Treg cell numbers and function in patients with antibiotic‐refractory or antibiotic‐responsive lyme arthritis

Objective

In a murine model of antibiotic‐refractory Lyme arthritis, the numbers of Treg cells are dramatically reduced. The aim of this study was to examine Treg cell numbers and function in patients with antibiotic‐refractory Lyme arthritis.

Methods

CD4+ T cell subsets were enumerated in the peripheral blood (PB) and synovial fluid (SF) of 12 patients with antibiotic‐refractory arthritis and 6 patients with antibiotic‐responsive arthritis. Treg cell function was examined using Borrelia‐specific and nonspecific Treg cell proliferation assays.

Results

In both patient groups, interferon‐γ–positive Th1 cells in SF were abundant and enriched (∼50% of CD4+ T cells). In patients with antibiotic‐refractory arthritis, the median percentages of FoxP3‐positive Treg cells were significantly higher in SF than in PB (12% versus 6%; P = 0.03) or in SF from patients with antibiotic‐responsive arthritis (12% versus 5%; P = 0.04). Moreover, in the antibiotic‐refractory group, a higher percentage of Treg cells in SF correlated with a shorter duration until resolution of arthritis (r = −0.74, P = 0.006). In contrast, patients with fewer Treg cells had suboptimal responses to disease‐modifying antirheumatic drugs and a longer duration of arthritis after antibiotic treatment, and they often required synovectomies for arthritis resolution. In each group, Treg cells in SF dampened Borrelia burgdorferi–specific proliferative responses, and in 2 patients with antibiotic‐refractory arthritis, Treg cells were functional in nonspecific suppression assays.

Conclusion

Treg cells were functional in patients with antibiotic‐refractory arthritis, and in some patients, higher numbers of these cells in SF appeared to participate in arthritis resolution. However, as in the murine model, patients with antibiotic‐refractory arthritis and lower numbers of Treg cells seemed unable to achieve resolution of synovial inflammation.

     

High levels of inflammatory chemokines and cytokines in joint fluid and synovial tissue throughout the course of antibiotic‐refractory lyme arthritis

Objective

To investigate the possible role of chemokines and cytokines in the pathogenesis of Lyme arthritis.

Methods

Using cytometric bead array and flow cytometry techniques, chemokine and cytokine levels were determined in 65 synovial fluid (SF) samples and 7 synovial tissue (ST) samples from 17 patients with antibiotic‐responsive Lyme arthritis and 35 patients with antibiotic‐refractory Lyme arthritis seen during the past 18 years. In the ST samples, expression of chemokine receptors was measured using immunohistochemistry.

Results

Before or during antibiotic therapy, when the majority of patients had positive polymerase chain reaction (PCR) results for Borrelia burgdorferi DNA, SF from patients with antibiotic‐refractory arthritis contained exceptionally high levels of Th1 chemoattractants and cytokines, particularly CXCL9 and interferon‐γ (IFNγ). Compared with the patients whose arthritis was responsive to antibiotic treatment, those with antibiotic‐refractory arthritis had significantly higher levels of CXCL9 and CXCL10 (both P ≤ 0.001) and CCL3, CCL4, CXCL8, IFNγ, tumor necrosis factor α, interleukin‐1β (IL‐1β), and IL‐6 (all P ≤ 0.01). During the post‐antibiotic period, when the results of PCR for B burgdorferi DNA in SF and ST were uniformly negative, patients with antibiotic‐refractory arthritis continued to exhibit high SF and ST levels of these chemokines and cytokines. In addition, synovial samples showed marked expression of the receptors for T cell or macrophage chemokines, CXCR3 and CCR5.

Conclusion

Patients with antibiotic‐refractory Lyme arthritis have high synovial fluid levels of proinflammatory chemokines and cytokines, especially CXCL9 and IFNγ, throughout the illness. Thus, even when antibiotic treatment reduces or completely clears the infection in these patients, the inflammatory response in synovium persists.

