Induction of proinflammatory cytokines in human osteoblastic cells by Chlamydia pneumoniae

Reduction of Chlamydia pecorum and Koala Retrovirus subtype B expression in wild koalas vaccinated with novel peptide and peptide/recombinant protein formulations

Koalas are an endangered species under threat of extinction from several factors, including infections agents. Chlamydia pecorum infection results in morbidity and mortality from ocular and urogenital diseases while Koala Retrovirus (KoRV) infection has been linked to increased rates of cancer and chlamydiosis. Both C. pecorum and KoRV are endemic in many wild Australian koala populations, with limited treatment options available. Fortunately, vaccines for these pathogens are under development and have generated effective immune responses in multiple trials. The current study aimed to improve vaccine formulations by testing a novel peptide version of the Chlamydia vaccine and a combination Chlamydia - KoRV vaccine. Utilising a monitored wild population in Southeast Queensland, this trial followed koalas given either a 'Chlamydia only' vaccine (utilising four peptides from the chlamydial Major Outer Membrane Protein, MOMP), a combination 'Chlamydia and KoRV' vaccine (comprised of the chlamydial peptides plus a KoRV recombinant envelope protein (rEnv)) or no treatment. Clinical observations, C. pecorum and KoRV gene expression, serum IgG, and mucosal immune gene expression were assessed over a 17-month period. Overall, both vaccine formulations resulted in a decrease in chlamydiosis mortality, with decreases in C. pecorum, CD4, CD8β and IL-17A gene expression observed. In addition, the combination vaccine group also showed an increase in anti-KoRV IgG production that corresponded to a decrease in detected KoRV-B expression. While these results are favourable, the chlamydial peptide vaccine did not appear to outperform the established recombinant chlamydial vaccine and suggests that a combination vaccine formulated with recombinant MOMP plus KoRV rEnv could capitalize on the demonstrated benefits of both for the betterment of koalas into the future.

Titanium Functionalized with Polylysine Homopolymers: In Vitro Enhancement of Cells Growth

In oral implantology, the success and persistence of dental implants over time are guaranteed by the bone formation around the implant fixture and by the integrity of the peri-implant mucosa seal, which adheres to the abutment and becomes a barrier that hinders bacterial penetration and colonization close to the outer parts of the implant. Research is constantly engaged in looking for substances to coat the titanium surface that guarantees the formation and persistence of the peri-implant bone, as well as the integrity of the mucous perimeter surrounding the implant crown. The present study aimed to evaluate in vitro the effects of a titanium surface coated with polylysine homopolymers on the cell growth of dental pulp stem cells and keratinocytes to establish the potential clinical application. The results reported an increase in cell growth for both cellular types cultured with polylysine-coated titanium compared to cultures without titanium and those without coating. These preliminary data suggest the usefulness of polylysine coating not only for enhancing osteoinduction but also to speed the post-surgery mucosal healings, guarantee appropriate peri-implant epithelial seals, and protect the fixture against bacterial penetration, which is responsible for compromising the implant survival.

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.

The Crosstalk between Prostate Cancer and Microbiota Inflammation: Nutraceutical Products Are Useful to Balance This Interplay?

The human microbiota shows pivotal roles in urologic health and disease. Emerging studies indicate that gut and urinary microbiomes can impact several urological diseases, both benignant and malignant, acting particularly on prostate inflammation and prostate cancer. Indeed, the microbiota exerts its influence on prostate cancer initiation and/or progression mechanisms through the regulation of chronic inflammation, apoptotic processes, cytokines, and hormonal production in response to different pathogenic noxae. Additionally, therapies' and drugs' responses are influenced in their efficacy and tolerability by microbiota composition. Due to this complex potential interconnection between prostate cancer and microbiota, exploration and understanding of the involved relationships is pivotal to evaluate a potential therapeutic application in clinical practice. Several natural compounds, moreover, seem to have relevant effects, directly or mediated by microbiota, on urologic health, posing the human microbiota at the crossroad between prostatic inflammation and prostate cancer development. Here, we aim to analyze the most recent evidence regarding the possible crosstalk between prostate, microbiome, and inflammation.

