IFN-gamma induced persistent Chlamydia pneumoniae infection in HL and Mono Mac 6 cells: characterization by real-time quantitative PCR and culture

Chlamydia pneumoniae Interferes with Macrophage Differentiation and Cell Cycle Regulation to Promote Its Replication

Chlamydia pneumoniae is a ubiquitous intracellular bacterium which infects humans via the respiratory route. The tendency of C. pneumoniae to persist in monocytes and macrophages is well known, but the underlying host-chlamydial interactions remain elusive. In this work, we have described changes in macrophage intracellular signaling pathways induced by C. pneumoniae infection. Label-free quantitative proteome analysis and pathway analysis tools were used to identify changes in human THP-1-derived macrophages upon C. pneumoniae CV6 infection. At 48-h postinfection, pathways associated to nuclear factor κB (NF-κB) regulation were stressed, while negative regulation on cell cycle control was prominent at both 48 h and 72 h. Upregulation of S100A8 and S100A9 calcium binding proteins, osteopontin, and purine nucleoside hydrolase, laccase domain containing protein 1 (LACC1) underlined the proinflammatory consequences of the infection, while elevated NF-κB2 levels in infected macrophages indicates interaction with the noncanonical NF-κB pathway. Infection-induced alteration of cell cycle control was obvious by the downregulation of mini chromosome maintenance (MCM) proteins MCM2-7, and the significance of host cell cycle regulation for C. pneumoniae replication was demonstrated by the ability of a cyclin-dependent kinase (CDK) 4/6 inhibitor Palbociclib to promote C. pneumoniae replication and infectious progeny production. The infection was found to suppress retinoblastoma expression in the macrophages in both protein and mRNA levels, and this change was reverted by treatment with a histone deacetylase inhibitor. The epigenetic suppression of retinoblastoma, along with upregulation of S100A8 and S100A9, indicate host cell changes associated with myeloid-derived suppressor cell (MDSC) phenotype.

Insights Into Host Cell Cytokines in Chlamydia Infection

Chlamydial infection causes a number of clinically relevant diseases and induces significant morbidity in humans. Immune and inflammatory responses contribute to both the clearance of Chlamydia infection and pathology in host tissues. Chlamydia infection stimulates host cells to produce a large number of cytokines that trigger and regulate host immune responses against Chlamydia. However, inappropriate responses can occur with excessive production of cytokines, resulting in overreactive inflammatory responses and alterations in host or Chlamydia metabolism. As a result, Chlamydia persists and causes wound healing delays, leading to more severe tissue damage and triggering long-lasting fibrotic sequelae. Here, we summarize the roles of cytokines in Chlamydia infection and pathogenesis, thus advancing our understanding chlamydial infection biology and the pathogenic mechanisms involved.

Parachlamydia acanthamoebae Detected during a Pneumonia Outbreak in Southeastern Finland, in 2017⁻2018

Community-acquired pneumonia (CAP) is a common disease responsible for significant morbidity and mortality. However, the definite etiology of CAP often remains unresolved, suggesting that unknown agents of pneumonia remain to be identified. The recently discovered members of the order Chlamydiales, Chlamydia-related bacteria (CRB), are considered as possible emerging agents of CAP. Parachlamydia acanthamoebae is the most studied candidate. It survives and replicates inside free-living amoeba, which it might potentially use as a vehicle to infect animals and humans. A Mycoplasma pneumoniae outbreak was observed in Kymenlaakso region in Southeastern Finland during August 2017-January 2018. We determined the occurrence of Chlamydiales bacteria and their natural host, free-living amoeba in respiratory specimens collected during this outbreak with molecular methods. Altogether, 22/278 (7.9%) of the samples contained Chlamydiales DNA. By sequence analysis, majority of the CRBs detected were members of the Parachlamydiaceae family. Amoebal DNA was not detected within the sample material. Our study further proposes that Parachlamydiaceae could be a potential agent causing atypical CAP in children and adolescents.

Chlamydia pneumoniae Infection Exacerbates Atherosclerosis in ApoB100only/LDLR-/- Mouse Strain

Aims

Hyperlipidaemia model animals have been used to elucidate the role of Chlamydia pneumoniae (Cpn) infection in atherosclerosis. The aims of this study were to investigate the proatherogenic effect of multiple Cpn infections in ApoB100only/LDLR^−/− mice which based on lipid profile can be regarded as the most suitable mouse model of human hypercholesterolemia and to compare the lesion development to that in a major atherosclerosis model ApoE^−/− mice.

