Reactive arthritis: defined etiologies, emerging pathophysiology, and unresolved treatment

Enteric Infection-Associated Reactive Arthritis: A Systematic Review and Meta-Analysis

Background. The objective of this systematic review and meta-analysis was to estimate the proportions of individuals infected with Campylobacter, Escherichia, Salmonella, Shigella, or Yersinia who develop reactive arthritis. Methods. A systematic review was conducted, encompassing English-language articles published before January 2024, sourced from the Embase, PubMed, Scopus, and Web of Science databases. This review included observational studies that reported the occurrence of reactive arthritis (ReA) among patients with Campylobacter, Escherichia, Salmonella, Shigella, or Yersinia infections. Data extraction was carried out independently by two reviewers. Subsequently, a random-effects meta-analysis was performed, with heterogeneity assessed using the I2 value. Additionally, meta-regression was employed to investigate the potential influence of study-level variables on the observed heterogeneity. Results. A total of 87 studies were identified; 23 reported on ReA development after Campylobacter infection, 7 reported on ReA after Escherichia infection, 30 reported ReA onset after salmonellosis, 14 reported ReA after shigellosis, and 13 reported ReA after Yersinia infection. The proportion of Campylobacter patients who developed ReA was 0.03 (95% CI [0.01, 0.06], I2 = 97.62%); the proportion of Escherichia patients who developed ReA was 0.01 (95% CI [0.00, 0.06], I2 = 92.78%); the proportion of Salmonella patients was 0.04 (95% CI [0.02, 0.08], I2 = 97.67%); the proportion of Shigella patients was 0.01 (95% CI [0.01, 0.03], I2 = 90.64%); and the proportion of Yersinia patients who developed ReA was 0.05 (95% CI [0.02, 0.13], I2 = 96%). Conclusion. A significant proportion of Salmonella, Shigella, and Yersinia cases resulted in ReA. Nonetheless, it is important to interpret the findings cautiously due to the substantial heterogeneity observed between studies.

Immunologic derangement caused by intestinal dysbiosis and stress is the intrinsic basis of reactive arthritis

Reactive arthritis (ReA) is defined as arthritis resulting from infections in other body parts, such as the gastrointestinal and urogenital tracts. The primary clinical manifestations involve acute-onset and self-limiting asymmetric large joint inflammation in the lower limbs. Although bacterial or chlamydia infections have long been recognized as playing a pivotal role in its pathogenesis, recent studies suggest that antibiotic treatment may perpetuate rather than eradicate chlamydia within the host, indicating an involvement of other mechanisms in Reactive arthritis. Reactive arthritis is currently believed to be associated with infection, genetic marker (HLA-B27), and immunologic derangement. As an autoimmune disease, increasing attention has been given to understanding the role of the immune system in Reactive arthritis. This review focuses on elucidating how the immune system mediates reactive arthritis and explores the roles of intestinal dysbiosis-induced immune disorders and stress-related factors in autoimmune diseases, providing novel insights into understanding reactive arthritis.

Reactive Arthritis in Children: Case Report, Narrative Review and Proposed Therapy

Reactive arthritis is an acute inflammatory aseptic arthritis that is preceded by an infectious process in genetically predisposed individuals. It has been associated with gastrointestinal or genitourinary infection. Reactive arthritis is rare in children. In this review, we present two index cases that need biologic treatment followed by a thorough review of reactive arthritis in children and adolescents with proposed treatment algorithm.