     

Analysis of Borrelia burgdorferi genotypes in patients with lyme arthritis: High frequency of ribosomal RNA intergenic spacer type 1 strains in antibiotic‐refractory arthritis

Objective

Most of the Borrelia burgdorferi genotypes have been isolated from erythema migrans (EM) skin lesions in patients with Lyme disease. OspC type K strains, which are 16S–23S ribosomal RNA intergenic spacer type 2 (RST2) strains, are most commonly recovered, but a higher percentage of OspC type A strains (RST1), the next most commonly recovered type, is detectable in blood. The goal of this study was to determine the B burgdorferi genotypes in the joints of patients with Lyme arthritis.

Methods

Joint fluid samples from 124 patients seen over a 30‐year period were analyzed for OspC types by semi‐nested polymerase chain reaction (PCR) and sequencing, and for RSTs by nested PCR and restriction fragment length polymorphism analysis. These results were correlated with clinical outcome.

Results

OspC and RST genotypes were identified in 49 of the 124 joint fluid samples (40%). In these 49 samples, OspC type K strains (RST2) were identified in 21 samples (43%), OspC type A strains (RST1) were identified in 11 samples (22%), and 8 other OspC types and all 3 RSTs were identified among the remaining 17 samples (35%). However, among the 17 patients who had been treated with antibiotics according to current guidelines, all 7 patients who were infected with RST1 strains had antibiotic‐refractory arthritis, compared with 4 of 6 patients infected with RST2 strains and only 1 of 4 infected with RST3 strains (P = 0.03).

Conclusion

Most of the B burgdorferi genotypes, particularly OspC type K (RST2), were identified in the joint fluid of patients with Lyme arthritis, and the genotype frequencies found in joints reflected those in EM skin lesions. However, RST1 strains were most frequent in patients with antibiotic‐refractory arthritis. Our results help to further the understanding of the differential pathogenicity of strains of B burgdorferi.

     

A novel human autoantigen,endothelial cell growth factor,is a target of T and B cell responses in patients with Lyme disease

Objective

Autoantigen presentation by HLA–DR molecules is thought to be a central component of many autoimmune diseases, but identifying disease‐relevant autoantigens has been a difficult challenge. In this study we aimed to identify autoantigens in patients with antibiotic‐refractory Lyme arthritis, in which infection‐induced autoimmunity is thought to play an important role.

Methods

Using tandem mass spectrometry, naturally presented HLA–DR self peptides from a patient's synovium were identified, synthesized, and reacted with his peripheral blood mononuclear cells (PBMCs). Immunoreactive peptides and their source proteins were then tested for T and B cell responses using large numbers of patient cells or sera.

Results

Of 120 HLA–DR–presented self peptides identified from one patient, one peptide derived from endothelial cell growth factor (ECGF) caused his PBMCs to proliferate. T and B cell responses to ECGF occurred systemically in ∼10–30% of patients with early or late manifestations of Lyme disease, primarily in those with refractory arthritis–associated HLA–DR alleles, such as DRB1*0101 and 0401. Compared with patients with antibiotic‐responsive arthritis, those with antibiotic‐refractory arthritis had significantly higher concentrations of ECGF in synovial fluid (P < 0.0001) and more often had ECGF antibody reactivity. Among non–antibiotic‐treated historical patients who developed arthritis, 26% had ECGF reactivity, which often developed before the onset of arthritis and was associated with significantly longer courses of arthritis.

Conclusion

T and B cell responses to ECGF occur in a subset of patients with Lyme disease, particularly in those with antibiotic‐refractory arthritis, providing the first direct evidence of autoimmune T and B cell responses in this illness.

     

Low prevalence of antibodies to glucose‐6‐phosphate isomerase in patients with rheumatoid arthritis and a spectrum of other chronic autoimmune disorders

Objective

Arthritis in the K/BxN mouse model results from pathogenic immunoglobulins that recognize glucose‐6‐phosphate isomerase (GPI), a glycolytic enzyme residing in the cytoplasm of all cells. Antibodies directed against GPI can, alone, transfer arthritis to healthy recipients. Previous experiments have revealed significant titers of anti‐GPI antibodies in the serum of many patients with rheumatoid arthritis (RA). We evaluated the generality of these observations in cohorts of patients with 12 different arthritic and chronic autoimmune diseases and in population‐matched healthy control subjects.