Methods and Results

Aorta samples of ApoB100only/LDLR^−/− mice infected three times with Cpn were subjected to morphometric analyses. Morphometric evaluation disclosed that Cpn infections exacerbated atherosclerosis development in the aortic root and descending aorta of the mice fed with normal diet. Viable Cpn was detected in the ascending aorta by RT-PCR. Chlamydial 16SrRNA expression showed the presence of viable Cpn in the aorta of infected animals. A similar rate of acceleration of atherosclerosis was observed when the infection protocol was applied in ApoB100only/LDLR^−/− and in ApoE^−/− mice.

Conclusion

Similar to ApoE^−/− mice, ApoB100only/LDLR^−/− mice with more human-relevant serum lipoprotein composition develop increased atherosclerosis after Cpn infections; thus this mouse strain can be used as a model of infection-related atherosclerosis enhancement and can provide further evidence for the proatherogenic influence of Cpn in mice.

Development of a multiplex real-time PCR assay for detection of Mycoplasma pneumoniae, Chlamydia pneumoniae and mutations associated with macrolide resistance in Mycoplasma pneumoniae from respiratory clinical specimens

The aim of this study was to improve detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in clinical specimens by developing a multiplex real-time PCR assay that includes identification of macrolide-resistant M. pneumoniae. Novel assays targeting a M. pneumoniae conserved hypothetical protein gene, M. pneumoniae 23S rRNA gene mutations associated with macrolide resistance and human β-globin gene (an endogenous internal control) were designed and combined with a previously published C. pneumoniae PCR targeting ompA gene. The resulting quadraplex PCR was validated with a panel of clinical specimens supplemented with external quality assessment specimens, simulated specimens and various bacterial and viral strains. The obtained results were compared to those obtained by reference PCRs or confirmed by sequencing (typing of macrolide resistance). The novel multiplex PCR assay was in 100 % agreement with reference PCRs. Four M. pneumoniae strains with macrolide resistance-associated mutations were identified among 42 strains, which comprises 9.5 % of the study material. Amplification of an internal control excluded sample-derived inhibition possibly leading to false-negative reporting. In conclusion, we have developed a resources conserving multiplex real-time PCR assay for simultaneous detection of M. pneumoniae, C. pneumoniae and the most common mutations leading to macrolide resistance in M. pneumoniae. The assay is a widely useful tool for detection of these respiratory pathogens and will also shed light on the occurrence of macrolide resistance in M. pneumoniae.

Evolution to a chronic disease niche correlates with increased sensitivity to tryptophan availability for the obligate intracellular bacterium Chlamydia pneumoniae

The chlamydiae are obligate intracellular parasites that have evolved specific interactions with their various hosts and host cell types to ensure their successful survival and consequential pathogenesis. The species Chlamydia pneumoniae is ubiquitous, with serological studies showing that most humans are infected at some stage in their lifetime. While most human infections are asymptomatic, C. pneumoniae can cause more-severe respiratory disease and pneumonia and has been linked to chronic diseases such as asthma, atherosclerosis, and even Alzheimer's disease. The widely dispersed animal-adapted C. pneumoniae strains cause an equally wide range of diseases in their hosts. It is emerging that the ability of C. pneumoniae to survive inside its target cells, including evasion of the host's immune attack mechanisms, is linked to the acquisition of key metabolites. Tryptophan and arginine are key checkpoint compounds in this host-parasite battle. Interestingly, the animal strains of C. pneumoniae have a slightly larger genome, enabling them to cope better with metabolite restrictions. It therefore appears that as the evolutionarily more ancient animal strains have evolved to infect humans, they have selectively become more "susceptible" to the levels of key metabolites, such as tryptophan. While this might initially appear to be a weakness, it allows these human C. pneumoniae strains to exquisitely sense host immune attack and respond by rapidly reverting to a persistent phase. During persistence, they reduce their metabolic levels, halting progression of their developmental cycle, waiting until the hostile external conditions have passed before they reemerge.

