk factors for the development of BV are associated with lower quantities of immune mediators in vaginal fluid. In contrast, the poor reproductive health outcomes associated with BV, such as preterm birth and human immunodeficiency virus type 1 acquisition, are associated with increased levels of proinflammatory immune mediators in the genital tract. In this article, we discuss how variations in the host immune profile and environmental effects on host immunity may influence the risk of BV, as well as the risk of complications associated with BV.

Vaginal Microbiota

The knowledge about the normal and abnormal vaginal microbiome has changed over the last years. Culturing techniques are not suitable any more for determination of a normal or abnormal vaginal microbiota. Non culture-based modern technologies revealed a complex and dynamic system mainly dominated by lactobacilli.The normal and the abnormal vaginal microbiota are complex ecosystems of more than 200 bacterial species influenced by genes, ethnic background and environmental and behavioral factors. Several species of lactobacilli per individuum dominate the healthy vagina. They support a defense system together with antibacterial substances, cytokines, defensins and others against dysbiosis, infections and care for an normal pregnancy without preterm birth.The numbers of Lactobacillus (L.) iners increase in the case of dysbiosis.Bacterial vaginosis (BV) - associated bacteria (BVAB), Atopobium vaginae and Clostridiales and one or two of four Gardnerella vaginalis - strains develop in different mixtures and numbers polymicrobial biofilms on the vaginal epithelium, which are not dissolved by antibiotic therapies according to guidelines and, thus, provoke recurrences.Aerobic vaginitis seems to be an immunological disorder of the vagina with influence on the microbiota, which is here dominated by aerobic bacteria (Streptococcus agalactiae, Escherichia coli). Their role in AV is unknown.Vaginal or oral application of lactobacilli is obviously able to improve therapeutic results of BV and dysbiosis.

Association of 4p14 TLR locus with antibodies to Helicobacter pylori

A genome-wide association study among Europeans related polymorphisms of the Toll-like receptor (TLR) locus at 4p14 and the Fcγ receptor 2a locus at 1q23.3 to Helicobacter pylori serologic status. We replicated associations of 4p14 but not 1q23.3 with anti-Helicobacter pylori antibodies in 1402 Finnish males. Importantly, our analysis clarified that the phenotype affected by 4p14 is quantitative level of these antibodies rather than association with seropositivity per se. In addition, we annotated variants at 4p14 as expression quantitative trait loci (eQTL) associated with TLR6/10 and FAM114A1. Our findings suggest that 4p14 polymorphisms are linked to host immune response to H. pylori infection but not to its acquisition.

Single nucleotide polymorphisms of Toll-like receptors and susceptibility to infectious diseases

Toll-like receptors (TLRs) are the best-studied family of pattern-recognition receptors (PRRs), whose task is to rapidly recognize evolutionarily conserved structures on the invading microorganisms. Through binding to these patterns, TLRs trigger a number of proinflammatory and anti-microbial responses, playing a key role in the first line of defence against the pathogens also promoting adaptive immunity responses. Growing amounts of data suggest that single nucleotide polymorphisms (SNPs) on the various human TLR proteins are associated with altered susceptibility to infection. This review summarizes the role of TLRs in innate immunity, their ligands and signalling and focuses on the TLR SNPs which have been linked to infectious disease susceptibility.

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.

The changing landscape of the vaginal microbiome

Deep sequence analysis of the vaginal microbiome is revealing an unexpected complexity that was not anticipated as recently as several years ago. The lack of clarity in the definition of a healthy vaginal microbiome, much less an unhealthy vaginal microbiome, underscores the need for more investigation of these phenomena. Some clarity may be gained by the careful analysis of the genomes of the specific bacteria in these women. Ongoing studies will clarify this process and offer relief for women with recurring vaginal maladies and hope for pregnant women to avoid the experience of preterm birth.

