Interleukin-6 in juvenile idiopathic arthritis

Abstract

Juvenile idiopathic arthritis (JIA) is a chronic childhood arthritis. Its pathogenesis is very complicated, with the involvement of not only immune cells but various types of parenchymal cells, and is affected by both genetic and environmental predispositions. The clinical spectrum from inflammation to related conditions is largely mediated by cytokines including interleukin (IL)-6. Fluctuations in IL-6 and its related molecules can modulate the pathogenesis and the clinical presentation positively or negatively. The recent clinical impact of IL-6 blockade on JIA has begun a therapeutic paradigm shift. This review describes the characteristics of JIA, mainly focused on IL-6 with the current therapeutic perspective.     

Interleukin-18 as a mediator of systemic juvenile idiopathic arthritis

The objective of this report is to explore the balance between serum and synovial fluid levels of interleukin (IL)-18 in children with juvenile idiopathic arthritis (JIA). Blood samples were obtained from 81 children with JIA and 18 control children. Synovial fluid samples were collected from 16 children with oligoarticular JIA. Concentrations of IL-18 were determined using commercial kit. Patients with systemic JIA had higher serum levels of IL-18 than patients with other forms of JIA or control children, both during the active (median, range: 6,240, 1,600–78,750 pg/ml) and inactive (1,615, 513–3,270 pg/ml) phase of disease [analysis of variance (ANOVA), P < 0.05). Levels of IL-18 in sera of children with oligoarticular JIA (255, 89–4,342 pg/ml) were similar to the respective synovial fluid levels (217, 89–1,245 pg/ml). Serum levels of IL-18 were proportional to the erythrocyte sedimentation rate and levels of C-reactive protein, but inversely proportional to the haemoglobin levels. IL-18 appears to be an important mediator of systemic JIA, while it seems of a lesser relevance in pathogenesis of other JIA forms. Therefore, inhibition of IL-18 might be a base for a successful biological therapy for systemic JIA.     

Switching the therapy from etanercept to infliximab in a child with rheumatoid factor positive polyarticular juvenile idiopathic arthritis

Abstract

Tumor necrosis factor α (TNFα)-blocking agents have been used increasingly in the treatment of severe refractory juvenile idiopathic arthritis (JIA). However, some patients have been forced to discontinue these agents because of the lack of efficacy or adverse events. In these situations, cases of switching from one TNF-blocking agent to another are reported in rheumatoid arthritis, but there are few cases in JIA. This report documents the case of a patient with JIA who improved following a switch from etanercept to infliximab.     

Switching the therapy from etanercept to infliximab in a child with rheumatoid factor positive polyarticular juvenile idiopathic arthritis

Tumor necrosis factor α (TNFα)-blocking agents have been used increasingly in the treatment of severe refractory juvenile idiopathic arthritis (JIA). However, some patients have been forced to discontinue these agents because of the lack of efficacy or adverse events. In these situations, cases of switching from one TNF-blocking agent to another are reported in rheumatoid arthritis, but there are few cases in JIA. This report documents the case of a patient with JIA who improved following a switch from etanercept to infliximab.     

Serum,synovial and mRNA expression of interleukin-33 in juvenile idiopathic arthritis patients: Potential role as a marker of disease activity and relation to musculoskeletal ultrasound

Aim of the workTo measure interleukin-33 (IL-33) serum and synovial fluid (SF) levels as well as its relative expression in peripheral blood mononuclear cells (PBMC) of juvenile idiopathic arthritis (JIA) patients and to study their relation to clinical, laboratory and musculoskeletal ultrasound characteristics, disease activity and functional status.Patients and methodsThe study included 60 JIA patients and 60 healthy controls and SF levels were measured in 20. Juvenile arthritis disease activity score (JADAS27) and Juvenile Arthritis Multidimensional Assessment Report (JAMAR) were assessed; Ten-joint grey scale (GS) and power Doppler (PD) MSUS score was performed. Rheumatoid factor (RF) titer and C-reactive protein (CRP) levels were measured.ResultsIn JIA patients, serum IL-33 levels (median 12.6; 7.4–23.8 ng/l) and its relative mRNA expression (median 3.3; 2.5–3.7) were significantly higher than their levels in the controls (median 1.7; 0.8–2.4 ng/l and median 1 ng/ml; p < 0.001). Polyarticular subtype (n = 20) had higher IL-33 serum levels compared to oligoarticular (n = 28, p < 0.001) and systemic-onset (n = 12, p = 0.006) subtypes. In JIA patients, the serum and SF levels of IL-33 significantly correlated with JADAS27 (p < 0.001 and 0.002 respectively), CRP (p < 0.001 and 0.007 respectively), GS (p < 0.001 and 0.001 respectively) and PD (p < 0.001 and 0.005 respectively). Serum IL-33 correlated with RF (p = 0.039) while, SF IL-33 correlated with physical function (p = 0.02).ConclusionsJIA patients have significantly elevated IL-33 serum concentrations and mRNA expression that considerably correlated with different inflammatory parameters, RF and physical function suggesting that it could be a valuable marker of JIA disease activity and implies a possible prognostic role.     

