The spontaneous remission of juvenile idiopathic arthritis is characterized by CD30+ T cells directed to human heat‐shock protein 60 capable of producing the regulatory cytokine interleukin‐10

Objective

To test the hypothesis that T cell reactivity to self heat‐shock protein 60 (Hsp60) in patients with remitting juvenile idiopathic arthritis (JIA) is part of an antiinflammatory, regulatory mechanism.

Methods

Using peripheral blood–derived mononuclear cells (PBMCs) and synovial fluid–derived mononuclear cells (SFMCs) obtained from patients with JIA, we analyzed the expression of CD30 and the induction of regulatory cytokines in response to human and mycobacterial Hsp60.

Results

In oligoarticular JIA patients, in vitro activation of PBMCs and SFMCs with Hsp60 induced a high expression of CD30 on CD4+, activated (HLA–DR–positive), memory (CD45RO+) T cells. The expression of CD30 induced by human Hsp60 was much higher than that induced by mycobacterial Hsp60. In oligoarticular JIA patients with active disease, the expression of CD30 in response to human Hsp60 was paralleled by a high interleukin‐10 (IL‐10):interferon‐γ (IFNγ) ratio. In addition, restimulated human Hsp60–specific T cell lines from oligoarticular JIA patients showed a high production of IL‐10 and a low production of IFNγ. In contrast, PBMCs and SFMCs from polyarticular JIA patients responded to human Hsp60 with virtually no expression of CD30 and a low IL‐10:IFNγ ratio.

Conclusion

The results show that T cells responding to human Hsp60 in oligoarticular JIA patients express CD30, and during active phases of the disease, these T cells have a cytokine profile with a high IL‐10:IFNγ ratio. These findings suggest that in oligoarticular JIA patients, human Hsp60–specific CD4+ cells have a regulatory function and contribute to disease remission.

     

A novel heat‐shock protein coinducer boosts stress protein Hsp70 to activate T cell regulation of inflammation in autoimmune arthritis

Objective

Stress proteins, such as members of the heat‐shock protein (HSP) family, are up‐regulated by cells in inflamed tissue and can be viewed functionally as “biomarkers” for the immune system to monitor inflammation. Exogenous administration of stress proteins has induced immunoregulation in various models of inflammation and has also been shown to be effective in clinical trials in humans. This study was undertaken to test the hypothesis that boosting of endogenous HSP expression can restore effective immunoregulation through T cells specific for stress proteins.

Methods

Stress protein expression was manipulated in vivo and in vitro with a food component (carvacrol), and immune recognition of stress proteins was studied.

Results

Carvacrol, a major compound in the oil of many Origanum species, had a notable capacity to coinduce cellular Hsp70 expression in vitro and, upon intragastric administration, in Peyer's patches of mice in vivo. As a consequence, carvacrol specifically promoted T cell recognition of endogenous Hsp70, as demonstrated in vitro by the activation of an Hsp70‐specific T cell hybridoma and in vivo by amplified T cell responses to Hsp70. Carvacrol administration also increased the number of CD4+CD25+FoxP3+ T cells, systemically in the spleen and locally in the joint, and almost completely suppressed proteoglycan‐induced experimental arthritis. Furthermore, protection against arthritis could be transferred with T cells isolated from carvacrol‐fed mice.

Conclusion

These findings illustrate that a food component can boost protective T cell responses to a self stress protein and down‐regulate inflammatory disease, i.e., that the immune system can respond to diet.

     

Wnt‐1–inducible signaling pathway protein 3 and susceptibility to juvenile idiopathic arthritis

Objective

To determine whether Wnt‐1–inducible signaling pathway protein 3 (WISP3) polymorphisms are associated with susceptibility to juvenile idiopathic arthritis (JIA).

