HLA DQ alleles and interleukin-10 polymorphism associated with Chlamydia trachomatis-related tubal factor infertility: a case-control study

HLA-DQB1*06 and Select Neighboring HLA Variants Predict Chlamydia Reinfection Risk

Associations of HLA class II alleles with genital chlamydial infection outcomes have been reported, especially HLA DQB1*06. However, the potential role of DQB1*06 in influencing reinfection risk has still not been established. The purpose of this study was to determine whether the association of DQB1*06 with chlamydia reinfection was impacted by any other nearby HLA class II variants that were also associated with reinfection. We used next-generation sequencing to map HLA class II variants spanning the HLA-DQ and -DR loci. DQB1*06 as well as DQB1*04 were confirmed as significant predictors of chlamydia reinfection, when controlling for age and percent African ancestry. SKAT analysis revealed one region each in DRB1, DRB5, DQA2, and three intergenic regions that had variants associated with reinfection. Further analyses of these variants revealed that rs112651494 within DRB5 and an intergenic SNP rs617058 in DRB1:DQA1 were significantly associated with reinfection, but this did not impact the significance of the association of DQB1*06 or DQB1*04 with reinfection.

TNFA and IL10 Polymorphisms and IL-6 and IL-10 Levels Influence Disease Severity in Influenza A(H1N1)pdm09 Virus Infected Patients

Cytokines are key modulators of immune response, and dysregulated production of proinflammatory and anti-inflammatory cytokines contributes to the pathogenesis of influenza A(H1N1)pdm09 virus infection. Cytokine production is impacted by single nucleotide polymorphisms (SNPs) in the genes coding for them. In the present study, SNPs in the IL6, TNFA, IFNG, IL17A, IL10, and TGFB were investigated for their association with disease severity and fatality in influenza A(H1N1)pdm09-affected patients with mild disease (n = 293) and severe disease (n = 86). Among those with severe disease, 41 patients had fatal outcomes. In a subset of the patients, levels of IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ, and IL-17 were assayed in the plasma for their association with severe disease. The frequency of TNFA rs1800629 G/A allele was significantly higher in severe cases and survived severe cases group compared to that of those with mild infection (OR with 95% for mild vs. severe cases 2.95 (1.52–5.73); mild vs. survived severe cases 4.02 (1.84–8.82)). IL10 rs1800896-rs1800872 G-C haplotype was significantly lower (OR with 95% 0.34 (0.12–0.95)), while IL10 rs1800896-rs1800872 G-A haplotype was significantly higher (OR with 95% 12.11 (2.23–76.96)) in fatal cases group compared to that of the mild group. IL-6 and IL-10 levels were significantly higher in fatal cases compared to that of survived severe cases. IL-6 levels had greater discriminatory power than IL-10 to predict progression to fatal outcome in influenza A(H1N1)pdm09 virus-infected patients. To conclude, the present study reports the association of TNFA and IL10 SNPs with severe disease in Influenza A(H1N1)pdm09 virus-infected subjects. Furthermore, IL-6 levels can be a potential biomarker for predicting fatal outcomes in Influenza A(H1N1)pdm09 virus infected subjects.

Predicting the Probability of Chlamydia Reinfection in African American Women Using Immunologic and Genetic Determinants in a Bayesian Model

BACKGROUND

African Americans have the highest rates of Chlamydia trachomatis (CT) infection in the United States and also high reinfection rates. The primary objective of this study was to develop a Bayesian model to predict the probability of CT reinfection in African American women using immunogenetic data.

METHODS

We analyzed data from a cohort of CT-infected African American women enrolled at the time they returned to a clinic in Birmingham, AL, for the treatment of a positive routine CT test result. We modeled the probability of CT reinfection within 6 months after treatment using logistic regression in a Bayesian framework. Predictors of interest were presence or absence of an HLA-DQB1*06 allele and CT-specific CD4+ IFN-γ response, both of which we had previously reported were independently associated with CT reinfection risk.

RESULTS

Among 99 participants evaluated, the probability of reinfection for those with a CT-specific CD4+ IFN-γ response and no HLA-DQB1*06 alleles was 14.1% (95% credible interval [CI], 3.0%-45.0%), whereas the probability of reinfection for those without a CT-specific CD4+ IFN-γ response and at least one HLA-DQB1*06 allele was 61.5% (95% CI, 23.1%-89.7%).

CONCLUSIONS

Our model demonstrated that presence or absence of an HLA-DQB1*06 allele and CT-specific CD4+ IFN-γ response can have an impact on the predictive probability of CT reinfection in African American women.

Identifying HLA DRB1-DQB1 alleles associated with Chlamydia trachomatis infection and in silico prediction of potentially-related peptides

HLA class II (HLA-II) genes' polymorphism influences the immune response to Chlamydia trachomatis (Ct), it is considered a sexually transmitted infection. However, associations between HLA-II alleles and Ct-infection have been little explored in humans; this study was thus aimed at determining HLA-DRB1-DQB1 alleles/haplotypes' effect on Ct-infection outcome in a cohort of Colombian women. Cervical sample DNA was used as template for detecting Ct by PCR and typing HLA-DRB1-DQB1 alleles/haplotypes by Illumina MiSeq sequencing. Survival models were adjusted for identifying the alleles/haplotypes' effect on Ct-outcome; bioinformatics tools were used for predicting secreted bacterial protein T- and B-cell epitopes. Sixteen HLA-DRB1 alleles having a significant effect on Ct-outcome were identified in the 262 women analysed. DRB1*08:02:01G and DRB1*12:01:01G were related to infection-promoting events. Only the DQB1*05:03:01G allele related to clearance/persistence events was found for HLA-DQB1. HLA-DRB1 allele homozygous women were associated with events having a lower probability of clearance and/or early occurrence of persistence. Twenty-seven peptides predicted in silico were associated with protective immunity against Ct; outer membrane and polymorphic membrane protein-derived peptides had regions having dual potential for being T- or B-cell epitopes. This article describes HLA-DRB1-DQB1 alleles/haplotypes related to Ct-infection resolution and the peptides predicted in silico which might probably be involved in host immune response. The data provides base information for developing future studies leading to the development of effective prevention measures against Ct-infection.

Can Previous Associations of Single Nucleotide Polymorphisms in the TLR2, NOD1, CXCR5, and IL10 Genes in the Susceptibility to and Severity of Chlamydia trachomatis Infections Be Confirmed?

Clear inter-individual differences exist in the response to C. trachomatis (CT) infections and reproductive tract complications in women. Host genetic variation like single nucleotide polymorphisms (SNPs) have been associated with differences in response to CT infection, and SNPs might be used as a genetic component in a tubal-pathology predicting algorithm. Our aim was to confirm the role of four genes by investigating proven associated SNPs in the susceptibility and severity of a CT infection. A total of 1201 women from five cohorts were genotyped and analyzed for TLR2 + 2477 G > A, NOD1 + 32656 T −> GG, CXCR5 + 10950 T > C, and IL10 − 1082 A > G. Results confirmed that NOD1 + 32656 T −>GG was associated with an increased risk of a symptomatic CT infection (OR: 1.9, 95%CI: 1.1–3.4, p = 0.02), but we did not observe an association with late complications. IL10 − 1082 A > G appeared to increase the risk of late complications (i.e., ectopic pregnancy/tubal factor infertility) following a CT infection (OR = 2.8, 95%CI: 1.1–7.1, p = 0.02). Other associations were not found. Confirmatory studies are important, and large cohorts are warranted to further investigate SNPs’ role in the susceptibility and severity of a CT infection.

