Persistence of Yersinia antigens in peripheral blood cells from patients with Yersinia enterocolitica O:3 infection with or without reactive arthritis

Looking back on 51 years of the Carol Nachman Prize in Rheumatology-significance for the field of spondyloarthritis research

The city and casino of Wiesbaden, capital of the German state Hessen, have endowed the Carol Nachman Prize to promote research work in the field of rheumatology since 1972. The prize, endowed with 37,500 €, is the second highest medical award in Germany and serves to promote clinical, therapeutic, and experimental research work in the field of rheumatology. In June 2022, the 50-year anniversary was celebrated. In the symposium preceding the award ceremony, an overview was given on the significance of spondyloarthritis for the work of the awardees in the past 30 years. This overview has now been put together to inform the interested community of the work performed, including the opinion of the awardees regarding what they consider to be their most important contribution.

Effect of Non-Specific Porins from the Outer Membrane of Yersinia pseudotuberculosis on Mice Brain Cortex Tissues

It was found that a single-dose immunization of mice with Yersinia pseudotuberculosis porins OmpF and OmpC causes development of pathological changes in the deep layers of cerebral cortex characterized by dystrophic changes in the cells against the background of the increasing titer of specific antibodies. At the same time, the increased level of caspase-3 expression is observed in the neurons, which indicates induction of proapoptotic signaling pathways. The obtained results indicate potential ability of nonspecific pore-forming proteins of the outer membrane of Gram-negative bacteria to initiate development of degenerative changes in brain cells.

Antibodies Recognizing Yersinia enterocolitica Lipopolysaccharides of Various Chemotypes in Synovial Fluids From Patients With Juvenile Idiopathic Arthritis

Yersinia enterocolitica O:3 (YeO3) is considered to be associated with reactive arthritis (ReA), and its lipopolysaccharide (LPS) has been detected in synovial fluids from patients. Interestingly, YeO3 wild-type LPS was processed by host cells, resulting in truncated LPS molecules presenting the core region. Previously, we reported the immunogenicity but not adjuvanticity of YeO3 LPSs of wild (S) type, Ra, Rd, or Re chemotypes in mice. Here, we demonstrate the presence of YeO3 LPS chemotype-specific antibodies in all analyzed synovial fluids (SF) from patients with juvenile idiopathic arthritis (JIA). Interestingly, the high titer of antibodies specific for the Kdo-lipid A region was found in most tested SF. In contrast, only a few were positive for antibodies recognizing O-specific polysaccharides. Western blot analysis revealed the presence of antibodies reacting with fast-migrating LPS fractions and enterobacterial common antigen (ECA) in synovial fluid samples. Our data also suggest the importance of LPS-associated ECA for the antigenicity of endotoxin. Furthermore, we confirmed in vitro that Yersinia LPS processing leads to the exposure of its core region and enhanced potency of complement lectin pathway activation.

The Role of Yersinia enterocolitica O:3 Lipopolysaccharide in Collagen-Induced Arthritis

Yersinia enterocolitica O:3 is mentioned among the most common arthritogenic pathogens. Bacterial components (including lipopolysaccharide (LPS)) may persist in the joint after eradication of infection. Having an adjuvant activity, LPS may enhance production of anticollagen antibodies, involved in the pathogenesis of rheumatoid arthritis. Furthermore, its ability to activate complement contributes to the inflammation. The aim of this work was to investigate whether Yersinia LPS (coinjected with collagen) is associated with arthritis progression or other pathological effects and to elucidate the mechanism of this association. It was demonstrated that murine mannose-binding lectin C (MBL-C) recognizes the inner core heptoses of the Rd1 chemotype LPS of Yersinia. In addition, the Rd1 LPS activates the MBL-associated serine protease 1 (MASP-1) stronger than the S and Ra chemotype LPS and comparable to Klebsiella pneumoniae O:3 LPS. However, in contrast to the latter, Yersinia Rd1 LPS was associated neither with the adjuvancity nor with the enhancement of pathological changes in animal paws/impairment of motility. On the other hand, it seemed to be more hepatotoxic when compared with the other tested endotoxins, while the enlargement of inguinal lymph nodes and drop in hepatic MBL-C expression (at the mRNA level) were independent of LPS chemotype. Our data did not suggest no greater impact Y. enterocolitica O:3 on the development or severity of arthropathy related to anticollagen antibody-induced arthritis in mice, although its interaction with MBL-C and subsequent complement activation may contribute to some adverse effects.

Evolving patterns of reactive arthritis

OBJECTIVE

To characterize rheumatologists' perspectives on evolving trends of reactive arthritis (ReA).

METHODS

After ethics approval, 548 members of the Canadian Rheumatology Association were surveyed with 37 questions covering their demographic information, subspecialty, level of experience, practice setting and opinions on prevalence, treatment, and causes of ReA. Results were analyzed with descriptive statistics.

RESULTS

Ninety-seven responded to the survey (18% response rate); 66 fully completed it. Nearly half of respondents believed that the incidence of ReA is declining and causes of ReA may be changing. Physicians reported that most of the ReA cases in their practices were caused by an unknown organism, sexually transmitted, or gastrointestinal infection. Full triad ReA increased the chance of recurrence according to their impressions. Common investigations in ReA included inflammatory markers, HLA-B27, chlamydia and gonorrhea testing, stool cultures, synovial fluid analyses, SI joint imaging. ReA treatment included NSAIDs, intra-articular corticosteroid injections, and DMARDs. Two-thirds said they used TNF alpha inhibitors in chronic ReA occasionally or more frequently.

CONCLUSION

ReA may be decreasing in frequency and severity in Canada. Changes could be due to less food borne illness, cleaner water, or more rapid treatment of sexually transmitted infections. The cause is often unknown in clinical practice.Key Points• Reactive arthritis (ReA) is likely decreasing in prevalence and severity.• Patients with classic trial of arthritis, urethritis, and conjunctivitis are more likely to have recurrent and/or chronic ReA.• The causal organisms are often not detected and seem to be changing over time.

