Patients with Chlamydia-associated arthritis have ocular (trachoma), not genital, serovars of C. trachomatis in synovial tissue

British Association of Sexual Health and HIV national guideline on the management of sexually acquired reactive arthritis 2021

These guidelines update the 2008 UK guideline for the management of sexually acquired reactive arthritis. The guideline is aimed at those over the age of 16 years, presenting to healthcare professionals working in sexual health services. The recommendations are primarily aimed at services offering level 3 care in sexually transmitted infection management within the United Kingdom. However, the principles will apply to those presenting to level 1 and 2 services, and appropriate local referral pathways will need to be developed.

Microbes, helminths, and rheumatic diseases

There has been a progressive interest on modifications of the human defense system following insults occurring in the interface between our body and the external environment, as they may provoke or worsen disease states. Studies suggest that billions of germs, which compose the gut microbiota influence one's innate and adaptive immune responses at the intestinal level, but these microorganisms may also impact rheumatic diseases. The microbiota of the skin, respiratory, and urinary tracts may also be relevant in rheumatology. Evidence indicates that changes in the gut microbiome alter the pathogenesis of immune-mediated diseases such as rheumatoid arthritis and ankylosing spondylitis but also of other disorders like atherosclerosis and osteoarthritis. Therapeutic strategies to modify the microbiota, including probiotics and fecal microbiota transplantation, have been received with skepticism, which, in turn, has drawn attention back to previously developed interventions such as antibiotics. Helminths adapted to humans over the evolution process, but their role in disease modulation, particularly immune-mediated diseases, remains to be understood. The present review focuses on data concerning modifications of the immune system induced by interactions with microbes and pluricellular organisms, namely helminths, and their impact on rheumatic diseases. Practical aspects, including specific microbiota-targeted therapies, are also discussed.

Antibody, but not B-cell-dependent antigen presentation, plays an essential role in preventing Chlamydia systemic dissemination in mice

The obligate intracellular bacterium Chlamydia trachomatis causes the most prevalent bacterial sexually transmitted infection worldwide. CD4 T cells play a central role in the protective immunity against Chlamydia female reproductive tract (FRT) infection, while B cells are thought to be dispensable for resolution of primary Chlamydia infection in mouse models. We recently reported an unexpected requirement of B cells in local Chlamydia-specific CD4 T-cell priming and bacterial containment within the FRT. Here, we sought to tackle the precise effector function of B cells during Chlamydia primary infection. Using mixed bone marrow chimeras that lack B-cell-dependent Ag presentation (MHCII^B - / - ) or devoid of circulating antibodies (AID^-/- × μS^-/- ), we show that Chlamydia-specific CD4 T-cell expansion does not rely on Ag presentation by B cells. Importantly, we demonstrate that antibody, but not B-cell-dependent Ag presentation, is required for preventing systemic bacterial dissemination following Chlamydia FRT infection.

The bioinformatics analyses reveal novel antigen epitopes in major outer membrane protein of Chlamydia trachomatis

PURPOSE

The aim of this study was to predict the T-cell and B-cell epitopes in major outer membrane protein (MOMP) of Chlamydia trachomatis (CT) by using online software and also to analyse the secondary structure of MOMP through bioinformatics tools.

MATERIALS AND METHODS

The predictions of secondary structure of MOMP protein were carried out using SOPMA software, and the prediction of B-cell epitopes in MOMP protein was carried out using IEDB and LEPS software, while the T-cell epitopes were predicted by the software of IEBD and SYFPEITHI. The predictions from the software were combined with MOMP protein characteristics, including surface features, hydrophilicity, flexibility, accessibility and plasticity, to analyse the common epitope areas' response by T-cells and B-cells.