Methods

Anti‐GPI antibodies were assayed in 811 individual serum samples by enzyme‐linked immunosorbent assay with 2 forms of GPI, recombinant and native. Results were confirmed by immunoblotting.

Results

Several patients had significantly elevated anti‐GPI antibody titers, but without the prevalence or the specificity reported previously. Only 15% of RA patients had anti‐GPI antibodies (range 12–29% in different cohorts), with a higher prevalence in patients with active disease. Psoriatic arthritis, undifferentiated arthritis, and spondylarthropathy patients also displayed anti‐GPI antibodies at similar frequencies (12–25%). Similar titers were detected in a proportion (5–10%) of control subjects or patients with Crohn's disease or sarcoidosis. Very high titers were found in rare cases of RA and systemic lupus erythematosus.

Conclusion

No disease‐specific pattern of antibody positivity to GPI was apparent. While the antibody‐mediated mechanism at play in the mouse model may exemplify a generic mechanism for some forms of arthritis in humans, GPI itself does not appear to be a target common to the majority of RA patients.

     

Host metalloproteinases in Lyme arthritis

Objective

: To assess the role of matrix metalloproteinases (MMPs) in cartilage and bone erosions in Lyme arthritis

Methods

We examined synovial fluid from 10 patients with Lyme arthritis for the presence of MMP‐2, MMP‐3, MMP‐9, and “aggrecanase” activity using gelatinolytic zymography and immunoblot analysis. We developed an in vitro model of Lyme arthritis using cartilage explants and observed changes in cartilage degradation in the presence of Borrelia burgdorferi and/or various protease inhibitors.

Results

Synovial fluid from patients with Lyme arthritis was found to contain at least 3 MMPs: gelatinase A (MMP‐2), stromelysin (MMP‐3), and gelatinase B (MMP‐9). In addition, there was evidence in 2 patients of “aggrecanase” activity not accounted for by the above enzymes. Infection of cartilage explants with B burgdorferi resulted in induction of MMP‐3, MMP‐9, and “aggrecanase” activity. Increased induction of these enzymes by B burgdorferi alone was not sufficient to cause cartilage destruction in the explants as measured by glycosaminoglycan (GAG) and hydroxyproline release. However, addition of plasminogen, which can act as an MMP activator, to cultures resulted in significant GAG and hydroxyproline release in the presence of B burgdorferi. The MMP inhibitor batimastat significantly reduced the GAG release and completely inhibited the collagen degradation.

Conclusion

MMPs are found in synovial fluids from patients with Lyme arthritis and are induced from cartilage tissue by the presence of B burgdorferi. Inhibition of MMP activity prevents B burgdorferi–induced cartilage degradation in vitro.

     

B cell activation biomarkers as predictive factors for the response to rituximab in rheumatoid arthritis: A six‐month,national, multicenter,open‐label study

Objective

To examine whether serum B cell markers can predict response to rituximab, a B cell–depleting monoclonal antibody, in patients with refractory rheumatoid arthritis (RA).

Methods

This rituximab re‐treatment dose study (SMART [eSsai MAbthera sur la dose de Re‐Traitement]) involved 208 patients with refractory RA. Serum markers of B cell activation (anti–cyclic citrullinated peptide [anti‐CCP] antibodies, rheumatoid factor [RF], serum IgG, IgA, and IgM levels, serum κ and λ free light chains, and serum BAFF) were assessed before the first rituximab cycle (1,000 mg on days 1 and 15). Univariate and multivariate analyses were performed to identify factors associated with a European League Against Rheumatism (EULAR) response at 24 weeks.

Results

There were 149 responders (72%). Two baseline factors were associated with a EULAR response at 24 weeks in multivariate analysis: the presence of anti‐CCP antibodies or RF (odds ratio 3.5 [95% confidence interval 1.6–7.6]) and a serum IgG concentration above normal (odds ratio 2.11 [95% confidence interval 1.02–4.33]), with synergy between them (odds ratio 6.0 [95% confidence interval 2.2–16.2]).