Sex Hormones and Inflammation Role in Oral Cancer Progression: A Molecular and Biological Point of View

Oral cancers have been proven to arise from precursors lesions and to be related to risk behaviour such as alcohol consumption and smoke. However, the present paper focuses on the role of chronic inflammation, related to chronical oral infections and/or altered immune responses occurring during dysimmune and autoimmune diseases, in the oral cancerogenesis. Particularly, oral candidiasis and periodontal diseases introduce a vicious circle of nonhealing and perpetuation of the inflammatory processes, thus leading toward cancer occurrence via local and systemic inflammatory modulators and via genetic and epigenetic factors.

Antibacterial Activity of Indolicidin-Coated Silver Nanoparticles in Oral Disease

(1) Background: In dentistry, silver nanoparticles (AgNPs) have progressively earned great interest as antimicrobial drugs and are widely used in several biomedical fields. Recent progress in the analysis of complex bacterial communities has demonstrated the richness of the oral microbiota and the presence of numerous previously unexplained strains. Several efforts have been dedicated to the investigation of antimicrobial peptides (AMPs). Those peptides are a widespread group of small peptides against invading microbes. We report the production of a hybrid molecule composed of AgNPs and indolicidin, a well-known antibacterial peptide. (2) Methods: Spectroscopy and microscopy were used to analyze the optical features and to determine the size of the generated AgNPs. The AgNP antibacterial activity was evaluated versus oral Gram-positive and Gram-negative bacteria. (3) Results: The coated nanoparticles’ antibacterial activity strongly inhibited the growth of microorganisms, with very low minimum inhibitory concentration (MIC) values in the range of 5–12.5 μg/mL. We hypothesize that this effect depended on the specific characteristics of the metal surface coated with indolicidin. The second result was that the coated nanoparticles observed cellular toxicity, was lower with respect to the toxicity of peptide and the naked AgNPs when used individually. (4) New investigations regarding antimicrobial effect of AgNPs coated with AMPs in oral infections are an urgent task.

The enigmatic role of matrix metalloproteinases in epithelial-to-mesenchymal transition of oral squamous cell carcinoma: Implications and nutraceutical aspects

The most prevalent malignancy in the oral cavity is represented by oral squamous cell carcinoma, an aggressive disease mostly detected in low-income communities. This neoplasia is mostly diffused in older men particularly exposed to risk factors such as tobacco, alcohol, and a diet rich in fatty foods and poor in vegetables. In oral squamous cell carcinoma, a wide range of matrix-cleaving proteinases are involved in extracellular matrix remodeling of cancer microenvironment. In particular, matrix metalloproteinases (MMPs) represent the major and most investigated protagonists. Owing to their strong involvement in malignant pathologies, MMPs are considered the most promising new biomarkers in cancer diagnosis and prognosis. The interest in studying MMPs in oral cancer biology is also owing to their prominent role in epithelial-to-mesenchymal transition (EMT). EMT is an intricate process involving different complex pathways. EMT-related proteins are attractive diagnostic biomarkers that characterize the activation of biological events that promote cancer's aggressive expansion. Different antioncogenic natural compounds have been investigated to counteract oral carcinogenesis, with the scope of obtaining better clinical results and lower morbidity. In particular, we describe the role of different nutraceuticals used for the regulation of MMP-related invasion and proliferation of oral cancer cells.

Chlamydia pneumoniae is present in the dental plaque of periodontitis patients and stimulates an inflammatory response in gingival epithelial cells

Chlamydia pneumoniae is an airborne, Gram-negative, obligate intracellular bacterium which causes human respiratory infections and has been associated with atherosclerosis. Because individuals with periodontitis are at greater risk for atherosclerosis as well as respiratory infections, we in-vestigated the role of C. pneumoniae in inflammation and periodontal dis-ease. We found that C. pneumoniae was more frequently found in subgingival dental plaque obtained from periodontally diseased sites of the mouth versus healthy sites. The known periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were also found in the plaque. In addition, C. pneumoniae could efficiently invade human gingival epithelial cells (GECs) in vitro, causing translocation of NF-κB to the nucleus along with increased secretion of mature IL-1β cytokine. Supernatants collected from C. pneumoniae-infected GECs showed increased activation of caspase-1 protein, which was significantly reduced when nlrp3 gene expression was silenced using shRNA lentiviral vectors. Our results demonstrate that C. pneumoniae was found in higher levels in periodontitis patients compared to control pa-tients. Additionally, C. pneumoniae could infect GECs, leading to inflammation caused by activation of NF-κB and the NLRP3 inflammasome. We propose that the presence of C. pneumoniae in subgingival dental plaque may contribute to periodontal disease and could be used as a potential risk indicator of perio-dontal disease.