Laboratory diagnosis of persistent human chlamydial infection

Diagnostic assays for persistent chlamydial infection are much needed to conduct high-quality, large-scale studies investigating the persistent state in vivo, its disease associations and the response to therapy. Yet in most studies the distinction between acute and persistent infection is based on the interpretation of the data obtained by the assays developed to diagnose acute infections or on complex assays available for research only and/or difficult to establish for clinical use. Novel biomarkers for detection of persistent chlamydial infection are urgently needed. Chlamydial whole genome proteome arrays are now available and they can identify chlamydial antigens that are differentially expressed between acute infection and persistent infection. Utilizing these data will lead to the development of novel diagnostic assays. Carefully selected specimens from well-studied patient populations are clearly needed in the process of translating the proteomic data into assays useful for clinical practice. Before such antigens are identified and validated assays become available, we face a challenge of deciding whether the persistent infection truly induced appearance of the proposed marker or do we just base our diagnosis of persistent infection on the presence of the suggested markers. Consequently, we must bear this in mind when interpreting the available data.

Intracellular survival and persistence of Chlamydia muridarum is determined by macrophage polarization

Macrophages can display a number of distinct phenotypes, known collectively as polarized macrophages. The best defined of these phenotypes are the classically-activated, interferon gamma (IFNγ)/LPS induced (M1) and alternatively-activated, IL-4 induced (M2) macrophages. The goal of this study is to characterize macrophage-Chlamydia interactions in the context of macrophage polarization. Here we use Chlamydia muridarum and murine bone-marrow derived macrophages to show Chlamydia does not induce M2 polarization in macrophages as a survival strategy. Unexpectedly, the infection of macrophages was silent with no upregulation of M1 macrophage-associated genes. We further demonstrate that macrophages polarized prior to infection have a differential capacity to control Chlamydia. M1 macrophages harbor up to 40-fold lower inclusion forming units (IFU) than non-polarized or M2 polarized macrophages. Gene expression analysis showed an increase in 16sRNA in M2 macrophages with no change in M1 macrophages. Suppressed Chlamydia growth in M1 macrophages correlated with the induction of a bacterial gene expression profile typical of persistence as evident by increased Euo expression and decreased Omp1 and Tal expression. Observations of permissive Chlamydia growth in non-polarized and M2 macrophages and persistence in M1 macrophages were supported through electron microscopy. This work supports the importance of IFNγ in the innate immune response to Chlamydia. However, demonstration that the M1 macrophages, despite an antimicrobial signature, fail to eliminate intracellular Chlamydia supports the notion that host–pathogen co-evolution has yielded a pathogen that can evade cellular defenses against this pathogen, and persist for prolonged periods of time in the host.

Chlamydia pneumoniae infection in atherosclerotic lesion development through oxidative stress: a brief overview

Chlamydia pneumoniae, an obligate intracellular pathogen, is known as a leading cause of respiratory tract infections and, in the last two decades, has been widely associated with atherosclerosis by seroepidemiological studies, and direct detection of the microorganism within atheroma. C. pneumoniae is presumed to play a role in atherosclerosis for its ability to disseminate via peripheral blood mononuclear cells, to replicate and persist within vascular cells, and for its pro-inflammatory and angiogenic effects. Once inside the vascular tissue, C. pneumoniae infection has been shown to induce the production of reactive oxygen species in all the cells involved in atherosclerotic process such as macrophages, platelets, endothelial cells, and vascular smooth muscle cells, leading to oxidative stress. The aim of this review is to summarize the data linking C. pneumoniae-induced oxidative stress to atherosclerotic lesion development.

Flotillin-1 (Reggie-2) contributes to Chlamydia pneumoniae growth and is associated with bacterial inclusion

Chlamydiae are obligate intracellular pathogens replicating only inside the eukaryotic host. Here, we studied the effect of human flotillin-1 protein on Chlamydia pneumoniae growth in human line (HL) and A549 epithelial cell lines. RNA interference was applied to disrupt flotillin-1-mediated endocytosis. Host-associated bacteria were detected by quantitative PCR, and C. pneumoniae growth was evaluated by inclusion counts. C. pneumoniae attachment to host cells was unaffected, but bacterial intracellular growth was attenuated in the flotillin-1-silenced cells. By using confocal microscopy, we detected flotillin-1 colocalized with the inclusion membrane protein A (IncA) in the C. pneumoniae inclusion membranes. In addition, flotillin-1 was associated with IncA in detergent-resistant membrane microdomains (DRMs) in biochemical fractioning. These results suggest that flotillin-1 localizes to the C. pneumoniae inclusion membrane and plays an important role for intracellular growth of C. pneumoniae.