Altered immune parameters associated with Koala Retrovirus (KoRV) and Chlamydial infection in free ranging Victorian koalas (Phascolarctos cinereus)

Koala Retrovirus (KoRV) has been widely speculated to cause immune suppression in koalas (Phascolarctos cinereus) and to underlie the koala's susceptibility to infectious disease, however evidence for immunomodulation is limited. The aim of this study is to determine whether immunophenotypic changes are associated with KoRV infection in free ranging Victorian koalas. qPCR was used to examine mRNA expression for Th1 (IFNγ), Th2-promoting (IL6, IL10) and Th17 (IL17A) cytokines, along with CD4 and CD8 in whole blood of koalas (n = 74) from Mt Eccles and Raymond Island in Victoria, Australia, with and without natural chlamydial infection. KoRV positive koalas had significantly lower levels of IL17A (p`0.023) and IFNγ (p = 0.044) gene expression along with a decreased CD4:CD8 gene expression ratio (p = 0.025) compared to negative koalas. No effect of chlamydial infection or combined effect of KoRV and chlamydial infection was detected in these populations. The decreased expression of IFNγ could make KoRV infected koalas more susceptible to persistent chlamydial infection, and a decrease in IL17A could make them more susceptible to gram negative bacterial, fungal and mycobacterial infection; but more tolerant of chlamydial infection.

The relative contribution of causal factors in the transition from infection to clinical chlamydial disease

Chlamydia is a major bacterial pathogen in humans and animals globally. Yet 80% of infections never progress to clinical disease. Decades of research have generated an interconnected network linking pathogen, host, and environmental factors to disease expression, but the relative importance of these and whether they account for disease progression remains unknown. To address this, we used structural equation modeling to evaluate putative factors likely to contribute to urogenital and ocular chlamydial disease in the koala (Phascolarctos cinereus). These factors include Chlamydia detection, load, and ompA genotype; urogenital and ocular microbiomes; host sex, age, weight, body condition; breading season, time of year; location; retrovirus co-infection; and major histocompatibility complex class II (MHCII) alleles. We show different microbiological processes underpin disease progression at urogenital and ocular sites. From each category of factors, urogenital disease was most strongly predicted by chlamydial PCR detection and load, koala body condition and environmental location. In contrast, ocular disease was most strongly predicted by phylum-level Chlamydiae microbiome proportions, sampling during breeding season and co-infection with koala retrovirus subtype B. Host MHCII alleles also contributed predictive power to both disease models. Our results also show considerable uncertainty remains, suggesting major causal mechanisms are yet to be discovered.

Koala immunology and infectious diseases: How much can the koala bear?

Infectious diseases are contributing to the decline of the iconic Australian marsupial, the koala (Phascolarctos cinereus). Infections with the obligate intracellular bacteria, Chlamydia pecorum, cause debilitating ocular and urogenital-tract disease while the koala-retrovirus (KoRV) has been implicated in host immunosuppression and exacerbation of chlamydial pathogenesis. Although histological studies have provided insight into the basic architecture of koala immune tissues, our understanding of the koala immune response to infectious disease has been limited, until recently, by a lack of species-specific immune reagents. Recent advances in the characterisation of key immune genes have focused on advancing our understanding of the immune response to Chlamydia infection, revealing commonalities in disease pathologies and immunity between koalas and other hosts and paving the way for the development of a koala Chlamydia vaccine. This review summarises these recent findings and highlights key aspects of the koala immune system requiring further attention with particular regard to their most prominent infectious diseases.

HLA-DQB1*06 is a risk marker for chlamydia reinfection in African American women

Associations between human leukocyte antigen (HLA) variants and chlamydia-related outcomes have been inconsistent. We previously identified HLA-DQB1*06 as a risk marker for chlamydia reinfection in a cohort of predominately HIV-infected adolescents. As chlamydia reinfection can lead to reproductive complications, validation of this finding in HIV-seronegative women may help reveal the underlying biology. We performed HLA-DQB1 genotyping in HIV-seronegative, chlamydia-infected African American women who were evaluated for reinfection at 3- and 6-month visits after treatment. Of 185 evaluable women for whom HLA-DQB1 genotyping was performed, only HLA-DQB1*06 was associated with chlamydia reinfection (P = 0.009), with no evidence of a dose-response effect for this allele. African American women with HLA-DQB1*06 may warrant more frequent chlamydia screening. More comprehensive genotyping of HLA class II and neighboring genes is needed to establish whether HLA-DQB1*06 is a causal variant for chlamydia reinfection or a surrogate for other causal variants in the major histocompatibility complex.

Development of a Chlamydia trachomatis vaccine for urogenital infections: novel tools and new strategies point to bright future prospects

INTRODUCTION

The "cloaked" bacterial pathogen that is Chlamydia trachomatis continues to cause sexually transmitted infections (STIs) that adversely affect the health and well-being of children, adolescents and adults globally. The reproductive disease sequelae follow unresolved or untreated chronic or recurrent asymptomatic C.trachomatis infections of the lower female genital tract (FGT) and can include pelvic pain, pelvic inflammatory disease (PID) and ectopic pregnancy. Tubal Factor Infertility (TFI) can also occur since protective and long-term natural immunity to chlamydial infection is incomplete, allowing for ascension of the organism to the upper FGT. Developing countries including the WHO African (8.3 million cases) and South-East Asian regions (7.2 million cases) bear the highest burden of chlamydial STIs.

AREAS COVERED

Genetic advances for Chlamydia have provided tools for transformation (including dendrimer-enabled transformation), lateral gene transfer and chemical mutagenesis. Recent progress in these areas is reviewed with a focus on vaccine development for Chlamydia infections of the female genital tract.

EXPERT COMMENTARY

A vaccine that can elicit immuno-protective responses whilst avoiding adverse immuno-pathologic host responses is required. The current technological advances in chlamydial genetics and proteomics, as well as novel and improved adjuvants and delivery systems, provide new hope that the elusive chlamydial vaccine is an imminent and realistic goal.