The Role of Oxidative Stress and Hormones in Controlling Obesity

The accumulation of adipose tissue in the body occurs because the energy introduced with food and drink exceeds that expense, but to understand why this imbalance is established and why it is maintained over time, it is important to consider the main causes and risk factors of excess weight. In this review, we will refer to the main factors linked to obesity, starting from oxidative stress to hormonal factors including the role of obesity in breast cancer. Among the many hypotheses formulated on the etiopathology of obesity, a key role can be attributed to the relationship between stress oxidative and intestinal microbiota. Multiple evidences tend to show that genetic, epigenetic, and lifestyle factors contribute to determine in the obese an imbalance of the redox balance correlated with the alteration of the intestinal microbial flora. Obesity acts negatively on the wound healing, in fact several studies indicate morbid obesity significantly increased the risk of a post-operative wound complication and infection. Currently, in the treatment of obesity, medical interventions are aimed not only at modifying caloric intake, but also to modulate and improve the composition of diet with the aim of rebalancing the microbiota-redox state axis.

Effect of restriction vegan diet's on muscle mass, oxidative status, and myocytes differentiation: A pilot study

This study was conceived to evaluate the effects of three different diets on body composition, metabolic parameters, and serum oxidative status. We enrolled three groups of healthy men (omnivores, vegetarians, and vegans) with similar age, weight and BMI, and we observed a significant decrease in muscle mass index and lean body mass in vegan compared to vegetarian and omnivore groups, and higher serum homocysteine levels in vegetarians and vegans compared to omnivores. We studied whether serum from omnivore, vegetarian, and vegan subjects affected oxidative stress, growth and differentiation of both cardiomyoblast cell line H9c2 and H-H9c2 (H9c2 treated with H₂ O₂ to induce oxidative damage). We demonstrated that vegan sera treatment of both H9c2 and H-H9c2 cells induced an increase of TBARS values and cell death and a decrease of free NO^2- compared to vegetarian and omnivorous sera. Afterwards, we investigated the protective effects of vegan, vegetarian, and omnivore sera on the morphological changes induced by H₂ O₂ in H9c2 cell line. We showed that the omnivorous sera had major antioxidant and differentiation properties compared to vegetarian and vegan sera. Finally, we evaluated the influence of the three different groups of sera on MAPKs pathway and our data suggested that ERK expression increased in H-H9c2 cells treated with vegetarian and vegan sera and could promote cell death. The results obtained in this study demonstrated that restrictive vegan diet could not prevent the onset of metabolic and cardiovascular diseases nor protect by oxidative damage.

Signal transduction growth factors: the effective governance of transcription and cellular adhesion in cancer invasion

Giulio Bizzozero classified the tissues concerning their capacity to self-renew during the adult life in labile, stable and permanent tissues. In 1940 Viktor Hamburger and Rita Levi Montalcini exposed the possibility to induce the growth of permanent cells thanks to a specific ligand Nerve Growth Factor (NGF). Stanley Cohen purified a protein the Epidermal Growth Factor (EGF), able to induce epidermis proliferation and to elicit precocious eye disclosure and teeth eruption, establishing the “inverse” relationships between the proliferation and differentiation. These two biological effects induced by EGF were according to EGFR signaling is involved in a large array of cellular functions such as proliferation, survival, adhesion, migration and differentiation. This review is focused on the key role of growth factors signaling and their downstream effectors in physiological and in pathological phenomena, the authors highlight the governance of Growth factors during the EMT in cancer invasion.