Conclusion

The presence of RF or anti‐CCP antibodies and elevated IgG are 2 simple biomarkers that can be used routinely before therapy to predict response to rituximab in patients with refractory RA.

     

Autoantibodies that bind glomeruli: Cross‐reactivity with bacterial antigen

Objective

Systemic lupus erythematosus (SLE) is characterized by the production of multiple autoantibodies. Anti‐DNA antibodies are associated with glomerulonephritis in SLE. It has been shown that anti‐DNA antibodies cross‐react with bacterial polysaccharide and, thus, might be elicited by microbial exposure. Non–DNA‐binding antibodies also contribute significantly to the pathogenesis of lupus nephritis. The goal of this study was to characterize non–DNA‐binding, kidney‐binding antibodies.

Methods

We generated a combinatorial library derived from spleen cells of a patient with SLE who had just previously received pneumococcal vaccine. The phage library was used in an in vivo biopanning technique to identify non–DNA‐binding, kidney‐binding antibodies. Antibodies were then analyzed for binding to bacterial polysaccharide and to renal antigens.

Results

Eight antibodies were characterized that bound glomeruli, but not DNA. All antibodies isolated by this protocol were IgG class, suggesting that there is affinity maturation for glomerular binding. Four of the antibodies cross‐reacted with pneumococcal polysaccharide. Six of the antibodies bound to renal antigens that have previously been reported to be cross‐reactive with DNA; the other 2 bound to histone.

Conclusion

This study suggests that both DNA‐binding and non–DNA‐binding antibodies in SLE may be elicited by the same bacterial antigens.

     

Trans heterodimer between two non–arthritis‐associated HLA alleles can predispose to arthritis in humanized mice

Objective

Certain HLA class II alleles are associated with susceptibility to the development of arthritis. However, the development of arthritis in some persons carrying non–rheumatoid arthritis (RA)–associated alleles remains unexplained. An individual who is heterozygous for the DQA1 and DQB1 genes can express the DQ molecule in cis or trans heterodimers. In a cis heterodimer, the α‐chain interacts with the β‐chain coded by the same chromosome, while in a trans heterodimer it interacts with the β‐chain on the other chromosome. In this study, we used a humanized mouse model of arthritis in an attempt to determine whether a trans heterodimer of 2 nonassociated alleles, DQB1*0601 and DQB1*0604, can predispose to arthritis.

Methods

DQB1*0601 and *0604 occur in linkage with DQA1*0103 and *0102, respectively. To understand the role of trans heterodimers, we generated DQB1*0604/DQA1*0103‐transgenic mice lacking endogenous HLA class II molecules.

Results

Severe arthritis developed in the DQB1*0604/A1*0103‐trangenic mice, and an antigen‐specific response was generated in vitro. DQB1*0604/DQA1*0103 presented type II collagen–derived peptides that were not presented by the arthritis‐resistant DQB1*0601 allele, suggesting that trans heterodimer molecules between 2 DQB1 and DQA1 molecules may result in the presentation of unique antigens and susceptibility to the development of arthritis. Molecular modeling of type II collagen peptides showed that DQB1*0604/DQA1*0103 shares a p4 pocket with the arthritis‐susceptible DQB1*0302 allele, suggesting a critical role of the p4 and p9 pockets in susceptibility to arthritis.

Conclusion

These results provide a possible explanation for the parental inheritance of nonsusceptibility alleles in some patients with RA and a mechanism by which they can predispose to the development of arthritis.

     

Gamma/delta T cells are the predominant source of interleukin‐17 in affected joints in collagen‐induced arthritis,but not in rheumatoid arthritis

Objective

Although interleukin‐17 (IL‐17)–producing γ/δ T cells were reported to play pathogenic roles in collagen‐induced arthritis (CIA), their characteristics remain unknown. The aim of this study was to clarify whether γ/δ T cells or CD4+ T cells are the predominant IL‐17–producing cells, and to determine what stimulates γ/δ T cells to secret IL‐17 in mice with CIA. The involvement of IL‐17–producing γ/δ T cells in SKG mice with autoimmune arthritis and patients with rheumatoid arthritis (RA) was also investigated.

