Hip involvement in children with enthesitis related arthritis (ERA) is associated with poor outcomes in adulthood

Juvenile Spondyloarthropathies: Diagnostic and Therapeutic Advances-A Narrative Review

Spondyloarthropathies (SpAs) represent a diverse group of seronegative immune-mediated inflammatory diseases characterized by a genetic predisposition and an association with human leukocyte antigen-B27. This narrative review aims to explore juvenile spondyloarthropathies (JSpAs), their classification, clinical manifestations, diagnostic challenges, and contemporary treatment strategies. According to the International League of Associations for Rheumatology criteria, JSpAs include several specific forms: enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis. Despite established classifications, the terms and definitions surrounding these conditions can often lead to confusion among healthcare professionals. This ambiguity underscores the need for a standardized approach to nosological classification. The clinical presentation of JSpAs can be multifaceted, encompassing both articular and extra-articular manifestations. Articular symptoms may include enthesitis and varying forms of arthritis, while extra-articular involvement can range from uveitis to gastrointestinal, cardiovascular, pulmonary, neurological, and renal complications. These diverse manifestations highlight the systemic nature of the disease and the importance of a holistic approach to diagnosis and treatment. While laboratory tests for SpAs are often non-specific, imaging modalities such as musculoskeletal ultrasound and magnetic resonance imaging play a crucial role in the early detection of inflammatory lesions. These imaging techniques can provide valuable insights into disease progression and aid in the formulation of appropriate treatment plans. Current treatment guidelines advocate for a "stepwise" approach to therapy, beginning with nonsteroidal anti-inflammatory drugs and progressing to glucocorticoids, disease-modifying antirheumatic drugs, and biological agents, particularly anti-tumor necrosis factor alpha agents. The primary objective of treatment is to achieve clinical remission or, at a minimum, to attain low disease activity. Regular monitoring of disease activity is imperative; however, the lack of validated assessment tools for the pediatric population remains a significant challenge. JSpAs pose unique challenges in terms of diagnosis and management due to their diverse manifestations and the complexities of their classification. Ongoing research and clinical efforts are essential to refine our understanding of these conditions, improve treatment outcomes, and enhance quality of life for affected children and their families. Effective management hinges on early detection, individualized treatment plans, and continuous monitoring, ensuring that patients receive the most appropriate care tailored to their specific needs.

Assessment of sacroiliitis using zero echo time magnetic resonance imaging: a comprehensive evaluation

BACKGROUND

Enthesitis-related arthritis (ERA), a subset of juvenile idiopathic arthritis (JIA), is characterized by frequent involvement of the sacroiliac (SI) joints.

OBJECTIVE

The aim of this study was to assess the effectiveness of zero echo time (ZTE) magnetic resonance imaging (MRI) in identifying structural lesions in patients with ERA. Conventional MRI pulse sequences often struggle to adequately visualize osseous and calcified tissues.

MATERIALS AND METHODS

All MRI examinations were conducted using a 1.5-T (T) scanner. The MRI protocol included standard sequences such as fat-suppressed axial T2-weighted, axial T1-weighted, coronal short tau inversion recovery (STIR), and axial T2-weighted sequences. In addition to conventional MRI, a ZTE sequence was employed. Low-dose computed tomography (CT) served as the reference standard and was performed using a 640-multislice CT device. Structural lesions, including erosions, sclerosis, and changes in joint space, were compared between imaging modalities.

RESULTS

A total of 20 patients were included in the study (12 boys, 8 girls), with a median age at diagnosis of 14 years. ZTE-MRI demonstrated similar sensitivity to low-dose CT in detecting erosion (7 vs 8, P = 0.707). The interclass correlation coefficient (ICC) between low-dose CT and ZTE-MRI was 0.993 (P < 0.001), indicating excellent agreement. Moreover, ZTE-MRI showed strong agreement with low-dose CT in detecting sclerosis (ICC = 0.954, P < 0.001) and changes in joint space (ICC = 0.998, P < 0.001).

CONCLUSIONS

Zero echo time imaging shows promise in providing sacroiliac joint visualization comparable to low-dose CT scans, thereby improving the detection of subtle erosion and sclerosis in these joints.