IL-12/23p40 overproduction by dendritic cells leads to an increased Th1 and Th17 polarization in a model of Yersinia enterocolitica-induced reactive arthritis in TNFRp55-/- mice

Dendritic cells (DCs) play critical functions in the initiation of immune responses. Understanding their role in reactive arthritis (ReA) will help delineate the pathogenesis of this arthropathy. In early studies, we detected IL-12/23p40 deregulation in Yersinia entercolitica (Ye)-induced ReA in TNFRp55-deficient (TNFRp55^-/-) mice. In this study, we assessed the contribution of DCs in this overproduction. First, greater levels of IL-12/23p40, IFN-γand IL-17A were confirmed in supernatants of lipopolysaccharide (LPS)-stimulated TNFRp55^-/-splenocytes obtained on arthritis onset (day 14 after Ye infection). Later, DCs were identified as a precise source of IL-12/23p40 since increased frequency of splenic IL-12/23p40⁺DCs was detected in TNFRp55^-/- mice. After robust in vivo amplification of DCs by injection of Fms-like tyrosine kinase 3-Ligand (Flt3L)-transfected BL16 melanoma, DCs were purified. These cells recapitulated the higher production of IL-12/23p40 under TNFRp55deficiency. In agreement with these results, TNFRp55^-/- DCs promoted Th1 and Th17 programs by co-culture with WT CD4⁺lymphocytes. A mechanistic study demonstrated that JNK and p38 MAPK pathways are involved in IL-12/23p40 overproduction in purified TNFRp55^-/- DCs as well as in the JAWS II cell line. This deregulation was once again attributed to TNFRp55 deficiency since CAY10500, a specific inhibitor of this pathway, compromised TNF-mediated IL-12/23p40 control in LPS-stimulated WT DCs. Simultaneously, this inhibition reduced IL-10 production, suggesting its role mediating IL-12/23p40 regulation by TNFRp55 pathway. These results provide experimental data on the existence of a TNFRp55-mediated anti-inflammatory circuit in DCs. Moreover, these cells may be considered as a novel target in the treatment of ReA.

Detection of Shigella spp. nucleic acids in the synovial tissue of Tunisian rheumatoid arthritis patients and other forms of arthritis by quantitative real-time polymerase chain reaction

Enterobacterial components in the joints of patients are believed to contribute to a perpetuating inflammation leading to a reactive arthritis (ReA), a condition in which microbial agents cannot be recovered from the joint. At present, it is unclear whether nucleic acids from Shigella spp. are playing a pathogenic role in causing not only ReA but also other forms of arthritis. Quantitative real-time polymerase chain reaction assay (qPCR) is the method of choice for the identification of bacteria within the synovium. The aim of our study was to detect the presence of Shigella spp. nucleic acids in the synovial tissue (ST) of Tunisian arthritis patients. We investigated 57 ST samples from rheumatoid arthritis (RA) n = 38, undifferentiated oligoarthritis (UOA) n = 12, and spondyloarthritis (SpA) n = 7 patients; 5 ST samples from healthy individuals were used as controls. Shigella spp. DNA and mRNA transcripts encoding the virulence gene A (VirA) were examined using an optimized qPCR with newly designed primers and probes. Using qPCR, Shigella spp. DNA was found in 37/57 (65%) ST samples (24/38, i.e., 63.2% of RA, 8/12, i.e., 67% of UOA, and 5/7, i.e., 71.4% of SpA patients). Paired DNA and mRNA were extracted from 39 ST samples, whose VirA cDNA was found in 29/39 (74.4%) patients. qPCR did not yield any nucleic acids in the five healthy control ST samples. The qPCR assay was sensitive and showed a good intra- and inter-run reproducibility. These preliminary findings generated by an optimized, highly sensitive PCR assay underline a potential role of past gastrointestinal infections. In Tunisian patients, a bacterial etiology involving Shigella spp. in the manifestation of arthritic disorders including RA might be more common than expected.

Serologic Evidence of Gut-driven Systemic Inflammation in Juvenile Idiopathic Arthritis

OBJECTIVE

Accumulating evidence links juvenile idiopathic arthritis (JIA) to nonhost factors such as gut microbes. We hypothesize that children with new-onset JIA have increased intestinal bacterial translocation and circulating lipopolysaccharide (LPS).

METHODS

We studied systemic treatment-naive patients with JIA [polyarticular JIA, n = 22, oligoarticular JIA, n = 31, and spondyloarthropathies (SpA), n = 16], patients with established inflammatory bowel disease-related arthritis (IBD-RA, n = 11), and 34 healthy controls. We determined circulating IgG reactivity against LPS, LPS-binding protein (LBP), α-1-acid glycoprotein (α-1AGP), and C-reactive protein (CRP) in plasma or serum from these patients and controls. Juvenile Arthritis Disease Activity Score (JADAS-27) was calculated for patients with JIA.

RESULTS

Circulating anticore LPS antibody concentrations in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.024), and SpA (p = 0.001) were significantly greater than in controls, but there were no significant intergroup differences. Circulating LBP concentrations were also significantly greater in patients with polyarticular JIA (p = 0.001), oligoarticular JIA (p = 0.002), and SpA (p = 0.006) than controls, as were α-1AGP concentrations (p = 0.001, 0.001, and 0.003, respectively). No differences were observed between controls and patients with IBD-RA in any of the assays. Circulating concentrations of LBP and α-1AGP correlated strongly with CRP concentrations (r = 0.78 and r = 0.66, respectively). Anticore LPS antibody levels and CRP (r = 0.26), LBP (r = 0.24), and α-AGP (r = 0.22) concentrations had weaker correlations. JADAS-27 scores correlated with LBP (r = 0.66) and α-1AGP concentrations (r = 0.58).

CONCLUSION

Children with polyarticular JIA, oligoarticular JIA, and SpA have evidence of increased exposure to gut bacterial products. These data reinforce the concept that the intestine is a source of immune stimulation in JIA.

A case of reactive arthritis due to Clostridium difficile colitis

Reactive arthritis is an acute, aseptic, inflammatory arthropathy following an infectious process but removed from the site of primary infection. It is often attributed to genitourinary and enteric pathogens, such as Chlamydia, Salmonella, Shigella, Campylobacter, and Yersinia, in susceptible individuals. An uncommon and less recognized cause of this disease is preceding colonic infection with Clostridium difficile, an organism associated with pseudomembranous colitis and diarrhea in hospitalized patients and those recently exposed to antibiotics. Recognition of this association may be complicated by non-specific presentation of diarrhea, the interval between gastrointestinal and arthritic symptoms, and the wide differential in mono- and oligoarthritis. We present the case of a 61-year-old, hospitalized patient recently treated for C. difficile colitis who developed sudden, non-traumatic, right knee pain and swelling. Physical examination and radiographs disclosed joint effusion, and sterile aspiration produced cloudy fluid with predominant neutrophils and no growth on cultures. Diagnostic accuracy is enhanced by contemporaneous laboratory investigations excluding other entities such as gout and rheumatoid arthritis and other infections that typically precede reactive arthritis. Contribution of Clostridium infection to reactive arthritis is an obscure association frequently difficult to prove, but this organism is warranted inclusion in the differential of reactive arthritis.