Methods

IL‐17–producing cells in the affected joints of mice with CIA were counted by intracellular cytokine staining during 6 distinct disease phases, and these cells were stimulated with various combinations of cytokines or specific antigens to determine the signaling requirements. Similar studies were performed using SKG mice with arthritis and patients with RA.

Results

Gamma/delta T cells were the predominant population in IL‐17–producing cells in the swollen joints of mice with CIA, and the absolute numbers of these cells increased in parallel with disease activity. IL‐17–producing γ/δ T cells expressed CC chemokine receptor 6, were maintained by IL‐23 but not by type II collagen in vitro, and were induced antigen independently in vivo. Furthermore, IL‐17 production by γ/δ T cells was induced by IL‐1β plus IL‐23 independently of T cell receptor. In contrast to what was observed in mice with CIA, IL‐17–producing γ/δ T cells were nearly absent in the affected joints of SKG mice and patients with RA, and Th1 cells were predominant in the joints of patients with RA.

Conclusion

Gamma/delta T cells were antigen independently stimulated by inflammation at affected joints and produced enhanced amounts of IL‐17 to exacerbate arthritis in mice with CIA but not in SKG mice with arthritis or patients with RA.

     

sE‐selectin for stratifying outcome in rheumatoid arthritis

Objectives

To determine the usefulness of sE‐selectin as a marker for early diagnosis and stratification of rheumatoid arthritis.

Methods

We investigated several markers of disease activity, including circulating adhesion molecules and other standard laboratory tests, in a 2–3 year followup analysis of patients with rheumatoid arthritis.

Results

The mean ± SD levels of sE‐selectin (91.68 ± 31.8 ng/ml versus 49.83 ± 14.76 ng/ml) and rheumatoid factor (375.7 ± 394.4 U versus 44.66 ± 37.63 U) were strongly elevated in severe (n = 15) versus mild (n = 7) courses of disease. Statistical calculation of mean and standard deviation revealed that sE‐selectin represents a highly significant marker for the presence of persistent and aggressive disease over time, regardless of therapeutic intervention and observation time points (P = 0.0004). Notably, regression analysis identified constant values for all parameters analyzed and, therefore, a stable course of the disease could be predicted from the beginning.

Conclusion

sE‐selectin appears to be a powerful marker to predict the severity of rheumatoid arthritis.

     

CTLA‐4Ig blocks the development and progression of citrullinated fibrinogen–induced arthritis in DR4‐transgenic mice

Objective

To assess the role of T cells in the mouse model of citrullinated human fibrinogen–induced rheumatoid arthritis (RA) using CTLA‐4Ig, an agent that blocks T cell costimulation, which is required for T cell activation.

Methods

Humanized HLA–DRβ1*0401–transgenic (DR4‐Tg) mice were immunized with Cit–human fibrinogen to induce arthritis. Prior to, and at the onset or peak of, arthritis, the DR4‐Tg mice were treated with CTLA‐4Ig or control human IgG1 or were left untreated. Arthritis development and progression were monitored by measuring ankle swelling with calipers and by assessing histopathologic changes. The immune responses to the citrullinated antigens and the corresponding unmodified antigens, as well as the arthritogenicity of lymphocytes from these mice, were examined. The latter was performed using lymphocyte transfers from CTLA‐4Ig–treated or control mice via intraperitoneal injection into naive DR4‐Tg mice. Recipient mice also received an intraarticular injection of Cit–human fibrinogen, unmodified human fibrinogen, or vehicle.

Results

CTLA‐4Ig–treated, but not human IgG1‐treated, arthritic mice had significantly reduced ankle swelling and pathologic joint damage. Treatment with CTLA‐4Ig, but not human IgG1, suppressed Cit–human fibrinogen–induced T cell activation, including citrulline‐specific T cell activation, when given prior to disease onset. Transfer of splenic lymphocytes from untreated or human IgG1–treated arthritic mice caused arthritis in recipients, and this occurred when Cit–human fibrinogen, but not unmodified fibrinogen, was deposited into the joint. Splenocytes from CTLA‐4Ig–treated mice were unable to transfer arthritis.

