Comparison of soluble adhesion molecules in juvenile idiopathic arthritis between the active and remission stages

Review of biomarkers in systemic juvenile idiopathic arthritis: helpful tools or just playing tricks?

BACKGROUND

Diagnosing systemic juvenile idiopathic arthritis (SJIA) can be extremely challenging if typical arthritis is lacking. A variety of biomarkers have been described for the diagnosis and management of SJIA. However, very few markers have been well-validated. In addition, increasing numbers of biomarkers are identified by high throughput or multi-marker panels.

METHOD

We identified diagnostic or prognostic biomarkers by systematic literature review, evaluating each according to a predefined level of verification, validation or clinical utility. Diagnostic biomarkers were those identifying SJIA versus (1) non-SJIA conditions or healthy controls (HC) or (2) other non-systemic JIA subtypes. Prognostic biomarkers were those specifically tested for the prediction of (1) disease flare, (2) increased disease activity +/- discrimination of active versus inactive disease, or (3) macrophage activation syndrome (MAS).

RESULTS

Fifty-five studies fulfilled the inclusion criteria identifying 68 unique biomarkers, of which 50/68 (74 %) were investigated by only a single research group. Candidate marker verification and clinical utility was evaluated according to whether markers were readily and reliably measurable, investigated by independent study groups, discovered by more than one method (i.e. verified markers) and validated in independent cohorts. This evaluation revealed diagnostic biomarkers of high interest for further evaluation in the diagnostic approach to SJIA that included heme oxygenase-1, interleukin-6 (IL-6), IL-12, IL-18, osteoprotegerin, S100 calcium-binding protein A12 (S100A12) and S100A8/A9.

CONCLUSION

In summary, a number of biomarkers were identified, though most had limited evidence for their use. However, our findings combined with the identified studies could inform validation studies, whether in single or multi-marker assays, which are urgently needed.

Reduced levels of circulating progenitor cells in juvenile idiopathic arthritis are counteracted by anti TNF-α therapy

Background

Endothelial progenitor cells (EPC) promote angiogenesis and vascular repair. Though reduced EPC levels have been shown in rheumatoid arthritis, no study has so far evaluated EPCs in children with juvenile idiopathic arthritis (JIA). We aimed to study circulating EPCs in children with JIA, their relation to disease activity, and effects of anti TNF-α treatment.

Methods

Circulating EPCs were quantified by flow cytometry based on CD34, CD133 and KDR expression in peripheral blood of 22 patients with oligoarticular JIA and 29 age-matched controls. EPCs were re-assessed in children with methotrexate-resistant oligo-extended JIA before and up to 12 month after initiation of anti-TNF-alpha therapy. Plasma concentrations of inflammatory and EPC-regulating factors were measured using a multiplex array. Confocal immunofluorescence was used to demonstrate EPCs in synovial tissues.

Results

Children with active JIA showed a significant reduction of relative and absolute counts of circulating progenitor cells and EPCs compared to age-matched healthy controls. CD34⁺ cell levels were modestly and inversely correlated to disease activity. A strong inverse correlation was found between serum TNF-α and EPC levels. In 8 patients treated with anti TNF-α agents, the number of EPCs rose to values similar to healthy controls. CD34⁺KDR⁺ EPCs were found in the synovial tissue of JIA children, but not in control.

Conclusions

Children with JIA have reduced levels of the vasculoprotective and proangiogenic EPCs. While EPCs may contribute to synovial tissue remodelling, EPC pauperization may indicate an excess cardiovascular risk if projected later in life.

Persistent improper upregulation of Th17 and TReg cells in patients with juvenile idiopathic arthritis

OBJECTIVES

Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease. A break in the balance between Th17 and TReg cells has been reported as an important factor in the development of autoimmune diseases. This study aimed to analyze peripheral Th17 and TReg cell levels in patients with JIA.

METHODS

The balance of Th17 and TReg cells among active and inactive JIA patients and normal control subjects were compared. Human peripheral blood mononuclear cells were isolated from the patients and controls. Surface and intracellular staining for CD4, CD25, Foxp3, IL-17, Th17, and TReg were analyzed.

RESULTS

Twenty-eight JIA patients, including 12 with active JIA and 16 with inactive JIA, and 20 health controls were analyzed. Patients with active JIA had higher Th17 (1.85 ± 1.15 vs. 1.05 ± 0.72, p = 0.008) and TReg cells (1.1 ± 0.8 vs. 0.6 ± 0.7, p = 0.04) levels than those with inactive JIA. Among active JIA patients, remission days were highly correlated with the CD4(+)IL17A(+) T cell percentage, 276.5 ± 137.40 days (range, 130 ∼ 525 days), p < 0.01. There were no differences in Th17/TReg percentage between JIA patients and controls in the peripheral blood.