Altered PKR Signalling and C / EBPβ Expression is Associated with HLA-B27 Expression in Monocytic Cells

Infection caused by certain gram-negative bacteria, e.g. Salmonella, can trigger inflammatory joint disease reactive arthritis (ReA). It is suggested that the disease-triggering bacteria or bacterial components persist in patients for an abnormally long time. Development of ReA is strongly associated with tissue antigen HLA-B27. Previously, we reported an enhanced replication of Salmonella enteritidis and altered p38 MAP kinase signalling in HLA-B27-expressing monocytic cells. Here we aimed to investigate the role of HLA-B27 in regulation of double-stranded RNA-activated kinase (PKR)-related signalling in Salmonella-infected or Salmonella lipopolysaccharide (LPS)-stimulated human U937 monocytic cells, as PKR has been reported to modify p38 signalling in Salmonella-infected cells. In cells expressing HLA-B27, PKR is overexpressed and hypophosphorylated, and the expression of transcription factor CCAAT enhancer binding protein beta (C/EBPβ) is increased upon Salmonella infection and LPS stimulation. The expression of C/EBPβ is PKR-dependent in LPS-stimulated mock cells, whereas in LPS-stimulated B27 cells the majority of C/EBPβ is expressed in a PKR-independent manner. Our results show that the expression of HLA-B27 disturbs the PKR-mediated signalling pathway. Moreover, altered signalling is related to misfolding-linked Glu45 in the B pocket of the HLA-B27 heavy chain. We suggest that the expression of HLA-B27 HCs modulates the intracellular environment of monocyte/macrophages and the mechanisms that are important in eliminating intracellular S. enteritidis by altering the intracellular signalling. This phenomenon is at least partly dependent on the misfolding feature of the B27 molecule. These observations offer a novel mechanism by which HLA-B27 may modulate inflammatory response induced by ReA-triggering bacteria.

A review of serological tests to assist diagnosis of reactive arthritis: critical appraisal on methodologies

On a population-based level, the incidence of reactive arthritis (ReA) is 0.6–27/100,000. The definition of ReA varies and its pathogenesis is not yet clear. Attempts in basic immunology to suggest hypotheses for proliferation of forbidden B cell clones, molecular mimicry, and involvement of cross-reactive antibodies are helpful but not sufficient. Importantly, for the clinical diagnosis of the preceding infection, serology is widely used. Unfortunately, the accuracy of associations between serologic findings and clinical conclusions is plagued by poor standardization of methods. So far, few attempts have been done to examine the pitfalls of different approaches. Here, we review several serologic techniques, their performance and limitations. We will focus on serology for Yersinia, Campylobacter, Salmonella, Shigella, and Chlamydia trachomatis because these bacteria have a longer history of being associated with ReA. We also address controversies regarding the role of serology for some other bacteria linked to autoimmune disorders.

Post-infectious sequelae of travelers' diarrhea

BACKGROUND

Travelers' diarrhea (TD) has generally been considered a self-limited disorder which resolves more quickly with expeditious and appropriate antibiotic therapy given bacteria are the most frequently identified cause. However, epidemiological, clinical, and basic science evidence identifying a number of chronic health conditions related to these infections has recently emerged which challenges this current paradigm. These include serious and potentially disabling enteric and extra-intestinal long-term complications. Among these are rheumatologic, neurologic, gastrointestinal, renal, and endocrine disorders. This review aims to examine and summarize the current literature pertaining to three of these post-infectious disorders: reactive arthritis, Guillain-Barré syndrome, and post-infectious irritable bowel syndrome and the relationship of these conditions to diarrhea associated with travel as well as to diarrhea associated with gastroenteritis which may not be specifically travel related but relevant by shared microbial pathogens. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

METHODS

Data for this article were identified by searches of PubMed and MEDLINE, and references from relevant articles using search terms "travelers' diarrhea" "reactive arthritis" "Guillain-Barré syndrome" "Post-Infectious Irritable Bowel Syndrome." Abstracts were included when related to previously published work.

RESULTS AND CONCLUSIONS

A review of the published literature reveals that potential consequences of travelers' diarrhea may extend beyond the acute illness and these post-infectious complications may be more common than currently recognized. In addition since TD is such a common occurrence it would be helpful to be able to identify those who might be at greater risk of post-infectious sequelae in order to target more aggressive prophylactic or therapeutic approaches to such individuals. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

Altered regulation of ELAVL1/HuR in HLA-B27-expressing U937 monocytic cells

OBJECTIVE

To investigate the role of HLA-B27 expression in the regulation of RNA binding protein (RBP) Embryonic Lethal Abnormal Vision (ELAV) L1/Human antigen R (HuR) expression in Salmonella-infected or LPS-stimulated human monocytic cells, since HuR is a critical regulator of the post-transcriptional fate of many genes (e.g. TNFα) important in inflammatory response.

METHODS

U937 monocytic cells were stably transfected with pSV2neo resistant vector (mock), wild type HLA-B27, or mutated HLA-B27 with amino acid substitutions in the B pocket. Cells were differentiated, infected with Salmonella enteritidis or stimulated with lipopolysaccharide. The expression levels of HuR protein and cleavage products (CP1 and CP2) were detected by Western blotting and flow cytometry. Specific inhibitors were used to study the role of PKR and p38 in HuR expression and generation of CPs. TNFα and IL-10 secretion after p38 and PKR inhibition were measured by ELISA.

RESULTS

Full length HuR is overexpressed and HuR cleavage is disturbed in U937 monocytic cells expressing HLA-B27 heavy chains (HC). Increased full length HuR expression, disturbed cleavage and reduced dependence on PKR after infection correlate with the expression of glutamic acid 45 in the B pocket that is linked to the misfolding of HLA-B27.

CONCLUSION

Results show that the expression of HLA-B27 HCs modulates the intracellular environment of U937 monocyte/macrophages by altering HuR regulation. This phenomenon is at least partly dependent on the misfolding feature of the B27 molecule. Since HuR is an important regulator of multiple genes involved in inflammatory response observations offer an explanation how HLA-B27 may modulate inflammatory response.

