Immunomodulatory effects of etanercept on peripheral joint synovitis in the spondylarthropathies

OBJECTIVE

Because different tumor necrosis factor alpha (TNFalpha) blockers may have distinct immunomodulatory effects on specific disease manifestations, the present study was carried out to investigate the immunomodulating effects of etanercept on peripheral synovitis in the spondylarthropathies (SpA).

METHODS

Peripheral joint disease was assessed clinically, histologically, and radiologically in a prospective 2-year study of 20 patients with SpA treated with etanercept. Synovial tissue biopsy samples obtained at weeks 0, 12, and 52 were analyzed by histology and immunohistochemistry for the extent of inflammation, changes to tissue architecture, and matrix degradation. Serum levels of myeloid-related protein 8 (MRP-8)/MRP-14, matrix metalloproteinase 3 (MMP-3), and cartilage oligomeric matrix protein (COMP) were determined by enzyme-linked immunosorbent assay.

RESULTS

Etanercept induced a rapid and sustained clinical improvement of peripheral joint disease. Histologic synovitis was down-regulated, with a profound reduction in global cellular infiltration and T lymphocytes, but not B lymphocytes. The most prominent change in markers of inflammation was a reduction in the different macrophage subsets (CD68, CD163, MRP-8, and MRP-14), but this was not paralleled by a decrease in serum MRP-8/MRP-14. Structural changes included normalization of lining layer hyperplasia and a moderate reduction in vascularity. However, no effect on the microarchitecture of lymphoid aggregates was observed. In terms of an effect on matrix degradation, the synovial expression of MMP-3 and MMP-9 was down-modulated in correlation with a rapid and profound decrease in serum MMP-3. At week 52, serum COMP levels were also reduced. No significant radiologic disease progression was observed in these patients over a 2-year period.

CONCLUSION

Use of etanercept effectively down-modulated the immunopathologic processes of SpA synovitis, both in the short term and in the long term.

[Hla-B27 gene: polymorphism, evolution, distribution, and association with spondyloartopathies]

The association between HLA-B27 and ankylosing spondylitis is well established more than thirty years. In spite of numerous studies in this field, a lot of unknown is still present. In this review, polymorphism, evolution, distribution and current pathogenetic hypotheses are presented.

Biological therapies in autoimmune chronic inflammatory diseases (ACIDs)

Autoimmune chronic inflammatory diseases (ACIDs) represent a growing part of chronic diseases and their cellular and molecular pathways have been deeply investigated in recent years in order to disclose some clue aspects that could be optimal targets of specific therapies. Among the autoimmune rheumatic diseases a major molecular driver was discovered (TNFalpha) which represents along with IL1beta, a key driver of the ongoing chronic inflammation. The same molecule arose as a major player in the pathological mechanism of Crohn's disease. The biomolecular pathways of Ulcerative Colitis appear more complex and not yet defined, although targeting specific integrins (alpha4beta7) has shown some promises, pending the severe side effects related to treatment.

Chronic intestinal inflammation and seronegative spondyloarthropathy in children

BACKGROUND

Spondyloarthropathy in adults has been shown to be associated with either clinical or subclinical intestinal inflammation, however this association has rarely been described in children.

AIM

To report paediatric patients primarily referred to a paediatric gastroenterology centre for suspected inflammatory bowel disease and found to be affected by a seronegative spondyloarthropathy. Intestinal inflammatory lesions and rheumatological features have been described in them.

SUBJECTS

During a 18-month period, 129 children were referred because of symptoms and signs suggesting an inflammatory bowel disease; 31 of them (range age: 5-17 years) were selected because they also had signs of axial and/or peripheral arthropathy and form the basis of our study.

METHODS

The investigated patients underwent ileo-colonoscopy with biopsy and rheumatological assessment that also included X-ray and magnetic resonance imaging of the sacroiliac joints.

RESULTS

Only seven children had a classical inflammatory bowel disease (four had ulcerative colitis, three had Crohn's disease), 12 had an indeterminate colitis, 12 a lymphoid nodular hyperplasia of the distal ileum as main feature. In the latter two groups, endoscopy and histology revealed an intestinal inflammation of chronic type distinct from the classical pattern found in inflammatory bowel disease. All were HLA B27 negative and fulfilled the European Spondyloarthropathy Study Group criteria for spondyloarthropathy (except five children classified as undifferentiated spondyloarthropathy).

CONCLUSIONS

In a group of children primarily investigated for suspected inflammatory bowel disease and also presenting a seronegative spondyloarthropathy we have described both intestinal and rheumatological features. The majority of them exhibited either an indeterminate colitis or a lymphoid nodular hyperplasia of the distal ileum as main feature. These patients may be a population at risk of developing a full inflammatory bowel disease phenotype.

Oral and salivary parameters in patients with rheumatic diseases

We studied the presence of secondary Sjögren's syndrome (SS) and the composition of saliva, prevalence of oral pathogens, periodontitis, mouth mucosa, and teeth in patients with various rheumatic diseases and in healthy controls. The hypothesis was that different rheumatic diseases might cause differences in oral health characteristics because of the liability of secondary SS in the patients. The study involved 77 patients and 77 age-matched and sex-matched controls. Twenty patients were suffering from spondylarthropathy (SPA), 18 from ankylosing spondylitis (AS), 24 from rheumatoid arthritis (RA), and 15 from mixed connective tissue disease (MCTD). Clinical and radiographic oral health status was recorded and salivary flow rates were measured. Selected salivary proteins and immunoglobulins were analysed by routine methods. Minor salivary gland biopsy samples were taken from the patients for assessment of inflammatory focus scores. Differences between patients and controls and in between the different rheumatic diseases were analysed statistically. Secondary SS was diagnosed in 39% (30/77) of the patients. A severe periodontal condition (community periodontal index of treatment needs score 3 or 4) occurred in 58% (45/77) of the rheumatic patients compared with only 26% (20/77) of the controls (p < 0.0001). The severity of focal sialadenitis (focus score) correlated significant with salivary IgA, IgG, and IgM concentrations. Salivary albumin, total protein, IgG, and IgM concentrations were higher in all patient groups than in the controls. The number of patients with low salivary flow rates was higher in all patient groups compared to controls. Oral yeast counts were significantly higher in the patients than in the controls (p < 0.001). In a subgroup analysis, patients with SS had higher values for salivary IgA and IgM than patients without SS. Dental caries and oral lactobacilli were more frequent in patients with SS, but SS was not associated with periodontitis. No major differences were noted in other salivary biochemical parameters between these two groups. Patients with rheumatic diseases, irrespective of specific diagnosis, thus had various alterations in salivary flow and composition and oral health. The findings may reflect the autoimmune inflammation of the salivary glands frequently observed in these patients.

Spondylarthropathies et médicaments anti-TNFα

PURPOSE

Spondylarthropathies are a heterogeneous group of disorders including ankylosing spondylitis, psoriatic arthritis, reactive arthritis, arthritis associated with inflammatory bowel disease, and undifferentiated spondylarthropathies. These diseases are characterised by inflammation in the spine, sacroiliac joints, entheses, peripheral joints, and a strong association with HLA-B27; they may cause severe destruction and/or ankylosis in a minority of patients. Conventional treatment includes non steroidal anti-inflammatory drugs, corticosteroid injections, and DMARDs such as sulfasalazine in patients with peripheral arthritis. TNFalpha appears as an important actor in the pathogenesis of spondylarthropathies.

METHOD AND RESULTS

Among the anti-TNFalpha drugs, etanercept and infliximab have proved to be effective in the symptomatic treatment of ankylosing spondylitis and psoriatic arthritis. A clinical relapse was observed within a few weeks after treatment discontinuation in a majority of patients. Potential beneficial effects on the destructive and/or ankylosing evolution remains to be confirmed.