Serum ferritin levels as a useful diagnostic marker for the distinction of systemic juvenile idiopathic arthritis and Kawasaki disease

Objectives: The clinical features and laboratory parameters of patients with Kawasaki disease (KD) and systemic juvenile idiopathic arthritis (s-JIA) tend to overlap. Furthermore, there have been no definitive biomarkers for these diseases, making clinical diagnosis difficult. The purpose of this study was to investigate the diagnostic value of serum ferritin levels for differentiating KD from s-JIA and predicting the disease severity of KD.

Methods: We analyzed 228 patients with KD and 81 patients with s-JIA. Serum ferritin levels were compared between patients with s-JIA and KD. Furthermore, serum ferritin levels in patients with KD were compared with respect to clinical features such as responsiveness to intravenous immunoglobulin (IVIG) therapy.

Results: Serum ferritin levels in KD patients with no response to IVIG therapy were significantly higher than those in KD patients with a good response to IVIG therapy. Serum ferritin levels in patients with KD needing plasma exchange (PE) were significantly higher than those in patients not needing PE. However, serum ferritin levels overlapped between severe KD patients with nonresponsiveness to IVIG therapy or needing PE and other patients with mild KD. Furthermore, patients with s-JIA showed a distinct elevation of serum ferritin levels compared with KD patients. The cutoff value of serum ferritin levels for differentiating KD from s-JIA was 369.6?ng/ml.

Conclusions: Serum ferritin levels were significantly elevated in s-JIA patients compared with KD patients. Measurement of serum ferritin levels can be useful for differentiating s-JIA from KD.     

Early prediction for over two years efficacy of the first biologic agent for polyarticular juvenile idiopathic arthritis: A multi-institutional study in Japan

Objective: To estimate target of treatment for long-term efficacy of the first biologic agent used to treat polyarticular juvenile idiopathic arthritis (pJIA).

Methods: A retrospective cohort of patients with pJIA treated at six medical institutions in Japan between 1 March 2005 and 31 October 2014 was identified. The patients were divided by 2-year treatment periods with the first biologic agent into continuous treatment group and switching group. Three markers were examined: matrix metalloproteinase-3 (MMP-3), erythrocyte sedimentation rate (ESR), and disease activity score (DAS) 28-ESR.

Results: Thirty-two pJIA patients (8 boys, 24 girls) from 43 recruited patients were included in this study. The treatment periods with the first biologic agent in continuous treatment group (24 patients, 75%) was 40 months (median, range 24–119) and switching group (8 patients; 25%) was 9.5 months (median, 6–18). Markers [odds ratio (95% confidence interval)] at 3 months were MMP-3 [1.02 (0.99–1.05), p?=?.219], ESR [1.00 (0.78–1.30), p?=?.998], and DAS28-ESR [13.9 (2.08–409.82), p?=?.035]. The cut-off point for DAS28-ESR at 3 months to distinguish the two groups was 2.49 (sensitivity, 87.5%; specificity, 87.5%).

Conclusion: DAS28-ESR of 2.49 at 3 months after initiating the first biologic agent can be a target of sustained treatment in pJIA patients.     

