Chlamydia trachomatis in reactive arthritis

Incidence of Chlamydia trachomatis infection in patients with reactive arthritis

Objectives

The aim of the study was to evaluate the incidence of Chlamydia trachomatis in patients with reactive arthritis (ReA) within the area of the Podlaskie province (north eastern Poland).

Material and methods

The study concerned 323 patients including 132 women and 191 men diagnosed with ReA. The material for C. trachomatis was collected from the urethra in men and the cervical canal in women. Also, every patient was tested for the presence of anti-C. trachomatis IgG class antibodies, while 121 individuals were additionally tested for IgA class antibodies. In the direct studies, the direct immunofluorescence (DIF) method or polymerase chain reaction (PCR) was used. The immunoenzymatic method was used to detect anti-C. trachomatis antibodies. The control group in the case of direct studies comprised 125 individuals, while in the case of serology research it included 127 (IgG) and 109 (IgA) persons.

Results

Chlamydia trachomatis infection in the urethral and cervical smears was found in 42 patients (13.0%) including 20 women (15.2%) and 22 men (11.5%). In the control group chlamydia was detected in 3 patients (2.4%) including 4% of women and 2% of men. IgA class antibodies were present in 10/121 (8.3%) patients, similarly in women and in men (8.2% and 8.3% respectively). In the control group the specific IgA class antibodies were found in 3/85 patients (3.5%). Anti-C. trachomatis IgG antibodies were found in 70/323 patients (21.7%), similarly in men and women.

Conclusions

Chlamydia trachomatis is a common bacterial factor observed in the genitourinary system of patients with ReA. The outcomes of studies within the Podlaskie province indicate less frequent presence of chlamydial infection compared with Dolnośląskie province.

No correlations between detecting the presence of C. trachomatis in the urogenital tract and the presence of specific antibodies in the serum of ReA patients were observed.

Concurrent direct studies of the urogenital tract and a serological blood test increase the chance of detecting C. trachomatis infection.

Is the role of Chlamydia trachomatis underestimated in patients with suspected reactive arthritis?

Reactive arthritis is usually caused by bacteria of either the enteric or genital tracts. In the genital tract, Chlamydia trachomatis is perhaps the only aetiological agent. In Iran, newer evidence suggests that as C. trachomatis is more commonly found in the general population than was previously believed, its role in reactive arthritis may well be currently overlooked. In this review, as well as emphasizing the potential role of C. trachomatis in reactive arthritis in patients from developing countries, we also make recommendations for further clinical studies to determine its prevalence. Moreover, we also stress the need for standardization of new testing methodologies for C. trachomatis, including the use of new commercial systems in an attempt to determine a truer picture of chlamydial infection in reactive arthritis.

A Case of Chronic Infectious Arthritis of the Temporomandibular Joint Associated with Osteomyelitis without Malocclusion

Infectious arthritis of the temporomandibular joint (TMJ) is rare, and previous reports have identified malocclusion resulting from condylar deformity and displacement of the condyle as one of the clinical characteristics of the disease. Here we report the case of a 33-year-old man with chronic infectious arthritis of the TMJ without malocclusion associated with osteomyelitis of the right mandible. Based on radiological findings of more prominent inflammation at the TMJ than in other regions and on the observed efficacy of antibiotic administration, we made a diagnosis of suppurative arthritis of the TMJ. Based on our empirical experience, including the present case, we speculate that refusal to cooperate with medical care may be a factor in the development of infectious arthritis of the TMJ.

