Reactive arthritis: the role of bacterial antigens in inflammatory arthritis

Campylobacter reactive arthritis: a systematic review

OBJECTIVE

To review the literature on the epidemiology of Campylobacter-associated reactive arthritis (ReA).

METHODS

A Medline (PubMed) search identified studies from 1966 to 2006 that investigated the epidemiology of Campylobacter-associated ReA. Search terms included: "reactive arthritis," "spondyloarthropathy," "Reiter's syndrome," "gastroenteritis," "diarrhea," "epidemiology," "incidence," "prevalence," and "Campylobacter."

RESULTS

The literature available to date suggests that the incidence of Campylobacter ReA may occur in 1 to 5% of those infected. The annual incidence of ReA after Campylobacter or Shigella may be 4.3 and 1.3, respectively, per 100,000. The duration of acute ReA varies considerably among reports, and the incidence and impact of chronic ReA from Campylobacter infection is virtually unknown.

CONCLUSIONS

Campylobacter-associated ReA incidence and prevalence varies widely among reviews due to case ascertainment differences, exposure differences, lack of diagnostic criteria for ReA, and perhaps genetics and ages of exposed individuals. At the population level it may not be associated with HLA-B27, and inflammatory back involvement is uncommon. Follow-up for long-term sequelae is largely unknown. Five percent of Campylobacter ReA may be chronic or relapsing (with respect to musculoskeletal symptoms).

Randomised, blinded, placebo controlled trial of doxycycline for chronic seronegative arthritis

OBJECTIVE

To determine whether long term doxycycline improves symptoms in patients with chronic seronegative or reactive arthritis.

METHODS

A randomised, triple blind, controlled clinical trial of three months' treatment with doxycycline or placebo of patients with chronic reactive or seronegative arthritis was conducted. The primary study end points were three month pain and functional status measured by a self administered Arthritis Impact Measurement Scales version 2 (AIMS2) quality of life questionnaire. Secondary end points were pain and functional status at 6-12 months, three month rheumatologist assessed joint count, pain, and arthritis activity, and treatment efficacy in those with previous exposure to chlamydia.

RESULTS

Of 60 patients randomly allocated to receive doxycycline or placebo, results from 37 were evaluable at three months. Groups were well balanced for major prognostic variables. Doxycycline had no detectable effect at three months on pain change scores (mean difference 1.5, 95% CI -1.2 to 4.2, p=0.25) or composite functional change scores (mean difference 0.8, 95% CI -5.6 to 7.1, p=0.81). Furthermore, there were no differences in secondary study end points, and no apparent treatment effect in patients with previous chlamydia infection.

CONCLUSION

Three months' treatment with doxycycline did not improve pain or functional status in patients with chronic reactive or seronegative arthritis.

The anti-idiotypic antibody to chlamydial glycolipid exoantigen (GLXA) protects mice against genital infection with a human biovar of Chlamydia trachomatis

Despite more than three decades of anti-chlamydial vaccine research and improved vaccine strategies with new technologies, no vaccine candidate has protected against heterologous challenge, nor at more than one site of infection. The majority of experimental anti-chlamydial vaccines to date have targeted the chlamydial major outer membrane protein (MOMP). Many MOMP-directed vaccine candidates have been highly immunogenic, but have failed to protect against infectious challenge. We have extended our previous studies of a different anti-chlamydial vaccine, a monoclonal anti-idiotypic antibody (anti-Id; mAb2) which is a molecular mimic of the chlamydial glycolipid exoantigen (GLXA). The present studies demonstrate that the mAb2 vaccine is protective in a murine genital infection model utilizing a human urogenital strain. After either mucosal (oral or intranasal) or systemic (subcutaneous) immunization with the poly (lactide) encapsulated-mAb2 to GLXA, C3H/HeJ mice were significantly protected against topical vaginal challenge with Chlamydia trachomatis (K serovar; UW-31). Reduced vaginal shedding of organism and genital tract inflammation were associated with GLXA-specific and/or anti-EB neutralizing serum antibody. Our results demonstrate that the anti-Id (mAb2) vaccine is protective against an additional human biovar of C. trachomatis in C3H/HeJ mice, which are allogeneic to the source of mAb2 (BALB/c).

Development of a disease activity index for the assessment of reactive arthritis (DAREA)

OBJECTIVES

The objectives of this study were to investigate and validate individual variables and to develop a composite score for disease activity measurement in patients with reactive arthritis (REA).

METHODS

In the first cross-sectional part, the clinical and laboratory evaluation of 45 patients was used to elaborate the most important individual disease activity measures. In the second prospective part, these variables as well as a composite score for disease activity measurement of REA were prospectively validated in 23 patients at two points in time.

RESULTS

The following variables emerged as the most useful for the composite measure: number of swollen and tender joints, patient's pain and global assessment, and C-reactive protein. The score was calculated by simple addition of the individual figures.

CONCLUSION

DAREA constitutes a reliable score which can easily be assessed on a day-to-day office work basis.

Heat shock proteins and arthritis--new readers start here

The possible roles of heat shock proteins in the pathogenesis of inflammatory arthritis have been discussed for a number of years, and investigated intensively in both animal models and human disease. This review surveys evidence which has pointed, on the one hand, to hsp as targets of a pathogenic immune response, and on the other, to an immunoregulatory role for T cell recognition of self hsp. The extent to which findings in experimental animals have led to further insights applicable to human disease is also emphasised.