Serum interleukin-18 level as a possible early diagnostic marker of systemic juvenile idiopathic arthritis

Early diagnosis of systemic juvenile idiopathic arthritis (s-JIA) is a prerequisite for therapeutic efficacy. However, it is often challenging because most patients with s-JIA do not show arthritis at disease onset and are simply diagnosed with fever of unknown origin. Serum ferritin levels have commonly been used to diagnose s-JIA because they increase in patients with this condition by more than 5 times their normal value. However, there are no definite biomarkers for s-JIA, which makes the clinical diagnosis of s-JIA difficult. We report a case of s-JIA in which interleukin (IL)-18 elevation was observed before ferritin elevation at the early phase of s-JIA. We propose serum IL-18 levels as a more useful biomarker for the early diagnosis of s-JIA compared to serum ferritin levels.     

Chitotriosidase activity in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an inflammatory joint disease of unknown etiology. The pathogenesis is driven by T and B cells. The role of macrophages remains unclear. Chitotriosidase belongs to the chitinase protein family and is secreted by activated macrophages. The chitinases are able to catalyze the hydrolysis of chitin or chitin-like substrates such as 4-methylumbelliferyl chitotrioside. Chitotriosidase activity was determined using the substrate 4-methylumbelliferyl beta-DNN'N'-triacetylchitotrioside (4-MU-TCT, SIGMA Chemical Co.). The substrate and serum were incubated with the serum in a citrate/phosphate buffer. The reaction was stopped by adding a buffer (Na(2)CO(3)). The fluorescence of 4-methylumbelliferone was evaluated by fluorimeter at excitation 360 nm and emission 450 nm. We report about chitotriosidase measurements in patients with JIA. The chitotriosidase level in synovial fluid was up to approximately 1,000 nmol/(h ml) at disease onset before therapy. The level in the sera was below 600 nmol/(h ml). Serum chitotriosidase levels could represent the activity of macrophages in the synovial fluid in JIA.     

Unilateral pachydermodactyly misdiagnosed as juvenile idiopathic arthritis: A case report

Rationale:Pachydermodactyly is a rare, benign disease that can manifest in healthy adolescent boys as painless, spindle-shaped, soft-tissue swelling of the proximal interphalangeal joints in the hand. It is usually bilateral, with symmetrical joint enlargement. There are relatively few documented cases of pachydermodactyly worldwide, signifying either a low incidence or lack of recognition by physicians; therefore, its diagnosis is challenging.Patient concerns:A 16-year-old boy with a 3-year history of painless unilateral swelling of the proximal interphalangeal joints of his left hand was misdiagnosed with juvenile idiopathic arthritis and was treated with oral methotrexate for 1 year. He had a history of frequent finger cracking.Diagnosis:He had normal levels of inflammatory markers, including erythrocyte sedimentation rate and C-reactive protein. His autoantibody profile results were normal, and radiography of his hands showed soft tissue swelling with no bone abnormalities. Therefore, the patient was diagnosed with Parkinson disease.Interventions:Methotrexate was discontinued, and a skin biopsy was performed, which revealed hyperkeratosis in the epidermis with thick collagenous fibers in the dermis. Therefore, the patient was informed of the benign nature of the disease and was advised to stop cracking his fingers.Outcomes:After regular follow-up, there was no progression of the patient''s symptoms, and repeated blood tests revealed normal results.Lessons:Pachydermodactyly should be considered in the differential diagnosis of painless swelling in adolescent men with normal blood testing. Early recognition of this rare benign condition helps physicians appropriately reassure the patient and his parents without exposing them to unnecessary therapy.     

Plasma exchange successfully treated macrophage activation syndrome in rheumatoid factor‐positive polyarticular juvenile idiopathic arthritis with co‐existing pneumonia

Macrophage activation syndrome (MAS) is one of the serious complications associated with rheumatic diseases, especially systemic juvenile idiopathic arthritis (sJIA). Here we describe a 9‐year‐old girl with rheumatoid factor (RF)‐positive polyarticular JIA, not sJIA, combined with pneumonia who was successfully treated by plasma exchange. She was diagnosed with RF‐positive polyarticular JIA based on positive RF and multiple joint swelling and tenderness 3 years ago. She was admitted in our hospital with myalgia for 2 days and a high fever for half a day. Physical examination revealed relapsing joints symptoms and rough breathing sounds of lungs. The laboratory examination showed increased liver enzymes, elevated serum ferritin and procalcitonin (PCT), decreased percentage of nature killer (NK) cells and fibrinogen, and activated macrophage phagocytosing hematopoietic elements in bone marrow. The elevated PCT and chest computed tomography scan confirmed she also had pneumonia. Intravenous methylprednisolone and oral cyclosporine A followed by intravenous immunoglobulin were added on the basis of antibiotics therapy, but clinical symptoms and laboratory findings did not improve. Finally, we changed to plasma exchange once every other day for a total of three times. Within 1 week, the girl recovered from the MAS completely.     