Reactive and undifferentiated arthritis in North Africa: use of PCR for detection of Chlamydia trachomatis

Little is known about the possible role of Chlamydia in patients with reactive or unclassified arthritis in North Africa. This study used polymerase chain reaction (PCR) to survey this population. In addition, we compared the results in three different laboratories for PCR analyses for Chlamydia trachomatis (Ct) in synovial fluid (SF) and tissue (ST) from these North African patients with reactive arthritis (ReA), undifferentiated arthritis (UA), and in rheumatoid arthritis (RA) and osteoarthritis (OA). Eight ReA (six posturethritic, two postenteritic), 23 UA, 13 OA, and 12 RA patients were studied in Algeria, Morocco, and Tunisia. Serum, SF, and ST were obtained from each patient. Ct-PCR was performed in the three different laboratories and compared to Ct-serology [microimmunofluorescence (MIF) and anti-hsp60 enzyme-linked immunosorbent assay (ELISA)] performed in one laboratory. The rate of Ct-PCR positivity in SF/ST was low: none out of the eight ReA and three out of 23 UA patients. In the controls, Ct DNA was detected in two OA SF and in one RA SF. There was no concordance for Ct-PCR positivity between the three laboratories. MIF suggested previous Ct infection (IgG-positive) in two out of five posturethritic ReA, none out of one postenteritic ReA, one out of 17 UA, and nine out of 21 RA/OA patients tested. No MIF-positive patient was PCR-positive from SF or ST. However, anti-hsp60 IgG was detected in all four out of four patients positive by PCR and in 11 out of 44 PCR-negative patients (p = 0.002). In this multinational comparative study, the rate of Ct-PCR-positive synovial specimens in North African ReA/UA patients was low. Concordance among the three PCR testing laboratories was poor indicating the need for test standardization. All Ct-PCR-positive patients were found positive by anti-hsp60 IgG serology.

Reactive arthritis which occurred one year after acute chlamydial urethritis

A 30-year-old Japanese man developed dactylitis with sausage-like fingers in addition to balanitis and stomatitis. One year prior to these symptoms, acute chlamydial urethritis had been successfully treated by levofloxacin. On admission, Chlamydia trachomatis DNA was not detected in the urine sediment by PCR method, however, he was diagnosed to have reactive arthritis based on the clinical findings of asymmetric dactylitis, circinate balanitis, stomatitis and positivity for HLA B27 antigen. He was treated with methotrexate and his arthritis improved. The past chlamydial infection may have been involved in the pathogenesis of reactive arthritis in this patient.

Disc derangements of the temporomandibular joint

Disc-related derangement of the temporomandibular joint is common and epidemiological research has found that about 20% of the population may be affected. Although very few of these people have the more prominent symptoms, recent data indicate that the numbers who need treatment is increasing. The two clinical variants of disc derangement, reciprocal clicking and closed lock, have long been recognized, but the association between them and their aetiology and pathogenesis is still unclear. As a consequence, there is still uncertainty on how to treat the conditions, and this is even more evident when surgery is involved. This paper describes new tissue research related to disc derangement. A simplified scheme is presented and implications for surgical treatment are discussed.

The occurrence of antibodies against chlamydia species in patients with monoarthritis and chronic closed lock of the temporomandibular joint

PURPOSE

The study goal was to investigate the occurrence of serum antibodies to Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci in patients with temporomandibular joint (TMJ) monoarthritis or chronic closed lock and in control subjects.

PATIENTS AND METHODS

An indirect microimmunofluorescence test for detecting antibodies against C trachomatis was used. Twenty-three patients (12 with monoarthritis and 11 with chronic closed lock) and 42 control subjects were evaluated.

RESULTS

Six patients with monoarthritis, 5 patients with chronic closed lock of the TMJ, and 6 control individuals were considered to have had a past C trachomatis infection based on their immunoglobulin G titers. Corresponding groups for C pneumoniae investigation included 3 patients with monoarthritis, 4 patients with chronic closed lock, and 17 control subjects, and for C psittaci, 1 patient with monoarthritis, 2 patients with chronic closed lock, and 1 control subject. Statistically significant differences between patients and control subjects were found for C trachomatis only; monoarthritis versus control (P =.016), chronic closed lock versus control (P =.038), and all patients versus control (P =.007). Patients with monoarthritis did not differ from patients with chronic closed lock with regard to antibodies against C trachomatis.

CONCLUSION

The occurrence of serum antibodies to C trachomatis was significantly higher in patients than in control subjects, but this occurrence did not correlate with severity of observed tissue changes. Nevertheless, an association may exist between the presence of C trachomatis and TMJ disease.