Conclusion

Activated citrulline‐specific T cells play a direct role in the development and progression of arthritis in this model of Cit–human fibrinogen–induced RA.

     

Impact of synthetic and biologic disease‐modifying antirheumatic drugs on antibody responses to the AS03‐adjuvanted pandemic influenza vaccine: A prospective,open‐label,parallel‐cohort,single‐center study

Objective

To identify the determinants of antibody responses to adjuvanted split influenza A (H1N1) vaccines in patients with inflammatory rheumatic diseases.

Methods

One hundred seventy‐three patients (82 with rheumatoid arthritis, 45 with spondylarthritis, and 46 with other inflammatory rheumatic diseases) and 138 control subjects were enrolled in this prospective single‐center study. Controls received 1 dose of adjuvanted influenza A/09/H1N1 vaccine, and patients received 2 doses of the vaccine. Antibody responses were measured by hemagglutination inhibition assay before and 3–4 weeks after each dose. Geometric mean titers (GMTs) and rates of seroprotection (GMT ≥40) were calculated. A comprehensive medical questionnaire was used to identify the determinants of vaccine responses and adverse events.

Results

Baseline influenza A/09/H1N1 antibody levels were low in patients and controls (seroprotection rates 14.8% and 14.2%, respectively). A significant response to dose 1 was observed in both groups. However, the GMT and the seroprotection rate remained significantly lower in patients (GMT 146 versus 340, seroprotection rate 74.6% versus 87%; both P < 0.001). The second dose markedly increased antibody titers in patients, with achievement of a similar GMT and seroprotection rate as elicited with a single dose in healthy controls. By multivariate regression analysis, increasing age, use of disease‐modifying antirheumatic drugs (DMARDs) (except hydroxychloroquine and sulfasalazine), and recent (within 3 months) B cell depletion treatment were identified as the main determinants of vaccine responses; tumor necrosis factor α antagonist treatment was not identified as a major determinant. Immunization was well tolerated, without any adverse effect on disease activity.

Conclusion

DMARDs exert distinct influences on influenza vaccine responses in patients with inflammatory rheumatic diseases. Two doses of adjuvanted vaccine were necessary and sufficient to elicit responses in patients similar to those achieved with 1 dose in healthy controls.

     

Canakinumab for the treatment of acute flares in difficult‐to‐treat gouty arthritis: Results of a multicenter,phase II,dose‐ranging study

Objective

To assess the efficacy and tolerability of canakinumab, a fully human anti–interleukin‐1β monoclonal antibody, for the treatment of acute gouty arthritis.

Methods

In this 8‐week, single‐blind, double‐dummy, dose‐ranging study, patients with acute gouty arthritis whose disease was refractory to or who had contraindications to nonsteroidal antiinflammatory drugs and/or colchicine were randomized to receive a single subcutaneous dose of canakinumab (10, 25, 50, 90, or 150 mg; n = 143) or an intramuscular dose of triamcinolone acetonide (40 mg; n = 57). Patients assessed pain using a 100‐mm visual analog scale.

Results

Seventy‐two hours after treatment, a statistically significant dose response was observed for canakinumab. All canakinumab doses were associated with numerically less pain than triamcinolone acetonide; thus, a dose with equivalent efficacy to triamcinolone acetonide 72 hours after treatment could not be determined. The reduction from baseline in pain intensity with canakinumab 150 mg was greater than with triamcinolone acetonide 24, 48, and 72 hours after treatment (differences of −11.5 mm [P = 0.04], −18.2 mm [P = 0.002], and −19.2 mm [P < 0.001], respectively), and 4, 5, and 7 days after treatment (all P < 0.05). Canakinumab significantly reduced the risk of recurrent flares versus triamcinolone acetonide (P ≤ 0.01 for all doses) (relative risk reduction 94% for canakinumab 150 mg versus triamcinolone acetonide). The overall incidence of adverse events was similar for canakinumab (41%) and triamcinolone acetonide (42%); most were mild or moderate in severity.