Genetic dysbiosis: the role of microbial insults in chronic inflammatory diseases

Thousands of bacterial phylotypes colonise the human body and the host response to this bacterial challenge greatly influences our state of health or disease. The concept of infectogenomics highlights the importance of host genetic factors in determining the composition of human microbial biofilms and the response to this microbial challenge. We hereby introduce the term ‘genetic dysbiosis’ to highlight the role of human genetic variants affecting microbial recognition and host response in creating an environment conducive to changes in the normal microbiota. Such changes can, in turn, predispose to, and influence, diseases such as: cancer, inflammatory bowel disease, rheumatoid arthritis, psoriasis, bacterial vaginosis and periodontitis. This review presents the state of the evidence on host genetic factors affecting dysbiosis and microbial misrecognition (i.e. an aberrant response to the normal microbiota) and highlights the need for further research in this area.

The role of metagenomics in understanding the human microbiome in health and disease

The term microbiome refers to the genetic material of the catalog of microbial taxa associated with humans. As in all ecosystems, the microbiota reaches a dynamic equilibrium in the human body, which can be altered by environmental factors and external stimuli. Metagenomics is a relatively new field of study of microbial genomes within diverse environmental samples, which is of increasing importance in microbiology. The introduction of this ecological perception of microbiology is the key to achieving real knowledge about the influence of the microbiota in human health and disease. The aim of this review is to summarize the link between the human microbiota (focusing on the intestinal, vaginal, skin, and airway body sites) and health from this ecological point of view, highlighting the contribution of metagenomics in the advance of this field.

Longitudinal analysis of vaginal microbiome dynamics in women with recurrent bacterial vaginosis: recognition of the conversion process

Bacterial vaginosis (BV) affects ∼ 30% of women of reproductive age, has a high rate of recurrence, and is associated with miscarriage, preterm birth, and increased risk of acquiring other sexually transmitted infections, including HIV-1. Little is known of the daily changes in the vaginal bacterial composition as it progresses from treatment to recurrence, or whether any of these might be useful in its prediction or an understanding of its causes. We used phylogenetic branch-inclusive quantitative PCR (PB-qPCR) and Lactobacillus blocked/unblocked qPCR (Lb-qPCR) to characterize longitudinal changes in the vaginal microbiota in sequential vaginal self-swabs from five women with recurrent BV, from diagnosis through remission to recurrence. Both patients with acute BV samples dominated by G. vaginalis recurred during the study with similar profiles, whereas the three patients with acute BV samples dominated by other anaerobes did not recur or recurred to an intermediate Nugent score. L. iners dominated remission phases, with intermittent days of abnormal microbial profiles typically associated with menses. The exception was a newly discovered phenomenon, a sustained period of abnormal profiles, termed conversion, which preceded symptomatic acute BV. Species known to have antagonistic activity towards Lactobacillus were detected in pre-conversion samples, possibly contributing to the decline in Lactobacillus. Lb-qPCR scores define two categories of response in the initial post-treatment visit samples; scores <5 may correspond with poor response to treatment or rapid recurrence, whereas scores >8 may predict delayed or no recurrence. Amsel criteria or Nugent scores did not have this potential predictive capability. Larger studies are warranted to evaluate the prognostic potential of detecting conversion and poor Lb-qPCR scores at the post-treatment visit of recurrent BV patients.

Genetic variations in toll-like receptor pathway and lung function decline in Cystic fibrosis patients

The toll-like receptor (TLR) family maintains pulmonary homeostasis by pathogen recognition, clearance and regulation of inflammation. Genes affecting inflammation response play a key role in modifying Cystic fibrosis (CF) lung disease severity. We assessed the impact of single nucleotide polymorphisms (SNPs) of TLR genes (TLR1 to TLR10, CD14, lipopolyssacharide-binding protein (LBP)) on lung function in CF patients. Each SNP was tested for time-dependent effect on FEV1, using six genetic models. In addition, we investigated associations between SNP genotypes and extreme subject specific slopes of FEV1 decline. Variant alleles of polymorphisms of TLR2 rs1898830, rs5743708, and rs3804100 demonstrated a consistent association with lung disease severity (p = 0.008, p = 0.006 and p = 0.029 respectively). Patients homozygous for variant C allele of TLR5 polymorphism rs5744174 are more frequently associated with extreme fast FEV1 decline (OR: 20 (95% Confidence Interval:1.85-216.18)). Patients homozygous AA for TLR1 polymorphism rs5743551 are more frequently associated with faster decline of FEV1 compared to heterozygous genotype (OR:7.33 (95% CI:1.63-33.11). Our findings indicate that variations in TLR1, TLR2 and TLR5 genes may influence CF lung function decline. Further functional analysis is required to provide new insights into the pathogenesis of TLRs in CF lung disease severity.