Human and Pathogen Factors Associated with Chlamydia trachomatis-Related Infertility in Women

Chlamydia trachomatis is the most common bacterial sexually transmitted pathogen worldwide. Infection can result in serious reproductive pathologies, including pelvic inflammatory disease, ectopic pregnancy, and infertility, in women. However, the processes that result in these reproductive pathologies have not been well defined. Here we review the evidence for the human disease burden of these chlamydial reproductive pathologies. We then review human-based evidence that links Chlamydia with reproductive pathologies in women. We present data supporting the idea that host, immunological, epidemiological, and pathogen factors may all contribute to the development of infertility. Specifically, we review the existing evidence that host and pathogen genotypes, host hormone status, age of sexual debut, sexual behavior, coinfections, and repeat infections are all likely to be contributory factors in development of infertility. Pathogen factors such as infectious burden, treatment failure, and tissue tropisms or ascension capacity are also potential contributory factors. We present four possible processes of pathology development and how these processes are supported by the published data. We highlight the limitations of the evidence and propose future studies that could improve our understanding of how chlamydial infertility in women occurs and possible future interventions to reduce this disease burden.

CXCL10, CXCL11, HLA-A and IL-1β are induced in peripheral blood mononuclear cells from women with Chlamydia trachomatis related infertility

Chlamydia trachomatis infections can result in the development of serious sequelae such as pelvic inflammatory disease and tubal infertility. In this study, peripheral blood mononuclear cells from women who were undergoing or had recently undergone IVF treatment were cultured ex vivo with C. trachomatis to identify the immune responses associated with women who had serological evidence of a history of Chlamydia infection. Cytokines secreted into the supernatant from the cultures were measured using ELISA, and the level of IL-1β was found to be significantly higher in Chlamydia positive women than Chlamydia negative women. qRT-PCR analysis of the expression of 88 immune-related genes showed trends towards an upregulation of CXCL10, CXCL11 and HLA-A in Chlamydia positive women compared with Chlamydia negative women. These findings support that some women launch a more marked proinflammatory response upon infection with C. trachomatis and this may be associated with why C. trachomatis induces infertility in some infected women.

A vaccine formulated with the major outer membrane protein can protect C3H/HeN, a highly susceptible strain of mice, from a Chlamydia muridarum genital challenge

C3H/HeN female mice were vaccinated with native Chlamydia muridarum major outer membrane protein (MOMP), using Montanide+CpG or Alum+CpG as adjuvants. Negative control groups were immunized with ovalbumin (OVA) and the same adjuvants. As positive control, mice were inoculated intranasally with live Chlamydia. Mice were challenged in the ovarian bursa with 10(5) C. muridarum inclusion forming units. Six weeks after the genital challenge the animals were caged with male mice and monitored for pregnancy. Mice vaccinated with MOMP+Montanide+CpG developed high levels of C. muridarum-specific antibodies, with a high IgG2a/IgG1 ratio and neutralizing titres. Animals immunized using Alum+CpG had low antibody levels. Cellular immune responses were significantly higher in mice vaccinated with MOMP and Montanide+CpG, but not with Alum+CpG, when compared with negative controls. Following the genital challenge, only 20% (4/20) of mice vaccinated with MOMP+CpG+Montanide had positive vaginal cultures whereas 100% (9/9) of mice immunized with MOMP+CpG+Alum had positive cultures. Of the positive control animals inoculated with live Chlamydia only 15% (3/20) had positive vaginal cultures. In contrast, 100% (20/20) of mice immunized with OVA+CpG+Montanide, or minimal essential medium, had positive cultures. Following mating, 80% (16/20) of mice vaccinated with MOMP+CpG+Montanide, and 85% (17/20) of animals inoculated intranasally with live C. muridarum carried embryos in both uterine horns. No protection against infertility was observed in mice immunized with MOMP and CpG+Alum or OVA. In conclusion, this is the first time that a subunit vaccine has been shown to elicit a protective immune response in the highly susceptible C3H/HeN strain of mice against an upper genital challenge.

Significant roles played by IL-10 in Chlamydia infections

Chlamydia species are obligate intracellular parasites which cause usually asymptomatic genital tract infections and also are associated with several complications. Previous studies demonstrated that immune responses to Chlamydia species are different and the diseases will be limited to some cases. Additionally, Chlamydia species are able to modulate immune responses via regulating expression of some immune system molecules including cytokines. IL-10, as the main anti-inflammatory cytokine, plays important roles in the induction of immune-tolerance against self-antigen and also immune-homeostasis after microbe elimination. Furthermore, it has been documented that ectopic expression of IL-10 is associated with several chronic infectious diseases. Therefore, it can be hypothesized that changes in the regulation of this cytokine can be associated with infection with several species of Chlamydia and their associated complications. This review collected the recent information regarding the association and relationship of IL-10 with Chlamydia infections. Another aim of this review article is to address recent data regarding the association of genetic variations (polymorphisms) of IL-10 and Chlamydia infections.

Association of combinations of interleukin-10 and pro-inflammatory cytokine gene polymorphisms with dengue hemorrhagic fever

Pro-inflammatory and anti-inflammatory cytokines have been shown to play an important role in dengue disease pathogenesis. In the present study, to find out whether single nucleotide polymorphisms (SNPs) in the pro-inflammatory and anti-inflammatory cytokine genes are associated with dengue disease severity, SNPs in TNF, IFNG, IL1B, IL8, IL0, IL17A and IL17F genes were investigated using polymerase chain reaction based methods in 132 dengue (DEN) cases [87 dengue fever (DF), 45 dengue hemorrhagic fever (DHF) cases] and 108 apparently healthy controls (HC) from Pune, Maharashtra, western India. Under recessive genetic model (C/C vs. T/T+T/C), the TNF rs1799964 C/C genotype was significantly associated with DEN [P=0.014, OR with 95% CI 3.07 (1.18-7.98)]. Frequency of T/C genotype of IL17F rs763780 was significantly lower in DEN group as compared to HC [P=0.033, OR with 95% CI 0.43 (0.19-0.95)]. Under overdominant genetic model (A/T vs. A/A+T/T), IL8 rs4973 A/T genotype was negatively associated with DHF compared to HCs [p=0.029, OR with 95% CI 0.43 (0.20-0.93)]. Under overdominant genetic model, A/G genotype of IL10 rs1800871 was significantly negatively associated with DHF compared to DF cases [p=0.014, OR with 95% CI 0.35 (0.15-0.84)]. Significantly higher frequency of the combined genotype IL10 A/A-IFNG A/T and lower frequency of the combined genotypes IL10 A/G-IL1B A/A, IL10 A/G-IL8 A/T and IL10 A/G-IL17F T/T were observed in DHF cases compared to DF. The results suggest that heterozygous genotypes of IL8 rs4973 and IL10 rs1800871 are associated with reduced risk of DHF. Combinations of IL10 rs1800871 and pro-inflammatory cytokine genotypes influence the risk of DHF.