Chlamydia pneumoniae and Helicobacter pylori IgG seropositivities are not predictors of osteoporosis-associated bone loss: a prospective cohort study

The potential link between infection with Chlamydia pneumoniae or Helicobacter pylori and osteoporosis has not been investigated in population-based longitudinal studies. A total of 250 healthy postmenopausal women who participated in a prospective cohort study were evaluated for IgG antibodies directed against C. pneumoniae and H. p ylori, osteoprotegerin (OPG), the receptor activator of nuclear factor kappa B ligand (RANKL), CrossLaps, and osteocalcin. Bone mineral density (BMD) was measured at the femoral neck and lumbar spine at baseline and at follow-up 5.8 years later. There were no significant differences in age-adjusted bone turnover markers, OPG, RANKL, the RANKL/OPG ratio, and BMD between the C. p neumoniae and H. p ylori IgG seropositive and seronegative subjects (P > 0.05). Neither C. p neumoniae nor H. p ylori IgG seropositivity was associated with age-and body mass index-adjusted BMD at the femoral neck and lumbar spine or bone loss at the 5.8-year follow-up. In logistic regression analysis, neither C. p neumoniae nor H. p ylori IgG seropositivities predicted incident lumbar or spine osteoporosis 5.8 years later. In conclusion, neither C. p neumoniae nor H. p ylori IgG seropositivity was associated with bone turnover markers, the RANKL/OPG ratio, BMD, or bone loss in postmenopausal women. In addition, chronic infection with C. p neumoniae or H. p ylori did not predict incident osteoporosis among this group of women.

Human blood monocytes support persistence, but not replication of the intracellular pathogen C. pneumoniae

Background

Intracellular pathogens have devised various mechanisms to subvert the host immune response in order to survive and replicate in host cells. Here, we studied the infection of human blood monocytes with the intracellular pathogen C. pneumoniae and the effect on cytokine and chemokine profiles in comparison to stimulation with LPS.

Results

Monocytes purified from peripheral blood mononuclear cells by negative depletion were infected with C. pneumoniae. While immunofluorescence confirmed the presence of chlamydial lipopolysaccharide (LPS) in the cytoplasm of infected monocytes, real-time PCR did not provide evidence for replication of the intracellular pathogen. Complementary to PCR, C. pneumoniae infection was confirmed by an oligonucleotide DNA microarray for the detection of intracellular pathogens. Raman microspectroscopy revealed different molecular fingerprints for infected and non-infected monocytes, which were mainly due to changes in lipid and fatty acid content. Stimulation of monocytes with C. pneumoniae or with LPS induced similar profiles of tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6, but higher levels of IL-1β, IL-12p40 and IL-12p70 for C. pneumoniae which were statistically significant. C. pneumoniae also induced release of the chemokines MCP-1, MIP-1α and MIP-1β, and CXCL-8, which correlated with TNF-α secretion.

Conclusion

Infection of human blood monocytes with intracellular pathogens triggers altered cytokine and chemokine pattern as compared to stimulation with extracellular ligands such as LPS. Complementing conventional methods, an oligonucleotide DNA microarray for the detection of intracellular pathogens as well as Raman microspectroscopy provide useful tools to trace monocyte infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-014-0060-1) contains supplementary material, which is available to authorized users.

Inflammatory cytokines in Paget's disease of bone

This study was undertaken to evaluate the expression of inflammatory cytokines in patients with Paget's disease of bone (PDB). Serum levels of tumoral necrosis factor-α, interleukin 1β, interleukin-6 and interleukin-17 were measured in 51 patients with PDB and in 24 controls with primary osteoarthritis. Compared to controls, patients with Paget's disease of bone presented higher levels of interleukin 6 and reduced interleukin 17, but levels of tumoral necrosis factor α and interleukin 1 β did not differ significantly. We found no significant differences when patients were compared according to disease activity or current treatment. There were no correlations between cytokine levels and bone-specific alkaline phosphatase or extension of Paget's disease of bone on bone scintigraphs. In conclusion, patients with PDB present significant differences on levels of certain cytokines in comparison to primary osteoarthritis patients, but these alterations did not appear to have a clear correlation with parameters of disease activity or severity.