RESULTS

In the secondary structure of CT MOMP, the alpha-helices accounted for 41.62% of total amino acid, while the beta sheets and random coil accounted for 19.80% and 32.49%, respectively. Predictions combined with MOMP protein surface features, hydrophilicity, flexibility, accessibility and plasticity were further characterised, and three high-score B-cell epitope areas were found as located in 24-31, 307-311 and 318-327 amino acids of MOMP protein, respectively; in the meanwhile, three high-score T-cell epitope areas were found in 234-236, 323-329 and 338-343 amino acids of MOMP using major histocompatibility complex (MHC) class I HLA-A 0201 restrictive T-cell epitope analyser.

CONCLUSION

We established the methods by using the biological information network technologies for looking the T-cell antigen epitopes and B-cell antigen epitopes in MOMP of CT, and three novel T-cell epitopes as well as three novel B-cell epitopes were identified in the current study. It provides important information for further studying the antigenicity of CT MOMP protein and also provides useful information for developing highly efficient subunit vaccines for CT.

Painful Acute Corneal Ulceration and Anterior Stromal Keratitis in an Adolescent With Reactive Arthritis

Reactive arthritis is occasionally associated with conjunctivitis and uveitis, but rarely keratitis. The authors describe a patient with paracentral anterior stromal keratitis with overlying epithelial erosion and multiple satellite subepithelial infiltrates. The initial appearance and the severe pain were suggestive of an infectious process. Recovery was rapid following introduction of topical steroid, with features suggesting an immune process in the recovery phase. The authors suggest that a history of arthritis and/or recent enteritis should be sought in the work-up of an atypical keratitis with or without epithelial defect. [J Pediatr Ophthalmol Strabismus. 2016;53:e61-e63.].

Recent advances and future directions in understanding and treating Chlamydia-induced reactive arthritis

INTRODUCTION

Reactive arthritis (ReA) is an inflammatory disease that can follow gastrointestinal or genitourinary infections. The primary etiologic agent for post-venereal ReA is the bacterium Chlamydia trachomatis; its relative, C pneumoniae, has also been implicated in disease induction although to a lesser degree. Studies have indicated that the arthritis is elicited by chlamydiae infecting synovial tissue in an unusual biologic state designated persistence. We review clinical aspects, host-pathogen interactions, and treatments for the disease. Areas covered: We briefly discuss both the historic and,more extensively, the current medical literature describing ReA, and we provide a discussion of the biology of the chlamydiae as it relates to elicitation of the disease. A summary of clinical aspects of Chlamydia-induced ReA is included to give context for approaches to treatment of the arthritis. Expert commentary: Basic research into the biology and host-pathogen interactions characteristic of C trachomatis has provided a wealth of information that underlies our current understanding of the pathogenic processes occurring in the ReA synovium. Importantly, a promising approach to cure of the disease is at hand. However, both basic and clinical research into Chlamydia-induced ReA has lagged over the last 5 years, including required studies relating to cure of the disease.

Sexually acquired reactive arthritis

Sexually acquired reactive arthritis (SARA) may present acutely to general physicians. It is important to consider the condition and to identify key features in the history and examination so that appropriate investigations are taken and optimum treatment is given. Involvement of relevant specialists in the management is essential and where sexually transmitted infections are identified, partner notification is required.

Causality of Chlamydiae in Arthritis and Spondyloarthritis: a Plea for Increased Translational Research

Current molecular genetic understanding of the metabolically active persistent infection state of Chlamydia trachomatis and Chlamydia pneumoniae in the synovium in patients with arthritis and spondyloarthritis favors a causal relationship. Here, we examine how adequately the accepted criteria for that etiologic relationship are fulfilled, emphasizing the situation in which these microorganisms cannot be cultivated by standard or other means. We suggest that this unusual situation of causality by chlamydiae in rheumatic disease requires establishment of a consensus regarding microorganism-specific terminology as well as the development of new diagnostic and classification criteria. Recent studies demonstrate the value of molecular testing for diagnosis of reactive arthritis, undifferentiated spondyloarthritis, and undifferentiated arthritis caused by C. trachomatis and C. pneumoniae in clinical practice. Data regarding combination antibiotic therapy is consistent with the causative role of chlamydiae for these diseases. Observations of multiple intra-articular coinfections require more research to understand the implications and to respond to them.