CONCLUSIONS

Patients with active, severe and refractory spondylarthropathies are potential candidates for treatment with anti-TNFalpha drugs. Taking into account not only the efficacy but also the side effects, with rare but potentially severe complications such as tuberculosis or other opportunistic infections, and the relatively high cost of these drugs, preliminary criteria for the initiation, monitoring and discontinuation of these drugs in the treatment of spondylarthropathies were proposed. Long-term follow-up in large populations of patients with spondylarthropathies is necessary to better define the benefit/risk/cost ratio of anti-TNFalpha drugs.

Animal models of HLA-B27-associated diseases: new outcomes

The HLA-B27 molecule is strongly associated with the spondyloarthropathies, a group of chronic inflammatory diseases, affecting the skeleton, the bowel and the skin. This association has been largely studied, but mechanisms of pathology remain unclear. The HLA-B27 transgenic rats develop a spontaneous disease that strikingly resembles human spondyloarthropathies, dependent of bacterial flora and implicating the immune system. The presence of CD4+ T cells is required, and antigen presenting cells (APC) expressing high levels of HLA-B27 likely play an important role. Indeed, APC are defective in naive T lymphocytes stimulation. This default appears to implicate the APC/T cells contact, and may result in a loss of tolerance toward microbial flora. Two models of skeletal inflammation linked to HLA-B27 have been developed in mice. The ANKENT mice develop a spontaneous ossifying enthesitis affecting ankle and tarsal joints, with increased frequency in the presence of an HLA-B27 transgene. The HLA-B27 transgenic mice lacking endogenous beta2 microglobulin develop arthritis of hind-paws. In this model, homodimers of B27 heavy chains could be implicated in the pathogenesis by presenting exogenous peptides to CD4+ T cells.

Arthritis accompanying ileal pouchitis or undifferentiated HLA B27-related spondyloarthropathy?

The case of an HLA B27(+) patient who developed inflammatory arthritis accompanying ileal pouchitis, following total proctocolectomy for familial adenomatous polyposis is presented for the first time in the literature. Based on its clinical presentation and serology, it can be classified either as arthritis accompanying ileal pouchitis, or as an undifferentiated spondyloarthropathy.

Two Major Interacting Chromosome Loci Control Disease Susceptibility in Murine Model of Spondyloarthropathy

Autoimmune spondylitis was induced in BALB/c mice and their MHC-matched (BALB/c x DBA/2)F1 and F2 hybrids by systemic immunization with cartilage/intervertebral disk proteoglycan (PG). As in human ankylosing spondylitis, the MHC was the major permissive genetic locus in murine PG-induced spondylitis (PGIS). Two major non-MHC chromosome loci with highly significant linkage were found on chromosomes 2 (Pgis2) and 18 (Pgis1) accounting for 40% of the entire F2 trait variance. The dominant spondylitis-susceptibility allele for Pgis2 locus is derived from the BALB/c strain, whereas the Pgis1 recessive allele was present in the disease-resistant DBA/2 strain. The Pgis1 locus significantly affected the disease-controlling Pgis2 locus, inducing as high incidence of spondylitis in F2 hybrids as was found in the spondylitis-susceptible parent BALB/c strain. Additional disease-controlling loci with suggestive linkage were mapped to the chromosomes 12, 15, and 19. Severity of spondylitis in F2 mice positively correlated with serum levels of amyloid A, IL-6, and Pg-specific Abs, and showed negative correlation with Ag-induced T cell proliferation, IFN-gamma, IL-4, and TNF-alpha production. A major locus controlling serum IL-6 was found on chromosome 14 near osteoclast differentiation factor Tnfsf11. Locus on chromosome 11 near the Stat3 and Stat5 genes controlled serum level of the Ig IgG2a isotype. The two major genetic loci Pgis1 and Pgis2 of murine spondylitis were homologous to chromosome regions in human genome, which control ankylosing spondylitis in human patients. Thus, this animal model of experimentally induced spondylitis might facilitate the identification of spondylitis-susceptibility genes in humans.

Gut inflammation in the spondyloarthropathies

In this paper, the ample experimental, clinical, genetic, histopathologic, and immunologic evidence for an important role of the gut in the pathogenesis of spondylarthropathy (SpA) and for an overlap between SpA and Crohn's disease is reviewed. These data suggest that SpA and Crohn's disease should be scientifically and clinically considered as distinct phenotypes of common immune-mediated inflammatory disease pathways rather than as separate disease entities. Classification, diagnosis, and therapy based on pathophysiologic insights is likely to become superior to an approach based exclusively on signs and symptoms, as evidenced by the recent evolution in treatment of SpA by tumor necrosis factor-a blockade.

Bisphosphonates as anti-inflammatory agents in ankylosing spondylitis and spondylarthropathies

NSAIDs remain the cornerstone of the treatment of ankylosing spondylitis (AS) and spondylarthropathies (SpA), and have been successfully used for a long time in these diseases. However, some patients remain refractory or intolerant to NSAIDs and new effective treatments have recently emerged, namely TNF-alpha-blocker agents. Other therapeutic options targeting the bone, such as bisphosphonates, have also been tried in refractory AS or SpA patients. The anti-inflammatory properties of bisphosphonates give the rationale for the use of these compounds in AS and SpA, and include the inhibition of antigen presenting cells, the modulation of pro-inflammatory cytokine generation, and also a decreased bone mass in AS. Open trials using pamidronate gave favourable results, and one controlled study comparing the efficacy of pamidronate 10 versus 60mg showed that the 60mg dose was effective in AS. Further studies are required to confirm these preliminary data and to better determine the optimal regimen (dosage and rhythm) of administration.

Association study of LMP gene polymorphisms in Mexican patients with spondyloarthritis

To evaluate the role of LMP (low molecular weight protein) genes as susceptibility markers for spondyloarthritis (SpA), LMP gene polymorphisms were analyzed in 223 Mexican patients with SpA (81 undifferentiated SpA [U-SpA], 117 with ankylosing spondylitis [AS], 25 with reactive arthritis) and in 139 ethnically matched healthy individuals. LMP genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. The LMP2 and LMP7 allele frequencies were similar in patients and healthy controls. Genotype analysis revealed an increased frequency of LMP2 R/R genotype in the whole group of SpA (pC = 0.003, OR = 2.06, 95%CI = 1.3-3.25) and in the clinical subgroups of AS (pC = 0.039, OR = 1.88, 95%CI = 1.1-3.22) and U-SpA (pC = 0.003, OR = 2.56, 95%CI = 1.37-4.8) compared with healthy controls. Analysis in the LMP7 did not reveal significant differences in patients and healthy controls. The HLA-B27-negative AS subgroup also showed an increased frequency of LMP2 R/R genotype (pC = 0.027, OR = 4.81, 95%CI = 1.21-22.13). The LMP2-R/R AS patients were younger than LMP2-H/R and H/H patients at onset of the disease (16.0 +/- 6.8 years for R/R, 22.0 +/- 11.2 years for H/R and 28.6 +/- 10.9 years for H/H) (p < 0.05). The data suggest that, besides HLA-B27, LMP2 genotypes are also involved in the genetic susceptibility to develop AS in Mexicans. Furthermore, the age at onset of this disease might also be influenced by genotypes of this gene.

HLA-B27 in the Greek Cypriot population: distribution of subtypes in patients with ankylosing spondylitis and other HLA-B27-related diseases. The possible protective role of B*2707

The major purpose of the present study was to investigate the frequency of human leukocyte antigen (HLA)-B27 alleles in healthy controls and in patients with ankylosing spondylitis (AS) and other HLA-B27-related diseases in the Greek Cypriot population. We selected 102 HLA-B27-positive individuals (60 controls and 42 patients). Typing of the HLA-B27 alleles was performed by polymerase chain reaction amplification with sequence-specific primers. Only two alleles were detected in the patient group: B*2702 (n = 31, 73.8%) and B*2705 (n = 11, 26.2%). The HLA-B*2707 allele was detected (n = 10, 16.7%) only in the healthy controls in addition to the B*2702 (n = 31, 51.7%) and B*2705 (n = 19, 31.7%) alleles. Our results show a restricted number of HLA-B27 subtypes associated with AS and other B27-related diseases and an elevated frequency of the B*2702 allele in the AS patients. The allele B*2707 seems to have a protective role in the population studied because it was found only in the healthy controls.