The presence of bacteria in the synovial fluid of the temporomandibular joint and clinical significance: preliminary study

PURPOSE

The objective of this study was to find any relation between the presence of specific bacterial species in the synovial fluid of the temporomandibular joint (TMJ) and clinical parameters.

PATIENTS AND METHODS

We studied 43 patients (male-to-female ratio, 1:1.69; average age, 34.37 +/- 14.55 years). Thirty-three patients had a displaced disc in the TMJ (DD group), and 10 patients did not have a displaced disc of the TMJ or any symptom related to TMJ disorders (NDD group). Clinical examinations were made to determine maximum mouth opening, joint sounds, previous trauma history, systemic disease, and TMJ pain. Six bacterial species that were reported in other studies were chosen to evaluate the presence of bacteria in the TMJ for this study.

RESULTS

Mycoplasma genitalium was most frequently detected in synovial fluid (86.0%). Staphylococcus aureus, Mycoplasma fermentans/orale, Actinobacillus actinomycetemcomitans, and Streptococcus mitis were detected in 51.2%, 37.2%, 25.6%, and 7.0% of samples, respectively. beta-Hemolytic Streptococcus was not detected. The prevalence of S aureus was significantly higher in the DD group than in the NDD group (P <.05). The patients who had M. fermentans/orale were 5.40 times more likely to be younger than 30 years than were those without M. fermentans/orale (P <.05). Those with M. genitalium were 5.81 times more likely to be female than were those without M. genitalium (P <.05).

CONCLUSION

The presence of S. aureus in TMJ synovial fluid was related to TMJ disorder symptoms and clinical parameters seemed to be influenced by bacterial presence in TMJ synovial fluid.

Substance P and mast cells: preliminary histologic analysis of the human temporomandibular joint

PURPOSE

Neuropeptide-containing nerves can serve as a mechanism for nervous system regulation of host defense responses. Because bacteria associated with reactive arthritis have been identified in the temporomandibular joint (TMJ), this study investigates whether the presence of substance P (SP) neuropeptide-containing nerves and mast cells can be identified in the TMJ.

MATERIAL AND METHODS

Posterior bilaminar tissue removed during TMJ surgery from 9 women was evaluated for the presence of neuropeptide-containing nerves by staining with a monoclonal antibody to SP. Staining of the TMJ tissue sections with 0.5% toluidine blue was performed to identify the presence of mast cells.

RESULTS

SP-containing nerves and mast cells were identified within the posterior bilaminar tissue associated with the vasculature.

CONCLUSIONS

The presence of neuropeptide nerves and mast cells within the TMJ has been shown. Mast cell degranulation products and SP release can contribute to TMJ inflammation.

Reactive arthritis: preliminary microbiologic analysis of the human temporomandibular joint

PURPOSE

The presence of Chlamydia trachomatis has been previously shown in the temporomandibular joint (TMJ). This study investigated whether the presence of other bacteria associated with reactive arthritis (ReA) can be identified in the TMJ.

MATERIALS AND METHODS

Posterior bilaminar tissue removed during TMJ surgery from 26 patients (24 F, 2 M) was evaluated for the presence of C. trachomatis, Mycoplasma fermentans, Mycoplasma genitalium, Campylobacter jejuni, Yersinia enterocolitica, Salmonella spp, and Shigella spp by highly specific polymerase chain reaction (PCR) assays.

RESULTS

Bacterial DNA was identified in the TMJ as follows: C. trachomatis, 11 of 26 (42%); M. fermentans/orale, 6 of 26 (23%); M. genitalium, 9 of 26 (35%). Nine of 26 TMJs (35%) had the presence of a single bacterial species. Eight of 26 TMJs (31%) had more than 1 species, as follows: C. trachomatis with either M. genitalium or M. fermentans/orale in 5 of 26 (19%), M. fermentans/orale with M. genitalium 2 of 26 (8%), and C. trachomatis/M. fermentans/orale/M. genitalium, 1 of 26 (4%). A total of 17 of 26 (65%) of TMJs had the presence of bacteria identified in the TMJ. Campylobacter jejuni, Y. enterocolitica, Salmonella spp, and Shigella spp were not identified in any samples.

