Imbalance of Th17 and T-regulatory cells in peripheral blood and synovial fluid in treatment naïve children with juvenile idiopathic arthritis

Th17/1 and ex-Th17 cells are detected in patients with polyarticular juvenile arthritis and increase following treatment

BACKGROUND

A better understanding of the pathogenesis of polyarticular juvenile idiopathic arthritis (polyJIA) is needed to aide in the development of data-driven approaches to guide selection between therapeutic options. One inflammatory pathway of interest is JAK-STAT signaling. STAT3 is a transcription factor critical to the differentiation of inflammatory T helper 17 cells (Th17s). Previous studies have demonstrated increased STAT3 activation in adult patients with rheumatoid arthritis, but less is known about STAT3 activation in polyJIA. We hypothesized that Th17 cells and STAT3 activation would be increased in treatment-naïve polyJIA patients compared to pediatric controls.

METHODS

Blood from 17 patients with polyJIA was collected at initial diagnosis and again if remission was achieved (post-treatment). Pediatric healthy controls were also collected. Peripheral blood mononuclear cells were isolated and CD4 + T cell subsets and STAT activation (phosphorylation) were evaluated using flow cytometry. Data were analyzed using Mann-Whitney U and Wilcoxon matched-pairs signed rank tests.

RESULTS

Treatment-naïve polyJIA patients had increased Th17 cells (CD3 + CD4 + interleukin(IL)-17 +) compared to controls (0.15% v 0.44%, p < 0.05), but Tregs (CD3 + CD4 + CD25 + FOXP3 +) from patients did not differ from controls. Changes in STAT3 phosphorylation in CD4 + T cells following ex vivo stimulation were not significantly different in patients compared to controls. We identified dual IL-17 + and interferon (IFN)γ + expressing CD4 + T cells in patients, but not controls. Further, both Th17/1 s (CCR6 + CD161 + IFNγ + IL-17 +) and ex-Th17s (CCR6 + CD161 + IFNγ + IL-17neg) were increased in patients' post-treatment (Th17/1: 0.3% v 0.07%, p < 0.05 and ex-Th17s: 2.3% v 1.4%, p < 0.05). The patients with the highest IL-17 expressing cells post-treatment remained therapy-bound.

CONCLUSIONS

Patients with polyJIA have increased baseline Th17 cells, potentially reflecting higher tonic STAT3 activation in vivo. These quantifiable immune markers may identify patients that would benefit upfront from pathway-focused biologic therapies. Our data also suggest that inflammatory CD4 + T cell subsets not detected in controls but increased in post-treatment samples should be further evaluated as a tool to stratify patients in remission on medication. Future work will explore these proposed diagnostic and prognostic biomarkers.

Comparison of Oral Health and Salivary Biomarkers in Children with Juvenile Idiopathic Arthritis and Healthy Individuals

AIM

This study examines the effects of juvenile idiopathic arthritis (JIA) on the oral health and detectability of inflammatory biomarkers IL-17, tumour necrosis factor-alpha (TNF-α) and total antioxidant status (TAS) in the saliva of children with JIA.

PATIENTS AND METHODS

This study included 117 participants (39 patients with JIA and 78 systemically healthy subjects aged 8-12 years). Demographic data, responses to an oral health-related questionnaire, saliva samples, periodontal parameters [plaque index (PI), gingival index (GI) and bleeding on probing (BOP)] and dental recordings [facial profile (FP) and dental occlusion relationship (DOR)] were obtained. Enzyme-linked immunosorbent assays were used to determine the levels of salivary IL-17, TNF-α and TAS.

RESULTS

The Caries Assessment Spectrum and Treatment (CAST) index, FP and DOR distributions did not change between groups (P > 0.05). JIA patients had more temporomandibular joint (TMJ) discomfort than gingivitis patients and healthy subjects (P < 0.05). JIA patients had greater salivary IL-17 levels than healthy subjects (P < 0.05). The healthy group's TAS was higher than that of the JIA and gingivitis groups (P < 0.05). Saliva TNF-α levels were similar between groups (P > 0.05). PI, GI, BOP and TNF-α were positively associated with salivary IL-17 (P < 0.001).

CONCLUSION

Elevated salivary IL-17 and TAS levels could be used as biological markers for discriminating the clinical health status of children with JIA and gingivitis.