Soluble CD21 in sera and synovial fluid of arthritic patients

Soluble CD21 (sCD21) is the ectodomain of the CD21 glycoprotein released by shedding from the cellular membrane. The ectodomain of CD21 is capable of binding complement fragments, Epstein-Barr virus (EBV) and CD23. Functionally sCD21 can activate monocytes and abrogate B-cell/follicular dendritic cell interaction, thereby inhibiting antibody production by antigen primed B cells. Levels of sCD21 vary in several clinical conditions. Here we analyzed sCD21 in synovial fluids and sera in arthritic patients. sCD21 concentrations were consistently lower in synovial fluids compared to paired sera samples from the same patients. In contrast to healthy donors, sCD21 levels are significantly reduced in rheumatoid arthritis patient's sera. Potential causes and consequences of the data are discussed.

Drug-induced agranulocytosis during treatment with infliximab in enteropathic spondyloarthropathy

Agranulocytosis is a disorder characterized by a severe decrease in the number of granulocytes in blood, that frequently occurs as an adverse reaction to some drugs. By now, there are no reports in literature of agranulocytosis caused by tumur necrosis factor-alpha blockers. We describe the case of a 20-year-old Caucasian male affected by enteropathic (Crohn's disease) spondyloarthropathy HLA B27 negative, successfully treated with infliximab. After the second infliximab infusion, he was found to have a severe transient neutropenia (0.5 x 10(9)/L). Routine serum chemistry and full blood cell count (apart from neutrophil count) were normal. Serology excluded an active infection. Bone marrow needle aspirate showed a normal trilineage differentiation. Autoantibody assessment showed negative ANA, anti-dsDNA, anti-ENA, and ANCA, but positive granulocyte-bound antibodies (GBA) and neutrophil-specific (CD 16+)-bound antibodies (anti-NA). Ten weeks after infliximab infusion, neutrophil count and GBA and anti-NA assay returned spontaneously within normal range and we observed the same progress after every successive infliximab infusion we performed. These data indicated that infliximab possibly triggered production of granulocyte and neutrophil autoantibodies with resultant autoimmune agranulocytosis.

Sacroiliitis in familial Mediterranean fever and seronegative spondyloarthropathy: importance of differential diagnosis

Familial Mediterranean fever (FMF) is a multisystemic autosomal recessive disease, occasionally accompanied by sacroiliitis. Transient and non-erosive arthritis of the large joints is the most frequent articular involvement. Amyloidosis is also the most significant complication of FMF, leading to end stage renal disease. Here we present three cases of FMF with sacroiliitis and review the literature for spinal arthritic involvement of FMF. All cases were referred to our clinic with a diagnosis of seronegative spondyloarthropathy and with low back pain sourced by sacroiliitis. They also had homozygous M694V gene mutations and negative HLA B27 antigens. Molecular analysis of the gene mutation is recommended during the evaluation of uncertain cases in order to clarify diagnostic discrimination. We suggest that FMF with sacroiliitis, which is rare in rheumatological practice, should be considered in the differential diagnosis of seronegative spondyloarthropathy or other rheumatologic diseases causing spinal involvement.

HLA-B27 associated spondyloarthropathy, vasculitis, and amyloid enteropathy: response to infliximab

In 2000 we described a patient with HLA-B27 associated spondyloarthropathy (SpA) and severe ascending aortitis requiring surgical intervention. Despite continued immunosuppressive therapy she developed narrowing of the distal part of the right subclavian artery and proximal axillary artery secondary to active vasculitis. In addition, biopsy-proven amyloid gastroenteropathy developed causing persistent diarrhea and iron deficiency anemia. Treatment with infliximab resulted in resolution of joint symptoms and rapid improvement in laboratory markers of inflammation. Diarrhea settled more gradually, such that her bowel habit had normalized 16 months after therapy commenced.

HLA-B27: portraying immunodominant viral epitopes

Although the crystal structure of HLA-B27 has been known for a long time, only recently have X-ray diffraction studies of this molecule in complex with individual peptides become available. The report of three such structures involving viral epitopes that are immunodominant in HLA-B27-restricted T cell responses against influenza, Epstein-Barr and HIV viruses significantly improves our perception of critical aspects of the immunological and pathogenetic roles of HLA-B27, including (1) the molecular basis of its peptide-binding specificity and how this is modulated by subtype polymorphism, (2) the relationship between the structural and the antigenic features of immunodominant viral epitopes, (3) the basis for long term non-progression to AIDS of HIV-infected HLA-B27+ individuals, and (4) the structural features of microbial peptides influencing NK receptor engagement. Here, I discuss the implications of this and related studies for the relevance of HLA-B27 in host defense and as a pathogenetic molecule in spondyloarthritis.

Two major spondylarthropathy phenotypes are distinguished by pattern analysis in multiplex families

OBJECTIVE

To examine whether spondylarthropathy (SpA) disease manifestations would combine in any ordered pattern among patients from SpA multiplex families.

METHODS

SpA patients (n = 540) belonging to 190 multiplex families were thoroughly investigated. Clinical data was collected, systematic pelvic radiographs were taken, and HLA-B27 status was determined. The patterns of SpA manifestations were examined by several methods, including multiple correspondence analysis, nonhierarchical and hierarchical clustering, and discriminant analysis.

RESULTS

The nonhierarchical cluster analysis allowed us to classify patients, independent of disease duration, into 2 major groups of comparable size. Group A contained a majority of the women, whereas group B predominantly consisted of men. The 2 groups were very similar regarding axial symptoms, radiographic sacroiliitis, and uveitis. Group B was characterized by a younger age at onset and a higher frequency of clinical enthesitis, peripheral arthritis, dactylitis, psoriasis, and inflammatory bowel disease than group A. Patients belonging to those groups exhibited some degree of familial aggregation, thereby supporting their intrinsic validity.

CONCLUSION

Pattern analysis of SpA manifestations among familial SpA allowed us to recognize 2 main clusters independent of disease duration. Furthermore, there was a trend toward aggregation by cluster among families, suggesting that they are determined by specific genetic factors. These clusters may indeed correspond to different severity patterns.

[Role of Salmonella and Yersinia in the pathogenesis of spondyloarthropathies and rheumatoid arthritis. II. Antibodies to Salmonella and Yersinia in sera and synovial fluids]

IgA, IgG and IgM antibodies against Yersinia Yop proteins, Yersinia LPS and Salmonella LPS from different serogroups were determined by enzyme-linked immunosorbent assay (ELISA) in a 885 serum samples and 92 synovial fluids. The control group consisted of 200 healthy blood donors. Compared with control subjects, patients with arthritis showed significantly increased titres of antibodies against Yersinia Yop, Yersinia LPS and Salmonella LPS appropriately in 21.7%, 44.0% and 56.0% serum samples. The prevalence of positive antibody levels was highest in Yersinia serogroup O3 and Salmonella serogroup B and D antibodies. The IgA titres were found to be much higher in adults than in children and youngsters but IgM titres consequently decreased with age. Investigation of synovial fluids obtained from patients with arthritis showed that Yersinia and Salmonella antibodies in synovial fluid mirror those in serum by concentration, by specificity and by distribution in classes.

Genetic control of experimental spondylarthropathy

OBJECTIVE

To characterize experimentally induced spondylarthropathy (SpA) in arthritis-susceptible inbred mice and in their F(1) and F(2) hybrid generations of susceptible and resistant mouse strains.