CONCLUSIONS

Th17 and TReg cell levels are elevated in patients with active JIA and there is no Th17/TReg imbalance. The higher Th17 level predicted longer period to reach disease inactive stage. Improper Th17 up-regulation might contribute to JIA activation.

Changes in vascular function and structure in juvenile idiopathic arthritis

OBJECTIVE

Chronic inflammatory diseases in adults have been associated with increased cardiovascular risk and impaired vascular function. We aimed to assess the presence of early vascular dysfunction in patients with juvenile idiopathic arthritis (JIA) and investigate the role of inherent inflammatory process of JIA in vascular health.

METHODS

Thirty patients with JIA (age range 7-18 years) were compared to 33 age- and sex-matched controls. Endothelial function (brachial artery flow-mediated dilation [FMD]), carotid intima-media thickness (IMT), and arterial stiffness were examined. Endothelial inflammation was assessed by intercellular adhesion molecule 1 (ICAM-1) and P-selectin measurements.

RESULTS

Patients with JIA showed decreased FMD compared to controls (P = 0.001), independent of age (P = 0.9 among age subgroups). Baseline differences in erythrocyte sedimentation rate, ICAM-1, and glucose between the 2 groups accounted for the difference in FMD. The presence of systemic JIA was associated with greater IMT compared to patients with oligoarticular disease, polyarticular disease, or controls (P = 0.014, P = 0.069, and P = 0.046, respectively). The difference in IMT between systemic versus oligoarticular/polyarticular JIA was attributed to the following risk factors: age, body mass index, blood pressure, disease activity, and corticosteroids use. There were no differences in arterial stiffness indices between JIA patients and controls or between patients with systemic versus nonsystemic disease.

CONCLUSION

Endothelial function is impaired in patients with JIA at a very young age, while IMT is increased only in the presence of systemic JIA. Vascular dysfunction may be partly attributed to the effects of disease-related characteristics (inflammation, disease activity, and medications).

Decreased levels of sCD21 and sCD23 in blood of patients with systemic-juvenile arthritis, polyarticular-juvenile arthritis, and pauciarticular-juvenile arthritis

A soluble form of CD21 (sCD21) and CD23 (sCD23) is released from the surface of human white blood cells upon shedding of the extracellular domain. sCD21 circulates in a complex with cleavage fragments of C3 and sCD23, which were previously identified as ligands of membrane and soluble CD21. sCD21 seems to be a marker of chronic inflammatory disease. To assess the sCD21 and sCD23 status in patients with subsets of juvenile arthritis (JA), we determined plasma levels sCD21 and sCD23. Plasma sCD21 levels were significantly decreased in all JA subtypes (O-JA P < 0.0068; P- and S-JA P < 0.0001) compared to healthy controls. Plasma sCD23 levels were significantly decreased in P-JA and S-JA (both P < 0.0001), but not in O-JA (P < 0.3843) in comparison with healthy controls, and data statistically analyzed. Our results suggest that pathological mechanisms relevant to autoimmune disorders interfere with the regulation of both CD21 and CD23 shedding.

Persistent elevation of fibrin D-dimer predicts longterm outcome in systemic juvenile idiopathic arthritis

OBJECTIVE

We previously demonstrated that levels of fibrin d-dimer correlate with disease activity and response to therapies in systemic juvenile idiopathic arthritis (sJIA). We hypothesized that persistence of D-dimer elevation in the patterns previously described, but over a longer followup period, would signal poor outcome.

METHODS

We studied 31 children identified from 2 centers. Subjects were assigned a risk category based on their first obtained D-dimer concentration. Risk categories were based on results of our initial study, where normalization of D-dimer in patients no longer taking immunosuppressive therapy predicted good short-term outcome, and persistent D-dimer elevation while taking immunosuppressives predicted bad outcome (radiographic abnormalities, joint replacement surgery, or poor functional class) or a severe systemic manifestation. Outcome was determined at the last followup visit, a minimum of 2 years after measurement of the initial d-dimer level.

RESULTS

The 31 children were a mean 16.4 years old at an average of 8.8 years after their initial diagnosis. Ten children had a severe outcome during this period; all 10 had a study baseline risk category of "high." Of the 14 subjects who had a high risk category at study baseline, none had a mild outcome.