Chlamydia pneumoniae entry into epithelial cells by clathrin-independent endocytosis

A gram-negative obligate intracellular bacterium, Chlamydia pneumoniae, is a common respiratory pathogen. Here, we examined the invasion and attachment of C. pneumoniae K6 into nonphagocytic HL epithelial cell line by manipulating host plasma membranes by using cholesterol-depleting methyl-beta-cyclodextrin (MβCD) and cholesterol-loading MβCD complexed cholesterol (chol-MβCD). The invasion was attenuated by MβCD-treatment while chol-MβCD augmented the attachment and invasion. In addition, the invasion was inhibited by cholesterol sequestering reagents, nystatin and filipin. Furthermore, exposure of host cells to sphingomyelinase inhibited the invasion. RNA interference was used to assay the role of clathrin and human scavenger receptor B, type I (SR-BI) in the entry of C. pneumoniae into A549 lung epithelial adenocarcinoma cells. In contrast to Chlamydia trachomatis L2, the entry of C. pneumoniae was found to be independent of clathrin. In addition, the entry was found to be SR-BI-independent, but interestingly, the chlamydial growth was attenuated in the SR-BI-silenced cells. These findings suggest that the attachment and invasion of C. pneumoniae into nonphagocytic epithelial cells is dependent on the formation of cholesterol- and sphingomyelin-rich plasma membrane microdomains, and the entry is a clathrin-independent process. In addition, our data indicate that SR-BI supports the growth of C. pneumoniae in epithelial cells.

Analysis of Chlamydia pneumoniae infection in mononuclear cells by reverse transcription-PCR targeted to chlamydial gene transcripts

Chlamydia pneumoniae (C. pneumoniae) is an important etiological agent of respiratory infections including pneumonia. C. pneumoniae DNA can be detected in peripheral blood mononuclear cells indicating that monocytes can assist the spread of infection to other anatomical sites. Persistent infection established at these sites could promote inflammation and enhance pathology. Thus, the mononuclear cells are in a strategic position in the development of persistent infection. To investigate the intracellular replication and fate of C. pneumoniae in mononuclear cells, we have established an in vitro model in the human Mono Mac 6 cell line. In the present study, we analyzed the transcription of 11 C. pneumoniae genes in Mono Mac 6 cells during infection by real-time RT-PCR. Our results suggest that the transcriptional profile of the studied genes in monocytes is different from that seen in epithelial cells. Furthermore, our study shows that genes related to secretion are transcribed, and secreted bacterial proteins are also translated during infection of monocytes, creating novel opportunities for the management of chlamydial infection of monocytes.

Chlamydia pneumoniae infection in polarized epithelial cell lines

We set up a polarized cell culture model to study the pathogenicity of a common respiratory tract pathogen, Chlamydia pneumoniae. Immunofluorescence staining of ZO-1 (a tight junction protein) and Na(+)K(+) ATPase (a protein pump localized at the basolateral membrane in the polarized epithelial cells), as well as TER measurements, suggested that the filter-grown Calu-3 cells, but not the A549 cells, were polarized when grown on collagen-coated membranes. Both the flat and the filter-grown cultures were infected with C. pneumoniae. Infection in the polarized Calu-3 cultures produced more C. pneumoniae genome equivalents than infection in the flat cultures. However, this progeny was not as infective as that in the flat cultures. The maximum amount of C. pneumoniae was detected at 6 days postinfection in the filter-grown A549 cells, indicating a slower developmental cycle than that observed in the flat A549 cultures. The effect of cycloheximide on the growth of C. pneumoniae in the polarized cells was negligible. Furthermore, the infection in the polarized Calu-3 cells was resistant to doxycycline, and several cytokines were released mainly on the apical side of the polarized cells in response to C. pneumoniae infection. These findings indicate that the growth of chlamydiae was altered in the filter-grown epithelial culture system. The diminished production of infective progeny of C. pneumoniae, together with the resistance to doxycycline and polarized secretion of cytokines from the infected Calu-3 cells, suggests that this model is useful for examining epithelial cell responses to C. pneumoniae infection, and it might better resemble in vivo infection in respiratory epithelial cells.