Can pediatric rheumatologists apply available hip scoring systems in daily practice for juvenile idiopathic arthritis?

Introduction

Scoring systems for hip involvement in juvenile idiopathic arthritis exist, however, they were not used in daily practice, and their reproducibility was not proven.

Objectives

We aimed to determine the applicability, reliability, and repeatability of the two scoring systems of the hip in juvenile idiopathic arthritis patients.

Methods

Two expert pediatrics rheumatologists analyzed pelvic radiographs from 25 children with JIA hip involvement. We scored the findings according to two previous valid scoring systems (The childhood Arthritis Radiographic Score of the Hip and the newly developed score proposed by the project Health-e-Child) at baseline and after three weeks. We used kappa statistics to rate inter- and intra-observer variability.

Results

The joint space narrowing, erosion, and growth abnormalities had moderate to good reliability when the first score was used. However, the subchondral cysts, malalignment, and sclerosis have poor concordance in the two observers. For the second score, the intraclass correlation coefficient (ICC) was high in only one reader for head erosion (κ = 0.833 vs. κ = 0.308; p < 0.001), enlarged fovea (κ = 0.279 vs. κ = 0.907; p < 0.05), and growth abnormalities (κ = 0.823 vs. κ = 0; p < 0.001; p = 0.5). Therefore, the intra-reader agreement for head femoral measuring and centrum-column-diaphysis angle showed good reliability for only one reader. Training has only improved the observers' agreement with the assessment of growth disorders in the first score. The interpretation agreement was also increased compared to the baseline in the femoral measurements.

Conclusion

The reliability of these tools seemed to be lower without electronic measurements and the pediatric rheumatologists needed more training before applying these scoring in the practice hip monitoring.

Clinical Trial Registration

NCT05206968 Last Update: 01/12/2022.

Clinical Features and Risk Factors for Early Bone Destruction in Enthesitis-Related Arthritis: A Cohort Study

OBJECTIVES

To explore the clinical characteristics and identify risk factors for early bone destruction in children with enthesitis-related arthritis (ERA).

METHODS

Clinical characteristics were retrospectively analyzed in 85 newly diagnosed cases with ERA at our hospital from January 2019 to December 2021. Logistic regression analyses were performed to identify risk factors for early bone destruction.

RESULTS

In this cohort of 85 ERA patients, early bone destruction was identified in 24.7% (21/85) of cases (ERA-BD group), predominantly affecting the sacroiliac joints (66.7%), knee (14.3%), hip (14.3%), and interphalangeal joints (4.8%). The ERA-BD group exhibited significantly higher rates of polyarticular involvement (≥ 5 joints) compared to the ERA-nBD group (76.2% vs. 12.5%, p < 0.001), with a notably higher incidence of knee joint involvement (66.7% vs. 40.6%, p < 0.05) and sacroiliitis (85.7% vs. 50.0%, p < 0.05). Additionally, the ERA-BD group had a longer disease duration (8.0 vs. 3.5 months, p = 0.009) and elevated C-reactive protein levels (median: 12.3 vs. 4.4 mg/L, p = 0.04). However, no significant differences were observed in ESR or IL-6 levels between the two groups. Multivariate analysis confirmed that polyarticular involvement (OR = 21.39, 95% CI 5.12-89.30) and longer disease duration (OR = 4.06, 95% CI 1.33-12.39) were independent predictors of early bone destruction.

CONCLUSIONS

Our study identifies polyarticular involvement (≥ 5 joints) and longer disease duration as key independent predictors of early bone destruction in ERA, highlighting the need for a shift from joint-specific to systemic risk stratification.