CONCLUSIONS

The presence of M. genitalium in the human TMJ has not been previously reported. The presence of bacteria in the TMJ, either singly or concurrently with other bacteria, may serve as the pathogenetic mechanism of TMJ inflammation. The presence of 2 bacteria from the urogenital tract in the TMJ suggests that internal derangement of the TMJ may occur as a result of a sexually acquired infection.

Identification of Chlamydia trachomatis in the human temporomandibular joint

PURPOSE

Reactive arthritis (ReA) as a consequence of triggering Chlamydia trachomatis infections has been extensively studied to better understand inflammatory arthritis. This study investigated whether the presence of C trachomatis can be shown in the TMJ of patients with internal derangement.

PATIENTS AND METHODS

Posterior bilaminar tissue removed from 31 patients (29 F, 2 M) during TMJ articular disc repositioning and posterior ligament repair was tested for the presence of C trachomatis. Cryosections were stained using a monoclonal antibody that identifies all chlamydial serovars. Highly specific polymerase chain reaction (PCR) assays independently targeting two genes of C trachomatis also were performed; these assays also identify all serovars of this organism.

RESULTS

TMJ tissue from 6 of 30 patients (20%) showed the presence of C trachomatis in the posterior bilaminar tissue on immunostaining. PCR screening identified 12 of 31 patients (39%) as having C trachomatis DNA in tissue, including four of six positive by immunostaining. All chlamydia-positive patients were female, with an average age of 36.7 years (15 to 48 years).

CONCLUSIONS

The presence of C trachomatis in the human TMJ has not been previously shown. The presence of this organism may serve as the pathogenetic mechanism for TMJ dysfunction, as demonstrated in other joints. Nonapparent chlamydial infection in females may also explain the marked prevalence of TMJ symptoms in women.

Bacterial antigens in reactive arthritis and spondarthritis. Rational use of laboratory testing in diagnosis and follow-up

An aetiological diagnosis of reactive arthritis is based on the demonstration of recent or ongoing infection with the causative bacterium. This may be done by serological demonstration of antibacterial antibodies, demonstration of the causative microorganism at an extra-articular site or by identification of bacterial nucleic acids or antigens in joint material from patients with aseptic arthritis. The finding of elevated titres of bacteria-specific IgG- and IgA-class antibodies may indicate recent or persistent infection, but has some limitations due to the prevalence of such antibodies among apparently healthy individuals and the persistence of such antibodies after the infection. While Chlamydia can be demonstrated in urogenital specimens in at least one-third of patients with Chlamydia-induced arthritis, the triggering microorganisms are usually no longer detectable in post-dysenteric reactive arthritides. Assays involving molecular amplifications have been successfully used to demonstrate bacterial nucleic acids in joint specimens from patients with reactive arthritis. In addition, bacterial antigens have been detected by immunofluorescence tests. Even though examination of synovial fluid and synovial membrane specimens for bacterial DNA by the polymerase chain reaction is increasingly used to diagnose reactive arthritis, such assays have not been standardized and are not generally available. While some problems remain, these techniques will facilitate the exact diagnosis of reactive arthritides in the near future.

Comparison of synovial tissue and synovial fluid as the source of nucleic acids for detection of Chlamydia trachomatis by polymerase chain reaction

OBJECTIVE

Difficulties in detecting Chlamydia trachomatis in human joints by polymerase chain reaction (PCR) may be related to whether synovial tissue or synovial fluid (SF) is used as the source of DNA in PCR amplification. In this study, a new PCR assay was developed and used to compare chlamydial DNA in paired samples of SF and synovial tissue from patients with arthritis.