METHODS

SpA was induced in susceptible BALB/c and C3H/HeJCr (C3H) strains of mice, and in their F(1) and F(2) generations derived from intercrosses with arthritis- and/or spondylitis-resistant DBA/2 and DBA/1 parent strains, by systemic immunization with cartilage proteoglycan (PG) aggrecan. The incidence and severity of PG-induced spondylitis (PGIS) were scored histologically, and these scores for spine involvement were correlated with serum antibody and cytokine levels and with in vitro T cell responses to cartilage PG.

RESULTS

PGIS was induced by systemic immunization with cartilage PG in adjuvant, and approximately 60-70% of susceptible mouse strains and their F(2) hybrids developed spondylitis either with or without arthritis. Adjuvants, particularly those activating the innate immune system and enforcing the Th1 dominance, had significant effects on the outcome and progression of SpA. The DBA/1 strain appeared to carry genes protecting this strain and its F(1) and F(2) hybrids from spondylitis, whereas the DBA/2 strain, although resistant to PGIS, harbored genes permitting PGIS in its hybrid generations. Arthritis- and/or spondylitis-susceptible BALB/c and C3H parent strains and their F(2) hybrids exhibited the highest incidence and severity of spondylitis.

CONCLUSION

PGIS, a murine model of autoimmune spondylitis, shows similarities to ankylosing spondylitis. Segregation of susceptibility to PG-induced arthritis (PGIA) from that to PGIS in different genetic crosses suggests that PGIA and PGIS are separate diseases. Therefore, this model allows for the elucidation of genetic components involved in the etiology of SpA, independent of those controlling the susceptibility to PGIA.

Tumor necrosis factor α blockade treatment down-modulates the increased systemic and local expression of toll-like receptor 2 and toll-like receptor 4 in spondylarthropathy

OBJECTIVE

Abnormal host defense against pathogens has been implicated in the pathogenesis of spondylarthropathy (SpA), a disease characterized by abundant synovial infiltration with innate immune cells. Given the role of Toll-like receptors (TLRs) in activation of innate inflammation and the occurrence of TLR-dependent infections after tumor necrosis factor alpha (TNFalpha) blockade treatment, the present study was undertaken to analyze TLRs and their modulation by TNFalpha blockade in SpA.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from SpA and rheumatoid arthritis (RA) patients during infliximab therapy, and from healthy controls. TLR-2 and TLR-4 expression and TNFalpha production upon lipopolysaccharide (LPS) stimulation were analyzed by flow cytometry on different monocyte subsets. Synovial biopsy specimens from 23 SpA patients before and after infliximab or etanercept treatment, from 15 RA patients, and from 18 osteoarthritis (OA) patients were analyzed by immunohistochemistry.

RESULTS

Expression of TLR-4, but not TLR-2, was increased on PBMCs from patients with SpA, whereas both TLRs were increased in RA patients. TLR expression was particularly increased on the CD163+ macrophage subset. Infliximab reduced TLR-2 and TLR-4 expression on monocytes of SpA and RA patients, leading to lower levels than in controls and to impaired TNFalpha production upon LPS stimulation. In inflamed synovium, the expression of both TLRs and of CD163 was significantly higher in patients with SpA than in those with RA or OA. Paralleling the systemic effect, TLRs in synovium were down-regulated following treatment with infliximab as well as etanercept, indicating a class effect of TNFalpha blockers.

CONCLUSION

Inflammation in SpA is characterized by increased TLR-2 and TLR-4 expression, which is sharply reduced by TNFalpha blockade. These findings suggest a potential role of innate immunity-mediated inflammation in SpA and provide an additional clue regarding the mechanism of action as well as the potential side effects of TNFalpha blockade.

Autoantibody induction in patients with refractory spondyloarthropathy treated with infliximab and methotrexate

OBJECTIVES

Induction of antinuclear antibodies (ANA) has been reported in patients taking infliximab to treat refractory spondyloarthropathy, without concomitant methotrexate therapy. We investigated antibody induction in patients with spondyloarthropathy treated with both infliximab and methotrexate.

METHODS

In 33 patients meeting ESSG criteria for spondyloarthropathy, infliximab was given (infusions at weeks 0, 2, 6, 14, 22, and 30) in combination with methotrexate (10-25 mg/week). At baseline, 6 and 30 weeks after treatment initiation, the patients underwent indirect immunofluorescence testing for ANA and ELISAs for antibodies to double-stranded DNA, soluble nuclear antigens, and histones.

RESULTS

As compared to baseline, significant increases were found at week 30 in the number of patients with ANA (4% vs. 29%, P = 0.02), IgG antihistone antibodies (7% vs. 29%, P = 0.04), and IgM antihistone antibodies (29% vs. 57%, P = 0.03). No significant increases were noted for antibodies to double-stranded DNA or to soluble nuclear antigens. No cases of clinical lupus syndrome were recorded.

CONCLUSION

Autoantibody induction was far less common in our patients than in the population studied by De Rycke et al. [Arthritis Rheum. 48 (2003) 1015], who found ANA in 88.6% and antibodies to double-stranded DNA in 17.1% of 35 patients taking infliximab without methotrexate. Methotrexate may reduce the risk of autoantibody induction and disimmunity associated with infliximab therapy.

Diagnostic classification of spondylarthropathy and rheumatoid arthritis by synovial histopathology: a prospective study in 154 consecutive patients

OBJECTIVE

To explore prospectively the value of synovial histopathology in comparison with the value of classic parameters for diagnostic classification of spondylarthropathy (SpA) and rheumatoid arthritis (RA) in patients with an atypical disease presentation.

METHODS

Synovial biopsy samples were obtained from 154 consecutive patients presenting for diagnostic evaluation; 67 patients fulfilled the classification criteria for RA, SpA, or other well-defined disease at the time of arthroscopy (cohort 1), and an additional 53 patients were classified after a full diagnostic reevaluation at 6 months (cohort 2). Synovial parameters with diagnostic value were identified in cohort 1 and were compared prospectively with classic diagnostic parameters in cohort 2.

RESULTS

Staining with anticitrulline, staining with monoclonal antibody 12A (recognizing HLA-DR shared epitope-human cartilage glycoprotein 39(263-275) complexes), and crystal deposition had positive predictive values (PPVs) for diagnosis of >90% in patients with an atypical disease presentation (cohort 2). Using these 3 parameters, a diagnosis was predicted by synovial histopathology in 39.6% of cohort 2 patients and turned out to be correct in 90.5% of these patients at 6 months of followup. Using a multiparameter model rather than single histopathologic parameters, even better results were obtained, with a diagnostic prediction in 79.2% of samples and a PPV of 81.0%. In comparison, a similar multiparameter model using classic diagnostic criteria rather than synovial histopathology performed poorly in cohort 2; the sensitivity was 56.6% and the PPV was 73.3%, with an inferior capacity to predict SpA. Especially for the presence of crystals and anticitrulline staining, the analysis of synovial tissue had a clear added value to the analysis of synovial fluid or serum in patients with an atypical presentation.

CONCLUSION

This proof-of-concept study indicates that synovial histopathology can contribute to the multiparametric diagnostic classification of inflammatory arthritis in patients with an atypical presentation.

Histological evidence that infliximab treatment leads to downregulation of inflammation and tissue remodelling of the synovial membrane in spondyloarthropathy

OBJECTIVE

To confirm and extend the immunopathological evidence of effects of infliximab on the synovium in active spondyloarthropathy.

METHODS

Synovial biopsies obtained in patients with spondyloarthropathy at baseline and week 12 were stained and scored by two independent observers. Two study populations were evaluated: I, a cohort of 10 patients treated with 5 mg/kg infliximab at week 0, 2, and 6, plus three placebo treated patients; and II, a pooled cohort of 20 patients fulfilling identical inclusion and exclusion criteria and treated with the same loading dose regimen.