Immunologic mechanisms in common rheumatologic diseases

Rheumatoid arthritis and seronegative spondyloarthropathies are rheumatologic diseases that likely are caused by inflammatory reactions occurring in genetically predisposed individuals mounting an immune response to the antigen. Understanding the immunopathology of these diseases provides insight into their etiology, pathogenesis, and a rationale for therapies targeting immune component interactions. Although the antigen in rheumatoid arthritis is not known, several bacterial antigens have been associated with seronegative spondyloarthropathies. These antigens result in an interaction between the human leukocyte antigen-B27 restricted CD8 positive T lymphocytes and the antigen presenting cell, producing an inflammatory response. Rheumatoid factors are autoantibodies directed against the fragment crystallizable portion of the immunoglobulin G. Rheumatoid factor immunoglobulin G immune complexes contribute to the inflammatory events in the rheumatoid joint, and may play an important role in antigen presentation. A novel antigen capture enzyme linked immunosorbent assay was developed that mimicked B cell surface expressed rheumatoid factor. Conversely, a direct binding enzyme linked immunosorbent assay mimicked secreted rheumatoid factor. Comparison of rheumatoid binding enzyme linked immunosorbent assays showed that the physical state of rheumatoid factor can affect binding characteristics. The state of glycosylation of immunoglobulin G may contribute to its antigenic structure. These physical characteristics may be important in rheumatoid factor's pathogenic role in rheumatoid arthritis.

The immunobiology and immunopathology of chlamydial infections

Chlamydiae are obligate intracellular bacterial pathogens of eukaryotic cells responsible for a wide variety of important human and animal infections. In humans, chlamydial infections are generally localised to superficial epithelial or mucosal surfaces, are frequently asymptomatic and may persist for long periods of time if untreated, inducing little protective immunity. Nevertheless, neutralising antibodies of limited efficacy are produced against the main chlamydial outer envelope protein, while gamma interferon (IFN gamma) is chlamydiastatic and paradoxically may play a role both in chlamydial persistence and in protective immunity. Delayed hypersensitivity responses to chlamydiae caused by repeated or persistent infection are thought to be important in the development of the severe scarring sequelae characteristic of cicatricial trachoma and of chronic salpingitis. Chlamydial heat shock proteins bearing close homology with their human equivalents may be major targets for immunopathological responses and their expression is upregulated in IFN gamma induced persistent infection. C. pneumoniae, a common cause of acute respiratory infection in humans, may persist in coronary arteries and is strongly implicated as a risk factor in atherosclerosis and in acute myocardial infarction. This paper reviews the immunology and immunopathology of chlamydial infections in the context of the unique biology of this fascinating but challenging group of organisms.

Reiter's syndrome and reactive arthritis: a current view

This paper reviews advances in the understanding of the pathogenesis of reactive arthritis that have occurred over the last decade. Inflammatory aseptic joint disease has been linked with prior infection initiated by many different species of microorganisms. The presence of intra-articular bacterial antigens has now been firmly established with the demonstration of bacteria, bacterial fragments, DNA, RNA, and bacterial lipopolysaccharide in joints of patients with reactive arthritis. Chlamydia trachomatis, Salmonella enteritidis, and Shigella flexneri have all been detected in the joint by immunological techniques, although there is still some doubt as to the form in which they reach the joint and whether or not they persist. A number of phlogistic bacterial components could be acting as arthritogens. Negative joint culture results from patients with reactive arthritis make it unlikely that bacteria in the joint are viable, although chlamydial DNA has been shown in the joints of patients with sexually acquired reactive arthritis using the polymerase chain reaction. The use of antimicrobial therapy in the treatment of reactive arthritis is under review; data suggests that long-term antibiotic treatment warrants further study. The role of HLA-B27 in disease pathogenesis is discussed as are possible mechanisms of interplay between germ and gene. HLA-B27 might confer disease susceptibility by affecting immune mechanisms other than classical antigen presentation. The immunopathogenesis of joint inflammation in reactive arthritis is explored with reference to studies of humoral and cellular immune responses. Serological evidence to support the concept of molecular mimicry is far from conclusive; the results of relevant studies are summarized. Lymphocyte proliferation experiments suggest that antigen presenting cells play an important role. Finally, our views on reactive arthritis in the 1990s, and areas of new and potentially fruitful future research are presented.

Silicone-reactive disorder: a new autoimmune disease caused by immunostimulation and superantigens

Over 100 cases of disorders closely resembling classic autoimmune diseases have been reported among patients who were injected or implanted with a diverse group of chemicals including paraffins, vegetable oils or silicone. Most cases have occurred in silicone breast implant recipients, especially those who received their prostheses 2-10 years prior to onset of symptoms. A high proportion of patients exhibit classic signs and symptoms of Sjogren's syndrome or scleroderma. Affected patients typically experience some combination of fatigue, myalgia, joint pain, sicca syndrome (dry eyes and mouth), synovitis, rash, alopecia, muscular weakness or lymphadenopathy, and autoantibody formation. Less commonly, patients may have the CREST syndrome (calcinosis, Raynaud's phenomena, esophageal hypomotility, sclerodactyly and telangiectasias), hypertension, pulmonary fibrosis, or central nervous system pathology.