GMP manufacture of Shigella flexneri 2a Artificial Invaplex (InvaplexAR) and evaluation in a Phase 1 Open-label, dose escalating study administered intranasally to healthy, adult volunteers

Shigella species cause severe disease among travelers to, and children living in, endemic countries. Although significant efforts have been made to improve sanitation, increased antibiotic resistance and other factors suggest an effective vaccine is a critical need. Artificial Invaplex (InvaplexAR) is a subunit vaccine approach complexing Shigella LPS with invasion plasmid antigens. In pre-clinical studies, the InvaplexAR vaccine demonstrated increased immunogenicity as compared to the first generation product and was subsequently manufactured under cGMP for clinical testing in a first-in-human Phase 1 study. The primary objective of this study was the safety of S. flexneri 2a InvaplexAR given by intranasal (IN) immunization (without adjuvant) in a single-center, open-label, dose-escalating Phase 1 trial and secondarily to assess immunogenicity to identify a dose of InvaplexAR for subsequent clinical evaluations. Subjects received three IN immunizations of InvaplexAR, two weeks apart, in increasing dose cohorts (10 µg, 50 µg, 250 µg, and 500 μg). Adverse events were monitored using symptom surveillance, memory aids, and targeted physical exams. Samples were collected throughout the study to investigate vaccine-induced systemic and mucosal immune responses. There were no adverse events that met vaccination-stopping criteria. The majority (96%) of vaccine-related adverse events were mild in severity (most commonly nasal congestion, rhinorrhea, and post-nasal drip). Vaccination with InvaplexAR induced anti-LPS serum IgG responses and anti-Invaplex IgA and IgG antibody secreting cell (ASC) responses at vaccine doses ≥250 µg. Additionally, mucosal immune responses and functional antibody responses were seen from the serum bactericidal assay measurements. Notably, the responder rates and the kinetics of ASCs and antibody lymphocyte secretion (ALS) were similar, suggesting that either assay may be employed to identify IgG and IgA secreting cells. Further studies with InvaplexAR will evaluate alternative immunization routes, vaccination schedules and formulations to further optimize immunogenicity. (Clinical Trial Registry Number NCT02445963).

One Joint Aspirate: Three Diagnoses

Gout is a frequently diagnosed condition. However, it is rarely diagnosed with concomitant pseudogout or reactive arthritis (ReA) from ​​​​​Chlamydophila pneumoniae (C. pneumoniae). This case report describes an interesting case of a 67-year-old man who presented with a two-week history of malaise, chills, and shortness of breath. He also reported a one-day history of polyarthritis, which limited his ambulation. The results of polarized microscopy revealed uric acid and calcium pyrophosphate crystals. The respiratory panel was positive for C. pneumoniae and rhinovirus. Therefore, he was diagnosed with gout, pseudogout, and ReA. Appropriate management led to a full clinical recovery. This is the first report documenting the simultaneous occurrence of ReA, gout, and pseudogout in a single patient. The association between these rheumatic diseases and a summary of similar cases in the literature are also discussed.

Treatment of reactive arthritis with biological agents: a review

The pathogenesis of reactive arthritis (ReA) has not been fully elucidated. In recent years, many researchers have confirmed that multiple cytokines are involved in the occurrence and development of ReA. Although ReA is self-limiting, it is still incurable for some patients who have no or a weak response to traditional drugs, such as non-steroidal anti-inflammatory agents, glucocorticoids and immunosuppressive agents. This is called refractory reactive arthritis. Currently, there is insufficient evidences for the treatment of refractory ReA with biological agents, though biological agents against cytokines have been developed over the past few years. This review summarizes the current development of clinical treatments of ReA with biological agents, which provides future investigations on refractory ReA with more evidence and references.

Reactive Arthritis: Update

Purpose of Review

The aim of this paper is to provide an overview about reactive arthritis, with an update regarding pathophysiology and therapeutic approach of the disease, outlining the clinical features and diagnostic approach, based on recent literature review.

Recent Findings

Reactive arthritis is considered to be part of the spectrum of the spondyloarthritis. Its epidemiology is changing worldwide due to several reasons, among them are as follows: different diagnosis approach and clinical presentations, different grades of infection, microbiome changes, etc. The understanding of pathophysiological models is challenging, but recent studies contribute to elucidate the major factors involved in the development of the disease. The management of ReA depends on the triggering agent and the phase of disease, whether it is acute or chronic.

