Primary and secondary immune responses of mucosal and peripheral lymphocytes during Chlamydia trachomatis infection

HIV, asymptomatic STI, and the rectal mucosal immune environment among young men who have sex with men

Young men who have sex with men (YMSM) are disproportionately affected by HIV and bacterial sexually transmitted infections (STI) including gonorrhea, chlamydia, and syphilis; yet research into the immunologic effects of these infections is typically pursued in siloes. Here, we employed a syndemic approach to understand potential interactions of these infections on the rectal mucosal immune environment among YMSM. We enrolled YMSM aged 18-29 years with and without HIV and/or asymptomatic bacterial STI and collected blood, rectal secretions, and rectal tissue biopsies. YMSM with HIV were on suppressive antiretroviral therapy (ART) with preserved blood CD4 cell counts. We defined 7 innate and 19 adaptive immune cell subsets by flow cytometry, the rectal mucosal transcriptome by RNAseq, and the rectal mucosal microbiome by 16S rRNA sequencing and examined the effects of HIV and STI and their interactions. We measured tissue HIV RNA viral loads among YMSM with HIV and HIV replication in rectal explant challenge experiments among YMSM without HIV. HIV, but not asymptomatic STI, was associated with profound alterations in the cellular composition of the rectal mucosa. We did not detect a difference in the microbiome composition associated with HIV, but asymptomatic bacterial STI was associated with a higher probability of presence of potentially pathogenic taxa. When examining the rectal mucosal transcriptome, there was evidence of statistical interaction; asymptomatic bacterial STI was associated with upregulation of numerous inflammatory genes and enrichment for immune response pathways among YMSM with HIV, but not YMSM without HIV. Asymptomatic bacterial STI was not associated with differences in tissue HIV RNA viral loads or in HIV replication in explant challenge experiments. Our results suggest that asymptomatic bacterial STI may contribute to inflammation particularly among YMSM with HIV, and that future research should examine potential harms and interventions to reduce the health impact of these syndemic infections.

Association of Chlamydia trachomatis, C. pneumoniae, and IL-6 and IL-8 Gene Alterations With Heart Diseases

Atherosclerosis is a progressive disease characterized by chronic inflammation of the arterial walls, associated with genetic and infectious factors. The present study investigated the involvement of Chlamydia trachomatis and Chlamydia pneumoniae infections and immunological markers (C-reactive protein, CRP, TNF-α, IL-6, IL-8, and IL-10) in the process of atherosclerosis. The evaluation included 159 patients for surgical revascularization (CAD) and 71 patients for surgical heart valve disease (HVD) at three hospitals in Belém, Brazil. The control group (CG) comprised 300 healthy individuals. Blood samples collected before surgery were used for antibodies detection (enzyme immunoassay), CRP (immunoturbidimetry) and IL-6 levels (enzyme immunoassay). Tissue fragments (atheroma plaque, heart valve and ascending aorta) were collected during surgery and subjected to qPCR for detection of bacterial DNA. Promoter region polymorphisms of each marker and relative quantification of TNF-α, IL-8, and IL-10 gene expression were performed. Demography and social information were similar to the general population involved with both diseases. Antibody prevalence to C. trachomatis was 30.6, 20.3, and 36.7% (in the CAD, HVD, and CG, respectively) and to C. pneumoniae was 83.6, 84.5, and 80.3% (in the CAD, HVD, and CG, respectively). C. trachomatis cryptic plasmid DNA was detected in 7.4% of the samples. Frequency of IL6−174G>C polymorphism was higher in CAD and HVD than in CG regardless of previous exposure to Chlamydia. Previous C. trachomatis infection showed involvement in HVD and CAD. Significant association between disease and previous C. pneumoniae infection was found only among HVD. GG genotype of IL6−174G>C is apparently a risk factor for heart disease, whereas AT genotype of IL8−251A>T was mainly involved in valvulopathies, including patients with prior exposure to C. pneumoniae.