Pediatric Society of the African League Against Rheumatism juvenile idiopathic arthritis recommendations for enthesitis-related arthritis and juvenile psoriatic arthritis

The objective of this study is to develop evidence-based recommendations for the diagnosis and management of enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (JPsA) in the African context. The recommendations for ERA and JPsA were combined into a single document. The steering committee and task force identified 15 key questions and formulated 35 research questions. A comprehensive literature review, utilizing Medline and a manual search for African local data, was conducted to gather evidence. Following this synthesis, the task force developed draft recommendations and engaged in a Delphi process with an expert panel, including 17 African and three international experts, to reach a consensus and ensure alignment with global standards. The final recommendations were assigned a level of evidence and subsequently approved by the task force members, the expert panel, and the PAFLAR Board. Fifteen recommendations on the diagnosis and management of ERA and JPsA were developed, covering the role of the pediatric rheumatologist in multiple aspects of disease management, including diagnosis, monitoring of disease and extra-articular manifestations, determining treatment strategies, and guiding interventions. The level of evidence supporting these recommendations was variable, leading to the identification of a research agenda to address African particularities and answer pending questions. The final recommendations achieved a high level of agreement, with consensus ranging from 90 to 100%. These recommendations represent an important achievement for pediatric rheumatology in Africa, being the first of their kind, tailored specifically to the region. Developed through a rigorous methodology and collaboration between international and African experts, they aim to standardize care and address the unique challenges faced in African setting.

Axial radiographic structural damage in patients with Enthesitis-Related Arthritis presents a distinct phenotype compared to adults with axial spondyloarthritis: A cross-sectional cohort study

Enthesitis-related arthritis (ERA), a distinct subtype of juvenile idiopathic arthritis (JIA) related to HLA-B27 and peripheral and axial involvement, presents with insidious onset of arthritis and/or enthesitis. However, there is a lack of data concerning axial new bone formation in patients transitioning into adulthood. To evaluate the axial radiographic structural damage (axRxSD), encompassing the sacroiliac joints (SIJ), hips, and spine, in ERA patients across various age groups. A cross-sectional cohort study was conducted with patients aged up to 35 years. Specific tools were used for measuring disease activity (BASDAI, ASDAS), function (BASFI, HAQ-S), mobility (BASMI), clinical enthesitis (MASES), ultrasound evaluation (MASEI), and axRxSD, including mSASSS for spine, Kellgren-Lawrence for hips and modified New York criteria for SIJ. A total of 26 patients were included, of whom 76.9% were males, with a mean age at diagnosis and assessment of 11.9 and 19.7 years, respectively. HLA-B27 positivity was found in 58.3%. Current active arthritis and enthesitis were present in 19.2% and 23%, respectively, with mean MASEI score of 12 (IQR 6-17). Peripheral joint limitation was observed in 50%, despite a BASMI score of 2.2 and 16% occurrence of abnormal FABER test. Most patients were in remission or low disease activity [ASDAS-ESR = 1.2 (0.6-2.3); ASDAS-CRP = 1.55 (0.6-2.4)]. Modified New York criteria were fulfilled by 73.1% of patients and 15.4% had radiographic hip involvement. Spine involvement, measured by mSASSS, was low (IQR 0-4.2), with only two patients exhibiting syndesmophytes. There was no statistical association between any imaging methods and clinical, laboratory, and ultrasound variables, including scores for activity, functionality, and mobility. Significant association was found only between axRxSD and BASMI. Our results showed high frequency of SIJ ankylosis alongside lower radiographic involvement in the spine and hips, suggesting a distinct structural damage phenotype. The early recognition of this outcome and the use of immunobiological therapy may mitigate syndesmophyte occurrence over time.

Prevalence of HLA-B27, clinical characteristics and treatment outcomes in children with enthesitis-related arthritis

BACKGROUND

Enthesitis-related arthritis (ERA) is a subtype of juvenile idiopathic arthritis with high disease burden. The objectives of this study were to explore the prevalence of HLA-B27, clinical characteristics, and treatment outcomes in children with ERA and compare the differences between HLA-B27 positive and negative patients.

METHODS

A retrospective cohort study at a pediatric rheumatology clinic in a tertiary referral hospital in Bangkok, Thailand, including ERA patients with at least 6 months of follow-up (July 2011-April 2022) was performed. Data were collected from medical records from diagnosis to recent follow-up, assessing disease activity and treatment outcomes, with an analysis comparing HLA-B27 positive and negative patients. Descriptive statistics were used for data analysis.