NOD1 in contrast to NOD2 functional polymorphism influence Chlamydia trachomatis infection and the risk of tubal factor infertility

Intracellular pattern-recognition receptors NOD1 and NOD2 are capable of sensing common structural units of bacterial walls. Recognition triggers specific immune signalling pathways and leads to pro-inflammatory cytokine upregulation and adequate immune response. We investigated whether two functional polymorphisms in NOD1 and NOD2 exert an effect on susceptibility to (STD patients) and severity of (female patients visiting the fertility clinic) Chlamydia trachomatis infection in 807 Dutch Caucasian women. A significant association of the NOD1 +32656 GG insertion variant with protection against infection with C. trachomatis has been detected [p: 0.0057; OR: 0.52]. When comparing C. trachomatis-positive women without symptoms to C. trachomatis-positive women with symptoms, and to C. trachomatis-positive women with TFI, we observed an increasing trend in carriage of the GG allele [Ptrend: 0.0003]. NOD2 1007fs failed to reveal an association. We hypothesize that the underlying mechanism might be a functional effect of the GG insertion on IFN-beta-dependent regulation of immune response in the genital tract. The research is part of an ongoing effort of identifying key polymorphisms that determine the risk of TFI and effectively translating them into the clinical setting for the purpose of optimizing diagnostic management of women at risk for developing TFI.

CD43-, but not CD43+, IL-10-producing CD1dhiCD5+ B cells suppress type 1 immune responses during Chlamydia muridarum genital tract infection

Regulatory B (Breg) cells are known to modulate immune responses through predominantly interleukin-10 (IL-10)-dependent mechanisms and can be hypothetically divided into innate and adaptive subsets based on the nature of their activating signals. However, the specific role of different Breg subsets in modulating immune responses remains ambiguous. Here we have shown that Chlamydia induces IL-10-producing splenic B-cell populations consisting of CD43(+) and CD43(-) subsets of IgM(hi)IgD(lo) innate-like B (ILB) cells in vitro. While CD43(+)IL-10-producing B cells displayed innate type features and were readily induced by Chlamydia via Toll-like-receptor (TLR) signaling, CD43(-)IL-10-producing B cells required additional B-cell activating factor (BAFF)-mediated signals from dendritic cells (DCs) for their differentiation and activation, thereby classifying them as adaptive type Bregs. Importantly, CD43(-), but not CD43(+), IL-10-producing ILB cells displayed bona fide Breg activity by potently suppressing interferon-γ (IFN-γ) production in vitro in an IL-10-dependent manner. Furthermore, a novel CD43(-)CD1d(hi)CD5(+) IL-10-producing Breg population was predominantly induced by Chlamydia genital infection in vivo. Correspondingly, mixed bone marrow chimeric mice with B-cell-specific IL-10 deficiency exhibited significantly increased type 1 immune responses, decreased bacterial burden, and reduced oviduct pathology upon infection. Our data demonstrate for the first time a distinct role for CD43(-)CD1d(hi)CD5(+)-adaptive Bregs over CD43(+) innate counterparts in controlling mucosal responses against intracellular bacterial infection.

Chlamydia trachomatis and Genital Mycoplasmas: Pathogens with an Impact on Human Reproductive Health

The most prevalent, curable sexually important diseases are those caused by Chlamydia trachomatis (C. trachomatis) and genital mycoplasmas. An important characteristic of these infections is their ability to cause long-term sequels in upper genital tract, thus potentially affecting the reproductive health in both sexes. Pelvic inflammatory disease (PID), tubal factor infertility (TFI), and ectopic pregnancy (EP) are well documented complications of C. trachomatis infection in women. The role of genital mycoplasmas in development of PID, TFI, and EP requires further evaluation, but growing evidence supports a significant role for these in the pathogenesis of chorioamnionitis, premature membrane rupture, and preterm labor in pregnant woman. Both C. trachomatis and genital mycoplasmas can affect the quality of sperm and possibly influence the fertility of men. For the purpose of this paper, basic, epidemiologic, clinical, therapeutic, and public health issue of these infections were reviewed and discussed, focusing on their impact on human reproductive health.

Identification of MHCII variants associated with chlamydial disease in the koala (Phascolarctos cinereus)

Chlamydiosis, the most common infectious disease in koalas, can cause chronic urogenital tract fibrosis and infertility. High titres of serum immunoglobulin G against 10 kDa and 60 kDa chlamydial heat-shock proteins (c-hsp10 and c-hsp60) are associated with fibrous occlusion of the koala uterus and uterine tube. Murine and human studies have identified associations between specific major histocompatibility complex class II (MHCII) alleles or genotypes, and higher c-hsp 60 antibody levels or chlamydia-associated disease and infertility. In this study, we characterised partial MHCII DAB and DBB genes in female koalas (n = 94) from a single geographic population, and investigated associations among antibody responses to c-hsp60 quantified by ELISA, susceptibility to chlamydial infection, or age. The identification of three candidate MHCII variants provides additional support for the functional role of MHCII in the koala, and will inform more focused future studies. This is the first study to investigate an association between MHC genes with chlamydial pathogenesis in a non-model, free-ranging species.

Genetic variation in Chlamydia trachomatis and their hosts: impact on disease severity and tissue tropism

Chlamydia trachomatis infections are a global health problem. This obligate intracellular bacterial pathogen comprises lymphogranuloma venereum (L1-L3), ocular (A-C) and genital (D-K) serovars. Although genetically similar, each serovar group differs in disease severity and tissue tropism through mechanisms that are not well understood. It is clear that host genetic differences also play a role in chlamydial disease outcome and key host polymorphisms are beginning to emerge from both human and experimental animal studies. In this review, we will highlight pathogen and host genes that link genetic diversity, disease severity and tissue tropism. We will also use this information to provide new insights that may be helpful in developing improved management strategies for these important pathogens.

Translational potential into health care of basic genomic and genetic findings for human immunodeficiency virus, Chlamydia trachomatis, and human papilloma virus

Individual variations in susceptibility to an infection as well as in the clinical course of the infection can be explained by pathogen related factors, environmental factors, and host genetic differences. In this paper we review the state-of-the-art basic host genomic and genetic findings' translational potential of human immunodeficiency virus (HIV), Chlamydia trachomatis (CT), and Human Papilloma Virus (HPV) into applications in public health, especially in diagnosis, treatment, and prevention of complications of these infectious diseases. There is a significant amount of knowledge about genetic variants having a positive or negative influence on the course and outcome of HIV infection. In the field of Chlamydia trachomatis, genomic advances hold the promise of a more accurate subfertility prediction test based on single nucleotide polymorphisms (SNPs). In HPV research, recent developments in early diagnosis of infection-induced cervical cancer are based on methylation tests. Indeed, triage based on methylation markers might be a step forward in a more effective stratification of women at risk for cervical cancer. Our review found an imbalance between the number of host genetic variants with a role in modulating the immune response and the number of practical genomic applications developed thanks to this knowledge.