Mucolipidosis: A mimicker of juvenile idiopathic arthritis

Juvenile idiopathic arthritis is the most common form of chronic arthritis in children and at times misdiagnosed in those presenting with arthropathy secondary to non-inflammatory causes. The overlap of symptoms often pose a diagnostic challenge for clinicians. This mostly results in a delayed diagnosis subjecting children to unnecessary use of long-term immunosuppressants and disease-modifying drugs. We present the case of a 9-year-old boy who was previously misdiagnosed as a case of juvenile idiopathic arthritis. Detailed evaluation later led to the diagnosis of mucolipidosis (type III) which was confirmed on genetic testing. Emphasis on detailed history and clinical examination including the subtle hints like lack of signs of inflammation, family history, no morning stiffness and normal inflammatory markers should be picked up to make a timely diagnosis. In today's era of genetic testing and diagnosis, it is prudent to offer these tests for such patients to make an accurate diagnosis and prognosticate them for the long-term outcome.     

Interleukin-10 promoter polymorphism in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which interleukin (IL)-10 plays an important role. There are, however, controversial reports that IL-10 promoter polymorphism may be an independent marker of susceptibility and severity of RA. The aim of the present study was to examine the IL-10 promoter polymorphism in patients with RA. We examined 95 patients with rheumatoid arthritis diagnosed according to the criteria of the American College of Rheumatology. Polymerase chain reaction amplification was used for analysis of the promoter polymorphism of the IL-10 gene. In RA patients, the prevalence of genotypes encoding high expression of IL-10 was observed. Nevertheless, there was no association between IL-10 genotypes and age at disease diagnosis, disease activity in a physicians global assessment, and joint and extra-articular involvement. There was also no correlation between IL-10 polymorphism and disease activity parameters—erythrocyte sedimentation rate, C-reactive protein, number of swollen and tender joints, and duration of morning stiffness. We suggest that IL-10 promoter polymorphism is not a genetic risk factor for RA activity.     

A survey of foot problems in juvenile idiopathic arthritis

Background: Evidence suggests that foot problems are common in juvenile idiopathic arthritis (JIA), with prevalence estimates over 90%. The aim of this survey was to describe foot‐related impairment and disability associated with JIA and foot‐care provision in patients managed under modern treatment paradigms, including disease‐modifying anti‐rheumatic drugs (DMARDs) and biologic therapies. Methods: The Juvenile Arthritis Foot Disability Index (JAFI), Child Health Assessment Questionnaire (CHAQ), and pain visual analogue scale (VAS) were recorded in 30 consecutive established JIA patients attending routine outpatient clinics. Foot deformity score, active/limited joint counts, walking speed, double‐support time (s) (DS) and step length symmetry index % (SI) were also measured. Foot‐care provision in the preceding 12 months was determined from medical records. Results: Sixty‐three per cent of children reported some foot impairment, with a median (range) JAFI subscale score of 1 (0–3); 53% reported foot‐related activity limitation, with a JAFI subscale score of 1 (0–4); and 60% reported participation restriction, with a JAFI subscale score of 1 (0–3). Other reported variables were CHAQ 0.38 (0–2), VAS pain 22 (0–79), foot deformity 6 (0–20), active joints 0 (0–7), limited joints 0 (0–31), walking speed 1.09 m/s (0.84–1.38 m/s), DS 0.22 s (0.08–0.26 s) and SI ±4.0% (±0.2–±31.0%). A total of 23/30 medical records were reviewed and 15/23 children had received DMARDS, 8/23 biologic agents and 20/23 multiple intra‐articular corticosteroid injections. Ten children received specialist podiatry care comprising footwear advice, orthotic therapy and silicone digital splints together with intrinsic muscle strengthening exercises. Conclusion: Despite frequent use of DMARD/biologic therapy and specialist podiatry‐led foot care, foot‐related impairment and disability persists in some children with JIA. Copyright © 2008 John Wiley & Sons, Ltd.