Evaluation of the relationship between Chlamydia pecorum sequence types and disease using a species-specific multi-locus sequence typing scheme (MLST)

Chlamydia pecorum is globally associated with several ovine diseases including keratoconjunctivitis and polyarthritis. The exact relationship between the variety of C. pecorum strains reported and the diseases described in sheep remains unclear, challenging efforts to accurately diagnose and manage infected flocks. In the present study, we applied C. pecorum multi-locus sequence typing (MLST) to C. pecorum positive samples collected from sympatric flocks of Australian sheep presenting with conjunctivitis, conjunctivitis with polyarthritis, or polyarthritis only and with no clinical disease (NCD) in order to elucidate the exact relationships between the infecting strains and the range of diseases. Using Bayesian phylogenetic and cluster analyses on 62 C. pecorum positive ocular, vaginal and rectal swab samples from sheep presenting with a range of diseases and in a comparison to C. pecorum sequence types (STs) from other hosts, one ST (ST 23) was recognised as a globally distributed strain associated with ovine and bovine diseases such as polyarthritis and encephalomyelitis. A second ST (ST 69) presently only described in Australian animals, was detected in association with ovine as well as koala chlamydial infections. The majority of vaginal and rectal C. pecorum STs from animals with NCD and/or anatomical sites with no clinical signs of disease in diseased animals, clustered together in a separate group, by both analyses. Furthermore, 8/13 detected STs were novel. This study provides a platform for strain selection for further research into the pathogenic potential of C. pecorum in animals and highlights targets for potential strain-specific diagnostic test development.

The role of intracellular organisms in the pathogenesis of inflammatory arthritis

Inflammatory arthritis is a condition which is characterised by recurrent episodes of joint pain and swelling. It encompasses a spectrum of disorders ranging from rheumatoid arthritis to ankylosing spondylitis. In these conditions, for reasons that are poorly understood, the immune system raises an inflammatory response within the joint space. In some cases, autoantigens have been identified (e.g., anticitrullinated peptides in rheumatoid arthritis), but the absence of these, in the seronegative arthritides, for example, raises question as to the underlying pathogenesis. Interest has, therefore, turned to host-pathogen interactions and whether aberrant immune responses to these could explain the development of arthritis. This has been most widely studied in reactive arthritis (ReA), where an infectious episode precedes the development of the joint symptoms. In this review, we present the evidence for the role of host-bacterial interactions in the pathogenesis of joint inflammation with particular emphasis on ReA. We discuss a range of possible mechanisms including molecular mimicry, persistent low grade infections, and abnormal host responses to common bacterial causes of reactive arthritis as well as discussing some of the clinical challenges that we face in making the diagnosis and in treatment of persistent symptoms.

Observations on Chlamydia trachomatis and other microbes in reactive arthritis

There are problems in attributing causality in inflammatory arthritis. So far as C. trachomatis and sexually acquired reactive arthritis are concerned, there is much in favour of a causal relationship, although there are important caveats which need to be explored before it is possible to say unreservedly that C. trachomatis plays a causative role in reactive arthritis. For example, micro-organisms have never been cultured from synovial effusions in early disease, and only once has substantial benefit of antimicrobial treatment been reported. The claim that ocular strains of C. trachomatis are of over-riding importance in pathogenesis needs confirmation before it can be accepted. No conclusion can be made about the possibility of other small intracellular bacteria in joints having a role in causing disease. However, if it can be shown that eradication of the micro-organism, which may be difficult to prove, coincides with clinical recovery, it would go some way to recognising causality. In spite of the recognised difficulties, antibiotic studies have an important role in identifying aetiology. They need to focus on very early disease and on eradication of intra-articular bacteria. Treatment of established disease is likely to be less informative. Although a combination of antibiotics might have a future in treating established disease, diagnosing and treating non-gonococcal urethritis as soon as possible should be the aim in order to prevent the development of reactive arthritis.