Summary

The association between the microbiome changes and spondyloarthropathies (ReA) is becoming increasingly evident. The results regarding the biologic treatment on refectory ReA are promising.

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.

Reactive Arthritis Provoked by Campylobacter jejuni Enterocolitis Mimicking Prosthetic Joint Infection: A Case Report

CASE

A 59-year-old man with previously well-functioning partial knee replacement was admitted with a warm, swollen, and painful knee. The clinical presentation was consistent with prosthetic joint infection (PJI), but the synovial fluid analysis was negative for microbial growth. Further discussion revealed earlier Campylobacter jejuni enterocolitis that subsequently provoked reactive arthritis (ReA) mimicking PJI. The patient was treated with oral naproxen and intra-articular injection of triamcinolone and recovered completely without antibiotics or surgery. After 29 months, the knee is functioning normally.

CONCLUSION

ReA is rare but should be included in the differential diagnosis of PJI.

Disruption of Intestinal Homeostasis and Intestinal Microbiota During Experimental Autoimmune Uveitis

Purpose

We determine the changes in intestinal microbiota and/or disruptions in intestinal homeostasis during uveitis.

Methods

Experimental autoimmune uveitis (EAU) was induced in B10.RIII mice with coadministration of interphotoreceptor retinoid-binding protein peptide (IRBP) and killed mycobacterial antigen (MTB) as an adjuvant. Using 16S rRNA gene sequencing, we looked at intestinal microbial differences during the course of uveitis, as well as intestinal morphologic changes, changes in intestinal permeability by FITC-dextran leakage, antimicrobial peptide expression in the gastrointstinal tract, and T lymphocyte prevalence before and at peak intraocular inflammation.

Results

We demonstrate that increased intestinal permeability and antimicrobial peptide expression in the intestinal tract coincide in timing with increased effector T cells in the mesenteric lymph nodes, during the early stages of uveitis, before peak inflammation. Morphologic changes in the intestine were most prominent during this phase, but also occurred with adjuvant MTB alone, whereas increased intestinal permeability was found only in IRBP-immunized mice that develop uveitis. We also demonstrate that the intestinal microbiota were altered during the course of uveitis, and that some of these changes are specific to uveitic animals, whereas others are influenced by adjuvant MTB alone. Intestinal permeability peaked at 2 weeks, coincident with an increase in intestinal bacterial strain differences, peak lipocalin production, and peak uveitis.

Conclusions

An intestinal dysbiosis accompanies a disruption in intestinal homeostasis in autoimmune uveitis, although adjuvant MTB alone promotes intestinal disruption as well. This may indicate a novel axis for future therapeutic targeting experimentally or clinically.

A controlled survey of less typical long-term consequences after an extensive waterborne epidemic

Background

Extensive backflow of treated wastewater caused household water contamination in a Finnish town in 2007. The drinking water of 9 500 residents became heavily polluted with faecal microbes, resulting in a large gastroenteritis epidemic. Cases of reactive arthritis, milder joint symptoms and prolonged gastrointestinal symptoms were observed after the outbreak. A follow-up survey was performed to study less familiar long-term health consequences within a year from the outbreak.

Methods

The contaminated group comprised a sample of residents of the area with polluted water supply (N = 323) and the control group a sample of residents in a nearby municipality (N = 186). The presence of 20 general symptoms or complaints was inquired by a mail survey. Quarterly prevalence of each symptom or complaint was measured. Twelve of these proceeded to further analysis.

Results

The response rate was 53% (323/615) in the contaminated group and 54% (186/343) in the control group. Rash, eye irritation, heartburn and weight loss were more prevalent in the contaminated group during the first year quarter. In the last year quarter, only eye irritation was significantly more common in the contaminated group.

Conclusion

The excess prevalence of four complaints at the first year quarter can be explained by acute gastroenteritis or intensive water chlorination. The excess prevalence of eye irritation at the fourth year quarter cannot be explained by chlorination anymore but might be a sign of co-existing reactive joint disease. In general, long-term consequences of the outbreak can be considered minor in terms of the surveyed symptoms or complaints.