Association Between Reduced Risk of Intracerebral Hemorrhage and Pelvic Inflammatory Disease

This study examines whether pelvic inflammatory disease (PID) facilitates the development of intracerebral hemorrhage (ICH).By using outpatient claims data from the National Health Insurance Research Database (NHIRD) of Taiwan, we included the data of 25,508 patients who were newly diagnosed with PID between 1999 and 2004, and also from the Taiwan NHIRD, we randomly selected 102,032 women without PID, who were frequency-matched by age and entry-year and with 4 times the number of the PID patients, as the control cohort. We measured ICH risks associated with PID and comorbidities, including hyperlipidemia, diabetes, hypertension, ischemic heart disease, and atrial fibrillation, by the end of 2011.In comparison with the controls, the ICH hazard was less in the PID group with an adjusted hazard ratio (aHR) of 0.67 (95% confidence interval [CI]:0.50-0.90), which was noted by calculation with the Cox proportional regression model. The ICH risk in the PID patients reduced progressively with the advance of age, with aHRs of 0.75 (95% CI:0.41-1.39) and 0.50 (95% CI:0.29-0.88), respectively, in the age <35-year and age ≥50-year groups. ICH risk lowered gradually with the progress of PID severity, from mild PID with an aHR of 0.72 (95% CI:0.53-0.98) to severe PID with that of 0.30 (95% CI:0.10-0.92). PID patients without any comorbidites had lower ICH risk (aHR = 0.63, 95% CI:0.42-0.94) than the controls without any comorbidites did.Our findings revealed that PID is associated with reduced ICH development, especially for older patients.

Effect of cytokine level variations in individuals on the progression and outcome of bacterial urogenital infections--a meta-analysis

Bacterial urogenital infections such as chlamydia, gonorrhoea and syphilis are widespread inflammatory diseases, which may be accompanied by severe complications. These complications can range from basic inflammation to tubal pathology, infertility and neurological dysfunction, though infections go unnoticed in the majority of cases. Cytokines in the host play a vital role in both the initial and long-term immune response and inflammation. However, levels of cytokine expression vary between individuals. A meta-analysis was performed to evaluate the effect of cytokine expression differences on severity of infections with these pathogens. Studies comparing expression of cytokines in humans with inflammation or inflammation-based complications were identified using NCBI, Google Scholar and Cochrane databases. Only studies into human cytokine expressions were included, and three articles per subject were required to be suitably analysed during meta-analysis. A total of 52 articles were included for meta-analysis. It was shown that differences in IL-1, IL-6, IL-8, IL-10, TNFα and IFNγ affect the clinical outcome of Chlamydia trachomatis infection significantly. Similarly, IL-1 and IL-8 expression during Neisseria gonorrhoeae infection significantly affects the outcome of the disease. For Treponema pallidum infection, it was shown that IFNγ variation in hosts could be linked to severity of disease. However, a lack of studies to use in the meta-analysis and fluctuation in the resulting data depending on the adjustments makes adequate evaluation difficult.

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.

Interleukin 17A is an immune marker for chlamydial disease severity and pathogenesis in the koala (Phascolarctos cinereus)

The koala (Phascolarctos cinereus) is an iconic Australian marsupial species that is facing many threats to its survival. Chlamydia pecorum infections are a significant contributor to this ongoing decline. A major limiting factor in our ability to manage and control chlamydial disease in koalas is a limited understanding of the koala's cell-mediated immune response to infections by this bacterial pathogen. To identify immunological markers associated with chlamydial infection and disease in koalas, we used koala-specific Quantitative Real Time PCR (qrtPCR) assays to profile the cytokine responses of Peripheral Blood Mononuclear Cells (PBMCs) collected from 41 koalas with different stages of chlamydial disease. Target cytokines included the principal Th1 (Interferon gamma; IFNγ), Th2 (Interleukin 10; IL10), and pro-inflammatory cytokines (Tumor Necrosis Factor alpha; TNFα). A novel koala-specific IL17A qrtPCR assay was also developed as part of this study to quantitate the gene expression of this Th17 cytokine in koalas. A statistically significant higher IL17A gene expression was observed in animals with current chlamydial disease compared to animals with asymptomatic chlamydial infection. A modest up-regulation of pro-inflammatory cytokines, such as TNFα and IFNγ, was also observed in these animals with signs of current chlamydial disease. IL10 gene expression was not evident in the majority of animals from both groups. Future longitudinal studies are now required to confirm the role played by cytokines in pathology and/or protection against C. pecorum infection in the koala.