A novel inhibitor of Chlamydophila pneumoniae protein kinase D (PknD) inhibits phosphorylation of CdsD and suppresses bacterial replication

Background

We have shown previously that Chlamydophila pneumoniae contains a dual-specific Ser/Thr protein kinase that phosphorylates CdsD, a structural component of the type III secretion apparatus. To further study the role of PknD in growth and development we sought to identify a PknD inhibitor to determine whether PknD activity is required for replication.

Results

Using an in vitro kinase assay we screened 80 known eukaryotic protein kinase inhibitors for activity against PknD and identified a 3'-pyridyl oxindole compound that inhibited PknD autophosphorylation and phosphorylation of CdsD. The PknD inhibitor significantly retarded the growth rate of C. pneumoniae as evidenced by the presence of very small inclusions with a reduced number of bacteria as seen by electron microscopy. These inclusions contained the normal replicative forms including elementary bodies (EB), intermediate bodies (IB) and reticulate bodies (RB), but lacked persistent bodies (PB), indicating that induction of persistence was not the cause of reduced chlamydial growth. Blind passage of C. pneumoniae grown in the presence of this PknD inhibitor for 72 or 84 hr failed to produce inclusions, suggesting this compound blocks an essential step in the production of infectious chlamydial EB. The compound was not toxic to HeLa cells, did not block activation of the MEK/ERK pathway required for chlamydial invasion and did not block intracellular replication of either Chlamydia trachomatis serovar D or Salmonella enterica sv. Typhimurium suggesting that the inhibitory effect of the compound is specific for C. pneumoniae.

Conclusion

We have identified a 3'-pyridyl oxindole compound that inhibits the in vitro kinase activity of C. pneumoniae PknD and inhibits the growth and production of infectious C. pneumoniae progeny in HeLa cells. Together, these results suggest that PknD may play a key role in the developmental cycle of C. pneumoniae.

In vitro characterisation of koala Chlamydia pneumoniae: morphology, inclusion development and doubling time

Chlamydia pneumoniae is a common human and animal pathogen associated with upper and lower respiratory tract infections. Of the animal C. pneumoniae isolates, the koala nasal isolate (LPCoLN) is by far the best genetically characterised. This current study was designed to characterise the morphology and developmental events for the LPCoLN isolate, and our results showed several striking in vitro growth differences when compared to the human isolate, AR39. The LPCoLN inclusion size and morphology was distinct from AR39, and a much faster doubling time (3.4-4.9h versus 5.9-8.7h doubling time) was observed when grown in HEp-2 cell monolayers. Confocal and electron microscopy of LPCoLN confirmed large (9-30 microm in diameter) inclusions, that were heterogeneously shaped, compared to the small (5-9 microm in diameter), uniformly shaped inclusions of AR39. The morphology of the LPCoLN elementary body was round, and had a narrow or nonexistent periplasmic space, compared to the 'pear-shaped' morphology of AR39 EBs. While both isolates showed evidence of inclusion fusion, the level of fusion was much higher for LPCoLN (100%) compared to AR39 (30-40%). Our findings have provided new insights and identified key differences in the in vitro doubling time, size and morphology of an animal C. pneumoniae isolate.

Simvastatin Reduces Chlamydophila pneumoniae –Mediated Histone Modifications and Gene Expression in Cultured Human Endothelial Cells

Inflammatory activation of the endothelium by Chlamydophila pneumoniae infection has been implicated in the development of chronic vascular lesions and coronary heart disease by seroepidemiological and animal studies. We tested the hypothesis that C pneumoniae induced inflammatory gene expression is regulated by Rho-GTPase–related histone modifications. C pneumoniae infection induced the liberation of proinflammatory interleukin-6, interleukin-8, granulocyte colony-stimulating factor, macrophage inflammatory protein-1β, granulocyte/macrophage colony-stimulating factor, and interferon-γ by human endothelial cells. Cytokine secretion was reduced by simvastatin and the specific Rac1 inhibitor NSC23766 but was synergistically enhanced by inhibitors of histone deacetylases trichostatin A and suberoylanilide hydroxamic acid. Infection of endothelial cells with viable C pneumoniae , but not exposure to heat-inactivated C pneumoniae or infection with C trachomatis , induced acetylation of histone H4 and phosphorylation and acetylation of histone H3. Pretreatment of C pneumoniae –infected cells with simvastatin or NSC23766 reduced global histone modifications as well as specific modifications at the il8 gene promoter, as shown by chromatin immunoprecipitation. Reduced recruitment of nuclear factor κB p65/RelA as well as of RNA polymerase II was observed in statin-treated cells. Taken together, Rac1-mediated histone modifications seem to play an important role in C pneumoniae –induced cytokine production by human endothelial cells.