Methods

The exons and the intron/exon boundaries of the WISP3 gene were mutation‐screened by denaturing high‐performance liquid chromatography in 86 patients with polyarticular‐course JIA (≥5 joints affected) and 15 controls. Seven single‐nucleotide polymorphisms (SNPs) were genotyped, using allelic discrimination, in a case–control study. Initially, 159 patients with polyarticular‐course JIA and 263 controls were studied, followed by study of a replication cohort of 181 patients with polyarticular‐course JIA and 355 controls. Available parents of patients with polyarticular‐course JIA were also genotyped. Finally, other JIA subgroups were studied (initial cohort, n = 218; replication cohort, n = 213). Single‐point and haplotype analysis was carried out.

Results

Positive association with SNP WISP3*G84A was observed and replicated in 2 cohorts of patients with polyarticular‐course JIA. Specifically, homozygosity of the mutant allele (WISP3*84AA) conferred a 2‐fold increased risk of disease susceptibility (for the initial cohort, odds ratio [OR] 2.1, 95% confidence interval [95% CI] 1.1–4.2, P = 0.03; for the replication cohort, OR 2.0, 95% CI 1.0–4.3, P = 0.05). Strong linkage disequilibrium was observed between SNPs; however, no haplotypic effect of an order of magnitude greater than the single‐point WISP3*G84A association was observed. Using the transmission disequilibrium test, a trend toward overtransmission of the WISP3*84A allele was observed in patients with polyarticular‐course JIA. No association of any WISP3 polymorphism was observed in the other JIA subgroups.

Conclusion

Association and replication of a polymorphism within the first intron of the WISP3 gene have been shown in patients with polyarticular‐course JIA. The functional significance of the WISP3*G84A SNP is being determined.

     

Interaction between heat‐shock protein 73 and HLA–DRB1 alleles associated or not with rheumatoid arthritis

Objective

HLA–DRB1 alleles whose third hypervariable region contains a QKRAA/QRRAA/RRRAA motif are associated with rheumatoid arthritis (RA) through unknown mechanisms. We previously demonstrated that the QKRAA motif was also expressed on the Escherichia coli 40‐kd heat‐shock protein (HSP) DnaJ. The QKRAA motif helps DnaJ bind its partner chaperone, the E coli 70‐kd HSP DnaK. Furthermore, we observed that in lymphoblastoid cells, Hsp73, the constitutive 70‐kd HSP, associates with HLA–DRB1*0401 (an allele with a QKRAA motif) and targets it to lysosomes. In this study, we sought to classify different HLA–DRB1 alleles according to their ability to bind Hsp73.

Methods

To evaluate how well different HLA–DRB1 alleles could bind Hsp73, we developed a quantitative precipitation assay and a direct binding assay.

Results

Quantitative precipitation assay from total cellular proteins and from lysosomal extracts demonstrated that RA‐associated HLA–DRB1 alleles bound Hsp73 better than did HLA–DRB1 alleles that were not associated with RA. HLA–DRB1*0401 was the best Hsp73 binder. These findings were confirmed by direct binding assay between purified proteins.

Conclusion

HLA–DRB1*0401 was the best Hsp73 binder among the 8 different HLA–DRB1 alleles that were tested.

     

Heat shock protein 70 membrane expression on fibroblast-like synovial cells derived from synovial tissue of patients with rheumatoid and juvenile idiopathic arthritis

OBJECTIVE: To screen fibroblast-like synovial cells derived from synovial tissue of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) patients for the membrane expression of the heat shock protein Hsp70. METHODS: We performed flow cytometric (fluorescence-activated cell sorting, or FACS) analysis on fibroblast-like synovial cells of 15 RA patients and three JIA patients to investigate Hsp70 membrane expression. Skin fibroblasts derived from the operation wound (n = 4) and peripheral blood mononuclear cells (PBMC) of seven RA and three JIA patients were also tested. Peripheral blood lymphocytes (PBL) and skin fibroblasts of 10 healthy individuals were used as negative controls. RESULTS: A significantly higher percentage of Hsp70 membrane expression was found on fibroblast-like synovial cells derived from arthritis-affected joints in RA patients (mean 47.7%) when compared with autologous skin fibroblasts (mean 9.5%, p < 0.001) and control skin fibroblasts (mean 5.6%, p < 0.001) or autologous PBL (mean CD45/Hsp70-positive 10.4%, p < 0.001) and control PBL (mean CD45/Hsp70-positive 7.7%, p < 0.001). A high percentage of Hsp70 membrane expression was also observed on fibroblast-like synovial cells derived from three patients with JIA (mean 35.2%) when compared with autologous PBL (mean CD45/Hsp70-positive 10.4%). Synovial cells derived from non-affected joints in a patient with RA who underwent synovectomy for trauma showed low expression of Hsp70 (10.9%). CONCLUSION: Fibroblast-like synovial cells derived from patients with severe course of RA and JIA are strongly positive for membrane-expressed Hsp70.     