RESULTS

There were 59 ERA patients with mean age ± SD at diagnosis 11.2 ± 2.5 years, 53 males (89.8%), and positive HLA-B27 in 38 patients (64.4%). The HLA-B27 positive group had significantly higher levels of inflammatory markers at initial diagnosis (p = 0.001), lower baseline hemoglobin (p = 0.001) and hematocrit (p = 0.002), higher disease activity assessed by the Juvenile Spondyloarthritis Disease Activity score at 6 and 12 months of follow-up (p = 0.028 and 0.040, respectively), increased utilization of bridging systemic corticosteroids (60.5% vs. 14.3%, p = 0.001) and anti-TNF (39.5% vs. 9.5%, p = 0.018), and longer duration of methotrexate (median[IQR] 1.7[1.1-3.1] vs. 1.3[0.6-1.9] years, p = 0.040). The HLA-B27 negative group had more prevalent hip arthritis than the positive group at initial diagnosis (66.7% vs. 28.9%, p = 0.005) and during the course of the disease (71.4% vs. 36.8%, p = 0.011).

CONCLUSION

Most of the ERA patients tested positive for HLA-B27. Throughout the follow-up period, these patients demonstrated greater disease activity, greater use of corticosteroids and anti-TNF, and longer duration of methotrexate to control the disease.

The childhood arthritis radiographic score of the hip: the proposal cut-off value using cluster analysis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease that affects children. It is crucial to detect and treat hip involvement in JIA early to prevent functional impairment and reduced quality of life. The Childhood Arthritis Radiographic Score of the Hip (CARSH) is a validated radiographic scoring system used to assess hip involvement in JIA. In this study, we aimed to determine cut-off values for CARSH scores using cluster analysis.

METHODS

The study was conducted as a cross-sectional analysis and included JIA patients with hip involvement who underwent a pelvic radiograph. The same pelvic radiograph was interpreted by two experienced pediatric rheumatologists at baseline and after 3 weeks by both readers for reliability. The CARSH scores were calculated for each hip four times (twice by each reader). For the 50 hips, a total of 200 interpretations of the CARSH score were obtained. Model-based clustering was employed to identify distinct groups of CARSH score interpretations and characterize the phenotype of each cluster.

RESULTS

Twenty-five children with hip involvement were included. The mean age was 13.9 ± 4.6 years. JIA subtypes were as follows: ERA in 64%, oligoarthritis in 16%, psoriatic arthritis in 12%, polyarthritis RF + in 4%, and RF - in 4% of patients. For the 200 hip interpretations, three clusters based on the level of the CARSH were identified by model-based clustering. Cluster 1 consisted of 17 CARSH score interpretations with a median score of 7 ± 3 (ranging from 1 to 15). This group primarily comprised patients with enthesitis-related arthritis (ERA) and psoriatic arthritis. Patients in cluster 1 were generally older, experienced longer diagnostic delays, and had a longer disease duration compared to the other clusters. Cluster 2 exhibited a moderate CARSH score, with an average score of 4 ± 3 (1 to 15). Patients in this group had significantly higher body weight compared to the other clusters. Cluster 3 represented the group with the least severe hip involvement, characterized by CARSH scores of 2 ± 1 (ranging from 0 to 9). This cluster had a higher proportion of male patients and higher C-reactive protein (CRP) levels than the other clusters. Regarding the individual items of the CARSH score, cluster 1 showed higher percentages of hip radiograph abnormalities such as joint space narrowing, erosions, growth abnormalities, and subchondral cysts. Cluster 2 was characterized by a high rate of acetabular sclerosis, with little to no abnormalities in other CARSH score items. Cluster 3 was the only group that exhibited hip subluxation, with minimal abnormalities in the other score items. In conclusion, this study identified three distinct groups of CARSH scores, representing varying levels of severity in hip involvement in JIA. These findings provide valuable insights for clinicians in assessing and managing JIA patients with hip involvement, enabling tailored treatment strategies based on the severity of the condition. Key Points • While a Childhood Arthritis Radiographic Score of the Hip (CARSH) is a valid and reliable tool in hip-related juvenile idiopathic arthritis, its use is limited in daily practice due to the lack of available cut-off values. • The cluster analysis defined three clusters based on the CARSH levels. • Cluster 1 exhibited the highest score with more damage and disability. Cluster 2 involved a moderate score and more overweight patients. Cluster 3 included the least level of the score but with an active disease parameter.