A bicentre retrospective study of features and outcomes of patients with reactive arthritis

OBJECTIVE

Reactive arthritis (ReA) is a sterile arthritis following an extra-articular infection, usually of the gastrointestinal or genitourinary tract. The aim of this study was to assess the incidence and the clinical and therapeutic characteristics of ReA and to compare them with those of a historical cohort. We hypothesised that improved hygiene together with prevention and treatment of sexually transmitted infections may have decreased the incidence of ReA.

METHODS

All patients with ReA diagnosed in the University Hospital Centres of Lyon Sud and Besançon from January 2002 to December 2012 were included in the study retrospectively and were compared with ReA patients diagnosed from January 1986 to December 1996 in the same two hospitals. Medical records were reviewed, clinical features, treatments and outcomes were analysed and diagnoses were compared with international diagnostic criteria.

RESULTS

Twenty-seven patients were included between 2002 and 2012 compared with 31 between 1986 and 1996. The overall incidence of ReA in patients hospitalised in the rheumatology department did not change, although the current evolution is more severe with development of chronic disease in the form of more frequent spondyloarthritis. While the incidence of Chlamydiae trachomatis has decreased, new microbes are now found to be involved.

CONCLUSIONS

ReA still exists and its incidence has been stable over the last 30 years. However, ReA currently more often progress to spondyloarthritis. Our study also highlights the need for diagnostic criteria that accurately detect ReA.

Safety and Immunogenicity of a Candidate Bioconjugate Vaccine against Shigella flexneri 2a Administered to Healthy Adults: a Single-Blind, Randomized Phase I Study

Several candidate vaccines against Shigella spp. are in development, but the lack of a clear correlate of protection from challenge with the induction of adequate immune responses among the youngest age groups in the developing world has hampered Shigella vaccine development over the past several decades. Bioconjugation technology, exploited here for an Shigella flexneri 2a candidate vaccine, offers a novel and potentially cost-effective way to develop and produce vaccines against a major pathogen of global health importance. Flexyn2a, a novel S. flexneri 2a bioconjugate vaccine made of the polysaccharide component of the S. flexneri 2a O-antigen, conjugated to the exotoxin protein A of Pseudomonas aeruginosa (EPA), was evaluated for safety and immunogenicity among healthy adults in a single-blind, phase I study with a staggered randomization approach. Thirty subjects (12 receiving 10 μg Flexyn2a, 12 receiving Flexyn2a with aluminum adjuvant, and 6 receiving placebo) were administered two injections 4 weeks apart and were followed for 168 days. Flexyn2a was well-tolerated, independently of the adjuvant and number of injections. The Flexyn2a vaccine elicited statistically significant S. flexneri 2a lipopolysaccharide (LPS)-specific humoral responses at all time points postimmunization in all groups that received the vaccine. Elicited serum antibodies were functional, as evidenced by bactericidal activity against S. flexneri 2a. The bioconjugate candidate vaccine Flexyn2a has a satisfactory safety profile and elicited a robust humoral response to S. flexneri 2a LPS with or without inclusion of an adjuvant. Moreover, the bioconjugate also induced functional antibodies, showing the technology's features in producing a promising candidate vaccine. (This study has been registered at ClinicalTrials.gov under registration no. NCT02388009.).

Reactive arthritis following a Microsporidia infection

Reactive arthritis may be caused by both sexually transmissible and enteric organisms, though Microsporidia is not currently recognised as a causative agent. This case report describes the development of reactive arthritis following Microsporidia infection in an immunocompetent man.

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.