Phosphorylation of STAT-1 serine 727 is prolonged in HLA-B27-expressing human monocytic cells

A tissue antigen, HLA-B27, is strongly associated with a group of rheumatic diseases called spondyloarthritides. Despite the intensive research, the exact role of HLA-B27 in the pathogenesis of these diseases is still unclear. Here we studied whether HLA-B27 modulates the phosphorylation of signal transducer and activator of transcription 1 (STAT-1) serine 727 residue and the localization of STAT-1 in Salmonella-infected human monocytic cells. In addition, we studied the role of signaling molecule double-stranded RNA activated protein kinase (PKR) in these modulatory effects. U937 human monocytic cell transfectants stably expressing wild type HLA-B27 or mutated HLA-B27 heavy chains with amino acid substitutions in the B pocket were prepared. The PMA-differentiated cells were infected with S. enteritidis. Western blotting was used to detect the phosphorylation of STAT-1, and to visualize the localization of STAT-1 in the cells confocal microscopy was used. Specific inhibitors were employed to study the role of PKR in STAT-1 phosphorylation. We discovered that the phosphorylation of STAT-1 serine 727 is prolonged in cells expressing misfolding forms of HLA-B27 after S. enteritidis infection, whereas in mock cells and in cells expressing mutated, non-misfolding HLA-B27 the phosphorylation of serine 727 is transient. Interestingly, STAT-1 serine 727 phosphorylation is partly dependent on PKR. In addition, more STAT-1 is localized in the nucleus of HLA-B27-expressing cells, even before an external trigger, when compared to mock cells. In conclusion, our results show that the phosphorylation of STAT-1 serine 727 residue is prolonged in HLA-B27-expressing monocyte-macrophage U937 cells after bacterial infection. This is of interest since the phosphorylation of serine 727 on STAT-1 is suggested to contribute to macrophage activation and promote inflammatory responses. Therefore, our results provide a mechanism which explains how the expression of an HLA-B27 molecule can impact the course of Salmonella infection and reactive arthritis.

Chronic Lyme Disease and Co-infections: Differential Diagnosis

In Lyme disease concurrent infections frequently occur. The clinical and pathological impact of co-infections was first recognized in the 1990th, i.e. approximately ten years after the discovery of Lyme disease. Their pathological synergism can exacerbate Lyme disease or induce similar disease manifestations. Co-infecting agents can be transmitted together with Borrelia burgdorferi by tick bite resulting in multiple infections but a fraction of co-infections occur independently of tick bite. Clinically relevant co-infections are caused by Bartonella species, Yersinia enterocolitica, Chlamydophila pneumoniae, Chlamydia trachomatis, and Mycoplasma pneumoniae. In contrast to the USA, human granulocytic anaplasmosis (HGA) and babesiosis are not of major importance in Europe. Infections caused by these pathogens in patients not infected by Borrelia burgdorferi can result in clinical symptoms similar to those occurring in Lyme disease. This applies particularly to infections caused by Bartonella henselae, Yersinia enterocolitica, and Mycoplasma pneumoniae. Chlamydia trachomatis primarily causes polyarthritis. Chlamydophila pneumoniae not only causes arthritis but also affects the nervous system and the heart, which renders the differential diagnosis difficult. The diagnosis is even more complex when co-infections occur in association with Lyme disease. Treatment recommendations are based on individual expert opinions. In antibiotic therapy, the use of third generation cephalosporins should only be considered in cases of Lyme disease. The same applies to carbapenems, which however are used occasionally in infections caused by Yersinia enterocolitica. For the remaining infections predominantly tetracyclines and macrolides are used. Quinolones are for alternative treatment, particularly gemifloxacin. For Bartonella henselae, Chlamydia trachomatis, and Chlamydophila pneumoniae the combination with rifampicin is recommended. Erythromycin is the drug of choice for Campylobacter jejuni.

HLA-B27 modulates intracellular growth of Salmonella pathogenicity island 2 mutants and production of cytokines in infected monocytic U937 cells

BACKGROUND

Salmonella enterica serovar Enteritidis PT4 KS8822/88 replicates rapidly in HLA-B27-transfected human monocytic U937 cells. In this process, Salmonella pathogenicity island 2 (SPI-2) genes play a crucial role. Our previous study indicated that 118 Salmonella genes, including 8 SPI-2 genes were affected by HLA-B27 antigen during Salmonella infection of U937 cells.

METHODS/PRINCIPAL FINDINGS

To further investigate Salmonella replication in HLA-B27-positive U937 monocytic cells, two SPI-2 genes, ssaS and sscA up-regulated most during Salmonella infection of HLA-B27-transfected U937 cells, were mutated by using one-step gene disruption method. Intracellular survival and replication of the mutants in the U937 cells was compared to that of the wild type strain. Surprisingly, the two mutated strains replicated significantly more than the wild type bacteria in HLA-B27-transfected cells. Secretion of tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) was significantly induced during the infection of HLA-B27-transfected U937 cells with the mutants. The results indicated that the certain SPI-2 genes in wild type bacteria suppress Salmonella intracellular growth and production of cytokines in infected HLA-B27-transfected cells. HLA-B27-associated modulation of Salmonella SPI-2 genes and cytokine production may have importance in the persistent infection of the bacteria and the pathogenesis of reactive arthritis.

CONCLUSIONS

The study provides evidence that certain virulence factors of pathogens can reduce the intracellular growth in the host cells. We suggest that the limiting intracellular growth might be a strategy for persistence of bacteria in host cells, keeping a balance between pathogenic growth and pathogenesis.

[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.

Anti-Yersinia antibodies are not associated with microscopic colitis in an American case-control study

BACKGROUND

Microscopic colitis (MC), which consists of lymphocytic colitis and collagenous colitis, may be triggered by gastrointestinal infections. Studies have suggested a relationship between MC and Yersinia enterocolitica infection. We tested this hypothesis in a case-control study of American patients with MC.

METHODS

Serum was collected from 47 patients with MC and 44 age- and gender-matched healthy controls at a large referral center in the mid-western United States. Anti-IgA and IgG antibodies to Y. enterocolitica were measured using an enzyme-linked immunosorbent assay (ELISA). Fisher's exact test was used to assess statistical significance.

RESULTS

There were no differences between the two groups for seroprevalence of anti-Yersinia IgA (cases 2.1%, controls 2.3%, p = 1.00) or IgG antibodies (cases 4.3%, controls 6.8%, p = 0.67). There was no correlation between antibody titers and duration of MC diagnosis.