Perforin is detrimental to controlling [corrected] C. muridarum replication in vitro, but not in vivo

CD4 T cells are critical for clearing experimental Chlamydia muridarum genital tract infections. Two independent in vitro CD4 T cell mechanisms have been identified for terminating Chlamydia replication in epithelial cells. One mechanism, requiring IFN-γ and T cell-epithelial cell contact, terminates infection by triggering epithelial production of nitric oxide to chlamydiacidal levels; the second is dependent on T cell degranulation. We recently demonstrated that there are two independent in vivo clearance mechanisms singly sufficient for clearing genital tract infections within six weeks; one dependent on iNOS, the other on Plac8. Redundant genital tract clearance mechanisms bring into question negative results in single-gene knockout mice. Two groups have shown that perforin-knockout mice were not compromised in their ability to clear C. muridarum genital tract infections. Because cell lysis would be detrimental to epithelial nitric oxide production we hypothesized that perforin was not critical for iNOS-dependent clearance, but posited that perforin could play a role in Plac8-dependent clearance. We tested whether the Plac8-dependent clearance was perforin-dependent by pharmacologically inhibiting iNOS in perforin-knockout mice. In vitro we found that perforin was detrimental to iNOS-dependent CD4 T cell termination of Chlamydia replication in epithelial cells. In vivo, unexpectedly, clearance in perforin knockout mice was delayed to the end of week 7 regardless of iNOS status. The discordant in vitro/in vivo results suggest that the perforin's contribution to bacterial clearance in vivo is not though enhancing CD4 T cell termination of Chlamydia replication in epithelial cells, but likely via a mechanism independent of T cell-epithelial cell interactions.

Chlamydia trachomatis infections and subfertility: opportunities to translate host pathogen genomic data into public health

Chlamydia trachomatis (CT) infections in women can result in tubal pathology (TP). Worldwide 10-15% of all couples are subfertile, meaning they did not get pregnant after 1 year. Part of the routine subfertility diagnostics is the Chlamydia Antibody Test (CAT) to decide for laparoscopy or not in order to diagnose TP. The CAT positive and negative predictive value is such that many unneeded laparoscopies are done and many TP cases are missed. Addition of host genetic markers related to infection susceptibility and severity could potentially improve the clinical management of couples who suffer from subfertility. In the present study, the potential translational and clinical value of adding diagnostic host genetic marker profiles on the basis of infection and inflammation to the current clinical management of subfertility was investigated. This review provides an overview of the current state of the art of host genetic markers in relation to CT infection, proposes a new clinical diagnostic approach, and investigates how the Learning-Adapting-Leveling model (LAL, a public health genomic (PHG) model) can be of value and provide insight to see whether these host genetic markers can be translated into public health. This review shows that the preliminary basis of adding host genetic marker profiles to the current diagnostic procedures of subfertility is present but has to be further developed before implementation into health care can be achieved. CT infection is an example in the field of PHG with potential diagnostic to be taken up in the future in the field of subfertility diagnosis with a time line for integration to be dependent on enhanced participation of many stakeholders in the field of PHG which could be advanced through the LAL model.

Immune predictors of complications of the urogenital chlamydial infection leading to infertility

Goal: determination of immune predictors of the development of complications of the urogenital chlamydial infection (UGCI) in women and further disorder of the reproductive function (infertility) due to the past infection. Маterials and methods. 80 women have been examined: 40 patients with uGCI (20 — with UGCI of lower sections of the urogenital tract and 20 — with pelvic UGCI), 20 patients with secondary (tubal) infertility with the previous UGCI in the anamnesis and 20 clinically healthy women. The qualitative and quantitative study of the spectrum of cytokines (IL-2, -4, -6, -8, -10, INF-γ, TNF α and GM-CSF) with the use of the хМАР multiplex technology in blood and the cervical secretion. Results. The research has determined the spectrum of cytokines with a change in their concentration having an effect on the outcome of UGCI and the development of complications causing disorders of the reproductive function in women: these are TNF-α, IFN-γ, IL-2 inflammatory cytokines аs well as the IL-10 inflammatory cytokine.

Effect of IL12A and IL12B polymorphisms on the risk of Chlamydia trachomatis-induced tubal factor infertility and disease severity

BACKGROUND

Interleukin-12 (IL-12) and related cytokines induce activation and differentiation of T cells. Our aim was to investigate the associations between genetic differences in IL-12-family cytokines and the pathogenesis of chlamydial disease.

METHODS

The final study population consisted of 100 women with Chlamydia trachomatis-induced tubal factor infertility (TFI) and 125 pregnant women as controls. Three single nucleotide polymorphisms (SNPs) of IL12A and seven SNPs of IL12B genes were determined from isolated DNA using the Sequenom system with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.

RESULTS

We found that the IL12B SNP rs3212227 was associated with both susceptibility and severity of TFI. The minor allele C was rare and only one CC homozygote was found among the controls. AC heterozygotes were more common among TFI cases than among controls (P = 0.009) and were associated with increased risk of TFI [odds ratios (OR) = 2.44, 95% confidence intervals (CI) = 1.23-4.87]. Carrying the minor allele C was also associated with disease severity (P for trend = 0.008) and moderate (OR = 2.51, 95% CI = 1.06-5.95) and severe tubal damage (OR = 2.73, 95% CI = 1.15-6.52).

CONCLUSIONS

The results suggest that variation in the IL12B gene partly explains inter-individual differences in disease susceptibility and severity.

Mapping immunodominant antigens and H-2-linked antibody responses in mice urogenitally infected with Chlamydia muridarum

To identify immunodominant antigens and MHC-restricted antibody responses, seven different strains of mice were intravaginally infected with Chlamydia muridarum and compared for antibody responses to 257 C. muridarum proteins. The 7 strains of mice recognized a total of 109 proteins as antigens, of which, 5 antigens (TC0660, TC0727, TC0828, TC0726 & TC0268) were each recognized by 60% or more mice from each mouse strain and thus designated as immunodominant antigens. Furthermore, antibody responses to 19 other antigens displayed strong associations with mouse H-2 haplotypes, including 6 antigens (TC0480, TC0912, TC0229, TCA04, TC0289 & TC0892) whose antibody responses were linked to H-2(b), 8 (TC0035, TC0387, TC0052, TC0781, TC0373, TC0117, TC0066 & TC0396) to H-2(d) and 5 (TC0512, TC0177, TC0589, TC0794 & TC0596) to H-2(k) haplotypes respectively. Interestingly, H-2(b) was negatively associated with antibody responses to most of the antigens that were positively linked to H-2(d) or H-2(k) haplotypes. These results by mapping Chlamydia trachomatis antigens commonly recognized by mice with different strain background and H-2 genes and revealing antigen association with H-2 haplotypes have provided important information for developing chlamydial subunit vaccines and understanding chlamydial pathogenesis.

Induction of protective immunity against Chlamydia muridarum intravaginal infection with a chlamydial glycogen phosphorylase

We evaluated 7 C. muridarum ORFs for their ability to induce protection against chlamydial infection in a mouse intravaginal infection model. These antigens, although encoded in C. muridarum genome, are transcriptionally regulated by a cryptic plasmid that is known to contribute to C. muridarum pathogenesis. Of the 7 plasmid-regulated ORFs, the chlamydial glycogen phosphorylase or GlgP, when delivered into mice intramuscularly, induced the most pronounced protective immunity against C. muridarum intravaginal infection. The GlgP-immunized mice displayed a significant reduction in vaginal shedding of live organisms on day 14 after infection. The protection correlated well with a robust C. muridarum-specific antibody and a Th1-dominant T cell responses, which significantly reduced the severity but not overall incidence of hydrosalpinx. The GlgP-induced partial protection against upper genital tract pathology suggests that GlgP may be considered a component for a multi-subunit vaccine. These results have demonstrated that intramuscular immunization of mice with purified proteins can be used to identify vaccine antigens for preventing intravaginal infection with C. trachomatis in humans.