METHODS

The PCR assay targeted the ribosomal RNA operons, which are present in 2 copies on the C trachomatis chromosome. DNA from several relevant bacteria and chlamydial serovars was used for testing this screening system. The detection of chlamydial DNA in nucleic acid preparations from matched samples of SF and synovial tissue was compared by PCR assay. Samples were obtained from 55 patients, including patients with reactive arthritis, Reiter's syndrome, and other arthropathies.

RESULTS

Testing of the PCR screening system confirmed it to be highly specific and sensitive. Use of this assay to screen DNA from SF and synovial tissue samples showed that 29 (53%) of 55 synovial tissue preparations were positive for chlamydial DNA, but only 16 (29%) of the matched SF samples from these 29 patients were similarly positive. Five (9%) of 55 SF samples, but not their tissue counterparts, were positive for chlamydial DNA by PCR.

CONCLUSION

Detection of chlamydial DNA in the joints of patients by PCR gives positive results more often when synovial tissue rather than SF is the source of target nucleic acids. Although synovial tissue is the source of choice for the most reliable determination of chlamydia in the joint, both synovial tissue and SF should be assayed if possible.

Case report: in situ hybridization for detection of inapparent infection with Chlamydia trachomatis in synovial tissue of a patient with Reiter's syndrome

The authors have shown that protein antigens, RNA, and DNA from Chlamydia trachomatis are present in synovial tissues of patients with Reiter's syndrome (RS). However, those studies gave no insight into the host cell type involved or the precise tissue location of the bacteria. To address such issues, the authors developed an in situ hybridization system to detect chlamydia, and they used that system to examine synovial biopsies from a patient with RS and a patient without RS. The in situ system uses a previously described digoxigenin-labeled DNA probe that hybridizes with chlamydial 16S rRNA sequences in paraformaldehyde-fixed samples. Control studies with chlamydia-infected and uninfected HeLa cells confirmed that the in situ system is as sensitive as is direct fluorescence cytology for detection of the organism. Morphology of host and chlamydia cells is preserved after hybridization. Studies using synovial tissue from an osteoarthritis patient produced no in situ hybridization signal, but similar hybridization to tissue from a culture-/direct fluorescence cytology- negative RS patient had a strong intracellular signal for chlamydia within a subsynovial cell layer. These in situ hybridization results confirm the extensive presence of chlamydia in synovia and extend the authors' earlier observation that chlamydia RNA is present in the synovia of patients with RS. The data also confirm their electron microscopy studies, indicating that chlamydia are intracellular in synovial tissue, and they further show that infected host cells are located beneath the synovial lining.

Spondyloarthropathies of childhood

The term spondyloarthropathy, currently used to describe some forms of idiopathic arthritis of childhood, may be inappropriate because most children included in this category do not have arthritis of the spine, and inflammatory disease of the sacroiliac joints is an infrequent or late finding. Juvenile AS, the archetype, or "complete" disease may account for only one fifth of the so-called "spondyloarthropathies". "Incomplete" or "early" spondyloarthropathies are most frequent. Such children may not develop axial symptoms and signs for 5 to 10 years after onset, and they may be better characterized as having enthesitis-related arthritis, a term proposed by a recent task force of the International League Against Rheumatism (ILAR). Reactive arthritis, although etiologically linked with the spondyloarthropathies, uncommonly progresses to AS in childhood; most patients have peripheral arthritis with or without enthesitis resolving in the relatively short term. The arthritis associated with IBD is more commonly peripheral than axial. Although axial disease undoubtedly occurs in JPsA, in the authors' experience it is very uncommon.

Amplification of plasmid and chromosome Chlamydia DNA in synovial fluid of patients with reactive arthritis and undifferentiated seronegative oligoarthropathies

OBJECTIVE

To investigate the hypothesis that whole bacteria might be found in the joints of patients with Chlamydia-associated reactive arthritis.

METHODS

The presence of 2 plasmid- and 2 chromosome-specific sequences of Chlamydia DNA was investigated by amplification with the polymerase chain reaction, in synovial fluid (SF) samples from 71 patients with various arthropathies.

RESULTS

Chlamydia DNA was found in SF samples from 22 patients.