RESULTS

In study population I, treatment with infliximab induced reduction in synovial lining layer thickness (p = 0.015), endothelial activation (E-selectin, p = 0.034), and inflammatory cell infiltration with neutrophils (p = 0.041), macrophages (p = 0.034), and T cells (p = 0.026), but not with B cells and plasma cells; no such trends were observed in the placebo treated patients. Besides confirming the highly significant downregulation of inflammation, analysis of cohort II showed structural changes such as normalisation of lining layer thickness (p = 0.030), reduction in the number of blood vessels (p = 0.039), and downregulation of follicular organisation (p = 0.050). No differences in histopathological response were observed between spondyloarthropathy subtypes.

CONCLUSIONS

Profound immunomodulatory changes in the synovium parallel the clinical benefit in patients with spondyloarthropathy treated with infliximab, independently of the subtype. The study provides histological evidence that TNF alpha blockade not only downregulates inflammation but also leads to tissue remodelling.

Relationship of psoriatic arthritis with the other spondyloarthropathies

PURPOSE OF REVIEW

The seronegative spondyloarthropathies are a group of disorders sharing common clinical features, the hallmark of which is sacroiliitis. Despite the 40 years since psoriatic arthritis was recognized, controversy still exists about which patients to include within this disease group and the relation of psoriatic arthritis with the other spondyloarthropathies.

RECENT FINDINGS

Early disease can present difficulties because it is inappropriate to use criteria developed on established cases in early arthritis, in which many cases may be initially undifferentiated. The taxonomy of juvenile spondyloarthropathy remains a contentious issue, and further modifications of the Durban criteria have been suggested. The predictive value of the European Spondyloarthropathy Study Group criteria for spondyloarthropathy varies with the prevalence of the disease in the population under consideration, as has been demonstrated in ambulatory practice in France and Spain. It appears that physicians differ in their interpretation of the individual features, particularly of such clinical items as asymmetry and predominantly lower limb involvement. The combination of dactylitis of a toe, heel pain, and oligoarthritis appears to be strongly suggestive of psoriatic arthritis. However, solitary heel pain can be problematic, and ultrasonographic entheseal erosion at the calcaneum has been shown equally in rheumatoid arthritis and psoriatic arthritis. MRI may be more sensitive and quantitatively discriminative in psoriatic arthritis. Spinal involvement in psoriatic arthritis can be asymptomatic, as in classical ankylosing spondylitis. Importantly, psoriatic spondylitis has been observed in the absence of sacroiliitis.

SUMMARY

Clinicians generally agree that psoriatic arthritis constitutes a discreet subset within the spondyloarthropathy group, but the demarcation continues to be the subject of clinical research. The matter is confounded by the lack of agreed classification criteria for psoriatic arthritis; although in both adult and juvenile disease criteria for spondyloarthropathy exist, the place of psoriatic arthritis within this larger group requires further definition.

Association of CD163+ macrophages and local production of soluble CD163 with decreased lymphocyte activation in spondylarthropathy synovitis

OBJECTIVE

Since CD163+ macrophages are selectively increased in spondylarthropathy (SpA) synovitis, we investigated the role of CD163+ macrophages in synovial inflammation.

METHODS

Synovial biopsy samples from 26 SpA and 23 rheumatoid arthritis (RA) patients were analyzed for macrophage and lymphocyte subsets. Synovial fluid (SF) samples were analyzed by Western blotting and enzyme-linked immunosorbent assay for soluble CD163 (sCD163) and by flow cytometry for lymphocyte activation. We also analyzed sCD163 in sera from 100 SpA patients, 23 RA patients, 20 healthy controls, and 20 SpA patients treated with infliximab. Polymorphism of haptoglobin (Hp), the CD163 ligand, was determined in 130 SpA and 23 RA patients.

RESULTS

CD163+ macrophages, but not CD68+ macrophages, were significantly increased in SpA versus RA synovium and in HLA-B27+ versus HLA-B27- SpA. Despite similar lymphocyte numbers, activated lymphocytes (CD69+) were significantly decreased in SpA versus RA patients, with an inverse correlation between CD163 and CD69 levels. Local production of sCD163 was evidenced by a 5-7-fold higher level of sCD163 in SF than in serum and by the correlation with synovial lining CD163+ macrophages in SpA. SF sCD163 levels correlated directly with global inflammation but correlated inversely with CD69+ SF T lymphocytes in the synovium. In contrast, serum sCD163 levels were only moderately increased, did not correlate with SF sCD163 levels or parameters of inflammation, and were unaffected by infliximab therapy. The distribution of Hp polymorphism was not altered in SpA and was not related to CD163 expression.

CONCLUSION

Increased numbers of CD163+ macrophages in SpA synovium and local production of sCD163 are associated with global inflammation as well as impairment of T cell activation, suggesting a dual role for CD163+ macrophages in SpA synovitis.

Defective costimulatory function is a striking feature of antigen-presenting cells in an HLA-B27-transgenic rat model of spondylarthropathy

OBJECTIVE

A disease resembling the human spondylarthropathies develops in HLA-B27-transgenic rats. This disease in rats is mediated by CD4+ T cells, but antigen-presenting cells (APCs) may also play a role. Dendritic cells (DCs) have been reported to be defective in allogeneic mixed lymphocyte culture in this model. Here, we further investigated the functional defect of APCs.

METHODS

DCs and B cells from nontransgenic, HLA-B27 (33-3)-transgenic, and HLA-B7 (120-4)-transgenic rats were used to stimulate T cells. Surface expression of HLA-B transgene and rat molecules on APCs and the formation of conjugates between DCs and T cells were monitored by flow cytometry.

RESULTS

We observed a strikingly defective stimulation of allogeneic and syngeneic T lymphocytes by APCs from HLA-B27 but not HLA-B7 rats, even if stimulation was driven in the presence of anti-T cell receptor (TCR) antibody. We found no evidence that HLA-B27 DCs were immature, lacked production of some diffusible factor, or produced an inhibitory factor for T cells. When comparing the levels of expression of class II major histocompatibility complex, CD2, intercellular adhesion molecule 1, lymphocyte function-associated antigen 1, B7, and CD40 molecules at the surface of DCs from 33-3, 120-4, and nontransgenic rats, we found little difference. However, HLA-B27-transgenic DCs formed fewer conjugates with T cells than did nontransgenic DCs. Furthermore, the proportion of conjugates formed between DCs and T cells, as well as the difference between nontransgenic and HLA-B27-transgenic DCs, were in large part reduced by blocking CD86 on DCs.

CONCLUSION

We confirmed defective stimulation of T cells by APCs in HLA-B27 rats, the mechanism of which appears to implicate APC/T cell contact, independent of TCR engagement. In addition, decreased use of the CD86 costimulatory molecule by B27 DCs was observed. Impaired costimulatory function could result in a loss of tolerance toward microbial flora in this model.

Outcome of patients with undifferentiated chronic monoarthritis: retrospective study of 46 cases

OBJECTIVE

To determine the natural history of undifferentiated monoarthritis of more than 3 months' duration and to evaluate the usefulness of classic diagnostic tools for identifying factors associated with outcomes.

METHOD

Retrospective study of 46 patients with undifferentiated monoarthritis of more than 3 months' duration.

RESULTS

Full resolution was the outcome in 50% of cases. Rheumatoid arthritis and spondyloarthropathy were the most common diagnoses in the remaining patients. HLA-B27 status was the only significant predictor of outcome: progression to spondyloarthropathy was significantly more common (P = 0.05) among HLA-B27-positive patients. Mean time to full recovery was significantly shorter than mean time to disease progression (12 vs. 45 months, P = 0.0015). Intraarticular glucocorticoid injections were effective in over 50% of patients. Arthritis relief during the month following the injection was associated with self-limited disease. The role for magnetic resonance imaging in managing patients with undifferentiated monoarthritis remains unclear.