Enhanced upper genital tract pathologies by blocking Tim-3 and PD-L1 signaling pathways in mice intravaginally infected with Chlamydia muridarum

Background

Although Tim-3 & PD-L1 signaling pathways play important roles in negatively regulating immune responses, their roles in chlamydial infection have not been evaluated.

Methods

Neutralization antibodies targeting Tim-3 and PD-L1 were used to treat mice. Following an intravaginal infection with C. muridarum organisms, mice with or without the dual antibody treatment were compared for live chlamydial organism shedding from the lower genital tract and inflammatory pathology in the upper genital tract.

Results

Mice treated with anti-Tim-3 and anti-PD-L1 antibodies displayed a time course of live organism shedding similar to that of mice treated with equivalent amounts of isotype-matched IgG molecules. The combined antibody blocking failed to alter either the lower genital tract cytokine or systemic humoral and cellular adaptive responses to C. muridarum infection. However, the antibody blocking significantly enhanced C. muridarum-induced pathologies in the upper genital tract, including more significant hydrosalpinx and inflammatory infiltration in uterine horn and oviduct tissues.

Conclusions

The Tim-3 and PD-L1-mediated signaling can significantly reduce pathologies in the upper genital tract without suppressing immunity against chlamydial infection, suggesting that Tim-3 and PD-L1-mediated negative regulation may be manipulated to attenuate tubal pathologies in women persistently infected with C. trachomatis organisms.

Immunopathogenesis in Chlamydia trachomatis Infected Women

We examine the Chlamydia trachomatis (Ct) immunopathogenesis on the basis of the complex interaction between host immune response and virulence microorganism factors. Ct infection can be asymptomatic or may produce an inflammation elicited and preserved by reinfections or persistent infections. We discuss the host polymorphisms that, with their anti- or proinflammatory effects, determine the course of the disease. We also took into account the inflammation process following the Chlamydia illness and the role of both CD4 cells producing IFN-γ and CD8 cells with their cytokines production. The crucial role of Ct-hsp60 and the double activity (either damaging or preserving from some kinds of tumors) of anti-Ct-hsp60 antibodies are considered.

Protective immunity against mouse upper genital tract pathology correlates with high IFNγ but low IL-17 T cell and anti-secretion protein antibody responses induced by replicating chlamydial organisms in the airway

To search for optimal immunization conditions for inducing protective immunity against upper genital tract pathologies caused by chlamydial intravaginal infection, we compared protection efficacy in mice immunized intranasally or intramuscularly with live or inactivated Chlamydia muridarum organisms. Mice immunized intranasally with live organisms developed strong protection against both vaginal shedding of infectious organisms and upper genital tract pathologies. The protection correlated with a robust antigen-specific T cell response with high IFNγ but low IL-17. Although a significant level of IL-5 was also detected, these mice maintained an overall Th1-dorminant immunity following immunization and challenge infection. On the contrary, mice immunized intranasally with inactivated organisms or intramuscularly with live or inactivated organisms produced high levels of IL-17 and still developed significant upper genital tract pathologies. High titers of antibodies against chlamydial secretion antigens were detected only in mice immunized intranasally with live organisms but not mice in other groups, suggesting that the intranasally inoculated live organisms were able to undergo replication and immune responses to the chlamydial secretion proteins may contribute to protective immunity. These observations have provided important information on how to develop subunit vaccines for inducing protective immunity against urogenital infection with Chlamydia trachomatis organisms.

Association of tubal factor infertility with elevated antibodies to Chlamydia trachomatis caseinolytic protease P

OBJECTIVE

The objective of the study was to assess antibodies against Chlamydia trachomatis heat shock proteins (HSP) in patients with tubal factor infertility (TFI), infertility controls (IFC), and fertile controls (FC). HSPs assist organisms in surviving caustic environments such as heat.

STUDY DESIGN

Twenty-one TFI, 15 IFC, and 29 FC patients were enrolled after laparoscopic tubal assessment. The titers of antibodies against C trachomatis organisms and 14 chlamydial HSPs were compared among the 3 groups.

RESULTS

TFI patients developed significantly higher levels of antibodies against C trachomatis and specifically recognizing chlamydial HSP60 and caseinolytic protease (Clp) P, a subunit of the ATP-dependent Clp protease complex involved in the degradation of abnormal proteins.

CONCLUSION

In addition to confirming high titers of antibodies against C trachomatis organisms and HSP60 in TFI patients, we identified a novel link of TFI with anti-ClpP antibodies. These findings may provide useful information for developing a noninvasive screening test for TFI and constructing subunit anti-C trachomatis vaccines.

Immunopathogenic consequences of Chlamydia trachomatis 60 kDa heat shock protein expression in the female reproductive tract

Chlamydia trachomatis is an obligate intracellular bacterium that infects chiefly urogenital and ocular epithelial cells. In some infected women the microorganism migrates to the upper reproductive tract resulting in a chronic, but asymptomatic, infection. The immune response to this infection, production of interferon-gamma and pro-inflammatory cytokines, results in interruption of chlamydial intracellular replication. However, the Chlamydia remains viable and enters into a persistent state. In this form, most chlamydial genes are inactive. An exception is the gene coding for the 60 kDa heat shock protein (hsp60), which is synthesized in increased amounts and is released into the extracellular milieu. The chronic release of chlamydial hsp60 induces a local pro-inflammatory immune response in fallopian tube epithelia and results in scar formation and tubal occlusion. In addition, long-term exposure of the maternal immune system to the chlamydial hsp60 eventually results in the release of tolerance and generation of an immune response that recognizes regions of the chlamydial hsp60 that are also present in the human hsp60. Production of cross-reacting antibodies and cell-mediated immunity to the human hsp60 is detrimental to subsequent pregnancy outcome and may also possibly increase susceptibility to atherosclerosis, autoimmune disorders, or malignancies.

Immunodominant regions of a Chlamydia trachomatis type III secretion effector protein, Tarp

We have previously shown that individuals infected with Chlamydia trachomatis can develop a robust antibody response to a Chlamydia type III secretion effector protein called Tarp and that immunization with Tarp induces protection against challenge infection in mice. The current study aimed to map the immunodominant regions of the Tarp protein by expressing 11 fragments of Tarp as glutathione S-transferase (GST) fusion proteins and detecting the reactivity of these fusion proteins with antisera from patients infected with C. trachomatis in the urogenital tract or in the ocular tissue and from rabbits immunized with C. trachomatis organisms. A major immunodominant region was strongly recognized by all antibodies. This region covers amino acids 152 to 302, consisting of three repeats (amino acids 152 to 201, 202 to 251, and 252 to 302). Each of the repeats contains multiple tyrosine residues that are phosphorylated by host cell kinases when Tarp is injected into host cells. Several other minor immunodominant regions were also identified, including those comprising amino acids 1 to 156, 310 to 431, and 582 to 682 (recognized by antisera from both humans and rabbits), that comprising amino acids 425 to 581 (recognized only by human antisera), and that comprising amino acids 683 to 847 (preferentially recognized by rabbit antisera). This immunodominance was also confirmed by the observations that six out of the nine monoclonal antibodies (MAbs) bound to the major immunodominant region and that the other three each bound to one of the minor fragments, comprising amino acids 1 to 119, 120 to 151, and 310 to 431. The antigenicity analyses have provided important information for further understanding the structure and function of Tarp.