Advances in the Diagnosis and Treatment of Enthesitis-Related Arthritis

Enthesitis-related arthritis (ERA) represents 5-30% of all cases of juvenile idiopathic arthritis (JIA) and belongs to the spectrum of the disorders included in the group of juvenile spondyloarthritis. In the last decade, there have been considerable advances in the classification, diagnosis, monitoring, and treatment of ERA. New provisional criteria for ERA have been recently proposed by the Paediatric Rheumatology INternational Trials Organisation, as part of a wider revision of the International League of Associations for Rheumatology criteria for JIA. The increased use of magnetic resonance imaging has shown that a high proportion of patients with ERA present a subclinical axial disease. Diverse instruments can be used to assess the disease activity of ERA. The therapeutic recommendations for ERA are comparable to those applied to other non-systemic JIA categories, unless axial disease and/or enthesitis are present. In such cases, the early use of a TNF-alpha inhibitor is recommended. Novel treatment agents are promising, including IL-17/IL-23 or JAK/STAT pathways blockers.

The Juvenile Spondyloarthritis Disease Activity Index Is a Useful Tool in Enthesitis-Related Arthritis: Real-Life Data

OBJECTIVE

To compare enthesitis-related arthritis (ERA) patients with active and inactive disease at 6 months and define baseline predictors for disease inactivity. In addition, to evaluate the demographic, clinical, and laboratory characteristics of ERA patients and to identify the real-life impact of the Juvenile Spondyloarthritis Disease Activity Index (JSpADA) in predicting active disease in ERA.

METHODS

This medical record review study was conducted with 56 patients who were diagnosed with ERA at our clinic between June 2009 and June 2022. Demographic and clinical characteristics, laboratory parameters, treatment, and JSpADA were recorded.

RESULTS

The patients were divided into 2 groups as active (n = 34) and inactive (n = 22) according to their disease activity at month six. Sex, age at diagnosis, number and type of affected joints, and presence of sacroiliitis were similar in both groups. There was no difference in baseline erythrocyte sedimentation rate, but there was a significant difference in erythrocyte sedimentation rate at the third month ( p = 0.52 and p = 0.018, respectively). The median JSpADA values at disease onset were 3.5 (interquartile range [IQR], 3.0-4.5) and 3.3 (IQR, 2.5-4.0) in the active and inactive groups, respectively ( p = 0.27). At the third month, the median JSpADA values were 1.5 (IQR, 0.5-2.1) in the active group and 0.5 (IQR, 0.5-1.5) in the inactive group ( p = 0.037). The cutoff value for JSpADA at the third month for active disease persisting at the month six was determined as 1 point (area under the curve, 0.662 ± 0.06; p = 0.042; 95% confidence interval, 0.51-0.80) by receiver operating characteristic curve analysis.

CONCLUSION

In ERA patients, a persistently high JSpADA value at follow-up is a predictive factor for active disease at the sixth month.

Predictors of long-term functional outcomes of juvenile idiopathic arthritis-enthesitis-related arthritis: a single centre experience

OBJECTIVES

Long-term functional outcomes in enthesitis-related arthritis (ERA) is limited from developing countries. We assessed the clinical and genetic factors that predicted the long-term functional outcome in ERA.

METHODS

Patients with ERA having ≥5 years of disease and >16 years of age were included in this cross-sectional study. Data on clinical features within 6 months of disease onset was collected from hospital records. Bath indices, HAQ Disability Index (HAQ-DI) and World Health Organization's Quality of Life (WHO-QOL) were assessed at last visit. Poor functional outcome (PFO) was defined as BASFI > 1.5 or HAQ-DI > 1. Persistent disease activity (PDA) was defined as BASDAI ≥ 4. Endoplasmic reticulum aminopeptidase 1 (ERAP1) and IL-23 receptor single nucleotide polymorphism genotyping was performed with the TaqMan method and HLA-B27 by PCR.