CONCLUSION

Our data do not support the role of exposure to Y. enterocolitica in an American group of patients with MC.

Microarray analysis of response of Salmonella during infection of HLA-B27- transfected human macrophage-like U937 cells

BACKGROUND

Human leukocyte antigen (HLA)-B27 is strongly associated with the development of reactive arthritis (ReA) in humans after salmonellosis. Human monocytic U937 cells transfected with HLA-B27 are less able to eliminate intracellular Salmonella enterica serovar Enteritidis than those transfected with control HLA antigens (e.g. HLA-A2). To investigate further the mechanisms by which HLA-B27-transfected cells allow increased replication of these bacteria, a DNA-based microarray was used for comparative genomic analysis of S. Enteritidis grown in HLA-B27- or HLA-A2-transfected cells. The microarray consisted of 5080 oligonucleotides from different serovars of Salmonella including S. Enteritidis PT4-specific genes. Bacterial RNA was isolated from the infected HLA-B27- or HLA-A2-transfected cells, reverse-transcribed to cDNA, and hybridized with the oligonucleotides on the microarrays. Some microarray results were confirmed by RT-PCR.

RESULTS

When gene expression was compared between Salmonella grown in HLA-B27 cells and in HLA-A2 cells, 118 of the 4610 S. Enteritidis-related genes differed in expression at 8 h after infection, but no significant difference was detectable at 2 h after infection. These differentially expressed genes are mainly involved in Salmonella virulence, DNA replication, energy conversion and metabolism, and uptake and metabolism of nutrient substances, etc. The difference suggests HLA-B27-dependent modulation of Salmonella gene expression, resulting in increased Salmonella replication in HLA-B27-positive cells. Among the up-regulated genes were those located in Salmonella pathogenicity island (SPI)-2, which play a central role in intracellular survival and replication of Salmonella.

CONCLUSIONS

This is the first report to show the regulation of Salmonella gene expression by HLA-B27 during infection of host cells. This regulation probably leads to increased Salmonella survival and replication in HLA-B27-positive cells. SPI-2 genes seem to contribute significantly to the increased replication.

The role of antibodies in inflammatory arthritis

Inflammatory arthritis presents in a variety of diseases, from rheumatoid arthritis to hepatitis. Antibodies to autoantigens or to microbial constituents are commonly associated with these conditions. In some cases, the antibodies have diagnostic and prognostic relevance. It cannot as yet be determined definitively that any of them mediate joint damage, although the evidence from animal models indicates that this mechanism is likely. The purpose of this article is to give an overview of the spectrum of antibodies found in a variety of inflammatory arthritides. The relevant animal models are also discussed.

Cellular and humoral markers of systemic inflammation in acute reactive arthritis and early rheumatoid arthritis

OBJECTIVE

To compare systemic inflammation in reactive arthritis (ReA), rheumatoid arthritis (RA), and sepsis using novel markers of systemic inflammation, and to study whether they are helpful in distinguishing between ReA and RA.

METHODS

In 28 patients with acute ReA, 16 patients with early untreated RA, and 25 patients with blood culture-positive sepsis, phagocyte CD 11b expression was measured by flow cytometry, serum procalcitonin (PCT) levels by immunoluminometric assay, and soluble E-selectin (sE-selectin) levels by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Neutrophil and monocyte CD11b expression and serum levels of PCT and sE-selectin were higher in patients with sepsis than patients with ReA or RA, or in healthy subjects (all p < 0.01). They were comparable in healthy subjects, ReA, and RA.

CONCLUSION

Patients with acute ReA and early RA have normal CD11b expression levels on phagocytes and normal PCT and sE-selectin levels in serum. Elevated levels suggest possible sepsis.

Yersinia EnterocoliticaO:3 Isolated from Patients with or without Reactive Arthritis Induces Polyclonal Activation of B Cells and Autoantibody ProductionIn Vivo

The mechanisms by which arthritis-provoking pathogens such as Yersinia enterocolitica interact with the human immune system to produce inflammatory synovitis are not well known. One of the immunomodulating mechanisms used against these pathogens is the polyclonal activation of lymphocytes. In this study, we investigated the extent of the B-lymphocyte activation induced in mice by a strain of Y. enterocolitica O:3 (FCF 526) isolated from a patient with arthritis, and compared it with two other strains, a virulent one (FCF 397[+]) isolated from a patient without arthritis and its plasmidless isogenic pair (FCF397[-]). Also we investigated the production of autoantibodies in mice infected with these different strains. SPF Swiss mice were infected intravenously with a suspension of Y. enterocolitica. Spleen cells were taken on days 7, 14, 21 and 28 after infection and the number of cells secreting nonspecific and specific antibodies of IgG1, IgG2a, IgG2b, IgG3, IgM and IgA isotypes were determined by the ELISPOT technique. The presence of autoantibodies in mouse serum was investigated by the dot-blot assay. The pattern of infection of the three bacterial strains were almost the same. We observed a general increase in the number of nonspecific Ig-secreting cells with all three strains, and the greatest increases observed were in the IgG2a and IgG3 isotypes. Only a small fraction of the immunoglobulins detected were antibacterial, suggesting that the rest resulted from polyclonal B cell activation. The strain isolated from the patient with arthritis (FCF526) induced the greatest production of autoantibodies, coinciding with the period in which the greatest activation of nonspecific B lymphocytes was seen. There were no signs of arthritis or inflammation in the joints of the infected animals. Based on our results, we were unable to determine whether there is an association between the arthritogenic capability of Y. enterocolitica and polyclonal activation of B cells.

Kinetics of B cell Response DuringYersinia enterocoliticaInfection in Resistant and Susceptible Strains of Mice

In this study we analyze the B-cell response in murine yersiniosis. To this end, we determined whether polyclonal activation of B-lymphocytes occurs during infection of susceptible (BALB/c) and resistant (C57BL/6) mice with Y. enterocolitica O:8 and compared the immunoglobulin (Ig) isotypes produced in response to the infection by the two strains. The number of splenic cells secreting nonspecific and specific immunoglobulins was determined by ELISPOT. The presence of anti-Yersinia antibodies in serum was detected by ELISA. In both strains, the number of specific Ig-secreting cells was relatively low. Polyclonal B-cell activation was observed in both strains of mice, and the greatest activation was observed in the BALB/c mice, mainly for IgG1- and IgG3- secreting cells. The C57BL/6 mice showed a predominance of IgG2a-secreting cells. The peak production of anti-Yersinia IgG antibodies in the sera of BALB/c mice was seen on the 28th day after infection. The greatest increase in IgM occurred on the 14th day. A progressive increase of specific IgG antibodies was observed in C57BL/6 mice up to the 28th day after infection while IgM increased on the 21st day after infection. The production of specific IgA antibodies was not detected in either BALB/c or C57BL/6 mice. We conclude that polyclonal activation of B lymphocytes occurs in both the Yersinia-resistant and Yersinia-susceptible mice and that the more intense activation of B lymphocytes observed in the susceptible BALB/c mice does not enhance their resistance to Y. enterocolitica infection.