Toll-like receptor polymorphisms, inflammatory and infectious diseases, allergies, and cancer

Toll-like receptors (TLRs) are germ-line-encoded innate immune sensors that recognize conserved microbial structures and host alarmins and signal expression of MHC proteins, costimulatory molecules, and inflammatory mediators by macrophages, neutrophils, dendritic cells, and other cell types. These processes activate immediate and early mechanisms of innate host defense, as well as initiate and orchestrate adaptive immune responses. Several single-nucleotide polymorphisms (SNPs) within the TLR genes have been associated with altered susceptibility to infectious, inflammatory, and allergic diseases, and have been found to play a role in tumorigenesis. Critical advances in our understanding of innate immune functions and genome-wide association studies (GWAS) have uncovered complex interactions of genetic polymorphisms within TLRs and environmental factors. However, conclusions obtained in the course of such analyses are restricted by limited power of many studies that is likely to explain controversial findings. Further, linkages to certain ethnic backgrounds, gender, and the presence of multigenic effects further complicate the interpretations of how the TLR SNPs affect immune responses. For many TLRs, the molecular mechanisms by which SNPs impact receptor functions remain unknown. In this review, I have summarized current knowledge about the TLR polymorphisms, their impact on TLR signaling, and associations with various inflammatory, infectious, allergic diseases and cancers, and discussed the directions of future scientific research.

Genetic polymorphisms in innate immunity receptors do not predict the risk of bacterial and fungal infections and acute rejection after liver transplantation

INTRODUCTION

We studied the influence of a broad range of genetic variants in recipient and donor innate immunity receptors on bacterial and fungal infections and acute rejection after liver transplantation (LT).

METHODS

Seventy-six polymorphisms in TLR 1-10, NOD2, LBP, CD14, MD2, SIGIRR, Ficolins 1, -2, and -3, MASP 1, -2, and -3, and the complement receptor C1qR1 were determined in 188 LT recipients and 135 of their donors. Associations with clinically significant infections and acute rejection were analyzed for 50 polymorphisms. Significant associations were validated in an independent cohort of 181 recipients and 167 donors.

RESULTS

Three recipient polymorphisms and 3 donor polymorphisms were associated with infections in the identification cohort, but none of these associations were confirmed in the validation cohort. Three donor polymorphisms were associated with acute rejection in the identification cohort, but not in the validation cohort.

CONCLUSION

In contrast to their effect in the general population, 50 common genetic variations in innate immunity receptors do not influence susceptibility to bacterial/fungal infections after LT. In addition, no reproducible associations with acute rejection after LT were observed. Likely, transplant-related factors play a superior role as risk factors for bacterial/fungal infections and acute rejection after LT.

Toll-like receptor gene variants associated with bacterial vaginosis among HIV-1 infected adolescents

Bacterial vaginosis (BV) is a common vaginal disorder in women of reproductive age, especially among women with HIV-1 infection. Several bacterial products including lipopolysaccharides (LPS), lipoteichoic acids (LTA), and peptidoglycans (PGN) are stimulatory ligands for Toll-like receptors (TLRs), and recent evidence indicates the important role of variation in TLR genes for permitting overgrowth of gram negative and BV-type flora. We assessed whether genetic polymorphisms in five TLR genes (TLR1, TLR2, TLR4, TLR6, and TLR9) could be determinants of differential host immune responses to BV in 159 HIV-1-positive African American adolescents enrolled in the Reaching for Excellence in Adolescent Care and Health (REACH) study. BV was assessed biannually and diagnosed either by a Nugent score of at least 7 of 10, or using the Amsel criteria. Cox-proportional hazards regression models, adjusted for concurrent Chlamydia and Gonorrhea infections, douching, and absolute CD4 cell count, were used to identify host genetic factors associated with BV. Two SNPs were associated with BV as diagnosed by the Nugent score and the combined criteria: a minor allele G of rs4986790 (frequency=0.07), which encodes a His to Tyr substitution in TLR4 (HR=1.47, 95% CI 1.15-1.87) and rs187084 (frequency=0.24) on TLR9. The minor allele of rs1898830 (frequency=0.13) was associated with an increased hazard of BV defined by the Amsel criteria (HR=1.86, 95% CI 1.17-2.95). Further studies are warranted to confirm the associations of TLR gene variants and also to understand the underlying pathways and immunogenetic correlates in the context of HIV-1 infection.