RESULTS

One hundred and eighty-one patients [170 male, median (interquartile range) age of disease onset 12.5 (10-15) years, disease duration 7 (5-11) years] were recruited. There was a delay in diagnosis of 3 (1-5) years. The median Ankylosing Spondylitis Disease Activity Score (ASDAS)-ESR, BASDAI, HAQ-DI and BASFI at inclusion were 2.6 (1.8-3.6), 2.6 (1-5.2), 0.5 (0-0.5) and 1.6 (0.3-3.2), respectively. BASFI and HAQ-DI correlated with ASDAS-ESR, ASDAS-CRP and WHO-QOL-BREF. Those with PFO (n = 98) had a longer delay in diagnosis (4 vs 2 years, P < 0.001), lower prevalence of arthritis at onset [odds ratio (OR) = 0.3; 95% CI: 0.1, 0.8], higher prevalence of ERAP1 (rs27044) allele C (OR = 7.2; 95% CI: 1.5, 33.7) and higher disease activity currently. Delay in diagnosis (OR = 1.2; 95% CI: 1.08, 1.4) was the sole predictor of PFO in multivariate analysis. One-third of patients had PDA. Tarsitis at disease onset was the sole predictor of PDA (OR = 2.3; 95% CI: 1.009, 5.4).

CONCLUSIONS

PFO was seen in one-half of JIA-ERA in the long-term and was associated with active disease with delay in diagnosis as its sole predictor.

C1-C2 subluxation in enthesitis-related arthritis: two case reports and literature review of ten cases

BACKGROUND

C1-C2 subluxation is a rare complication of enthesitis-related arthritis (ERA). If left untreated, it may lead to functional impairment or cervical spinal cord compression. This study aims to highlight key points regarding the management of C1-C2 subluxation in ERA.

CASE PRESENTATION

We present two cases of C1-C2 subluxation: an 8-year-old boy with ERA and 16-year-old boy with ERA with bilateral sacroiliitis. Ten cases of ERA in the literature were reviewed. The diagnosis of C1-C2 subluxation is mostly based on radiographs and cervical spine computed tomography. All patients were treated with non-steroidal anti-inflammatory drugs. Six ERA patients were treated surgically for cervical fusion. Most ERA patients with sacroiliitis had cervical collar protection. Neurologic abnormalities after treatment were not reported. Despite the use of cervical collar, cervical fusion and persisting ankylosis were found in two ERA patients with sacroiliitis without surgical treatment.

CONCLUSIONS

Cervical spine protection and ruling out spinal cord compression should be prioritized, in addition to controlling the underlying inflammation in ERA. Cervical halter traction may be applied after severe cervical inflammation is excluded. To reduce the risk of complications, early recognition and appropriate treatments of C1-C2 subluxation in ERA are essential.

Disability and disease-related damage in Thai children and adolescents with juvenile idiopathic arthritis

BACKGROUND

Children and adolescents with juvenile idiopathic arthritis (JIA) may suffer from disability and disease-related damage. This study aimed to investigate the prevalence of disability and damage, and identify the factors associated with articular and extra-articular damage in children and adolescents with JIA in a resource-restricted setting in Thailand.

METHODS

This cross-sectional study enrolled JIA patients during June 2019-June 2021. Disability was assessed using the Child Health Assessment Questionnaire (CHAQ) and Steinbrocker classification criteria. Damage was evaluated using the Juvenile Arthritis Damage Index (JADI) and the modified-JADI (mJADI) tools.

RESULTS

There were 101 patients (50.5% female) with median age of 11.8 years. Median disease duration was 32.7 months. Enthesitis-related arthritis (ERA) was the most common subtype (33.7%), followed by systemic JIA (25.7%). Thirty-three (32.7%) patients had delayed diagnosis ≥ 6 months. Moderate to severe disability was found in 20 (19.8%) patients. Patients with Steinbrocker functional classification > class I were seen in 17.9%. Thirty-seven (36.6%) patients had articular damage. Extra-articular complications were observed in 24.8%. Growth failure and striae were the most common complications in 7.8%. Leg-length discrepancy was documented in 5.0%. Ocular damage was found in 1 patient with ERA. Multivariable logistic regression analysis revealed Steinbrocker functional classification > class I (aOR: 18.1, 95% CI: 3.9-84.6; p < 0.001), delayed diagnosis ≥ 6 months (aOR: 8.5, 95%CI: 2.7-27.0; p < 0.001), and ERA (aOR: 5.7, 95%CI: 1.8-18.3; p = 0.004) as independent predictors of articular damage. Systemic corticosteroids use was the independent predictor of extra-articular damage (aOR: 3.8, 95%CI: 1.3-11.1; p = 0.013).