Proinflammatory responses to self HLA epitopes are triggered by molecular mimicry to Epstein‐Barr virus proteins in oligoarticular juvenile idiopathic arthritis

Objective

To evaluate whether abnormal T cell recognition may be generated by exposure to exogenous antigens presenting sequence homology with epitopes contained in self HLA alleles, and if such recognition may be part of the mechanisms that fuel inflammation in autoimmune diseases associated with certain HLA alleles.

Methods

Cytotoxic responses of peripheral blood mononuclear cells to 9‐mer peptides derived from HLA molecules (DRB1*1101, DRB1*0801, or DPB1*0201) associated with oligoarticular juvenile idiopathic arthritis (JIA) or homologous peptides derived from Epstein‐Barr virus (EBV) proteins (Bolf1 or Balf2) were analyzed in patients with oligoarticular JIA and in healthy controls matched for HLA–DRB1*1101, DRB1*0801, or DPB1*0201. Production of proinflammatory cytokines in culture supernatants was determined by enzyme‐linked immunosorbent assay.

Results

T cell cytotoxic responses and production of proinflammatory cytokines in response to stimulation with self HLA–derived peptides were found only in patients with oligoarticular JIA, and not in controls. Patients with oligoarticular JIA, but none of the healthy controls, had EBV–self HLA cross‐reactive T cells.

Conclusion

Our data suggest a disease‐ and allele‐specific mechanism of autoimmunity in oligoarticular JIA. This mechanism may be part of the pathogenesis of the disease, and could be the basis of one of the likely multiple candidates for antigen‐specific immunotherapy approaches in the future.

     

Serum heat shock protein 60 can predict remission of flare-up in juvenile idiopathic arthritis

Heat shock protein (Hsp) 60 has been implicated in the pathogenesis of various inflammatory and autoimmune diseases. This study aimed to investigate synovial fluid and serum concentrations of Hsp60 and anti-Hsp60 and their relationship with juvenile idiopathic arthritis (JIA). Forty-eight patients with JIA, including 22 oligo-articular, 19 poly-articular, and 7 systemic diseases, and 33 normal controls were enrolled in this study. Synovial fluid and serum Hsp60 and anti-Hsp60 concentrations were measured via ELISA. Serum concentrations of Hsp60 of active and inactive oligo- and poly-articular JIA were significantly higher than those of normal controls. Serum concentration of anti-Hsp60 in active oligo-articular JIA was higher than that of normal controls (49.25 vs. 35.76 ng/mL, p = 0.059). Similarly, serum concentration of anti-Hsp60 in active poly-articular JIA was significantly higher than that of inactive samples (65.05 vs. 26.54 ng/mL, p = 0.008). In addition, serum concentration of Hsp60 correlated with the time required for remission from flare-ups in patients with JIA. Serum concentration of Hsp60 correlated well with time required for remission from flare-ups in patients with JIA, representing a potential disease marker to monitor disease activity.     

Inhibition of adjuvant‐induced arthritis by DNA vaccination with the 70‐kd or the 90‐kd human heat‐shock protein: Immune cross‐regulation with the 60‐kd heat‐shock protein

Objective

Adjuvant arthritis can be induced in Lewis rats by immunization with Mycobacterium tuberculosis (Mt). The mycobacterial 65‐kd heat‐shock protein (Hsp65) is targeted by arthritogenic T cells. However, Hsp65 and the mycobacterial 71‐kd heat‐shock protein are also recognized by T cells that can down‐regulate adjuvant‐induced arthritis (AIA). We have recently demonstrated that vaccination with human Hsp60 DNA inhibits AIA. The present study was undertaken to analyze the role of the T cell responses to self HSP molecules other than Hsp60 in the control of AIA.