CONCLUSION

Whole chlamydiae are likely present in the SF of patients with Chlamydia-associated reactive arthritis.

Granzyme-positive cytotoxic cells are specifically increased in early rheumatoid synovial tissue

OBJECTIVE

To define the expression and the phenotype of granzyme (Gran) A and B positive cytotoxic cells in synovial tissue (ST) from patients with rheumatoid arthritis (RA) with respect to disease duration and activity.

METHODS

Using antibodies against GranA and GranB, which serve as markers of activated natural killer (NK) cells and cytotoxic T lymphocytes, ST sections from 10 patients with early RA, 10 patients with longstanding RA, and 10 patients with osteoarthritis were examined. The phenotype of Gran+ cells was determined with double-labeling techniques.

RESULTS

Gran+ cells, the majority of which were NK cells, were found in ST from patients in all groups. Several of these cells did not express the surface markers CD16, CD56, and CD57. The highest ST expression of GranB was found in patients with early RA. In RA patients, there was a positive correlation of GranB expression with serum levels of acute-phase reactants, but not with histologic scores for inflammation.

CONCLUSION

Gran+ cells are mainly NK cells, a substantial proportion of which do not express conventional NK cell surface markers. GranB expression is specifically increased in the synovial tissues of patients with RA of short duration.

Intracellular location of inapparently infecting Chlamydia in synovial tissue from patients with Reiter's syndrome

Culture of Chlamydia trachomatis from synovial tissues/fluids from Reiter's syndrome (RS) patients frequently yields negative results. However, we have identified chlamydial RNA at that site in such patients, suggesting that viable organisms may be present. Here we define the cellular location of chlamydia within the synovium via in situ hybridization. Using a chlamydial ribosomal RNA-directed probe, we show that synovial tissue from culture-negative RS patients gives strong hybridization which is often localized to a subsynovial cell layer, rather than to the synovial lining; in some cases, hybridizing cells are dispersed through the synovium. All hybridization signal is located within host cells, indicating that infectious extracellular elementary bodies are rare or absent. These data confirm the extensive intracellular presence of inapparent chlamydia in the synovia of RS patients and provide some insight into the usual culture negativity of synovial tissues for the organism.

Comparison of serological tests for the detection of antibodies against Chlamydia trachomatis and Chlamydia pneumoniae in rheumatological patients

In cases of reactive arthritis, a suspected Chlamydia trachomatis infection is often detected by serological methods. However, mostly tests with genus-specific antigens are used, neglecting the fact that antibodies against Chlamydia pneumoniae are highly prevalent in the adult population. Therefore we tested sera of 129 patients with various rheumatological disorders and of 18 healthy persons in parallel with a genus-specific test (IPAZYME) and with the species-specific microimmunofluorescence test for C. trachomatis and C. pneumoniae antibodies. The data showed that 55% of the 64 IPA-positive results were caused by antibodies (IgG) against Chlamydia pneumoniae, only 6% by anti-Chlamydia trachomatis IgG and 20% by both specificities. For IgA antibodies, the percentages were 44%, 12.5% and 12.5% respectively. In 12 IPA-positive cases, the MIF showed no reaction. 58% of all 147 sera tested with MIF had IgG antibodies against C. pneumoniae, 5% had anti-C. trachomatis IgG and 8% IgG against both species. The percentages for IgA were 29%, 2% and 2%, respectively. IgM positivity in MIF disappeared after absorption with rheumatoid factor absorbent. No significant differences were found between the various groups of patients. The data suggest that due to the high prevalence of anti-C. pneumoniae antibody, genus-species tests cannot be used as screening tests for the serological diagnosis of C. trachomatis infections.