A genome-wide profiling of the humoral immune response to Chlamydia trachomatis infection reveals vaccine candidate antigens expressed in humans

A whole genome scale proteome array consisting of 908 open reading frames encoded in Chlamydia trachomatis genome and plasmid was used to profile anti-chlamydial Ab responses. A total of 719 chlamydial proteins was recognized by one or more antisera from 99 women urogenitally infected with C. trachomatis. Revealing such a large C. trachomatis ANTIGENome in humans might partially be attributed to the significantly improved detection sensitivity of the whole genome scale proteome array assay because both linear and conformation-dependent Abs were detected by the array assay. Twenty-seven of the 719 Ags were recognized by >or=50% antisera, thus designated as immunodominant Ags. Comparison of Ag profiles recognized by live chlamydial organism-infected versus dead organism-immunized hosts led to the identification of infection-dependent or in vivo expressed Ags. The infection-dependent Ags induced Abs only in live organism-infected, but not in dead organism-immunized hosts. Many of these Ags were highly expressed during replication, but only minimally packaged into the infectious elementary bodies. Because inactivated whole chlamydial organism-based vaccines failed to induce protection in humans, identification of the infection-dependent or in vivo expressed immunodominant Ags in humans should greatly facilitate the selection of promising chlamydial subunit vaccine candidates for further evaluation. This approach may also be applicable to other pathogens.

A MyD88-dependent early IL-17 production protects mice against airway infection with the obligate intracellular pathogen Chlamydia muridarum

We found that IL-17, a signature cytokine of Th17, was produced early in the innate immunity phase after an intranasal infection with the obligate intracellular pathogen Chlamydia muridarum. The airway IL-17, which peaked at 48 h after infection, was dependent on live chlamydial organism replication and MyD88-mediated signaling pathways. Treatment with antibiotics or knockout of the MyD88 gene, but not Toll/IL receptor domain-containing adapter-inducing IFN-beta, can block the early IL-17 production. Treatment of mice with an anti-IL-17-neutralizing mAb enhanced growth of chlamydial organisms in the lung, dissemination to other organs, and decreased mouse survival, whereas treatment with an isotype-matched control IgG had no effect. Although IL-17 did not directly affect chlamydial growth in cell culture, it enhanced the production of other inflammatory cytokines and chemokines by Chlamydia-infected cells and promoted neutrophil infiltration in mouse airways during chlamydial infection, which may contribute to the antichlamydial effect of IL-17. These observations suggest that an early IL-17 response as an innate immunity component plays an important role in initiating host defense against infection with intracellular bacterial pathogens in the airway.

A chlamydial type III-secreted effector protein (Tarp) is predominantly recognized by antibodies from humans infected with Chlamydia trachomatis and induces protective immunity against upper genital tract pathologies in mice

Chlamydia trachomatis genome is predicted to encode a type III secretion system consisting of more than 40 open reading frames (ORFs). To test whether these ORFs are expressed and immunogenic during chlamydial infection in humans, we expressed 55 chlamydial ORFs covering all putative type III secretion components plus control molecules as fusion proteins and measured the reactivity of these fusion proteins with antibodies from patients infected with C. trachomatis in the urogenital tract (24 antisera) or in the ocular tissue (8 antisera). Forty-five of the 55 proteins were recognized by at least 1 of the 32 human antisera, suggesting that these proteins are both expressed and immunogenic during chlamydial infection in humans. Tarp, a putative type III secretion effector protein, was identified as a novel immunodominant antigen due to its reactivity with the human antisera at high frequency and titer. The expression and immunogenicity of Tarp were confirmed in cell culture and mouse systems. Tarp was mainly associated with the infectious form of chlamydial organisms and became undetectable between 13 and 24 h during the infection cycle in cell culture. Mice intravaginally infected with C. muridarum developed Tarp-specific humoral and cellular immune responses. More importantly, immunization of mice with Tarp induced Th1-dominant immunity that significantly reduced the shedding of live organisms from the lower genital tract and attenuated inflammatory pathologies in the fallopian tube tissues. These observations have demonstrated that Tarp, an immunodominant antigen identified by human antisera, can induce protective immunity against chlamydial infection and pathology in mice.

Characterization of fifty putative inclusion membrane proteins encoded in the Chlamydia trachomatis genome

Although the Chlamydia trachomatis genome is predicted to encode 50 inclusion membrane proteins, only 18 have been experimentally localized in the inclusion membrane of C. trachomatis-infected cells. Using fusion proteins and anti-fusion protein antibodies, we have systematically evaluated all 50 putative inclusion membrane proteins for their localization in the infected cells, distribution patterns, and effects on subsequent chlamydial infection when expressed ectopically, as well as their immunogenicity during chlamydial infection in humans. Twenty-two of the 50 proteins were localized in the inclusion membrane, and 7 were detected inside the inclusions, while the location of the remaining 21 was not defined. Four (CT225, CT228, CT358, and CT440) of the 22 inclusion membrane-localized proteins were visualized in the inclusion membrane of Chlamydia-infected cells for the first time in the current study. The seven intra-inclusion-localized proteins were confirmed to be chlamydial organism proteins in a Western blot assay. Further characterization of the 50 proteins revealed that neither colocalization with host cell endoplasmic reticulum nor inhibition of subsequent chlamydial infection by ectopically expressed proteins correlated with the inclusion membrane localization. Interestingly, antibodies from women with C. trachomatis urogenital infection preferentially recognized proteins localized in the inclusion membrane, and the immunodominant regions were further mapped to the region predicted to be on the cytoplasmic side of the inclusion membrane. These observations suggest that most of the inclusion membrane-localized proteins are both expressed and immunogenic during C. trachomatis infection in humans and that the cytoplasmic exposure may enhance the immunogenicity.

Susceptibility to sequelae of human ocular chlamydial infection associated with allelic variation in IL10 cis-regulation

Trachoma, an infectious disease of the conjunctiva caused by Chlamydia trachomatis, causes scarring and blindness in some infected individuals but not others. In an African community where trachoma is endemic, we have previously identified an IL10 haplotype that is associated with increased risk of scarring complications. Here we examine the hypothesis that the risk haplotype (H-RISK) affects levels of IL10 expression in the conjunctiva during active trachoma infection. To overcome potential genetic and environmental confounders we used the method of allele-specific quantification, which involved identifying subjects in the community who had active trachoma and were also heterozygous for the H-RISK. We find that there is allelic variation in cis-regulation of IL10 in the conjunctiva during active trachoma, with the H-RISK generating relatively more IL10 transcripts than other haplotypes in this population (average difference in IL10 allelic transcripts in the conjunctiva of heterozygous individuals infected with C. trachomatis of 23% (95% confidence interval: 14-32%, P < 0.0001). These findings provide a plausible functional explanation for the observed genetic association, and support the hypothesis that an excessive IL10 response to C. trachomatis infection is a risk factor for scarring and blindness.