Effect of HIV and chlamydia infection on rectal inflammation and cytokine concentrations in men who have sex with men

Asymptomatic Chlamydia trachomatis infections are common in HIV-infected men who have sex with men (MSM). Although C. trachomatis combined with HIV would be likely to enhance inflammation, the asymptomatic course suggests otherwise. We assessed local inflammation, mucosal damage, and cytokine concentrations in rectal mucosal fluid samples from patients with HIV (with or without the use of combination antiretroviral therapy [cART]) and with or without the presence of rectal C. trachomatis. Rectal swabs from 79 MSM (with and without C. trachomatis, HIV, and cART use) who reported a history of receptive anal sex were analyzed for neutrophil activation (measured by myeloperoxidase [MPO]), mucosal leakage (measured by albumin and alpha-2-macroglobulin), and proinflammatory and anti-inflammatory cytokines. C. trachomatis infection, HIV infection, and cART use in MSM had no differential effects on rectal neutrophilic inflammation and mucosal damage. Interleukin 8 (IL-8) was found to correlate with MPO, and MPO correlated with markers of mucosal damage. In HIV-negative participants, men with C. trachomatis infection had lower concentrations of monocyte chemotactic protein 1 (MCP-1), IL-1α, and IL-1 receptor antagonist (IL-1RA) than men without rectal C. trachomatis infection (P = 0.005, 0.007, and 0.07, respectively). We found no difference in anal cytokine concentrations in HIV-infected participants in relation to the presence of C. trachomatis infection or cART use. In participants with rectal C. trachomatis infection, those who were HIV negative had lower median concentrations of IL-8 and IL-1α than those with HIV (P = 0.05 and 0.06, respectively). The slope of the regression line between MPO and IL-8 was reduced in participants with rectal C. trachomatis infection. C. trachomatis dampens cytokine concentrations but not in HIV-infected patients. The extent of mucosal damage was comparable in all patient groups. The apparent reduced neutrophil response to IL-8 in HIV-infected patients with C. trachomatis infection is in accordance with its asymptomatic course.

Cytokines and chemokines production by mononuclear cells from parturient women after stimulation with live Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite that can cause variable clinical symptoms or can even be asymptomatic in immunocompetent individuals. More severe symptoms are observed in immunocompromised patients and congenital transmission of the parasite has been reported. The objective of this study was to evaluate the response of peripheral blood mononuclear cells (PBMC) in parturient and non-pregnant women exposed to live tachyzoites of T. gondii strain RH or ME49. PBMC were isolated from parturient and non-pregnant women with negative or positive serology for toxoplasmosis and cultured with live tachyzoites of the two T. gondii strains for 24 h. Next, the cell culture supernatants were collected and levels of CCL2, CCL5, IL-6, IL-10, IL-12, and TNF-α produced by PBMC after tachyzoite exposure were measured. Live tachyzoite forms of T. gondii significantly inhibited the synthesis of CCL2 in seropositive parturient women, whereas a stimulatory effect on CCL5 was observed in seronegative parturient women. Cells from T. gondii-seronegative non-pregnant women produced significantly higher levels of TNF-α and IL-12, demonstrating the proinflammatory profile induced by the presence of the parasite in culture. The results suggest that the immunomodulation seen during pregnancy contributes to the development of an environment that facilitates escape of the parasite from the immune response.

Recent insights into microbial triggers of interleukin-10 production in the host and the impact on infectious disease pathogenesis

Since its initial description as a Th2-cytokine antagonistic to interferon-alpha and granulocyte-macrophage colony-stimulating factor, many studies have shown various anti-inflammatory actions of interleukin-10 (IL-10), and its role in infection as a key regulator of innate immunity. Studies have shown that IL-10 induced in response to microorganisms and their products plays a central role in shaping pathogenesis. IL-10 appears to function as both sword and shield in the response to varied groups of microorganisms in its capacity to mediate protective immunity against some organisms but increase susceptibility to other infections. The nature of IL-10 as a pleiotropic modulator of host responses to microorganisms is explained, in part, by its potent and varied effects on different immune effector cells which influence antimicrobial activity. A new understanding of how microorganisms trigger IL-10 responses is emerging, along with recent discoveries of how IL-10 produced during disease might be harnessed for better protective or therapeutic strategies. In this review, we summarize studies from the past 5 years that have reported the induction of IL-10 by different classes of pathogenic microorganisms, including protozoa, nematodes, fungi, viruses and bacteria and discuss the impact of this induction on the persistence and/or clearance of microorganisms in the host.

Maternal self-reported genital tract infections during pregnancy and the risk of selected birth defects

BACKGROUND

Genital tract infections are common during pregnancy and can result in adverse outcomes including preterm birth and neonatal infection. This hypothesis-generating study examined whether these infections are associated with selected birth defects.