Broad-range PCR, cloning and sequencing of the full 16S rRNA gene for detection of bacterial DNA in synovial fluid samples of Tunisian patients with reactive and undifferentiated arthritis

Introduction

Broad-range rDNA PCR provides an alternative, cultivation-independent approach for identifying bacterial DNA in reactive and other form of arthritis. The aim of this study was to use broad-range rDNA PCR targeting the 16S rRNA gene in patients with reactive and other forms of arthritis and to screen for the presence of DNA from any given bacterial species in synovial fluid (SF) samples.

Methods

We examined the SF samples from a total of 27 patients consisting of patients with reactive arthritis (ReA) (n = 5), undifferentiated arthritis (UA) (n = 9), rheumatoid arthritis (n = 7), and osteoarthritis (n = 6) of which the latter two were used as controls. Using broad-range bacterial PCR amplifying a 1400 bp fragment from the 16S rRNA gene, we identified and sequenced at least 24 clones from each SF sample. To identify the corresponding bacteria, DNA sequences were compared to the EMBL (European Molecular Biology Laboratory) database.

Results

Bacterial DNA was identified in 20 of the 27 SF samples (74, 10%). Analysis of a large number of sequences revealed the presence of DNA from more than one single bacterial species in the SF of all patients studied. The nearly complete sequences of the 1400 bp were obtained for most of the detected species. DNA of bacterial species including Shigella species, Escherichia species, and other coli-form bacteria as well as opportunistic pathogens such as Stenotrophomonas maltophilia and Achromobacter xylosoxidans were shared in all arthritis patients. Among pathogens described to trigger ReA, DNA from Shigella sonnei was found in ReA and UA patients. We also detected DNA from rarely occurring human pathogens such as Aranicola species and Pantoea ananatis. We also found DNA from bacteria so far not described in human infections such as Bacillus niacini, Paenibacillus humicus, Diaphorobacter species and uncultured bacterium genera incertae sedis OP10.

Conclusions

Broad-range PCR followed by cloning and sequencing the entire 16S rDNA, allowed the identification of the bacterial DNA environment in the SF samples of arthritic patients. We found a wide spectrum of bacteria including those known to be involved in ReA and others not previously associated with arthritis.

HLA-B27 and host-pathogen interaction

HLA-B27 is a risk factor closely associated to spondyloarthropathies (SpA). One form of SpA is reactive arthritis (ReA), which develops as a complication after certain bacterial infections (e.g., Salmonellae, Yersiniae, Shigellae, Campylobacteriae and Chlamydiae). The development of infection-triggered complication is a complex train of events between the triggering bacteria and the host. Since most of the patients suffering from ReA are HLA-B27 positive, it has been proposed that HLA-B27 may modulate the interaction between ReA-triggering bacteria and host cell. Besides antigen presenting function, HLA-B27 displays other unusual properties that might be of importance in the development of ReA. These properties (homodimer formation and misfolding of HLA-B27 heavy chain in the endoplasmic reticulum (ER)) may trigger ER-stress signaling pathways in host cell, which in turn may modulate cell signaling in favor of ReA-triggering bacteria. Here we summarize the observations of HLA-B27 modulating the interaction between ReA-triggering bacteria and host cell and discuss potential mechanisms behind the interaction.

Evidence that the p38 MAP kinase pathway is dysregulated in HLA-B27-expressing human monocytic cells: correlation with HLA-B27 misfolding

OBJECTIVE

To investigate the cause of the enhanced intracellular replication of Salmonella enteritidis in HLA-B27-transfected U937 human monocytic cells and the contribution of HLA-B27 heavy chain (HC) misfolding.

METHODS

U937 monocytic cell transfectants stably expressing pSV2neo resistant vector (mock), wild-type HLA-B27, or mutated HLA-B27 HCs with amino acid substitutions in the B pocket were differentiated, infected with S enteritidis, and treated with signaling pathway inhibitors or specific p38 small interfering RNA (siRNA). The numbers of living intracellular bacteria were determined with the colony-forming unit method. To visualize S enteritidis, the bacteria were transformed with green fluorescent protein, and studied by microscopy.

RESULTS

Treatment with the p38 MAPK inhibitors or with p38 siRNA enhanced the replication of S enteritidis in U937 transfectants, whereas the other inhibitors had no effect. In mock-transfected cells and in cells expressing the mutated B27 HCs in which the misfolding had been corrected, p38 inhibitors impaired their ability to resist the replication of bacteria (mock, B27.A2B, B27.E45M, and B27.C67A). In contrast, the number of intracellular bacteria was not significantly increased in p38 inhibitor-treated cells expressing misfolded B27 HCs (B27g, B27cDNA, and B27.H9F).

CONCLUSION

Our results show that p38 activity plays a crucial role in controlling intracellular S enteritidis in U937 cells. Enhanced replication of bacteria in B27-expressing cells requires that the HCs contain glutamic acid at position 45 and cysteine at position 67. Furthermore, in transfectants expressing misfolded B27 HCs, p38 inhibition had no significant effect on bacterial replication, suggesting that in these cells, the p38 pathway may not function properly.

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).

Helicobacter pylori: an underestimated factor in acute anterior uveitis and spondyloarthropathies?