Antimicrobial effect of natural polyphenols with or without antibiotics on Chlamydia pneumoniae infection in vitro

Chlamydia pneumoniae is a human pathogen that causes multiple diseases worldwide. Despite appropriate therapy with antichlamydial antibiotics, chronic exacerbated diseases often occur and lead to serious sequelae. The use of the macrolide clarithromycin and the fluoroquinolone ofloxacin has improved the treatment of chlamydial infection, but therapy failure is still a major problem. In this work, we studied the pretreatment with natural polyphenols and subsequent treatment with clarithromycin or ofloxacin. The phenolic compounds resveratrol and quercetin improved the antichlamydial effect of clarithromycin and ofloxacin. In particular, resveratrol at 40 μM and quercetin at 20 μM exhibited significant growth inhibition on C. pneumoniae in presence of clarithromycin or ofloxacin compared to controls. In addition, we demonstrated that both resveratrol and quercetin decreased IL-17 and IL-23 production in a time-dependent manner in C. pneumoniae-infected cells. The results showed a particularly strong inhibition of the IL-23 levels released with combined treatment of resveratrol or quercetin and ofloxacin or clarithromycin, suggesting that the combined treatment may afford a synergistic effect in controlling Chlamydia infections.

Pulsed electromagnetic fields increased the anti-inflammatory effect of A₂A and A₃ adenosine receptors in human T/C-28a2 chondrocytes and hFOB 1.19 osteoblasts

Adenosine receptors (ARs) have an important role in the regulation of inflammation and their activation is involved in the inhibition of pro-inflammatory cytokine release. The effects of pulsed electromagnetic fields (PEMFs) on inflammation have been reported and we have demonstrated that PEMFs increased A_2A and A₃AR density and functionality in different cell lines. Chondrocytes and osteoblasts are two key cell types in the skeletal system that play important role in cartilage and bone metabolism representing an interesting target to study the effect of PEMFs. The primary aim of the present study was to evaluate if PEMF exposure potentiated the anti-inflammatory effect of A_2A and/or A₃ARs in T/C-28a2 chondrocytes and hFOB 1.19 osteoblasts. Immunofluorescence, mRNA analysis and saturation binding assays revealed that PEMF exposure up-regulated A_2A and A₃AR expression. A_2A and A₃ARs were able to modulate cAMP production and cell proliferation. The activation of A_2A and A₃ARs resulted in the decrease of some of the most relevant pro-inflammatory cytokine release such as interleukin (IL)-6 and IL-8, following the treatment with IL-1β as an inflammatory stimuli. In human chondrocyte and osteoblast cell lines, the inhibitory effect of A_2A and A₃AR stimulation on the release of prostaglandin E₂ (PGE₂), an important lipid inflammatory mediator, was observed. In addition, in T/C-28a2 cells, the activation of A_2A or A₃ARs elicited an inhibition of vascular endothelial growth factor (VEGF) secretion. In hFOB 1.19 osteoblasts, PEMF exposure determined an increase of osteoprotegerin (OPG) production. The effect of the A_2A or A₃AR agonists in the examined cells was enhanced in the presence of PEMFs and completely blocked by using well-known selective antagonists. These results demonstrated that PEMF exposure significantly increase the anti-inflammatory effect of A_2A or A₃ARs suggesting their potential therapeutic use in the therapy of inflammatory bone and joint disorders.

Chlamydia pneumoniae and osteoporosis-associated bone loss: a new risk factor?

We found an association between the presence of Chlamydia pneumoniae DNA both in osteoporotic bone tissue and peripheral blood mononuclear cells (PBMCs) and the increase in circulating resorptive cytokines.

INTRODUCTION

Our study was designed to determine whether C. pneumoniae infection may be involved in osteoporosis-associated bone loss.

METHODS

The study included 59 women undergoing hip joint replacement surgery for femoral neck fracture: 32 with osteoporosis and 27 with osteoarthritis. A total of 118 tissue specimens (59 bone tissues, 59 PBMCs) were examined for C. pneumoniae DNA by real-time polymerase chain reaction (PCR). Serum levels of soluble receptor activator of nuclear factor kappa B ligand (sRANKL), osteoprotegerin (OPG), interleukin (IL)-1β, tumor necrosis factor-α, and IL-6 were also measured.