Persistent and acute chlamydial infections induce different structural changes in the Golgi apparatus

Chlamydia trachomatis causes a wide range of diseases that have a significant impact on public health. Acute chlamydial infections can cause fragmentation of the Golgi compartment ensuring the lipid transportation from the host cell. However, the changes that occur in the host cell Golgi apparatus after persistent infections are unclear. Here, we examined Golgi-associated gene (golga5) transcription and expression along with the structure of the Golgi apparatus in cells persistently infected with Chlamydia trachomatis. The results showed that persistent infections caused little fragmentation of the Golgi. The results also revealed that Golgi fragmentation might be associated with the suppression of transcription of the gene golga5.

New insights into Chlamydia and arthritis. Promise of a cure?

Chlamydia trachomatis and Chlamydia pneumoniae together comprise the most frequent causative pathogens that elicit reactive arthritis (ReA). Advances in our understanding of the molecular biology/molecular genetics of these organisms have improved significantly the ability to detect chlamydiae in the joint for diagnostic purposes, as well as extending our current understanding of the pathogenic processes they elicit in the joint and elsewhere. An important aspect of the latter is that synovial chlamydiae infect the joint in an unusual but metabolically active state. While some standard treatments can provide a palliative effect on the ReA disease phenotype, many reports have indicated that standard antibiotic treatment does not provide a cure. Of critical importance, however, two recent reports of controlled clinical trials demonstrated that Chlamydia-ReA can be treated successfully using combination antibiotic therapy. These observations offer the opportunity of a cure for this disease, thereby increasing the practical importance of awareness and diagnosis of the spondyloarthritis caused by Chlamydia. In this viewpoint, we provide an overview of recent key findings in the epidemiology, pathophysiology, clinical manifestations, diagnosis and treatment of Chlamydia-induced arthritis. Our intention is for these insights to be translated rapidly into clinical practice to overcome misdiagnosis and underdiagnosis of the disease, and for them to stimulate the continued development of a cure.

Complete Genome Sequence of Chlamydia trachomatis Ocular Serovar C Strain TW-3

Chlamydia trachomatis is the etiological agent of trachoma, the leading infectious cause of blindness worldwide. We report here the first complete and annotated genome of a C. trachomatis trachoma-causing serovar C strain (strain TW-3). The chromosome and plasmid are 1,043,554 bp and 7,501 bp in length, respectively.

The gastrointestinal microbiome and musculoskeletal diseases: a beneficial role for probiotics and prebiotics

Natural medicines are an attractive option for patients diagnosed with common and debilitating musculoskeletal diseases such as Osteoarthritis (OA) or Rheumatoid Arthritis (RA). The high rate of self-medication with natural products is due to (1) lack of an available cure and (2) serious adverse events associated with chronic use of pharmaceutical medications in particular non-steroidal anti-inflammatory drugs (NSAIDs) and high dose paracetamol. Pharmaceuticals to treat pain may disrupt gastrointestinal (GIT) barrier integrity inducing GIT inflammation and a state of and hyper-permeability. Probiotics and prebiotics may comprise plausible therapeutic options that can restore GIT barrier functionality and down regulate pro-inflammatory mediators by modulating the activity of, for example, Clostridia species known to induce pro-inflammatory mediators. The effect may comprise the rescue of gut barrier physiological function. A postulated requirement has been the abrogation of free radical formation by numerous natural antioxidant molecules in order to improve musculoskeletal health outcomes, this notion in our view, is in error. The production of reactive oxygen species (ROS) in different anatomical environments including the GIT by the epithelial lining and the commensal microbe cohort is a regulated process, leading to the formation of hydrogen peroxide which is now well recognized as an essential second messenger required for normal cellular homeostasis and physiological function. The GIT commensal profile that tolerates the host does so by regulating pro-inflammatory and anti-inflammatory GIT mucosal actions through the activity of ROS signaling thereby controlling the activity of pathogenic bacterial species.