CONCLUSION

Our study indicated that a paradigm of risk of severe disease based upon persistent elevation of fibrin d-dimer on first measurements (greater than a mean of 29 months in our initial study and at least 24 months in the additional subjects) is promising to predict poor longer-term outcome in sJIA. A larger prospective study is warranted to substantiate the preliminary data and assess the relative comparative value to other biomarkers and clinical endpoints.

Effects of infliximab on cytokines, myeloperoxidase, and soluble adhesion molecules in patients with juvenile idiopathic arthritis

OBJECTIVE

Infliximab is effective and well tolerated in the treatment of juvenile idiopathic arthritis (JIA). The aim of the present study was to measure circulating levels of inflammatory mediators in patients with JIA during treatment with infliximab.

METHODS

Eight patients with active JIA refractory to standard treatments were treated with infliximab (3-4 mg/kg) at weeks 0, 2 and 6 and thereafter at approximately 6-week intervals up to 24 weeks.

RESULTS

All patients (n = 8) responded to the treatment. By 6 weeks of treatment the number of active joints had reduced from 16+/-4 (mean+/-SEM) to 4+/-1 (p<0.01) and C-reactive protein (CRP) levels had fallen from 31+/-8 to 8+/-3 (p<0.001). Infliximab treatment also reduced the serum concentrations of interleukin-6 (IL-6), myeloperoxidase (MPO), and soluble adhesion molecules ICAM-1 (intercellular adhesion molecule-1), and E-selectin. Tumour necrosis factor-alpha (TNFalpha) levels tended to increase while the concentrations of endogenous TNF antagonists (sTNF-RI and sTNF-RII) reduced in most patients during treatment.

CONCLUSIONS

Infliximab reduced serum levels of IL-6, MPO and soluble adhesion molecules in JIA patients, producing a good clinical response to the treatment.

Anti-endothelial cell antibodies are prevalent in juvenile idiopathic arthritis: implications for clinical disease course and pathogenesis

To determine the prevalence of anti-endothelial cell antibodies (AECA) in children with juvenile idiopathic arthritis (JIA) versus healthy control children. Twenty-eight children with active JIA were studied (ten each with polyarticular and oligoarticular disease, and eight with systemic onset disease). AECA were determined by a cell-based ELISA from samples obtained every 3 months over a 2 year period in each subject. These levels were compared against previously determined levels of von Willebrand factor antigen, fibrin d-dimer, and soluble forms of ICAM-1 and E-selectin, as well as clinical measures of disease activity. AECA were detected in 5/10 oligoarticular, 6/10 polyarticular, and 7/8 systemic JIA subjects and 0/14 controls. Mean levels of AECA were significantly higher in subjects with oligoarticular, and especially systemic disease as compared to polyarticular and control groups when analyzed by ANOVA. AECA are prevalent in JIA and are present more often and at higher levels in systemic disease.

RANTES and monocyte chemoattractant protein 1 as sensitive markers of disease activity in patients with juvenile rheumatoid arthritis: a six-year longitudinal study

OBJECTIVE

To longitudinally investigate serum and synovial fluid (SF) levels of RANTES and monocyte chemoattractant protein 1 (MCP-1) as well as in vitro migration of mononuclear cells toward SF in patients with juvenile rheumatoid arthritis (JRA).

METHODS

Serum and SF levels of RANTES and MCP-1 were determined by enzyme-linked immunosorbent assay. Chemotaxis was performed using the modified Boyden chamber method.

RESULTS

Serum RANTES levels were significantly increased in all onset types of JRA, with the highest levels present in systemic-onset JRA. Serum MCP-1 levels were significantly elevated in patients with systemic-onset JRA and were associated with current systemic features. Although serum levels of RANTES and MCP-1 decreased significantly after treatment, RANTES and MCP-1 levels during disease remission were still significantly higher in JRA patients than in controls. A relationship was found between serum RANTES levels during remission and the duration of clinical remission, with low levels being associated with prolonged clinical remission and high levels with shorter clinical remission. Serum RANTES levels correlated with C-reactive protein concentrations, hemoglobin values, white blood cell (WBC) counts, and platelet counts, whereas serum MCP-1 levels correlated with WBC counts and serum ferritin levels. Levels of RANTES and MCP-1 in SF were elevated as compared with levels in serum. SF chemotactic activity for mononuclear leukocytes was significantly inhibited by either anti-RANTES or anti-MCP-1 antibody.

CONCLUSION

RANTES is a key molecule in the pathogenesis of all onset groups of JRA, whereas MCP-1 is particularly important in systemic-onset JRA. Serum levels of these CC chemokines represent more highly sensitive markers of disease activity than conventional markers of inflammation.