Diagnosis and treatment of low back pain in the pediatric population

Back pain in the pediatric population is a common complaint presenting to sports medicine clinics. There is a wide differential that should be considered, including mechanical, infectious, neoplastic, inflammatory, and amplified musculoskeletal pain. The history, pain quality, and examination are key components to help distinguish the etiologies of the pain and direct further evaluation. Laboratory investigations, including blood counts and inflammatory markers, can provide insight into the diagnosis. The HLA-B27 antigen can be helpful if a spondyloarthropathy is suspected. Imaging as clinically indicated typically begins with radiographs, and the use of MRI, CT, or bone scan can provide additional information. Proper diagnosis of back pain is important because prognosis and treatments are significantly different. We review the pertinent evaluation, differential diagnoses, and treatment of low back pain in the pediatric population.

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.

Of bugs and joints: the relationship between infection and joints

The association between microbes and joints has existed since antiquity, and remains complex. Diagnosis is often times difficult to determine despite highly suspicious clinical characteristics for the presence of an underlying infection. Over the several past decades, considerable advances have occurred in diagnostic methodologies and therapy. However, the morbidity and mortality of septic arthritis remains high. Great advances have occurred in the diagnosis, pathogenesis, and therapeutic management of reactive arthritis, and there is evidence that when the responsible microorganism is Chlamydia trachomathis, complete remission and cure is possible. Emergent infections, especially viral, has been recognized, i.e. HIV, hepatitis C, and most recently Chikengunya virus, and in the case of HIV associated articular manifestations, the introduction of HAART has resulted in a decrease in the incidence and development of newer complications such as the immune reconstitution syndrome. The infectious etiology of rheumatoid arthritis is being strongly considered once again, and the exciting association with periodontal disease is at the forefront of intense research. The gut microbiota is also being investigated and new and most interesting data is being gathered of the potential role of commensal gut organisms and the pathogenesis of rheumatoid arthritis.

Treating reactive arthritis: insights for the clinician

THERE ARE TWO MAIN FORMS OF REACTIVE ARTHRITIS (REA): postvenereal and postdysentery. Chlamydia trachomatis (Ct) is the major causative organism of the postvenereal type; Salmonella, Shigella, Campylobacter, and Yersinia are the major triggers for the postenteric type. All of these causative organisms have been shown to traffic to the synovium in affected individuals. However, one important difference is that the chlamydial organisms have been shown to be viable, whereas, in general, the postenteric organisms are not. Although estimates vary widely, it is felt that 30-50% of all cases of ReA become chronic and the remainder resolve spontaneously within weeks to months. These important differences need to be considered when reviewing the available therapeutic outcomes data. There is a relative paucity of prospective clinical trial data assessing various treatment strategies. A large breadth of clinical experience demonstrates that nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids are efficacious, but there have only been two rather small trials assessing NSAIDs and none with corticosteroids. Disease modifying drugs are sometimes utilized in more severe or chronic cases, but only sulfasalazine (SSZ) has been studied. Anti-tumor necrosis factor (TNF) therapy has proved remarkably efficacious with other types of spondyloarthritides, but there is very little data to support their use in ReA; theoretical concerns also exist with this drug class in ReA, specifically. Finally, antibiotics have been studied in several trials. A thorough analysis of these trials reveals equivocal results with a possible particular benefit in postchlamydial ReA. These data are reviewed with an emphasis on postchlamydial and postenteric ReA.

Bacterial agents in spondyloarthritis: a destiny from diversity?

The spondyloarthritides (SpAs) are a group of diseases that share clinical, radiographic and laboratory features; these arthritides also display a tendency for family aggregation. Given the intimate relationship that these types of arthritis share, it suggests that the SpAs might share a common aetiology. Of all the SpAs, the role of bacteria is most clearly defined in reactive arthritis. Tremendous recent insights into the pathophysiology of reactive arthritis have been made, demonstrating that the causative bacteria play a much more complex role than previously thought. The bacteria that are proven to cause reactive arthritis, one of the five types of SpA, will be reviewed and their role in the pathophysiology of reactive arthritis will be examined. The speculative data suggesting links between various other bacteria and the other types of SpAs will be critically analysed. Although these data are not definitive, when viewed using the paradigm that the SpAs might actually represent a common end point from several diverse starting points, they are provocative, suggesting that bacteria might, indeed, be aetiological for the entire group of SpAs.