CONCLUSION

In patients with undifferentiated monoarthritis, the likelihood of a full recovery is 50%. The only significant predictor of outcome was positive HLA-B27 status, which was associated with progression to spondyloarthropathy.

Ophthalmic findings and frequency of extraocular manifestations in patients with HLA-B27 uveitis*1A study of 175 cases

OBJECTIVE

To analyze ocular and extraocular manifestations in patients with HLA-B27-associated uveitis.

DESIGN

Large, observational case series.

PARTICIPANTS

One hundred seventy-five consecutive patients with HLA-B27-associated uveitis seen in a single center between January 1996 and March 2001.

METHODS

Features of uveitis were noted and patients were referred systematically to rheumatologists. The history of previous uveitis attacks and extraocular manifestations of spondyloarthropathy was recorded. Assessments of spondyloarthropathies were based on criteria established by the European Spondyloarthropathy Study.

MAIN OUTCOME MEASURES

Percentage of patients with extraocular manifestations. The time between the first episode of uveitis and symptoms or diagnosis of extraocular disease was estimated. Characteristics of uveitis were analyzed.

RESULTS

The male-to-female ratio was 1.3 to 1, and the median age at the time of the first attack of uveitis was 31 years. An HLA-B27-associated extraocular disorder was seen in 136 cases (77.7%). Of these, ankylosing spondylitis was diagnosed in 81 patients (46.3%) and presumed in 17 (9.7%). Undifferentiated spondyloarthropathy was observed in 21 patients (12%) and other HLA-B27-associated diseases in 17 patients (9.7%). The onset of extraocular symptoms occurred at a younger age (mean+/-standard deviation [SD], 26.4+/-11.1 years) than the first attack of uveitis (mean+/-SD, 34.0+/-14.1 years; P<0.0001). The diagnosis of an extraocular disease was made only after the appearance of ophthalmic manifestations in 88 of 136 patients. Among 117 patients (66.9%) with more than 1 episode of uveitis, same eye attacks were observed in 48 of 117 patients (41.0%), more than the expected percentage than attacks of a random eye (P<0.0001). The median +/- SD frequency of active episodes of uveitis was 0.8+/-0.6 per year and decreased as the duration of the disease lengthened (P<0.0001). Patients with extraocular disease had a greater total number of attacks of uveitis (P = 0.02), but other ophthalmic findings did not differ between patients with and without an extraocular disorder.

CONCLUSIONS

Uveitis is frequently the first indication of a previously undiagnosed HLA-B27-associated extraocular disease. The most common of these diseases are spondyloarthropathies.

The Recognition of Abnormal Forms of HLA-B27 by CD4+ T Cells

The MHC class I molecule, HLA-B27 can be expressed as a number of non-conventional forms, in addition to conventional HLA-B27 heterodimers presenting peptide. This has lead to new avenues of research to explain the association of this molecule with SpA. Surprisingly, HLA-B27 transgenic animal models implicated CD4+ T cells, which conventionally interact with MHC class II molecules, not MHC class I molecules, in the pathogenesis of SpA. One hypothesis to explain these finding is that non-conventional forms of HLA-B27, specifically HLA-B27 homodimers, might mimic MHC class II molecules and be recognised by CD4+ T cells. We investigated whether CD4+ T cells from AS patients can interact with HLA-B27, discovering that indeed CD4+ T cells can interact with various forms of HLA-B27. Here we discuss how such interactions between HLA-B27 and CD4+ T cells could occur in vivo and potential contributions of such interactions to the pathogenesis of SpA.

Animal Models of HLA-B27-Associated Diseases

The HLA-B27 molecule is strongly associated with the spondyloarthropathies (SpA), a group of inflammatory conditions affecting the skeleton, the skin and several mucosae. The mechanism of this association remains unknown, largely because the HLA-B27 molecule displays normal function. A disease that closely mimicks SpA arises spontaneously in HLA-B27 transgenic rats. This disease is dependent on the presence of a normal bacterial flora and implicates the immune system. The presence of both CD4+ T cells and antigen presenting cells (APCs) expressing high levels of HLA-B27, seems of critical importance in its pathogenesis, whereas CD8+ T cells are dispensable. The T cell stimulatory function of APCs is disturbed by the HLA-B27 molecule. This disease could result from a failure of tolerance, related in part to high level of B27 expression in professional APCs and to the immune response to gut bacteria. In contrast, HLA-B27 transgenic mice have usually remained healthy. However, two types of inflammatory conditions affecting the skeleton, which arise in mice of susceptible background after exposure to a conventional bacterial flora, are increased by an HLA-B27 transgene. The first is ANKENT, a spontaneous ankylosing enthesitis that affects ankle and/or tarsal joints of ageing mice; the second is a spontaneous arthritis of hindpaws developing in mice lacking endogenous mbeta2m. As in rats, the absence of CD8+ T cells in the latter model, argues against the "arthritogenic peptide" hypothesis. In these mbeta2m0 mice, B27 free heavy chain could be implicated in the pathogenesis of arthritis by presenting extracellular peptides to CD4+ T cells.

The Immunobiology of HLA-B27: Variations on a Theme

In the thirty years since the initial discovery of a striking association between HLA-B27 and susceptibility to ankylosing spondylitis, numerous hypotheses have been proposed to explain the role of this molecule in the pathogenesis of spondyloarthropathies. In the past few years the focus has shifted from one centered largely on the physiological peptide-presenting function of HLA-B27, to include ideas based on aberrant aspects of its immunobiology. This has been driven in part by results from animal models of HLA-B27-associated disease where CD8+ T cells do not appear to be playing a major role in pathogenesis. In addition, the HLA-B27 heavy chain is unusual in that it has a tendency to misfold in the endoplasmic reticulum and to form disulfide linked heavy chain dimers that can be expressed on the cell surface. Although the data suggest misfolding and cell surface dimerization are fundamentally different processes, it appears that certain structural features of the heavy chain are common to both. Potential links between these aberrant characteristics of HLA-B27 and inflammatory disease are discussed in this and other reviews in this issue. Herein we consider how protein misfolding affects cell function through the activation of an 'unfolded protein response' and/or an 'ER overload response', and the potential impact on the immune system. Despite significant advances in the treatment of spondyloarthropathies over the past few years, a better understanding of pathogenesis is likely to improve outcome by identifying ways to provide greater and more sustained clinical responses.

Characterization of plasmacytoid dendritic cells in inflammatory arthritis synovial fluid

OBJECTIVE

To examine the phenotype of dendritic cell subsets in synovial fluid and peripheral blood from patients with rheumatoid arthritis (RA) or spondyloarthropathy (SpA).

METHODS

Multiparameter flow cytometry was used to identify and characterize dendritic cells in mononuclear cell populations isolated from synovial fluid and peripheral blood.

RESULTS

Synovial fluid contained two subsets of dendritic cells (DC), myeloid and plasmacytoid. These subsets could also be identified in peripheral blood, but there were lower numbers of DC in peripheral blood compared with synovial fluid. Plasmacytoid DC were distinguished from the myeloid subset by high expression of CD123 and lack of expression of CD11c. In comparison with myeloid dendritic cells, the plasmacytoid subset were less mature, similar to those in peripheral blood. They failed to express CD83 and DC-LAMP, and had relatively low levels of CD40 and CD86. Comparison of dendritic cells in synovial fluid from RA and SpA patients showed increased numbers of the plasmacytoid subset in SpA.

CONCLUSIONS

This is the first demonstration of the plasmacytoid subset of dendritic cells in synovial fluid. Since these cells are major producers of type I interferons, their increased numbers in SpA might be relevant to pathogenesis, but the immature phenotype in SpA synovial fluid may also indicate that conditions for maturation of this subset do not pertain in SpA synovium.