RESULTS

C. pneumoniae DNA was detected in osteoporotic bone tissue whereas it was not found in non-osteoporotic bone tissue (p < 0.05). A significantly higher rate of C. pneumoniae DNA (p < 0.05) was found in PBMCs of osteoporotic patients than in those of osteoarthritis patients. Among osteoporotic patients, serum sRANKL, IL-1, and IL-6 concentrations as well as sRANKL/OPG ratio significantly differ between patients with bone tissue and PBMCs positive to C. pneumoniae and C. pneumoniae-negative patients.

CONCLUSION

The association between the presence of C. pneumoniae DNA, both in bone tissue and PBMCs, and the increase in sRANKL/OPG ratio as well as in IL-1β and IL-6 levels observed in osteoporotic patients suggests C. pneumoniae infection as a new risk factor for osteoporosis.

Neutrophil gelatinase-associated lipocalin and interleukin-10 regulate intramacrophage Chlamydia pneumoniae replication by modulating intracellular iron homeostasis

Neutrophil gelatinase-associated lipocalin (NGAL/Lipocalin-2/Lcn-2) is a 25 kDa protein which is involved in host defence against certain Gram negative bacteria upon binding of iron loaded bacterial siderophores thereby limiting the availability of this essential nutrient to bacteria resulting in inhibition of their growth and pathogenicity. As iron is important for the growth of the intracellular bacterium Chlamydia pneumoniae we questioned whether Lcn-2 affects the course of this infection. We employed primary peritoneal macrophages obtained from wildtype and Lcn-2 −/− mice and RAW 264.7 cells which were infected with C. pneumoniae. In addition, we studied C. pneumoniae multiplication in vivo in mice receiving diets with varying iron contents. We analyzed C. pneumoniae numbers by immunohistochemistry and RT-PCR and studied the expression of iron metabolism and cytokine genes by RT-PCR, Western blot or ELISA.

Infection with Chlamydiae ex vivo and in vivo revealed a significantly higher bacterial growth in peritoneal macrophages of Lcn-2 −/− than of wildtype mice. These differences were significantly more pronounced upon iron challenge, which stimulated bacterial growth. Accordingly, treatment with an anti-Lnc-2 antibody increased whereas addition of recombinant Lcn-2 reduced bacterial growth in infected macrophages. When investigating the underlying mechanisms we observed partly different expression of several iron metabolism genes between Lcn-2 +/+ and Lcn-2 −/− macrophages and most strikingly an increased formation of the anti-inflammatory cytokine IL-10 by Lcn-2 −/− macrophages. Upon treatment with an anti-IL10 antibody we experienced a significant increase of Chlamydial growth within Lcn-2 −/− macrophages along with a reduction of the major iron storage protein ferritin. Herein we provide first time evidence that Lcn-2 is involved in host defence against Chlamydia presumably by limiting the availability of iron to the pathogen. In the absence of Lcn-2, increased formation of IL-10 exerts protective effects by increasing the intracellular formation of ferritin, thereby reducing the access of iron for bacteria.

Chlamydia pneumoniae-specific IgE is prevalent in asthma and is associated with disease severity

Background

Several Chlamydia pneumoniae (Cp) biomarkers have been associated with asthma but Cp-specific IgE (Cp IgE) has not been investigated extensively. Our objective was to investigate Cp IgE in community adult asthma patients.

Methods

(1) Prevalence of Cp IgE (measured by immunoblotting) and Cp DNA (by polymerase chain reaction) in peripheral blood, and biomarker associations with asthma severity. (2) Case-control studies of Cp IgE association with asthma using healthy blood donor (study 1) and non-asthmatic clinic patient (study 2) controls.

Results

Of 66 asthma subjects (mean age 40.9 years, range 5–75, 59% male, 45% ever-smokers) 33 (50%) were Cp IgE positive and 16 (24%) were Cp DNA positive (P = 0.001 for association of Cp IgE and DNA). Cp IgE was detected in 21% of mild intermittent asthma v 79% of severe persistent asthma (test for trend over severity categories, P = 0.002). Cp IgE detection was significantly (P = 0.001) associated with asthma when compared to healthy blood donor controls but not when compared to clinic controls.

Conclusions

Half of this sample of community asthma patients had detectable IgE against C. pneumoniae. Cp IgE was strongly and positively associated with asthma severity and with asthma when healthy blood donor controls were used. These results support the inclusion of Cp IgE as a biomarker in future studies of infectious contributions to asthma pathogenesis.