Chlamydia trachomatis is present and metabolically active during the remitting phase in synovial tissues from patients with chronic Chlamydia-induced reactive arthritis

BACKGROUND

Patients with chronic Chlamydia-induced reactive arthritis (ReA) often show a remitting-relapsing disease phenotype. Some information regarding bacterial and host responses to one another during active disease is available but no information for quiescence. This article presents the first molecular genetic insight into the behavior of bacterium and host during remitting ReA.

METHODS

Synovial biopsies were procured from the knees of 4 patients with quiescent ReA by the Parker-Pearson technique. Nucleic acids prepared from them were analyzed by real-time polymerase chain reaction (PCR) and reverse transcription-PCR, and results were compared with data averaged from the knee synovial tissue samples of 10 patients with active ReA.

RESULTS

Real-time PCR indicated that bacterial load in remitting samples was approximately 20% of that in active disease samples. Transcripts from the p60-encoding gene were equal to or higher than those seen in active disease. Messenger RNAs (mRNAs) from the paralog p60-encoding genes were equal to or lower than those of active disease. Host mRNAs encoding interleukin-10, tumor necrosis factor-α and interferon-γ were 4-fold lower than those in active disease samples, whereas monocyte chemotactic protein 1 and regulated upon activation, normal t-cell expressed, and secreted mRNA levels were equal to or higher.

CONCLUSIONS

Bacterial load in synovial tissue of patients with remitting disease is lower than that of active disease, but mRNAs encoding proinflammatory proteins are equal to or higher than those of active disease. Transcription in the host is attenuated for cytokines and chemokines. These initial results demonstrate that organism is present and metabolically active in synovium during the remitting phase of chronic Chlamydia-induced ReA and that the genetic events characterizing quiescence are complex.

Feast or famine: the host-pathogen battle over amino acids

Intracellular bacterial pathogens often rely on their hosts for essential nutrients. Host cells, in turn, attempt to limit nutrient availability, using starvation as a mechanism of innate immunity. Here we discuss both host mechanisms of amino acid starvation and the diverse adaptations of pathogens to their nutrient-deprived environments. These processes provide both key insights into immune subversion and new targets for drug development.

The molecular basis for disease phenotype in chronic Chlamydia-induced arthritis

Genital Chlamydia trachomatis infections can elicit an inflammatory arthritis in some individuals, and recent surprising studies have demonstrated that only ocular (trachoma) strains, not genital strains, of the organism are present in the synovial tissues of patients with the disease. This observation suggests an explanation for the small proportion of genitally-infected patients who develop Chlamydia-induced arthritis. Other recent studies have begun to identify the specific chlamydial gene products that elicit the synovial inflammatory response during both active and quiescent disease, although much more study will be required to complete the understanding of that complex process of host-pathogen interaction. Several newly developed experimental methods and approaches for study of the process will enable identification of new therapeutic targets, and possibly strategies for prevention of the disease altogether.

Chlamydia and chronic arthritis

Certain bacterial infections have been demonstrated to be causative of reactive arthritis. The most common bacterial trigger of reactive arthritis is Chlamydia trachomatis. Chlamydia pneumoniae is another known cause, albeit far less frequently. Although Chlamydia-induced reactive arthritis will often spontaneously remit, approximately 30% of patients will develop a chronic course. Modern medicine has provided rather remarkable advances in our understanding of the chlamydiae, as these organisms relate to chronic arthritis and the delicate balance between host and pathogen. C. trachomatis and C. pneumoniae both have a remarkable ability to disseminate from the initial site of infection and establish persistently viable organisms in distant organ sites, namely the synovial tissue. How these persistent chlamydiae contribute to disease maintenance remains to be fully established, but recent data demonstrating that long-term combination antimicrobial treatment can not only ameliorate the symptoms but eradicate the persistent infection suggest that these chronically infecting chlamydiae are indeed a driving force behind the chronic inflammation. We are beginning to learn that this all appears possible even after an asymptomatic initial chlamydial infection. Both C. trachomatis and C. pneumoniae are a clear cause of chronic arthritis in the setting of reactive arthritis; the possibility remains that these same organisms are culpable in other forms of chronic arthritis as well.