Acute anterior uveitis (AAU) is the most common form of intraocular inflammation, but its aetiology is still unclear. Fifty percent of AAU patients are HLA-B27-positive, and half of these also have spondyloarthropathies (SpA). Numerous serological studies have shown elevated levels of serum antibodies to various Gram-negative bacteria in HLA-B27-positive AAU and SpA patients. Antigenic similarities between these bacteria and host components (HLA-B27) have already been shown. Still, the mechanism underlying these diseases has not been clarified. Among the Gram-negative bacteria, Helicobacter pylori has not been screened in AAU patients. The purpose of our study was to see if this common human pathogen somehow interferes with AAU. In addition Chlamydia trachomatis, Yersinia enterocolitica 03 and 09, Salmonella sp. and Proteus OX19 were also examined. A total of 60 patients consisting of 4 groups (15 patients with AAU, 15 with SpA, 15 with AAU+SpA and 15 healthy control persons) were examined. A high percentage of the serological results of all investigated bacteria was positive: 80% in the AAU, 93.3% in the SpA and 100% in the AAU+SpA group, while it amounted to 66.7% in the control group (p < 0.05). H. pylori showed the highest percentage of positivity in all 3 patient groups (66.7% in the AAU, 73.3% in the SpA and 80% in the AAU+SpA group). In contrast, 26.7% of the controls were anti-H.-pylori-positive, thus showing a statistically significant difference between the patients and the control group (p < 0.05). HLA-B27/B7-CREG positivity was detected in 53.3% of the AAU, 66.7% of the SpA and 93.3% of the AAU+SpA patients and in none of the controls. Our results suggest that H. pylori might be a candidate participating in the development of AAU and SpA. They also support the theory of genetic (HLA-B27) and exogenous factors (Gram-negative bacteria) as probable background of these diseases.

When is arthritis reactive?

Reactive arthritis is an important cause of lower limb oligoarthritis, mainly in young adults. It is one of the spondyloarthropathy family; it is distinguishable from other forms of inflammatory arthritis by virtue of the distribution of affected sites and the high prevalence of characteristic extra-articular lesions. Many terms have been used to refer to this and related forms of arthritis leading to some confusion. Reactive arthritis is precipitated by an infection at a distant site and genetic susceptibility is marked by possession of the HLA-B27 gene, although the mechanism remains uncertain. Diagnosis is a two stage process and requires demonstration of a temporal link with a recognised "trigger" infection. The identification and management of "sexually acquired" and "enteric" forms of reactive arthritis are considered. Putative links with HIV infection are also discussed. The clinical features, approach to investigation, diagnosis, and management of reactive arthritis are reviewed.

Reactive arthritis

Reactive arthritis (ReA) has been recognized as a clinical disease entity for nearly 100 years. The prevalence is estimated to be 30-40/100,000 adults. The HLA-B27-associated form is part of the spondyloarthritis concept. According to the current hypothesis the arthritis follows a primary extra-articular infection and is characterized by the presence of bacterial antigen and/or of viable but non-culturable bacteria persisting within the joint. Pathogenesis involves the modification of host cells by pathogen-associated molecular patterns (PAMPs, e.g. lipopolysaccharide), bacterial effector proteins, the adaptive immune system, and the genetic background. Up to 30% of patients develop chronic symptoms, and therapeutic options for these patients are still limited. Data for recommendations to apply conventional disease-modifying anti-rheumatic drugs (DMARDs) are rare; however, sulfasalazine seems to be effective, and first reports on agents that block tumour necrosis factor (TNF) are promising. Combination therapy of several antibiotics might open the window to curing the disease; however, controlled clinical studies are needed.

Identification of immunodominant CD4+ T cell epitopes in patients withYersinia-induced reactive arthritis by cytometric cytokine secretion assay

OBJECTIVE

In reactive arthritis (ReA), a bacteria-specific T cell response to the triggering microbe is detected in synovial fluid. So far, direct characterization of bacteria-specific T cells and identification of the immunodominant fine specificities remain difficult due to the lack of appropriate techniques. The aim of the present study was to directly determine the fine specificity of CD4+ T cells specific to ReA-associated bacteria-derived protein.

METHODS

In 2 patients with Yersinia-induced ReA, live Yersinia Hsp60-specific CD4+ T cells were directly isolated from synovial fluid after stimulation with Yersinia-derived protein Hsp60 using a cytometric cytokine secretion assay. Generated short-term T cell lines were then tested in vitro for their peptide epitope specificity. Also, direct cross-reactivity of one line with Chlamydia- and human-derived Hsp60 was assessed.

RESULTS

Generated short-term CD4+ T cell lines were highly antigen-specific and revealed single immunodominant peptide epitopes that were confirmed by direct testing with single peptides in both peripheral blood and synovial fluid cells. Yersinia Hsp60-specific T cells of one patient cross-reacted directly with human Hsp60.

CONCLUSION

Our results demonstrate the feasibility of direct assessment of live, potentially pathogenic, antigen-specific interferon-gamma+ CD4+ T cells taken from inflammatory lesions of patients with rheumatic diseases such as ReA. This might have implications not only regarding pathogenesis, but also in the design of new immunotherapies.

Aetiology and pathogenesis of reactive arthritis: role of non-antigen-presenting effects of HLA-B27

Spondyloarthropathies are inflammatory diseases closely associated with human leukocyte antigen (HLA)-B27 by unknown mechanisms. One of these diseases is reactive arthritis (ReA), which is typically triggered by Gram-negative bacteria, which have lipopolysaccharide as an integral component of their outer membrane. Several findings in vivo and in vitro obtained from patients with ReA and from different model systems suggest that HLA-B27 modulates the interaction between ReA-triggering bacteria and immune cells by a mechanism unrelated to the antigen presentation function of HLA-B27. In this review we piece together a jigsaw puzzle from the new information obtained from the non-antigen-presenting effects of HLA-B27.

Three month treatment of reactive arthritis with azithromycin: a EULAR double blind, placebo controlled study

OBJECTIVE

To determine the efficacy of weekly treatment with oral azithromycin for 13 weeks on the severity and resolution of reactive arthritis (ReA).

METHODS

186 patients from 12 countries were enrolled in a randomised, double blind, placebo controlled trial. Inclusion criteria were inflammatory arthritis of < or =6 swollen joints, and disease duration of < or =2 months. All patients received a single azithromycin dose (1 g) as conventional treatment for possible Chlamydia infection, and were then randomly allocated to receive weekly azithromycin or placebo. Clinical assessments were made at 4 week intervals for 24 weeks.

RESULTS

152 patients were analysable (34 failed entry criteria), with a mean (SD) age of 33.8 (9.4) and duration of symptoms 30.7 (17.5) days. Mean C reactive protein (CRP) was 48 mg/l, and approximately 50% of those typed were HLA-B27+, suggesting that the inclusion criteria successfully recruited patients with acute ReA. Treatment and placebo groups were well matched for baseline characteristics. There were no statistical differences for changes in any end point (swollen and tender joint count, joint pain, back pain, heel pain, physician and patient global assessments, and CRP) between the active treatment and placebo groups, analysed on an intention to treat basis or according to protocol completion. The time to resolution of arthritis and other symptoms or signs by life table analyses was also not significantly different. Adverse events were generally mild, but were more commonly reported in the azithromycin group.