STAT1 regulates IFN-alpha beta- and IFN-gamma-dependent control of infection with Chlamydia pneumoniae by nonhemopoietic cells

STAT1 mediates signaling in response to IFN-alpha, -beta, and -gamma, cytokines required for protective immunity against several viral, bacterial, and eukaryotic pathogens. The protective role of STAT1 in the control of intranasal infection with the obligate intracellular bacterium Chlamydia pneumoniae was analyzed. IFN-gamma-/- or IFN-gamma receptor (R)-/- mice were highly susceptible to infection with C. pneumoniae. We found that STAT1-/- mice were even more susceptible to C. pneumoniae than IFN-gamma-/- or IFN-gammaR-/- mice. Phosphorylation of STAT1 was detected in the lungs of C. pneumoniae-infected wild-type, IFN-gammaR-/-, and IFN-alphabetaR-/- mice, but not in mice lacking both IFN-alphabetaR and IFN-gammaR. In line with this, IFN-alphabetaR-/-/IFN-gammaR-/- mice showed increased susceptibility to infection compared with IFN-gammaR-/- mice. However, C. pneumoniae-infected IFN-alphabetaR-/- or IFN regulatory factor 3-/- mice showed no increased susceptibility and similar IFN-gamma expression compared with wild-type mice. CD4+ or CD8+ cells released IFN-gamma in vivo and conferred protection against C. pneumoniae in a STAT1-independent manner. In contrast, STAT1 mediated a nonredundant protective role of nonhemopoietic cells but not of hemopoietic cells. Nonhemopoietic cells accounted for the expression of STAT1-mediated indoleamine 2, 3-dioxygenase and the p47 GTPase LRG-47, but not inducible NO synthase mRNA. In summary, we demonstrate that STAT1 mediates a cooperative effect of IFN-alphabeta and IFN-gamma on nonhemopoietic cells, resulting in protection against C. pneumoniae.

Chlamydia LPS and MOMP seropositivity are associated with different cytokine profiles in patients with coronary heart disease

BACKGROUND

Persistent Chlamydia pneumoniae infection within atherosclerotic plaques are possible stimulators of inflammation in atherosclerosis. Why the microbe develops persistency in some individuals is unknown, but experimental studies in cell cultures and animals have demonstrated the levels of gamma interferon (IFNgamma) and interleukin 10 (IL-10) to be of crucial importance.

DESIGN

We wanted to evaluate whether Chlamydia seropositivity in patients with coronary heart disease (CHD) (n = 193) was associated with elevated IFNgamma and IL-10. Two methods for detection of Chlamydia antibodies were included as well as analysis of tumour necrosis factor alpha (TNFalpha), soluble vascular cell adhesion molecule 1 (sVCAM-1) and soluble E-selectin for the evaluation of vascular inflammation.

RESULTS

We found that patients with IgA antibodies towards Chlamydia lipopolysaccharide (LPS) had elevated levels of IFNgamma (P = 0.048), IL-10 (P = 0.029), TNFalpha (P = 0.009) and sE-selectin (P = 0.045), while Chlamydia LPS IgG seropositivity predicted elevated levels of IL-10 (P = 0.013). Patients with IgA antibodies towards C. pneumoniae major outer membrane protein (MOMP) without simultaneous LPS IgA seropositivity had lower levels of IFNgamma and sVCAM-1 when compared to patients with Chlamydia LPS IgA alone (P = 0.005 for IFNgamma, P = 0.016 for VCAM-1) and patients with combined Chlamydia MOMP and LPS IgA seropositivity (P = 0.046 and P = 0.013, respectively).

CONCLUSIONS

In summary, we demonstrated an association between Chlamydia LPS IgA seropositivity and elevated levels of IFNgamma, IL-10, TNFalpha, sVCAM-1 and sE-selectin in CHD patients that might indicate persistent Chlamydia infection and a proinflammatory state. On the other hand, C. pneumoniae MOMP antibodies were not associated with elevated inflammatory markers and might merely be indicative of past infection, possibly with successful microbe clearance.