Macular infarction associated with reactive arthritis

A 53-year-old woman visited the Department of Rheumatology with a chief complaint of a 3-day history of fever and chills and also presented with pain occuring in both knees at the time of outpatient visit. Based on rheumatologic and hematological lab studies, ultrasonography, and a needle aspiration biopsy of the articular cavity, the patient was diagnosed with reactive arthritis. On hospitalization day 3, consultation with the Department of Ophthalmology was requested regarding decreased visual acuity lasting for 3 days. Upon ophthalmologic examination, the corrected visual acuity was 0.1 in the right eye and 0.05 in the left eye. Upon slit lamp microscopy, there were no abnormal findings in the anterior segment. Upon fundus examination, however, there were yellow-white lesions in the macular area of both eyes. Fluorescein angiographywas performed to assess the macular lesions, and the findings were suggestive of macular infarction in both eyes. Due to a lack of other underlying disease, a past surgical history, and a past history of drug administration, the patient was diagnosed with macular infarction in both eyes associated with reactive arthritis. To date, there have been no other such cases reported. In a patient with reactive arthritis, we experienced a case of macular infarction in both eyes, which occurred without association with a past history of specific drug use or underlying disease. Herein, we report our case, with a review of the literature.

Lack of TNFR p55 results in heightened expression of IFN-γ and IL-17 during the development of reactive arthritis

Reactive arthritis (ReA) is a type of arthritis originating from certain gastrointestinal or genitourinary infections. In previous studies, we reported the development of progressive Yersinia enterocolitica-induced ReA in mice lacking TNFR p55; however, the mechanisms underlying this effect are still uncertain. In this study, we investigated the impact of TNFR p55 deficiency in modulating Ag-specific Th1 and Th17 responses during this arthritogenic process. We found more severe ReA in TNFRp55(-/-) mice compared with their wild-type (WT) counterparts. This effect was accompanied by increased levels of Yersinia LPS in the joints of knockout mice. Analysis of the local cytokine profile revealed greater amounts of IFN-γ and IL-17 in arthritic joints of TNFRp55(-/-) mice compared with WT mice at day 21 postinfection. Moreover, altered IL-17 and IFN-γ production was observed in mesenteric and inguinal lymph nodes of Yersinia-infected TNFRp55(-/-) mice, as well as in spleen cells obtained from infected mice and restimulated ex vivo with bacterial Ags. Increased levels of cytokine secretion were associated with a greater frequency of CD4(+)IL-17(+), CD4(+)IFN-γ(+), and IL-17(+)IFN-γ(+) cells in TNFRp55(-/-) mice compared with WT mice. Remarkably, Ab-mediated blockade of IL-17 and/or IFN-γ resulted in reduced joint histological scores in TNFRp55(-/-) mice. A mechanistic analysis revealed the involvement of p40, a common subunit of heterodimeric IL-12 and IL-23, in the generation of augmented IFN-γ and IL-17 production under TNFR p55 deficiency. Taken together, these data indicate that, in the absence of TNFR p55 signaling, Th1 and Th17 effector cells may act in concert to sustain the inflammatory response in bacterial-induced arthritogenic processes.

Concurrent reactive arthritis, Graves' disease, and warm autoimmune hemolytic anemia: a case report

Warm antibody autoimmune hemolytic anemia is due to the presence of warm agglutinins that react with protein antigens on the surface of red blood cells causing premature destruction of circulating red blood cells. We report the first case of concurrent reactive arthritis, Graves’ disease, and autoimmune hemolytic anemia. A 40-year-old man with reactive arthritis, Graves’ disease, type 2 diabetes mellitus, mitral valve prolapse, and Gilbert’s disease presented with a one month history of jaundice, fatigue, and black stools. After diagnosis of warm autoimmune hemolytic anemia, the patient was started on prednisone 1 mg/kg with rapid improvement in his anemia and jaundice. Our subject’s mother and possibly his maternal grandmother also had autoimmune hemolytic anemia, which raises the possibility of hereditary autoimmune hemolytic anemia, a rarely reported condition.