Arthritis in the highlands of Papua New Guinea

Acute polyarthritis is an important cause of morbidity in many tropical countries. Classification has often been difficult, with the term tropical polyarthritis used for those in whom a diagnosis could not be made. The implication that this is a distinct entity is probably incorrect, with likely causes being septic arthritis or post-infective reactive arthritis. This study aimed to determine the types of arthritis found in 43 patients (30 men) presenting consecutively to the Goroka Base Hospital in the Eastern Highlands of Papua New Guinea. Gonococcal arthritis was diagnosed in eight patients (six men) on the basis of isolation of Neisseria gonorrhoeae from the joint aspirate. In all cases the N gonorrhoeae was identified by the closed culture system on chocolate agar, but not always by routine plating. There were no specific clinical features that identified patients with a gonococcal septic arthritis. The remaining 34 patients had an undifferentiated oligoarthritis. The pattern of arthritis in men and women was of a lower limb pauciarticular arthritis with a predilection for the knee and ankle joints. A total of 30% of male patients had a history of urethral discharge and 44% of all patients had preceding diarrhoea. Arthritis was the only feature in 59% of patients and in 32% there was an associated enthesitis. In this study most patients had an oligoarthritis consistent with a reactive arthritis or a septic arthritis due to N gonorrhoeae. Broth inoculation of synovial fluid was the best method to isolate N gonorrhoeae, with standard methods for gonococcal isolation failing in some patients. It is recommended that the term 'tropical polyarthritis' is no longer used as it does not refer to a specific entity but consists of several known arthritides.

Molecular evidence for the presence of chlamydia in the synovium of patients with Reiter's syndrome

OBJECTIVE

There is much evidence indicating that chlamydial antigens in the synovium may be critical in the pathogenesis of Reiter's syndrome (RS), but it is not known whether intact organisms are present in that tissue in any stage of the disease. The present study was undertaken to begin to address this question.

METHODS

We used a highly specific and sensitive molecular hybridization screening system which detects chlamydial RNA, to examine synovial biopsy samples from 22 patients with various arthropathies, including 9 with RS.

RESULTS

Seven of the 9 RS patients were positive for chlamydial RNA, while 3 of the 13 non-RS patients were also positive; positive results in the non-RS patients probably indicate the actual presence of the organism, since these patients had arthritis that was otherwise incompletely explained.

CONCLUSION

The detection of chlamydial RNA, in combination with previous findings of chlamydia-like particles and/or chlamydial antigens in the synovium of RS patients, suggests that whole bacterial cells are present in that tissue.

Inapparent genital infection with Chlamydia trachomatis and its potential role in the genesis of Reiters syndrome

An infectious etiology has been suggested for Reiter's syndrome (RS) because the disease has often been observed to follow episodes of urethritis or dysentery. Despite demonstrations of bacterial antigens in the synovial tissues of RS patients, it is not clear whether viable organisms are present in the synovium in any particular stage of this disease. Furthermore, it is not clear how either viable organisms or their product(s) might reach the joints. Infection with the bacterium Chlamydia trachomatis is the most common sexually transmitted disease in the United States, and as such this organism has emerged as a primary pathogen associated with RS. Previous work from our group has shown that synovial biopsy tissues from a majority of RS patients studied show significant levels of apparently intact chlamydial RNA, even when synovial or urethral cultures from the same patients are unequivocally negative for the organism. We show here that inapparent urethral infection with chlamydia occurs with high prevalence in men, and that inapparent cervical infection with the organism occurs at high prevalence in women. These data provide an important link in the relationship between initial chlamydial infection and possible subsequent genesis of RS, and they may give useful insight into mechanisms by which chlamydial infection can lead to development of this disease. Our data argue further that inapparent infection may be a significant factor in pathogenesis for all chlamydia-related diseases, and they suggest that, contrary to current ideas, C. trachomatis can generate disseminated infection.

Recurrent arthritis in Reiter's syndrome: a function of inapparent chlamydial infection of the synovium?