METHODS

We conducted a case-control study of 5913 children identified as controls and 12,158 cases with birth defects from the National Birth Defects Prevention Study (1997-2004). Maternal interviews provided data on genital tract infections that occurred from one month before pregnancy through the end of the first trimester. Infections were either grouped together as a single overall exposure or were considered as a subgroup that included chlamydia/gonorrhea/pelvic inflammatory disease. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression with adjustment for potential confounders.

RESULTS

Genital tract infections were associated with bilateral renal agenesis/hypoplasia (OR, 2.89; 95% CI, 1.11-7.50), cleft lip with or without cleft palate (OR, 1.46; 95% CI, 1.03-2.06), and transverse limb deficiency (OR, 1.84; 95% CI, 1.04-3.26). Chlamydia/gonorrhea/pelvic inflammatory disease was associated with cleft lip only (OR, 2.81; 95% CI, 1.39-5.69). These findings were not statistically significant after adjustment for multiple comparisons.

CONCLUSIONS

Caution is needed in interpreting these findings due to the possible misclassification of infection, the limited sample size that constrained consideration of the effects of treatment, and the possibility of chance associations. Although these data do not provide strong evidence for an association between genital tract infections and birth defects, additional research on the possible effects of these relatively common infections is needed.

The mucosal immune response to Chlamydia trachomatis infection of the reproductive tract in women

Sexually transmitted Chlamydia trachomatis infection is an important public health concern with major adverse effects on female reproductive tract health and function. The magnitude of reproductive morbidity associated with sexually transmitted C. trachomatis infection is enormous, however to date no prophylactic vaccine is available. In part this is due to the lack of information on the mucosal immunobiology of the host-pathogen interaction and correlates of protective immunity during genital C. trachomatis infection. In this review, we focus on current knowledge of mucosal innate and adaptive immune responses in the female genital tract during C. trachomatis infection, which will eventually help in the development of a vaccine for prevention of chlamydial infection.

Protective or pathogenic immune response to genital chlamydial infection in women--a possible role of cytokine secretion profile of cervical mucosal cells

Little is known about genital mucosal immune response to chlamydial infection in women with or without sequelae (Chlamydia positive women with or without fertility disorders as infertility and multiple spontaneous abortions). Cervical lymphocytes were stimulated with chlamydial EBs and cytokine secretion was determined by ELISA, RT-PCR and ELISPOT assays. Stimulated cervical cells from women with fertility disorders (FD) secrete significantly (P<0.05) higher levels of IL-1beta, IL-6, IL-8 and IL-10 and cells from fertile women secrete significantly higher levels of IL-12 and IFN-gamma compared to other groups. RT-PCR analysis showed similar results for IFN-gamma and IL-12. For IL-10 and IL-4, mRNA expression levels were significantly higher (P<0.05) in cells obtained from women with FD compared to other groups. Results for ELISPOT assay were similar as those of RT-PCR. The results suggest that cytokine secretion profile of cervical cells may decide whether infection does not hamper fertility or will develop fertility disorder.

Role of cervical dendritic cell subsets, co-stimulatory molecules, cytokine secretion profile and beta-estradiol in development of sequalae to Chlamydia trachomatis infection

BACKGROUND

Chlamydia trachomatis infection of the female genital tract can lead to serious sequelae resulting in fertility related disorders. Little is known about the mechanism leading to Chlamydia induced pathology and factors responsible for it. As only some of the women develops reproductive disorders while majority of the women clears infection without any severe sequalae, mucosal immune response in women with or without fertility disorders was studied to identify factors which may lead to final clinical outcome of chlamydial infection.

METHODS

Myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) populations in cervical mucosa and peripheral blood were analyzed in controls and Chlamydia positive women with or without fertility disorders with multicoloured flow cytometric analysis. Cervical cytokines (IL-6, IL-8, IL-10, IL-12, TNF-alpha and IFN-gamma), C-reactive protein levels and sex hormone levels in serum were quantified by ELISA.

RESULTS

In cervix of Chlamydia positive women with fertility disorders, significantly high (P < 0.05) numbers of pDCs were present with increased CD80 expression. pDCs correlated significantly with C-reactive protein levels, IL-6 and IFN-gamma levels in women with fertility disorders. In contrast, mDCs showed significant upregulation of CD1a during chlamydial infection and correlated significantly with IL-12 levels in Chlamydia positive fertile women. beta-estradiol levels were significantly higher in women having fertility disorders as compared to fertile women and have significant correlations (r = 0.65; P < 0.05) with pDCs numbers, CD80 expression, IL-6 levels and IFN-gamma levels in these women.