Contemporary risks of maternal morbidity and adverse outcomes with increasing maternal age and plurality

OBJECTIVE

To evaluate the risks of pregnancy complications and adverse outcomes associated with increasing maternal age and higher plurality.

DESIGN

Population-based, historic cohort study.

SETTING

US birth certificates and infant death certificates.

PATIENT(S)

Live births of > or =20 weeks gestation between 1995-2000: 22,991,306 singleton, 316,696 twin, and 12,193 triplet pregnancies.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Pregnancy-associated hypertension, incompetent cervix, tocolysis, premature rupture of membranes, excessive bleeding at delivery, delivery <29 weeks, and infant death.

RESULT(S)

Compared to singletons, the risks for all adverse outcomes among multiple pregnancies were significantly elevated, and were highest for tocolysis, delivery <29 weeks, and infant mortality. Within pluralities, increasing maternal age was associated with significantly higher risks of pregnancy-associated hypertension, excessive bleeding, and incompetent cervix, but for twin and triplet pregnancies, significantly lower risks for tocolysis (ages > or =40, singleton adjusted odds ratio [AOR] 0.97, twin AOR 0.67, triplet AOR 0.72), delivery <29 weeks (ages > or =40, singleton AOR 1.55, twin AOR 0.72, triplet AOR 0.52), and infant mortality (ages > or =40, singleton AOR 1.34, twin AOR 0.71, triplet AOR 0.42).

CONCLUSION(S)

Older maternal age and higher plurality are each associated with increasing risks for many pregnancy complications, but with significantly lower risks of tocolysis, early preterm birth, and infant mortality.

Interleukin-1 is the initiator of Fallopian tube destruction during Chlamydia trachomatis infection

Chlamydia trachomatis infection is associated with severe Fallopian tube tissue damage leading to tubal infertility and ectopic pregnancy. To explore the molecular mechanisms behind infection an ex vivo model was established from human Fallopian tubes and examined by scanning electron microscopy and immunohistochemistry. Extensive tissue destruction affecting especially ciliated cells was observed in C. trachomatis infected human Fallopian tube organ culture. Interleukin-1 (IL-1) produced by epithelial cells was detected after infection. Addition of IL-1 receptor antagonist (IL-1RA) completely eliminated tissue destruction induced by C. trachomatis. The anti-inflammatory cytokine IL-10 reduced the damaging effect of C. trachomatis infection, however, to a lesser extent than IL-1RA. Furthermore, IL-1 was found to induce IL-8, a neutrophil attractant, using a signal transduction pathway involving p38 MAP kinase. Consequently, IL-1 has the potential to generate a cellular infiltrate at the site of infection in vivo. Blocking the IL-1 receptors by IL-1RA eliminated tissue destruction and cytokine production. Hence, these studies show the importance of IL-1 in initiating the tissue destruction observed in the Fallopian tube following C. trachomatis infection. Because leukocytes are absent in the ex vivo model, this study strongly indicates that IL-1 is the initial proinflammatory cytokine activated by C. trachomatis infection.

The importance of chlamydial infections in obstetrics and gynaecology: An update

Chlamydia is now the most common notifiable infectious disease in many countries, a fact that has serious ramifications for the reproductive health of women. This review highlights the epidemiology, pathophysiology, clinical features and reproductive sequelae of the infection. Current screening and management methods are outlined. Obstetricians and gynaecologists are ideally placed to play a major role in the primary prevention of this significant sexually transmitted infection.

The hypothetical protein CT813 is localized in the Chlamydia trachomatis inclusion membrane and is immunogenic in women urogenitally infected with C. trachomatis

Using antibodies raised with chlamydial fusion proteins, we have localized a protein encoded by hypothetical open reading frame CT813 in the inclusion membrane of Chlamydia trachomatis. The detection of the C. trachomatis inclusion membrane by an anti-CT813 antibody was blocked by the CT813 protein but not unrelated fusion proteins. The CT813 protein was detected as early as 12 h after chlamydial infection and was present in the inclusion membrane during the entire growth cycle. All tested serovars from C. trachomatis but not other chlamydial species expressed the CT813 protein. Exogenously expressed CT813 protein in HeLa cells displayed a cytoskeleton-like structure similar to but not overlapping with host cell intermediate filaments, suggesting that the CT813 protein is able to either polymerize or associate with host cell cytoskeletal structures. Finally, women with C. trachomatis urogenital infection developed high titers of antibodies to the CT813 protein, demonstrating that the CT813 protein is not only expressed but also immunogenic during chlamydial infection in humans. In all, the CT813 protein is an inclusion membrane protein unique to C. trachomatis species and has the potential to interact with host cells and induce host immune responses during natural infection. Thus, the CT813 protein may represent an important candidate for understanding C. trachomatis pathogenesis and developing intervention and prevention strategies for controlling C. trachomatis infection.

Do host genetic traits in the bacterial sensing system play a role in the development of Chlamydia trachomatis-associated tubal pathology in subfertile women?

Background

In women, Chlamydia (C.) trachomatis upper genital tract infection can cause distal tubal damage and occlusion, increasing the risk of tubal factor subfertility and ectopic pregnancy. Variations, like single nucleotide polymorphisms (SNPs), in immunologically important host genes are assumed to play a role in the course and outcome of a C. trachomatis infection. We studied whether genetic traits (carrying multiple SNPs in different genes) in the bacterial sensing system are associated with an aberrant immune response and subsequently with tubal pathology following a C. trachomatis infection. The genes studied all encode for pattern recognition receptors (PRRs) involved in sensing bacterial components.

Methods

Of 227 subfertile women, serum was available for C. trachomatis IgG antibody testing and genotyping (common versus rare allele) of the PRR genes TLR9, TLR4, CD14 and CARD15/NOD2. In all women, a laparoscopy was performed to assess the grade of tubal pathology. Tubal pathology was defined as extensive peri-adnexal adhesions and/or distal occlusion of at least one tube.

Results

Following a C. trachomatis infection (i.e. C. trachomatis IgG positive), subfertile women carrying two or more SNPs in C. trachomatis PRR genes were at increased risk of tubal pathology compared to women carrying less than two SNPs (73% vs 33% risk). The differences were not statistically significant (P = 0.15), but a trend was observed.

Conclusion

Carrying multiple SNPs in C. trachomatis PRR genes tends to result in an aberrant immune response and a higher risk of tubal pathology following a C. trachomatis infection. Larger studies are needed to confirm our preliminary findings.