Molecular biology of infectious agents in chronic arthritis

Severe and chronic inflammatory arthritis sometimes follows urogenital infection with Chlamydia trachomatis or gastrointestinal infection with enteric bacterial pathogens. A similar clinical entity can be elicited by the respiratory pathogen Chlamydophila (Chlamydia) pneumoniae. Arthritogenesis does not universally require viable enteric bacteria in the joint. In arthritis induced by either of the chlamydial species, organisms are viable and metabolically active in the synovium. They exist in a "persistent" state of infection. Conventional antibiotic treatment of patients with Chlamydia-induced arthritis is largely ineffective. The authors outline the current understanding of the molecular genetic and biologic aspects underlying bacterially-induced joint pathogenesis, available information regarding host-pathogen interaction at that site, and several directions for future study to inform development of more effective therapies.

Reactive arthritis: clinical aspects and medical management

Reactive arthritis (ReA) is an inflammatory arthritis that arises after certain gastrointestinal or genitourinary infections, representing a classic interplay between host and environment. It belongs to the group of arthritidies known as the spondyloarthropathies. The classic syndrome is a triad of symptoms, including the urethra, conjunctiva, and synovium; however, the majority of patients do not present with this triad. Diagnostic criteria for ReA exist, but data suggest new criteria are needed. Epidemiologic and prospective studies have been difficult to perform because of over-reliance on the complete classic triad of symptoms and the different terms and eponyms used. Studies assessing various treatment strategies are ongoing.

Chlamydiae as etiologic agents in chronic undifferentiated spondylarthritis

OBJECTIVE

The majority of patients with Chlamydia-induced reactive arthritis do not present with the classic triad of arthritis, conjunctivitis/iritis, and urethritis. Moreover, acute chlamydial infections are often asymptomatic. The aim of the present study was to assess the prevalence of synovial Chlamydia trachomatis and Chlamydia pneumoniae infections in patients with chronic undifferentiated spondylarthritis (uSpA).

METHODS

Study patients met the European Spondylarthropathy Study Group criteria for SpA, without evidence of ankylosing spondylitis, psoriasis, inflammatory bowel disease, or preceding dysentery. Symptoms were present for >or=6 months. Each patient underwent a synovial biopsy; tissue and concomitantly obtained peripheral blood mononuclear cells (PBMCs) were analyzed by polymerase chain reaction (PCR) for C trachomatis and C pneumoniae DNA. Other data collected on the day of the biopsy included standard demographic information and medical history, including any known history of C trachomatis or C pneumoniae. Physical examination (including joint count, evaluation for dactylitis and/or enthesitis, and skin examination) and HLA-B27 typing were performed. Synovial tissue (ST) samples from 167 patients with osteoarthritis (OA) were used as controls.

RESULTS

Twenty-six patients met the entry criteria and underwent synovial biopsy (25 knee, 1 wrist). Sixteen of them (62%) were positive for C trachomatis and/or C pneumoniae DNA (10 for C trachomatis, 4 for C pneumoniae, and 2 for both). PCR analysis of ST revealed the presence of Chlamydia significantly more frequently in patients with uSpA than in OA controls (P<0.0001). No specific clinical characteristics differentiated Chlamydia-positive from Chlamydia-negative patients. PBMCs from 4 of the 26 uSpA patients (15%) were positive for Chlamydia, and Chlamydia was found in ST from 2 of these 4 patients. No significant correlation between PCR positivity and HLA-B27 positivity was found.

CONCLUSION

The frequency of Chlamydia-positive ST samples, as determined by PCR, was found to be significantly higher in patients with uSpA than in patients with OA. Our results suggest that in many patients with uSpA, chlamydial infection, which is often occult, may be the cause.