Present or prior infection with any of several common bacterial pathogens has been strongly implicated in the development of Reiter's syndrome (RS). However, because Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the western hemisphere, this organism has emerged as a major causative agent of the disease. An important but as yet poorly understood aspect of chlamydia-related RS is the recurrence of active arthritis in the absence of any overt infection or reinfection with the organism. In this article, a large body of published clinical and experimental observations strongly suggesting that some chlamydial infections in humans can be inapparent--not detectable by standard culture or antibody-based laboratory screening methods--is reviewed. The authors' own initial molecular genetic studies, which support that contention, are summarized. Based on these data, the argument is developed that not only does inapparent chlamydial infection occur in humans, but such infections may have significant consequences in terms of the pathogenesis of RS, including the possible causation of recurrent episodes of disease in the absence of active infection. The therapeutic implications of potential inapparent chlamydial infections as they relate to RS are discussed.

RNA-directed molecular hybridization screening: evidence for inapparent chlamydial infection

Both clinical and epidemiological data suggest that inapparent infection by Chlamydia trachomatis occurs in humans. To confirm and study such infections, we developed a hybridization screening system directed toward chlamydial ribosomal RNA (rRNA). Six restriction endonuclease fragments derived from the cloned rrnA operon of chlamydial serovar L2(434) were tested as hybridization screening probes, but only one fragment encoding the 5' portion of the 16s rRNA gene plus some upstream flanking sequence was both sensitive and highly specific in such experiments. In Northern slot blot assays, hybridization analyses with this fragment as probe routinely detected one picogram or less of chlamydial RNA when that RNA was bound to membranes alone or as part of a mixture with a vast excess of mammalian RNA. The probe did not hybridize to RNA from mammalian and relevant bacterial sources but did hybridize to rRNA from B (ocular) and E (genital) serovars of C. trachomatis. Experiments using RNA from conjunctival biopsies and standard conjunctival swab samples from cynomolgus monkeys showed that the probe reliably distinguishes between known chlamydia-infected and uninfected samples. This suggests that it may be useful for clinical screening. Characterization assays for the RNA-directed probe screening system in this monkey model of trachoma provide initial molecular evidence that ocular chlamydial infection may persist longer than previously thought, based solely on direct fluorescence antibody assay (DFA) and culture analyses.

Stress proteins, autoimmunity, and autoimmune disease

At birth, the immune system is biased toward recognition of microbial antigens in order to protect the host from infection. Recent data suggest that an important initial line of defense in this regard involves autologous stress proteins, especially conserved peptides of hsp60, which are presented to T cells bearing gamma delta receptors by relatively nonpolymorphic class lb molecules. Natural antibodies may represent a parallel B cell mechanism. Through an evolving process of "physiological" autoreactivity and selection by immunodominant stress proteins common to all prokaryotes, B and T cell repertoires expand during life to meet the continuing challenge of infection. Because stress proteins of bacteria are homologous with stress proteins of the host, there exists in genetically susceptible individuals a constant risk of autoimmune disease due to failure of mechanisms for self-nonself discrimination. That stress proteins actually play a role in autoimmune processes is supported by a growing body of evidence which, collectively, suggests that autoreactivity in chronic inflammatory arthritis involves, at least initially, gamma delta cells which recognize epitopes of the stress protein hsp60. Alternate mechanisms for T cell stimulation by stress proteins undoubtedly also exist, e.g., molecular mimicry of the DR beta third hypervariable region susceptibility locus for rheumatoid arthritis by a DnaJ stress protein epitope in gram-negative bacteria. While there still is confusion with respect to the most relevant stress protein epitopes, a central role for stress proteins in the etiology of arthritis appears likely. Furthermore, insight derived from the work thus far in adjuvant-induced arthritis already is stimulating analyses of related phenomena in autoimmune diseases other than those involving joints. Only limited data are available in the area of humoral autoimmunity to stress proteins. Autoantibodies to a number of stress proteins have been identified in SLE and rheumatoid arthritis, but their pathogenetic significance remains to be established. Nevertheless, the capacity of certain stress proteins to bind to multiple proteins in the nucleus and cytoplasm both physiologically and during stress or injury to cells, suggests that stress proteins may be important elements in the "immunogenic particle" concept of the origin of antinuclear and other autoantibodies. In short, this fascinating group of proteins, so mysterious only a few years ago, has impelled truly extraordinary new lines of investigation into the nature of autoimmunity and autoimmune disease.