Conclusion

Our findings indicate that canakinumab 150 mg provides rapid and sustained pain relief in patients with acute gouty arthritis, and significantly reduces the risk of recurrent flares compared with triamcinolone acetonide.

     

Reduced susceptibility to collagen‐induced arthritis in DBA/1J mice expressing the TSG‐6 transgene

Objective

Expression of TSG‐6 (tumor necrosis factor–stimulated gene 6) is induced by proinflammatory cytokines. This study was undertaken to examine the effects of local expression of TSG‐6 in arthritic joints of TSG‐6 transgenic mice, in the collagen‐induced arthritis (CIA) model.

Methods

We generated transgenic mice that harbored the TSG‐6 gene under the control of the T cell–specific lck promoter. Arthritis was induced by immunization with bovine type II collagen (CII), and its progression was monitored based on the incidence of arthritis, the arthritis index, and footpad swelling. Anti‐CII antibodies and cytokine production were determined by enzyme‐linked immunosorbent assay. Gene expression arrays were used to compare gene expression profiles of transgenic and control mice at various stages of CIA.

Results

TSG‐6 was expressed in limbs of transgenic mice after immunization with CII, while its expression in nontransgenic animals was insignificant. The incidence of CIA was reduced in TSG‐6 transgenic animals, its onset delayed, and all parameters of clinical arthritis significantly reduced. However, the immune response against CII was not significantly inhibited in TSG‐6 transgenic mice.

Conclusion

TSG‐6 expression has been demonstrated in patients with rheumatoid and other forms of arthritis. Our data show that local expression of TSG‐6 at sites of inflammation results in potent inhibition of inflammation and joint destruction in a model of autoimmune arthritis in mice. Therefore, it is likely that TSG‐6 plays a similar modulatory role in human rheumatoid arthritis and related diseases and may have potential for the treatment of autoimmune arthritis in humans.

     

Acute CD4+ T lymphocyte–dependent interleukin‐1–driven arthritis selectively requires interleukin‐2 and interleukin‐4, joint macrophages,granulocyte–macrophage colony‐stimulating factor,interleukin‐6, and leukemia inhibitory factor

Objective

To further investigate the effects of interleukin‐1 (IL‐1) in immune‐mediated joint inflammation, we examined the role of IL‐2, Th1 interferon‐γ (IFNγ), and Th2 (IL‐4) cytokines, joint macrophages, and macrophage‐derived cytokines (IL‐12 p40, IL‐6, leukemia inhibitory factor [LIF], oncostatin M [OSM], and granulocyte–macrophage colony‐stimulating factor [GM‐CSF]) in a CD4+ T lymphocyte–dependent model of acute arthritis.

Methods

Methylated bovine serum albumin (mBSA)/IL‐1–induced arthritis was elicited in wild‐type, gene‐knockout, and monoclonal antibody–treated mice. Synovial lining macrophages were selectively depleted by intraarticular injection of clodronate liposomes prior to disease induction. The severity of arthritis was assessed histologically.

Results

Mice deficient in IL‐2 were almost completely protected from arthritis, and neutralization of IL‐4 reduced the severity of disease. In contrast, arthritis severity and resolution appeared to be independent of IFNγ. Synovial lining macrophage depletion markedly reduced arthritis severity. IL‐6 or LIF deficiency was only modestly protective, although as previously reported, GM‐CSF deficiency conferred profound disease resistance. IL‐12 p40–deficient mice (which lack IL‐12 and IL‐23) and OSM receptor–deficient mice were susceptible to mBSA/IL‐1–induced arthritis.

Conclusion

Acute mBSA/IL‐1–induced arthritis is dependent on IL‐2 and IL‐4, but not IFNγ. In vivo, the Th1/Th2 paradigm may be distorted by the presence of macrophage‐derived cytokines such as IL‐1. Synovial lining macrophages are essential in mBSA/IL‐1–induced arthritis. However, the requirement for macrophage‐derived cytokines is selective; that is, IL‐6, LIF, and especially GM‐CSF are necessary, but IL‐12, IL‐23, and OSM are dispensable. IL‐1 may therefore influence both adaptive and innate immune mechanisms in acute inflammatory arthritis.