Rheumatologic manifestations with elevated levels of IL-6, IL-17A, and IL-23 in a patient with scurvy

Symptomatic vitamin C deficiency, scurvy, is a relatively rare disease in developed countries, but it has been reported in patients with autism spectrum disorder or developmental delay who tend to have selective diets. Patients with scurvy often demonstrate musculoskeletal manifestations with unknown pathophysiology. Herein, we report a case of scurvy in an 11-year-old boy who presented with iron-deficiency anaemia, systemic osteomyelitis, myositis predominantly in the lower extremities, and right ventricular volume overload with mild pulmonary hypertension and was diagnosed with scurvy. He had a mild developmental disorder and a selective diet, which resulted in severe vitamin C deficiency. He received intravenous and oral vitamin C supplementation, which relieved his arthralgia and muscle pain in a week. Following 4 months of vitamin C supplementation, he demonstrated no abnormal manifestations on laboratory or imaging examination and recovered without sequelae. Inflammatory cytokine and chemokine evaluations demonstrated elevated levels of interleukin (IL)-6, IL-17A, and IL-23, which are associated with T-helper (Th) 17 cell activation. This study is the first to suggest the association between the inflammation seen in scurvy, rheumatic manifestations in the patient, and Th17 cell activation. Further analysis of the association between the inflammation and vitamin C supplementation may contribute to new insights for the comprehension and treatment of other inflammatory diseases, such as rheumatic diseases.

B Cells on the Stage of Inflammation in Juvenile Idiopathic Arthritis: Leading or Supporting Actors in Disease Pathogenesis?

Juvenile idiopathic arthritis (JIA) is a term that collectively refers to a group of chronic childhood arthritides, which together constitute the most common rheumatic condition in children. The International League of Associations for Rheumatology (ILAR) criteria define seven categories of JIA: oligoarticular, polyarticular rheumatoid factor (RF) negative (RF-), polyarticular RF positive (RF+), systemic, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. The ILAR classification includes persistent and extended oligoarthritis as subcategories of oligoarticular JIA, but not as distinct categories. JIA is characterized by a chronic inflammatory process affecting the synovia that begins before the age of 16 and persists at least 6 weeks. If not treated, JIA can cause significant disability and loss of quality of life. Treatment of JIA is adjusted according to the severity of the disease as combinations of non-steroidal anti-inflammatory drugs (NSAIDs), synthetic and/ or biological disease modifying anti-rheumatic drugs (DMARDs). Although the disease etiology is unknown, disturbances in innate and adaptive immune responses have been implicated in JIA development. B cells may have important roles in JIA pathogenesis through autoantibody production, antigen presentation, cytokine release and/ or T cell activation. The study of B cells has not been extensively explored in JIA, but evidence from the literature suggests that B cells might have indeed a relevant role in JIA pathophysiology. The detection of autoantibodies such as antinuclear antibodies (ANA), RF and anti-citrullinated protein antibodies (ACPA) in JIA patients supports a breakdown in B cell tolerance. Furthermore, alterations in B cell subpopulations have been documented in peripheral blood and synovial fluid from JIA patients. In fact, altered B cell homeostasis, B cell differentiation and B cell hyperactivity have been described in JIA. Of note, B cell depletion therapy with rituximab has been shown to be an effective and well-tolerated treatment in children with JIA, which further supports B cell intervention in disease development.

Interleukin-6 in juvenile idiopathic arthritis

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.

Decreased PD-1 expression on circulating CD4+T cell and PD-L1 expression on myeloid dendritic cell correlate with clinical manifestations in systemic juvenile idiopathic arthritis

OBJECTIVES

Programmed cell death-1 (PD-1) and its ligand (PD-L1) mediate negative signal in autoimmune diseases. While little is known about its role in juvenile idiopathic arthritis (JIA). The study aimed to reveal the circulating cell profile and the relative PD-1/PD-L1 expression of JIA subsets, elucidating their underlying immunomodulatory mechanisms.

METHODS

We detected the circulating cells and the relative PD-1/PD-L1 signaling in 101 JIA patients and 50 controls by flow cytometry and analyzed their association with disease activity and clinical manifestations.