SNPs in toll-like receptor (TLR) genes as new genetic alterations associated with congenital toxoplasmosis?

Nearly 40 % of pregnant women are infected with Toxoplasma gondii. Primary infections in pregnant women result, in approximately 30–50 % of patients, in transmission of T. gondii through the placenta to the fetus and then in congenital infections with severe, sometimes fatal course. Studies still do not provide sufficient data on the genetic bases of the immunity in fetuses, newborns, and infants with congenital toxoplasmosis. Previous research showed the contribution of toll-like receptors (TLRs) to non-specific immunity against T. gondii invasion, observed in T. gondii-infected animals, especially mice. So far, the activity of TLRs in defense against T. gondii infections was observed particularly for TLR2, TLR4, and TLR9 molecules. Differential TLR activity associates with both cell types, including a variety of placental cells and stage of pregnancy. Several single-nucleotide polymorphisms (SNPs) residing in three genes encoding these receptors were reported as significant genetic modifications of TLRs associated with different pregnancy disorders. Despite those data, genetic alterations of TLRs which have contributed to innate immune response against T. gondii infections are still not precisely described. In this article, we present reasons for the research of the plausible role of SNPs residing in TLR2, TLR4, and TLR9 genes in congenital toxoplasmosis development.

Polymorphisms in the lectin pathway genes as a possible cause of early chronic Pseudomonas aeruginosa colonization in cystic fibrosis patients

Genes of innate immunity may be involved in early onset of chronic Pa (Pseudomonas aeruginosa) colonization (cPaC) in cystic fibrosis (CF) patients. We studied 19 single nucleotide polymorphisms (SNPs) in 5 genes coding for proteins of the lectin complement pathway: MBL2 (Mannose binding lectin 2), MASP 1, 2, 3 (MBL-associated serine Protease) and FCN 1, 2 (Ficolin) gene in 96 CF patients. Association survival analysis using different genetic models was performed looking for an association between SNPs and age at onset of cPaC. CF patients who are MBL deficient are earlier chronic Pa colonized compared to MBL sufficient patients. Also patients with MBL2 genotype YO/YO, YO/XA, XA/XA, YA/YO and YA/XA are earlier chronic Pa colonized. CF patients heterozygous or homozygous for mutant alleles of two linked SNPs in the FCN1 gene (rs2989727 and rs1071583) are earlier colonized with Pa. Similarly, earlier onset of Pa colonization is seen in CF patients heterozygous for linked SNPs of FCN2 gene (rs7865453 and rs7851696) and MASP3 gene (rs7851696). Variants in MBL2, FCN1, FCN2 and MASP3 genes are significantly associated with earlier onset of chronic P. aeruginosa colonization.

A new era of the vaginal microbiome: advances using next-generation sequencing

Until recently, bacterial species that inhabit the human vagina have been primarily studied using organism-centric approaches. Understanding how these bacterial species interact with each other and the host vaginal epithelium is essential for a more complete understanding of vaginal health. Molecular approaches have already led to the identification of uncultivated bacterial taxa associated with bacterial vaginosis. Here, we review recent studies of the vaginal microbiome and discuss how culture-independent approaches, such as applications of next-generation sequencing, are advancing the field and shifting our understanding of how vaginal health is defined. This work may lead to improved diagnostic tools and treatments for women who suffer from, or are at risk for, vaginal imbalances, pregnancy complications, and sexually acquired infections. These approaches may also transform our understanding of how host genetic factors, physiological conditions (e.g., menopause), and environmental exposures (e.g., smoking, antibiotic usage) influence the vaginal microbiome.