CONCLUSIONS

This large trial has demonstrated that prolonged treatment with azithromycin is ineffective in ReA.

HLA-B27-associated reactive arthritis: pathogenetic and clinical considerations

Current evidence supports the concept that reactive arthritis (ReA) is an immune-mediated synovitis resulting from slow bacterial infections and showing intra-articular persistence of viable, non-culturable bacteria and/or immunogenetic bacterial antigens synthesized by metabolically active bacteria residing in the joint and/or elsewhere in the body. The mechanisms that lead to the development of ReA are complex and basically involve an interaction between an arthritogenic agent and a predisposed host. The way in which a host accommodates to invasive facultative intracellular bacteria is the key to the development of ReA. The details of the molecular pathways that explain the articular and extra-articular manifestations of the disease are still under investigation. Several studies have been done to gain a better understanding of the pathogenesis of ReA; these constitute the basis for a more rational therapeutic approach to this disease.

Myeloid differentiation factor 88-dependent transcriptional regulation of cyclooxygenase-2 expression by CpG DNA: role of NF-kappaB and p38

CpG DNA induces macrophage cyclooxgenase-2 (Cox-2) production. In this study, we have investigated a biochemical signaling pathway and transcription factors responsible for transcriptional regulation of the Cox-2 gene expression induced by CpG DNA. CpG DNA-induced Cox-2 promoter activity was completely inhibited by an endosomal acidification inhibitor (chloroquine), a TLR9 antagonist inhibitory CpG DNA, or overexpression of a dominant negative (DN) form of MyD88. In contrast, overexpression of DN-IRAK1 or DN-TRAF6 only partially inhibited CpG DNA-induced Cox-2 promoter activity and NF-kappaB activation, indicating the presence of additional signaling modulators downstream of MyD88. CpG DNA-induced Cox-2 promoter activity was substantially suppressed in cells overexpressing super-suppressive IkappaB (IkappaB-arachidonic acid), DN-p38, or DN-CREB. In addition, Cox-2 promoter-luciferase reporters with alterations in predicted cis-acting transcriptional regulatory elements revealed that C/EBP, Ets-1, NF-kappaB, and CREB-binding sites are essential for optimal Cox-2 expression in response to CpG DNA. Conclusively, these results demonstrate that endosomal DNA processing and TLR9/MyD88-dependent activation of NF-kappaB and p38 are required for transcriptional regulation of Cox-2 expression induced by CpG DNA, and suggest that interleukin-1 receptor-associated kinase and/or TRAF6 may be a diverging point for NF-kappaB activation in response to CpG DNA in RAW264.7 cells.

Role of bacteria and HLA-B27 in the pathogenesis of reactive arthritis

Strictly speaking, "reactive arthritis" is a conventional term with no study-verified definition. This review will focus on the type of arthritis that is induced by the following species: Chlamydia, Shigella, Salmonella, Yersinia, and Campylobacter. The types of arthritis caused by these pathogens share a clinical pattern that is common in the spondyloarthropathies, especially undifferentiated spondyloarthropathy and Reiter's syndrome. All these diseases, including ankylosing spondylitis, must also share major pathogenetic pathways.

The role of infection in the pathogenesis of spondyloarthropathies with special reference to human leukocyte antigen-B27

Spondyloarthropathies consist of many inflammatory diseases that are closely associated with human leukocyte antigen (HLA)-B27. One of these diseases is reactive arthritis (ReA), which is a joint inflammation that occurs after infections that are caused by certain gram-negative bacteria. The importance of these infections as causative agents of ReA has been clearly established. It is not clear, however, whether these infections contribute to the development of other forms of spondyloarthropathies. The exact mechanism by which HLA-B27 influences disease susceptibility in spondyloarthropathies remains to be determined. The role of HLA-B27 as an antigen-presenting molecule is certainly important in the pathogenesis of these diseases; however, recent data indicate that this molecule may exhibit other functions unrelated to antigen presentation, which may be important in the pathogenesis of ReA. In this paper, the authors summarize the current knowledge of the role of infection in the spondyloarthropathies.

Restriction in the usage of variable beta regions in T-cells infiltrating valvular tissue from rheumatic heart disease patients

Rheumatic Heart Disease (RHD) is a delayed consequence of a pharyngeal infection with group A streptococcus (GAS), usually ascribed to a cross-reactive immune response to the host's cardiac tissues. Several GAS proteins have been reported to be superantigens, also raising the possibility that T cells in RHD could be driven by superantigens. We therefore analysed the variable beta (V beta) repertoire of T cells infiltrating heart valves from chronic RHD patients undergoing elective valvular surgery. We analysed 15 valve specimens from patients with longstanding quiescent RHD and control valves from four non-rheumatic individuals. Total RNA was extracted from fresh valve tissue and employed to amplify 22 V beta genes by RT-PCR. In valvular tissue, a restricted number of only 2 to 9 V beta regions were detected as opposed to the findings in control valves. In 8 RHD valves, the expression of V beta1, 2, 3, 5.1, 7, 8, 9 or 14 was marked. These V beta regions have been related to GAS superantigens. Our results evidence the presence of a restricted set of T lymphocytes in valvular tissue from a majority of patients with chronic RHD and suggest that valvular sequelae in these patients might be related to a local antigen or superantigen driven inflammatory process that persists even many years after the initial triggering event.

Seronegative spondyloarthritides

Epidemiological studies on the spondyloarthritides have been hindered in the past by the lack of adequate classification criteria for the whole group of these diseases. Using the Amor and the European Spondyloathropathy Study Group (ESSG) criteria the total prevalence of such diseases has been found to be higher than estimated in the past. The prevalence of ankylosing spondylitis varies across populations, but closely parallels the frequency of HLA B27-associated subtypes. The lack of well established criteria for reactive arthritis and the varying expression of its clinical manifestations are the principal reasons for the under-reporting of the true prevalence and incidence of this type of spondyloarthritis. Few data exist on the prevalence and incidence of psoriatic arthritis. A recent European study on an inception cohort of patients having inflammatory bowel disease has evaluated the prevalence of spondyloarthritis using the ESSG criteria. Of the patients studied, 18% met these criteria. Undifferentiated spondyloarthritis is one of the most frequent spondyloarthritides. It also includes a number of different subtypes.