Involvement of matrix metalloproteinases and their inhibitors in peripheral synovitis and down-regulation by tumor necrosis factor ? blockade in spondylarthropathy

OBJECTIVE

To investigate the role of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in spondylarthropathy (SpA) synovitis.

METHODS

Paired samples of synovial biopsy tissue as well as serum and synovial fluid (SF) from 41 patients with SpA and 20 patients with rheumatoid arthritis (RA) and serum samples from 20 healthy controls were analyzed by immunohistochemistry and enzyme-linked immunosorbent assay for the presence of MMPs 1, 2, 3, and 9 and TIMPs 1 and 2. In addition, sera from 16 patients with ankylosing spondylitis (AS) and peripheral synovitis and 17 patients with AS and exclusively axial involvement were analyzed. An additional cohort of SpA patients was analyzed at baseline and after 12 weeks of infliximab treatment.

RESULTS

Staining for MMPs and TIMPs showed a cellular and interstitial pattern in the synovial lining and sublining layers that was similar between the RA and SpA patients. Involvement of MMPs and TIMPs in SpA synovitis was suggested by the correlation with cellular infiltration, vascularization, and cartilage degradation. Higher serum levels of MMPs 3 and 9 were revealed in SpA and RA patients as compared with healthy controls. Production of MMP-3, but not MMP-9, in the serum reflected the presence of peripheral synovitis, as indicated by 1) the correlation between serum levels, SF levels (which were 1,000-fold higher than the serum levels), and synovial expression of MMP-3, 2) the increased levels of MMP-3 in AS patients with peripheral disease and not exclusively axial involvement, and 3) the correlation of serum and SF MMP-3 with parameters of synovial, but not systemic, inflammation. The modulation of the MMP/TIMP system by tumor necrosis factor alpha (TNFalpha) blockade was confirmed by the down-regulation of all MMPs and TIMPs in the synovium and a pronounced and rapid decrease of serum MMP-3.

CONCLUSION

MMPs and TIMPs are highly expressed in SpA synovitis and mirror both the inflammatory and tissue-remodeling aspects of the local disease process. Serum MMP-3, originating from the inflamed joint, represents a valuable biomarker for peripheral synovitis. Modulation of the MMP/TIMP system by infliximab could contribute to the antiinflammatory and tissue-remodeling effects of TNFalpha blockade in SpA.

Experimental immunity to the G1 domain of the proteoglycan versican induces spondylitis and sacroiliitis, of a kind seen in human spondylarthropathies

OBJECTIVE

Experimental immunity to the G1 domain of the cartilage proteoglycan (PG) aggrecan (AG1) leads to the development of spondylitis as well as polyarthritis in BALB/c mice. The PG versican contains a structurally similar G1 domain (VG1). This study was conducted to determine whether immunity to VG1 would elicit similar pathology in these mice.

METHODS

Recombinant natively folded VG1 and AG1 were prepared. BALB/c mice received either a series of 5 injections of human VG1 or AG1, or no protein. Polyarthritis was determined clinically, and spondylitis and sacroiliitis histologically. Immunohistochemistry of rat tissues was used to study the localization of versican. Enzyme-linked immunosorbent assays were employed to study humoral immunity to the recombinant proteins as well as to overlapping synthetic peptides covering all these human G1 domains and mouse homologs. Affinity-purified antibodies to human AG1 and VG1 were isolated from sera of hyperimmunized mice. T lymphocyte proliferation assays were performed using recombinant human proteins. T cell lines reactive with specific immunodominant T cell epitopes in human AG1 and VG1 were isolated. Synthetic peptides encoding sequences in these human proteins and in corresponding mouse proteins were used in these analyses. Guanidinium chloride extracts of mouse spines were also used in Western blots to study antibody cross-reactivity.

RESULTS

Immunity to recombinant VG1 did not result in clinical polyarthritis. There was, however, clear evidence that VG1, like AG1, could induce spondylitis in the lumbar spine and sacroiliitis. Accumulation of mononuclear cells was observed in spinal ligaments adjacent to the intervertebral disc, in the intervertebral disc, and in the sacroiliac joints, the same sites where versican is localized. In contrast to AG1-immunized mice, in which T cells reactive with human AG1 cross-reacted with mouse AG1, there was no evidence in VG1-immunized mice that T cell immunity to human VG1 was cross-reactive with a mouse synthetic peptide that contained the sequence corresponding to the single immunodominant T cell sequence recognized in human VG1. Antibodies to specific sequences in human VG1 did, however, cross-react with human AG1 and with corresponding peptide sequences in mouse versican and aggrecan and with mouse proteins containing VG1 and AG1, present in mouse spine extracts. Similarly, antibodies to human AG1 cross-reacted with human VG1 and with extracted mouse VG1 and AG1 and synthetic peptides containing mouse sequences that corresponded to the reactive human epitopes in AG1 and VG1.

CONCLUSION

These observations suggest that humoral immunity to human VG1 is involved in the induction of experimental spondylitis and sacroiliitis in BALB/c mice. This humoral immunity is cross-reactive with mouse versican and aggrecan but is not associated with polyarthritis, probably because of the lack of cross-reactive T cell immunity and the absence of detectable versican in articular cartilage limbs. Induction of polyarthritis by bovine or human aggrecan requires the involvement of immunity mediated by T lymphocytes that are cross-reactive to a mouse aggrecan epitope. Together these observations suggest that humoral immunity to versican as well as immunity to aggrecan may be of importance in the development of the spinal pathology characteristic of spondylarthropathies.

Rheumatologie 2003?Teil I

Due to the partial elucidation of the immunopathogenesis of chronic inflammatory diseases during the last years, clinical rheumatology has made a rapid development, which by the consequent use of immunomodulatory therapies including recombinant proteins (biologicals) led to a significantly ameliorated prognosis of these diseases. On this basis, new research projects are continuously performed in the fields of pathogenesis, new drug development, outcome and therapy studies. New developments of imaging techniques and serologic testing facilitate a better classification and definition of disease activity and remission criteria. The current state of research in the field of rheumatoid arthritis and spondylarthropathies with its clinical consequences is reviewed in this article on the basis of the most recent data available.

Systematic safety follow up in a cohort of 107 patients with spondyloarthropathy treated with infliximab: a new perspective on the role of host defence in the pathogenesis of the disease?

BACKGROUND

Recent studies with infliximab indicate the therapeutic potential of tumour necrosis factor alpha blockade in spondyloarthropathy (SpA). Because defective host defence is implicated in the pathogenesis of SpA, the potential side effects of this treatment due to impact on the antimicrobial defence are a major concern.

OBJECTIVE

To report systematically the adverse events seen in a large cohort of patients with SpA treated with infliximab, with special attention to bacterial infections.

PATIENTS AND METHODS

107 patients with SpA were treated with infliximab for a total of 191.5 patient years. All serious and/or treatment related adverse events were reported.

RESULTS

Eight severe infections occurred, including two reactivations of tuberculosis and three retropharyngeal abscesses, and six minor infections with clear bacterial focus. One patient developed a spinocellular carcinoma of the skin. No cases of demyelinating disease or lupus-like syndrome were seen. Two patients had an infusion reaction, which, however, did not relapse during the next infusion. Finally, three patients with ankylosing spondylitis developed palmoplantar pustulosis. All patients recovered completely with adequate treatment, and infliximab treatment had to be stopped in only five patients with severe infections.

CONCLUSIONS

Although the global safety of infliximab in SpA is good compared with previous reports in rheumatoid arthritis and Crohn's disease, the occurrence of infections such as tuberculosis and retropharyngeal abscesses highlights the importance of careful screening and follow up. Focal nasopharyngeal infections and infection related symptoms, possibly induced by streptococci, occurred frequently, suggesting an impairment of specific host defence mechanisms in SpA.