RESULTS

Different from other JIA types, active systemic JIA (sJIA) patients had lower percentage and count of CD4⁺T cells and lower PD-1 expression on them compared with healthy controls (P<0.05), active polyarthritis (P<0.05) and enthesitis-related arthritis (ERA) patients (P<0.05). Also, they had higher percentage and count of myeloid dendritic cell (mDC) and lower PD-L1 expression on mDC compared with healthy controls (P<0.05). Both PD-1 on CD4⁺T cell and PD-L1 on mDC were negatively correlated with JADAS-27 in sJIA patients (P<0.05). In addition, PD-1 expression on CD4⁺T cell was negatively associated with the number of involved joints (P<0.05) and PD-L1 on mDC was lower in patients with fever (P<0.01), which could further divide patients into two groups of different manifestations.

CONCLUSIONS

Our finding displayed decreased CD4⁺T cell, increased mDC and reduced PD-1/PD-L1 signal in sJIA PBMC comparing with other JIA subsets, which might be helpful in JIA differential diagnosis and responsible for distinct clinical manifestations via different mechanisms.

Interleukin-17A Levels Increase in Serum of Children With Juvenile Idiopathic Arthritis

Objectives

This study aims to determine the serum levels of interleukin-17A (IL-17A) in children with juvenile idiopathic arthritis (JIA) and analyze the correlation between IL-17A values and disease activity, certain clinical features, and laboratory markers of inflammation.

Patients and methods

The study included 30 children (7 boys, 23 girls; mean age 8.8±5.3 years; range 1 to 18 years), who had been diagnosed with JIA (18 children were diagnosed during the study period and 12 children were diagnosed before the start of the study) and had active disease during the study period. Control group included 30 healthy, age- and sex- matched children (9 boys, 21 girls; mean age 8.3±4.8 years; range 1 to 18 years). The enzyme-linked immunosorbent assay was used to assess the serum IL-17A levels of children with JIA in the active phase of the disease and control group. Clinical and laboratory features of the disease were evaluated for the children with JIA.

Results

Serum levels of IL-17A in children with JIA were significantly higher in comparison to control group. In children with JIA who were prospectively monitored, statistically significantly decreased IL-17A level was recorded in the inactive phase of the disease. The incidence of arthritis of coxofemoral joints was significantly more common, and the mean levels of erythrocyte sedimentation rate and C-reactive protein were significantly higher in the group of children with JIA with detectable levels of IL-17A. Children with JIA and detectable levels of IL-17A had significantly higher values of Juvenile Arthritis Disease Activity Score-27 in comparison to children with JIA and non-detectable IL-17A.

Conclusion

Assessment of serum IL-17A levels in early phases of JIA gives an opportunity for early detection of children that have higher risk for worse functional outcome.

The impact of disease activity and tumour necrosis factor-α inhibitor therapy on cytokine levels in juvenile idiopathic arthritis

The aim of this study was to evaluate prospectively cytokine levels and disease activity in juvenile idiopathic arthritis (JIA) patients treated with and without tumour necrosis factor (TNF)-α inhibitors. TNF-α inhibitor-naive JIA subjects were followed prospectively for 6 months. Cytokine levels of TNF-α, interleukin (IL)-1β, IL-6, IL-8, IL-10 and IL-17 were measured at baseline for JIA subjects and healthy controls (HCs). Cytokine levels were then measured at four time-points after initiation of TNF-α inhibition for anti-TNF-α-treated (anti-TNF) JIA subjects, and at two subsequent time-points for other JIA (non-TNF) subjects. JIA disease activity by Childhood Health Assessment Questionnaire (CHAQ) disability index/pain score and physician joint count/global assessment was recorded. Sixteen anti-TNF, 31 non-TNF and 16 HCs were analysed. Among JIA subjects, those with higher baseline disease activity (subsequent anti-TNFs) had higher baseline TNF-α, IL-6 and IL-8 than those with lower disease activity (non-TNFs) (P < 0·05). TNF-α and IL-10 increased, and IL-6 and IL-8 no longer remained significantly higher after TNF-α inhibitor initiation in anti-TNF subjects. Subgroup analysis of etanercept versus adalimumab-treated subjects showed that TNF-α and IL-17 increased significantly in etanercept but not adalimumab-treated subjects, despite clinical improvement in both groups of subjects. JIA subjects with increased disease activity at baseline had higher serum proinflammatory cytokines. TNF-α inhibition resulted in suppression of IL-6 and IL-8 in parallel with clinical improvement in all anti-TNF-treated subjects, but was also associated with elevated TNF-α and IL-17 in etanercept-treated subjects.