Methods

Lewis rats were immunized with DNA vaccines coding for human Hsp70 or Hsp90 (Hsp70 plasmid [pHsp70] or pHsp90), and AIA was induced. The T cell response to Mt, Hsp60, Hsp70, and Hsp90 (proliferation and cytokine release) was studied, and the T cell response to Hsp60 was mapped with overlapping peptides.

Results

The Hsp70 or Hsp90 DNA vaccines shifted the arthritogenic T cell response from a Th1 to a Th2/3 phenotype and inhibited AIA. We detected immune crosstalk between Hsp70/90 and Hsp60: both the Hsp70 and Hsp90 DNA vaccines induced Hsp60‐specific T cell responses. Similarly, DNA vaccination with Hsp60 induced Hsp70‐specific T cell immunity. Epitope mapping studies revealed that Hsp60‐specific T cells induced by pHsp70 vaccination reacted with known regulatory Hsp60 epitopes.

Conclusion

T cell immunity to Hsp70 and to Hsp90, like Hsp60‐specific immunity, can modulate the arthritogenic response in AIA. In addition, our results suggest that the regulatory mechanisms induced by Hsp60, Hsp70, and Hsp90 are reinforced by an immune network that connects their reactivities.

     

Proinflammatory responses to self HLA epitopes are triggered by molecular mimicry to Epstein-Barr virus proteins in oligoarticular juvenile idiopathic arthritis

OBJECTIVE: To evaluate whether abnormal T cell recognition may be generated by exposure to exogenous antigens presenting sequence homology with epitopes contained in self HLA alleles, and if such recognition may be part of the mechanisms that fuel inflammation in autoimmune diseases associated with certain HLA alleles. METHODS: Cytotoxic responses of peripheral blood mononuclear cells to 9-mer peptides derived from HLA molecules (DRB1*1101, DRB1*0801, or DPB1*0201) associated with oligoarticular juvenile idiopathic arthritis (JIA) or homologous peptides derived from Epstein-Barr virus (EBV) proteins (Bolf1 or Balf2) were analyzed in patients with oligoarticular JIA and in healthy controls matched for HLA-DRB1*1101, DRB1*0801, or DPB1*0201. Production of proinflammatory cytokines in culture supernatants was determined by enzyme-linked immunosorbent assay. RESULTS: T cell cytotoxic responses and production of proinflammatory cytokines in response to stimulation with self HLA-derived peptides were found only in patients with oligoarticular JIA, and not in controls. Patients with oligoarticular JIA, but none of the healthy controls, had EBV-self HLA cross-reactive T cells. CONCLUSION: Our data suggest a disease- and allele-specific mechanism of autoimmunity in oligoarticular JIA. This mechanism may be part of the pathogenesis of the disease, and could be the basis of one of the likely multiple candidates for antigen-specific immunotherapy approaches in the future.     

Comparison of clinical versus ultrasound‐determined synovitis in juvenile idiopathic arthritis

Objective

To compare clinical evaluation and ultrasonography (US) in the assessment of joint synovitis in children with juvenile idiopathic arthritis (JIA).

Methods

Thirty‐two patients underwent clinical evaluation of 52 joints by 2 pediatric rheumatologists. Joints were assessed for swelling, tenderness/pain on motion, and restricted motion. The same joints were scanned independently by an experienced sonographer for synovial hyperplasia, joint effusion, and power Doppler (PD) signal.

Results

In total, 1,664 joints were assessed both clinically and with US. On clinical examination, 98 joints (5.9%) were swollen, 59 joints (3.5%) were tender, and 40 joints (2.4%) had restricted motion. On US evaluation, 125 joints (7.5%) had synovial hyperplasia, 153 joints (9.2%) had joint effusion, and 53 joints (3.2%) had PD signal. A total of 104 (6.3%) and 167 (10%) joints had clinical and US synovitis, respectively. Of the 1,560 clinically normal joints, 86 (5.5%) had subclinical synovitis (i.e., had synovitis on US). US led to classifying 5 patients as having polyarthritis who were classified as having oligoarthritis or were found to have no synovitis on clinical evaluation. US variables were moderately correlated with clinical measures of joint swelling, but poorly correlated with those of joint tenderness/pain on motion and restricted motion. Overall, correlations were lower for PD signal than for synovial hyperplasia and joint effusion.