CONCLUSION

These results suggest that development of sequalae in some women can be a result of interplay of many factors including type of dendritic cell, co stimulatory molecule expression, cytokine secretion pattern and hormone levels.

In infertile women, cells from Chlamydia trachomatis infected sites release higher levels of interferon-gamma, interleukin-10 and tumor necrosis factor-alpha upon heat-shock-protein stimulation than fertile women

BACKGROUND

The magnitude of reproductive morbidity associated with sexually transmitted Chlamydia trachomatis infection is enormous. Association of antibodies to chlamydial heat shock proteins (cHSP) 60 and 10 with various disease sequelae such as infertility or ectopic pregnancy has been reported. Cell-mediated immunity is essential in resolution and in protection to Chlamydia as well as is involved in the immunopathogenesis of chlamydial diseases. To date only peripheral cell mediated immune responses have been evaluated for cHSP60. These studies suggest cHSPs as important factors involved in immunopathological condition associated with infection. Hence study of specific cytokine responses of mononuclear cells from the infectious site to cHSP60 and cHSP10 may elucidate their actual role in the cause of immunopathogenesis and the disease outcome.

METHODS

Female patients (n = 368) attending the gynecology out patient department of Safdarjung hospital, New Delhi were enrolled for the study and were clinically characterized into two groups; chlamydia positive fertile women (n = 63) and chlamydia positive infertile women (n = 70). Uninfected healthy women with no infertility problem were enrolled as controls (n = 39). cHSP60 and cHSP10 specific cytokine responses (Interferon (IFN)-gamma, Interleukin (IL)-10, Tumor Necrosis Factor (TNF)-alpha, IL-13 and IL-4) were assessed by ELISA in stimulated cervical mononuclear cell supernatants.

RESULTS

cHSP60 and cHSP10 stimulation results in significant increase in IFN-gamma (P = 0.006 and P = 0.04 respectively) and IL-10 levels (P = 0.04) in infertile group as compared to fertile group. A significant cHSP60 specific increase in TNF-alpha levels (P = 0.0008) was observed in infertile group as compared to fertile group. cHSP60 and cHSP10 specific IFN-gamma and IL-10 levels were significantly correlated (P < 0.0001, r = 0.54 and P = 0.004, r = 0.33 respectively) in infertile group.

CONCLUSION

Our results suggest that exposure to chlamydial heat shock proteins (cHSP60 and cHSP10) could significantly affect mucosal immune function by increasing the release of IFN-gamma, IL-10 and TNF-alpha by cervical mononuclear cells.

Prostaglandin E2 modulates dendritic cell function during chlamydial genital infection

Inflammatory responses mediated by antigen-presenting dendritic cells (DCs), can be modulated by the presence of prostaglandins (PG), including prostaglandin E2 (PGE2). PGE2 modifies the production of an immune response by altering DC function through PGE2 receptors. PGE2 is produced by epithelial cells lining the murine female reproductive tract during Chlamydia muridarum infection and likely manipulates the antichlamydial immune response during antigen uptake in the genital mucosa. Our data demonstrate that the PGE2 present locally in the genital tract upon chlamydial genital infection enhanced the recruitment of CD11b+ conventional DCs, but not CD45R+ plasmacytoid DCs, to infected genital tract tissue and draining lymph nodes in vivo. Furthermore, exposure to PGE2 in vitro during infection of murine bone-marrow-derived conventional DCs (cDCs) boosted interleukin-10 mRNA and protein while not influencing interleukin-12p40 production. Infection of cDCs markedly increased mRNA production of the costimulatory molecules CD86, CD40 and a member of the C-type lectin family, DEC-205, but addition of PGE2 increased other costimulatory molecules and C-type lectins. Also, exposure of PGE2 to infected cDCs increased FcgammaRIII and FcgammaRIIb, suggesting that PGE2 enhances the uptake and presentation of C. muridarum and augments production of the antichlamydial adaptive immune response. Taken together, the data suggest that exposure of infected cDCs to PGE2 drives production of a diverse adaptive immune response with implications for regulating tissue inflammation.