Diagnosis and treatment of enthesitis

The conceptual understanding of SpA and the ability to image sites of skeletal inflammation accurately and confirm that enthesitis is the primary lesion has occurred around the same time as the greatest therapeutic advances in AS and SpA with the advent of potent anti-TNF therapies for enthesitis. These therapies have transformed the understanding of enthesitis and revolutionized therapy of what was often an intractable problem. Now that clinicians better understand enthesitis-related disease mechanisms and have the ability to image them in early disease and monitor them, there is an urgent need to assess optimal conventional drug therapy in these conditions.

Identification of HLA-B27-restricted peptides in reactive arthritis and other spondyloarthropathies: computer algorithms and fluorescent activated cell sorting analysis as tools for hunting of HLA-B27-restricted chlamydial and autologous crossreactive peptides involved in reactive arthritis and ankylosing spondylitis

The illustrated clinical and experimental results demonstrate the strong relationship between the MHC class I antigen HLA-B27 and synovial CD8+ T cells with specificity for bacterial and possible self-antigen in SpA. These new aspects obtained in recent experimental and clinical studies might also provide clues to the pathomechanisms of joint inflammation in SpA. In particular, the newly developed techniques will be of great relevance in the near future. New and more precise bioalgorithms reflecting new insights in the biology and biochemistry of proteins as recently presented [98, 99] can be helpful (e.g., a program with an improved prediction of the features of immunoproteasomes). Intracellular and secreted cytokine staining by FACScan allows examination of a great number of cells expressing certain antigens in response to certain stimuli. The analysis of T-cell responses with tetramer/peptide complexes can be useful to screen tissue sections for TCR, recognizing foreign or self-derived epitopes on those complexes loaded with selected (e.g., bacterial) peptides. Identification of arthritogenic peptides and a further understanding of the immunology of the pathomechanisms in SpA might open ways to design new peptide vaccines to prevent inflammation, autoimmunity, and other diseases by early intervention [100].

Infliximab in patients who have spondyloarthropathy: clinical efficacy, safety, and biological immunomodulation

A major breakthrough has been achieved in the treatment of patients who have AS and other types of SpA. The identification of the expression and role of TNF-alpha in patients who have these diseases and the recognition of their relation with gut inflammation (where infliximab therapy has proven efficacious already) has led to the successful use of TNF-alpha blockade in SpA, establishing a new indication for this type of anticytokine therapy. Evidence supports equal response in cases of axial or peripheral disease. Infliximab therapy has been most extensively documented in this new indication for anti-TNF-alpha therapy, but other compounds are also in the field. Gorman et al reported on 40 patients who had active AS who were randomly assigned to receive twice-weekly subcutaneous injections of etanercept (25 mg) or placebo for 4 months [65]. The primary endpoint was a composite of improvements. Treatment with etanercept resulted in significant and sustained improvement (treatment response in 80% in the etanercept group versus 30% in the placebo). Data regarding the human anti-TNF-alpha monoclonal antibody adalimumab in SpA are not yet available. Different questions remain open, including optimal dosing, long-term safety, and effects of this new treatment on the structural articular level; however, a therapeutic breakthrough like the one currently reviewed has seldom occurred in arthritis care.

Determinants of synoviocyte clearance of arthritogenic bacteria

OBJECTIVE

Persistence of intracellular organisms may play a critical role in the initiation and perpetuation of synovitis in reactive arthritis (ReA). We investigated factors that may influence local clearance of arthritogenic pathogens in ReA.

METHODS

We studied 11 HLA-B27 positive patients with spondyloarthropathies and contrasted these patients with 6 HLA-B27 negative control patients with rheumatoid arthritis or osteoarthritis. We employed an ex vivo system in which human synoviocytes derived from patients with ReA are cocultured with arthritogenic pathogens, and intracellular clearance is measured by quantitating colony-forming units over time.

RESULTS

The clearance kinetics of the organisms bore no relationship to the HLA-B27 status of the patient. Clearance of S. typhimurium over a 10 day period was accompanied by a progressive rise in nitric oxide (NO) production, but this appeared not to be rate-limiting, since (1) clearance kinetics were comparable between high versus low NO-producing synoviocytes; and (2) L-NMMA inhibition of NO production did not alter clearance kinetics of S. typhimurium. Interferon-g (IFN-g) was observed to have a small but measurable effect on bacterial clearance. In certain patients with ReA there was a paradoxical stimulatory response to IFN-g, in which the addition of IFN-g was accompanied by an increase in intracellular bacteria. This effect was found to be attributable to IFN-g mediated suppression of NO production in these cells. This pattern was not observed in B27 negative synoviocytes.

CONCLUSION

Intracellular persistence of arthritogenic organisms may contribute to the cellular basis of ReA, but the molecular basis of the bacteriocidal pathways in synoviocytes has not been fully resolved. Our findings indicate that a direct effect of HLA-B27 on these events is unlikely, but that alterations in cytokine response profiles may play a contributory role. Characterizing these mechanisms holds the promise of more specific therapeutic interventions in this disease.

Anti-saccharomyces cerevisiae IgA antibodies are raised in ankylosing spondylitis and undifferentiated spondyloarthropathy

OBJECTIVES

To investigate whether anti-Saccharomyces cerevisiae antibodies (ASCA), a marker for Crohn's disease (CD), are present in spondyloarthropathies (SpA) and in the subgroups ankylosing spondylitis (AS), undifferentiated SpA (uSpA), and psoriatic arthritis (PsA), in comparison with healthy and inflammatory controls (patients with rheumatoid arthritis (RA)).

METHODS

ASCA IgA and IgG levels were measured with an enzyme linked immunosorbent assay (ELISA) kit (Medipan, Germany) in 26 patients with CD, 108 patients with SpA (43 patients with AS, 20 patients with uSpA, 45 patients with PsA), 56 patients with RA and 45 healthy controls. Gut biopsy samples were available in 18 AS and 10 patients with uSpA, these samples were screened for the presence of inflammation.

RESULTS

Both ASCA IgG and IgA levels were raised in CD compared with healthy controls and patients with RA. ASCA IgA, but not IgG levels, were higher in SpA than in both healthy and RA controls. ASCA IgA levels were raised in AS and uSpA, but not in PsA. No significant differences in ASCA IgA levels were noted between patients with SpA with and without histological gut inflammation.

CONCLUSION

ASCA IgA levels are significantly higher in SpA, and more specifically in AS, than in healthy controls and patients with RA. This is the first serum marker associated with SpA. No correlation between the presence of subclinical bowel inflammation and ASCA IgA levels was noted. However, it remains to be evaluated whether patients with SpA with ASCA have an increased risk of developing CD.

Elevated levels of synovial fluid antibodies reactive with the small proteoglycans biglycan and decorin in patients with rheumatoid arthritis or other joint diseases

OBJECTIVES

To determine whether patients with rheumatoid arthritis (RA) express humoral immunity to the small proteoglycans biglycan and decorin and to compare the response to that of patients suffering from other joint diseases.

METHODS

Serum and synovial fluid IgG and IgM antibody levels were determined by enzyme-linked immunosorbent assay. Antibodies to biglycan and decorin as well as to other known and extensively investigated cartilage matrix components such as type II collagen, aggrecan and fibronectin were investigated. Patients suffering from RA, osteoarthritis (OA), psoriatic arthritis and other seronegative spondylarthropathies were included in the study. Correlation between antibody levels and clinical/laboratory parameters was determined.

RESULTS

Patients with RA expressed an increased humoral immunity to biglycan, while patients with seronegative spondylarthropathies displayed elevated decorin-specific synovial antibody levels compared with OA patients.

CONCLUSION

These results indicate a significantly higher immunity to small proteoglycans in RA and seronegative spondylarthropathies than in OA suggesting a possible involvement in the pathogenesis of inflammatory rheumatic diseases.