Conclusion

We found that subclinical synovitis as detected by US is common in children with JIA. This finding may have important implications for patient classification and may affect the choice of the optimal therapeutic strategy in individual patients.     

Disease control and health‐related quality of life in juvenile idiopathic arthritis

Objective

To examine variability in health‐related quality of life (HRQOL) in children with juvenile idiopathic arthritis (JIA) experiencing no or minimal clinical symptoms, and in a subgroup with polyarticular JIA treated with biologic agents for 12 months.

Methods

We defined 3 samples using a database of patients ages 2–18 years with JIA (n = 524; patient visits [PV] = 2,354): visits (PV = 2,155) with no or minimal clinical symptoms on at least 1 of 4 measures (active joint count, pain, physician global disease rating, Childhood Health Assessment Questionnaire); visits (PV = 941) with no or minimal symptoms on all 4 measures; and children (n = 31) with polyarticular JIA treated with biologic agents for 12 months. HRQOL was measured using the Pediatric Quality of Life Inventory (PedsQL) and the percentage of patients with suboptimal HRQOL was determined.

Results

In PV with a PedsQL score, suboptimal HRQOL by self‐report occurred in 362 (20.6%) PV with at least 1 indicator of minimal symptoms, and in 64 (7.9%) PV with all 4 measures indicating minimal symptoms (519 [25.7%] and 95 [10.7%], respectively, by parent report). For children with polyarticular JIA treated for 12 months with biologic agents, 7 (25.9%) patients by self‐report and 10 (35.7%) patients by parent report were in the suboptimal range of HRQOL.

Conclusion

A substantial percentage of patients with JIA who report no or mild clinical symptoms experience suboptimal HRQOL. This is also true for patients with polyarticular JIA treated with biologic agents for 12 months. Although disease activity and clinical symptoms are related to HRQOL, considerable unexplained variation in HRQOL exists. HRQOL needs to be assessed independently regardless of clinical status.

     

Health‐related quality of life in adolescents with juvenile idiopathic arthritis

Objective

To describe the health‐related quality of life (HRQOL) of adolescents with juvenile idiopathic arthritis (JIA), and to examine the usefulness of the Juvenile Arthritis Quality of Life Questionnaire (JAQQ) in a UK context. It was hypothesized that HRQOL would decrease with worsening disease and disability.

Methods

Patients with JIA ages 11, 14, and 17 years were recruited from 10 major rheumatology centers. HRQOL was measured using the JAQQ. Other data were core outcome variables including the Childhood Health Assessment Questionnaire, demographic characteristics, arthritis‐related knowledge, and satisfaction with health care.

Results

Questionnaires were completed by 308 adolescents. One‐fifth had persistent oligoarthritis. Median disease duration was 5.7 years (range <1–16 years). The JAQQ was shown to have good psychometric properties when used in the UK, but was not without limitations. HRQOL of adolescents with JIA was less than optimal, particularly in the domains of gross motor and systemic functioning. Items most frequently rated as adolescents' biggest psychological problems were “felt frustrated” and “felt depressed,” rated by 30.2% and 23.4%, respectively. These were particularly problematic for the 17‐year‐olds, with 39% reporting frustration as one of their biggest problems and 63.6% reporting depression. Variation in the adolescent JAQQ scores was explained by functional disability, pain, and disease activity.

Conclusion

JIA can have a significant adverse effect on the HRQOL of adolescents. The JAQQ is a useful tool to assess the HRQOL of UK adolescents with JIA, but there is need for improved measures that incorporate developmentally appropriate issues.