     

Role of Crk‐associated substrate lymphocyte type in the pathophysiology of rheumatoid arthritis in tax transgenic mice and in humans

Objective

To investigate the role of Crk‐associated substrate lymphocyte type (Cas‐L), a downstream signaling molecule of β1 integrins, in the pathophysiology of rheumatoid arthritis (RA).

Methods

We analyzed human T lymphotropic virus type I (HTLV‐I) tax transgenic mice as well as samples from human RA patients. Splenocytes from tax transgenic mice were cultured on mouse endothelial cell–covered Transwell inserts, and cells migrating through the endothelial monolayer were counted. Biochemical studies were performed to analyze the protein expression and tyrosine phosphorylation of Cas‐L. Immunohistochemical analysis was performed to detect Cas‐L–positive cells that had infiltrated into the joints.

Results

Migratory activity of splenocytes from tax transgenic mice with arthritis (ATg) was much higher than that of tax transgenic mice without arthritis (NTg) and littermate control mice. The expression of Cas‐L protein and its tyrosine phosphorylation were increased in ATg mice compared with NTg and control mice, and this was accompanied by enhanced autophosphorylation of Fyn and Lck. Immunohistochemical analysis demonstrated a large number of Cas‐L–positive lymphocytes migrating into the affected joints. Furthermore, in human RA, Cas‐L–positive lymphocytes were shown to infiltrate to the inflammatory lesions.

Conclusion

These results strongly suggest that Cas‐L plays an important role in the pathophysiology of RA.

     

Validity of self‐administered quality of well‐being scale in musculoskeletal disease

Objective

To evaluate the self‐administered Quality of Well‐Being (QWB‐SA) Scale for patients with rheumatic diseases.

Methods

Family medicine patients (n = 562) and rheumatology patients (n = 334) were assessed using the following tools: QWB‐SA, Health Assessment Questionnaire (HAQ), Arthritis Impact Measurement Scales (AIMS), and Rapid Assessment of Disease Activity in Rheumatology (RADAR).

Results

Patients with arthritis had significantly lower QWB‐SA scores and significantly higher HAQ scores than family medicine patients with and without adjustment for covariates. The QWB‐SA was significantly associated with quartiles from the RADAR, AIMS, and HAQ, providing evidence for the validity of the generic measure in patients with arthritis. Discriminant function analysis was used to create an arthritis‐specific scoring system for the QWB‐SA. Analyses demonstrated systematic relationships between the Quality of Well‐Being arthritis composite and the disease‐specific RADAR, AIMS, and HAQ.

Conclusions

Evidence supports the validity of the QWB‐SA for patients with rheumatic diseases. QWB‐SA items can be used to calculate an arthritis‐specific score. The QWB‐SA can be used to gain generic information for cost‐utility analysis and disease‐specific outcomes information for patients with arthritis.

     

Suppressive oligonucleotides protect against collagen‐induced arthritis in mice

Objective

To examine whether systemic administration of oligonucleotides (ODNs), known to inhibit the production of proinflammatory cytokines, alters host susceptibility to collagen‐induced arthritis (CIA), a murine model of rheumatoid arthritis (RA).

Methods

CIA was induced by injecting DBA/1 mice with type II collagen (CII) in Freund's complete adjuvant, followed 3 weeks later by CII in Freund's incomplete adjuvant. The effect of suppressive ODNs on the incidence and severity of disease was monitored, as were immune correlates of CIA.

Results

Suppressive ODNs administered during the inductive phase of CIA significantly reduced the incidence and severity of arthritis. Treatment with suppressive ODNs significantly decreased serum titers of pathogenic IgG anti‐CII autoantibodies and interferon‐γ production by collagen‐reactive T cells.

Conclusion

Suppressive ODNs may be of therapeutic value in the treatment of RA, and potentially other autoimmune diseases.