[Diagnosis and treatment of Chlamydia-induced reactive arthritis]

Urogenital chlamydia infections are the most prevalent of all sexually transmitted diseases although the number of chlamydia-induced reactive arthritis cases are generally below the estimated incidence of the disease. This may be related with the high rate of asymptomatic chlamydial infections and the lack of adequate diagnostic criteria. Polymerase chain reaction (PCR), a new system for detection of Chlamydia, is one of the most useful techniques for the diagnosis of this disease. Biologic therapy produces theoretical doubts regarding its indication and there is little information related with chlamydia induced reactive arthritis treatment efficacy. Although the usefulness of long antibiotic treatment is not clear, the use of combination antibiotics opens new therapeutic strategies for chlamydia induced reactive arthritis.

Chlamydia-induced ReA: immune imbalances and persistent pathogens

Reactive arthritis (ReA), an inflammatory arthritic condition that is commonly associated with Chlamydia infections, represents a significant health burden, yet is poorly understood. The enigma of this disease is reflected in its problematic name and in its ill-defined pathogenesis. The existence of persistent pathogens in the arthritic joint is acknowledged, but their relevance remains elusive. Progress is being made in understanding the underlying mechanisms of ReA, whereby an imbalance between type 1 and type 2 immune responses seems to be critical in determining susceptibility to disease. Such an imbalance occurs prior to the initiation of an adaptive immune response, suggesting that innate cellular and molecular mechanisms in ReA should be prioritized as fruitful areas for investigation.

Each type of cause that initiates rheumatoid arthritis or RA flares differentially affects the response to therapy

The autoimmune disease rheumatoid arthritis (RA) presents difficulty in diagnosis, commonly observed flare ups, polycyclical nature of RA progression, and variable response to therapies. Congruent with multiple causes, literature has documented various infectious agents, environmental factors, physical trauma, silica and food sensitivities as potential causes of RA or RA flares in different populations. We propose that these>36 events can initiate RA or RA flares which complicates treatment decisions. Each pharmaceutical medicine benefits 15-82% of RA patients. Predictive factors are needed. Because the initiating cause of RA or RA flare affects the type of joint damage, initial inflammatory response, adaptive immune response, and potential molecular mimicry, we propose the "RA cause affects response to therapy" (RACART) theory. The potential cause combined with confounding factors such as genetic risk factors, nutritional status, epigenetic status, inflammatory levels, and detoxification ability may help predict responses to various therapies.

Combination antibiotics for the treatment of Chlamydia-induced reactive arthritis: is a cure in sight?

The inflammatory arthritis that develops in some patients subsequent to urogenital infection by the obligate intracellular bacterial pathogen Chlamydia trachomatis, and that induced subsequent to pulmonary infection with C. pneumoniae, both have proved difficult to treat in either their acute or chronic forms. Over the last two decades, molecular genetic and other studies of these pathogens have provided a good deal of information regarding their metabolic and genetic structures, as well as the detailed means by which they interact with their host cells. In turn, these insights have provided for the first time a window into the bases for treatment failures for the inflammatory arthritis. In this article we discuss the biological bases for those treatment failures, provide suggestions as to research directions that should allow improvement in treatment modalities, and speculate on how treatment regimens that currently show promise might be significantly improved over the near future using nanotechological means.