     

Induction of endothelial cell apoptosis by heat‐shock protein 60–reactive antibodies from anti–endothelial cell autoantibody–positive systemic lupus erythematosus patients

Objective

To determine whether anti–endothelial cell autoantibodies (AECAs) from systemic lupus erythematosus (SLE) patients with the antiphospholipid syndrome are involved in the initial endothelial cell (EC) membrane perturbation effect that is postulated to provide a target for antiphospholipid antibody (aPL) binding and, hence, to trigger the thrombotic cascade. To identify the AECA antigenic target on ECs and to determine the mechanism whereby the EC membrane is disrupted.

Methods

AECAs from SLE patients were assayed for binding to ECs by flow cytometry. Positive AECAs were assayed by immunoblotting, and a consensus antigen was identified by mass spectrometry. This candidate antigen was tested in recombinant form for AECA recognition. AECAs were affinity‐purified on this antigen and incubated with ECs to determine their physiologic effects. Anti‐Hsp60 antibody titers were determined by enzyme‐linked immunosorbent assay. The relationship of anti‐Hsp60 status and lupus anticoagulant (LAC) status to thrombotic manifestations between disease onset and the last followup visit were analyzed.

Results

Most of the SLE sera (73%) possessed IgG that bound to the surface of ECs. These positive IgG shared reactivity against a 60‐kd EC surface polypeptide that was identified as human Hsp60. The presence of Hsp60 at the EC surface was established using anti‐Hsp60 antibodies from commercial sources or affinity‐purified from SLE sera that bound ECs. Incubation of ECs with these anti‐Hsp60 antibodies induced apoptosis in a time‐ and dose‐dependent manner, as determined by Hoechst 33342 dye staining of condensed nuclei and by annexin V binding to surface phosphatidylserine. Anti‐Hsp60 antibodies were not restricted to SLE patients, but were found in patients with other autoimmune diseases. However, anti‐Hsp60 antibodies were significantly associated with an increased frequency of thrombosis when present in combination with LAC in the SLE patients.

Conclusion

The presence of Hsp60 at the surface of ECs serves as a target for the anti‐Hsp60 antibodies in SLE sera. These anti‐Hsp60 antibodies bind to ECs and induce apoptosis, particularly phosphatidylserine exposure, thus providing a target for the binding of aPL and inducing the subsequent thrombotic cascade.

     

Inhibition of adjuvant‐induced arthritis by interleukin‐10‐driven regulatory cells induced via nasal administration of a peptide analog of an arthritis‐related heat‐shock protein 60 T cell epitope

Objective

To prevent and treat experimental arthritis via nasal administration of an altered peptide ligand (APL) from the major arthritogenic epitope in adjuvant‐induced arthritis (AIA) and to explore the mechanisms involved.

Methods

Peptides were administered nasally before and after induction of arthritis. Splenocytes and lymph node cells draining both the site of inflammation and the site of tolerance induction were used for cell transfer and were studied for antigen‐specific T cell characteristics. In addition, attempts were made to stop T cell tolerance in vitro, using anticytokine antibodies.

Results

Nasal administration of a modulatory APL of the heat‐shock protein 60 (Hsp60) 180–188 T cell epitope, alanine 183, had a suppressive effect in AIA that far exceeded that of the wild‐type epitope. In addition to its effectiveness in preventing AIA, alanine 183 may be effective in the treatment of ongoing AIA. The protective effect of alanine 183 can be passively transferred using activated splenocytes. Nasal administration of alanine 183 did not lead to detectable T cell proliferation or interleukin‐2 (IL‐2) production in mandibular lymph node cells, while transforming growth factor β (TGFβ), IL‐10, and IL‐4 were readily produced. Likewise, after nasally induced tolerance, followed by induction of arthritis, inguinal lymph node cells produced IL‐4, TGFβ, and IL‐10. After neutralizing in vitro the individual cytokines with anticytokine antibodies, only blocking of IL‐10 production led to reversal of tolerance, at the site of tolerance induction and the site of inflammation.

Conclusion

Nasal administration of an APL of Hsp60 180–188 induces highly effective protection against AIA through generation of regulatory cells that produce IL‐4, TGFβ, and IL‐10, whereas the induced tolerance is driven mainly by production of IL‐10.