The interaction effect of bacterial vaginosis and periodontal disease on the risk of preterm delivery

The objective of this article is to determine if coexistence of periodontal disease (PD) and bacterial vaginosis (BV) is synergistic on the risk of spontaneous preterm delivery (sPTD). The study design was secondary analysis of a prospective cohort study. Women were screened 6 to 20 weeks gestation for PD and BV. Groups were defined by presence of BV and stratified on PD. The primary outcome was sPTD <37 weeks gestation. Univariable, stratified, and multivariable analyses were performed to estimate the main and interaction effects of BV and PD on sPTD. Of 1453 women screened, 792 (54.5%) were diagnosed with BV. Neither women with BV in the first trimester nor PD was at higher risk of sPTD (risk ratio [RR] for BV 1.1; 95% confidence interval (CI), 0.8-1.5, and RR for PD 0.9; 95% CI, 0.7-1.3). The interaction between BV and PD did not statistically significantly impact the odds of sPTD. Coexistence of PD and BV did not have a synergistic effect on sPTD.

A functional variant of lipopolysaccharide binding protein predisposes to sepsis and organ dysfunction in patients with major trauma

OBJECTIVE

To determine the hypothesis that genetic variations of the lipopolysaccharide-binding protein (LBP) gene influence risk for the development of sepsis and multiple organ dysfunction (MOD) in patients with major trauma.

BACKGROUND

Lipopolysaccharide-binding protein plays a central role in innate immune response as the first line of defense and directing the microbial-induced activation of the inflammatory host response. Although a total of 112 single nucleotide polymorphisms (SNPs) have been identified so far within the entire LBP gene, only a few SNPs have been studied.

METHODS

Nine haplotype tagging SNPs (htSNPs) were selected from 51 SNPs with a minor allele frequency of ≥5% using the HapMap database for the Chinese Han population. Two independent cohorts of major trauma patients were recruited. The 9 htSNPs were genotyped using pyrosequencing method and analyzed in relation to the risk of development of sepsis and MOD, LBP production, and lipopolysaccharide (LPS)-induced activation of peripheral blood leukocytes. Moreover, the functionality of the rs2232618 polymorphism was assessed by the observation of its effects on the binding and activation of LPS and the LBP-CD14 interaction.

RESULTS

Among the 9 htSNPs, only the rs2232618 was significantly associated with higher susceptibility to sepsis and MOD in the 2 independent cohorts of major trauma patients recruited from southwest and eastern China. This SNP was also significantly associated with LPS-induced activation of peripheral blood leukocytes. In addition, the rs2232618 polymorphism could enhance LBP protein activities, showing significant increases in LPS binding to macrophages, LPS-induced cellular activation, and LBP-CD14 interaction at the presence of the variant LBP protein.

CONCLUSIONS

The rs2232618 polymorphism is a functional SNP and confers host susceptibility to sepsis and multiple organ dysfunction in patients with major trauma.

The aetiology of bacterial vaginosis

Bacterial vaginosis (BV) is the most common vaginal infection among women of childbearing age. This condition is notorious for causing severe complications related to the reproductive health of women. Five decades of intense research established many risk factors for acquisition of BV; however, because of the complexity of BV and lack of a reliable animal model for this condition, its exact aetiology remains elusive. In this manuscript, we use a historical perspective to critically review the development of major theories on the aetiology of BV, ultimately implicating BV-related pathogens, healthy vaginal microbiota, bacteriophages and the immune response of the host. None of these theories on their own can reliably explain the epidemiological data. Instead, BV is caused by a complex interaction of multiple factors, which include the numerous components of the vaginal microbial ecosystem and their human host. Many of these factors are yet to be characterized because a clear understanding of their relative contribution to the aetiology of BV is pivotal to the formulation of an effective treatment for and prophylaxis of this condition.

Toll-like receptors and genital tract infection

Our knowledge of the immune response to genital tract infection has progressed appreciably in recent years. This review focuses on the innate immune system, in particular the role of Toll-like receptors (TLRs), in controlling genital tract infection. Research into the role of TLRs in recognizing 'pathogen-associated molecular patterns' (PAMPS) has provided an important insight into the host's early immune response. TLRs are activated following binding of microbial components leading to cytokine production, which, in turn, stimulate phagocytic and natural killer cells and mobilize T and B lymphocytes of the antigen-specific acquired immune system. The therapeutic use of TLR agonists as topical agents or for improving CD4+ and CD8+ T-cell responses to microbial vaccines is an important area of ongoing research, particularly with respect to genital mucosal infection.