CONCLUSIONS

Disability and disease-related damage was identified in one-fifth and one-third of JIA patients. Early detection and treatment are essential for preventing permanent damage.

Recent updates in enthesitis-related arthritis

Enthesitis-related arthritis (ERA) is a category of juvenile idiopathic arthritis which belongs to the spectrum of diseases that are included in juvenile spondyloarthropathy. In recent years, there have been significant advances in understanding pathogenesis, tools to assess disease activity, early recognition of the axial disease, and targeted therapy using IL-17 inhibitors and small molecule inhibitors. The current narrative review highlights these new advances. Among many hypotheses linking HLA B27 to ERA, one of them is the effect of HLA B27 on gut dysbiosis. However, recent data suggest that gut dysbiosis is probably not determined by HLA B27. Though children present with arthritis and enthesitis, axial disease is present in 50-60% on MRI. Using data-driven approach, discriminative MRI finding for active and chronic diseases has been defined for children. This will help in the early recognition of disease. An abridged version of juvenile spondyloarthropathy disease activity (JSpADA) score without the need for acute phase reactants and Schober test performed as well as the original score may increase its acceptance in routine practice. Secukinumab (anti-IL-17 antibody) has shown a more than 75% response rate in children with ERA and may be a good alternative to anti-TNF therapy. Initial data with tofacitinib also look promising. All these will translate into better outcomes for children with ERA.

Axial involvement in enthesitis-related arthritis: results from a single-center cohort

BACKGROUND

Axial involvement in children with enthesitis-related arthritis (ERA) has characteristics that differ from those of peripheral involvement. This study characterized their clinical characteristics and treatment.

METHODS

Patients with ERA at the Children's Hospital of Nanjing Medical University between January 2018 and December 2020 were included. The ERA cohort was divided into two based on the presence or absence of axial joint involvement. Demographic characteristics, clinical features, and treatments were described and compared.

RESULTS

In total, 105 children with ERA were enrolled (axial ERA, n = 57; peripheral ERA, n = 48). The age at disease onset of the axial group tended to be higher (11.93 ± 1.72 vs. 11.09 ± 1.91 years) and the diagnosis delay was bigger in patients with axial ERA (10.26 ± 11.66 months vs. 5.13 ± 7.92 months). The inflammatory marker levels were significantly higher in patients with axial. There were no differences in HLA-B27 positivity between the groups (34 [59.65%] vs. 28 [58.33%], P > 0.05). Hip involvement was more frequent in the axial group (52.63% vs 27.08%; X² = 7.033). A total of 38 (66.67%) and 10 (20.83%) patients with axial and peripheral ERA, respectively, were treated with biological disease-modifying anti-rheumatic drugs (DMARDs) at diagnosis. The administration of biologics increased gradually in the axial ERA group, peaking at 18 months and decreasing thereafter, whereas that in the peripheral ERA group peaked at 6 months and began to decline thereafter.

CONCLUSIONS

Axial ERA is a persistent active disease and requires a more aggressive treatment. Classification and early recognition of axial involvement may help with timely diagnosis and appropriate management.

Sacroiliitis at diagnosis as a protective predictor against disease flare after stopping medication: outcomes of a Southeast Asian enthesitis-related arthritis (ERA) longitudinal cohort

OBJECTIVES

To assess short- and long-term outcomes of ERA in a large monocentric cohort in Singapore.

METHODS

Children diagnosed with ERA according to ILAR criteria from 2002 to 2021 were recruited. Nonparametric statistics were used to describe the data. Outcomes were defined according to modified Wallace criteria, and probabilities and predictors were determined using Kaplan-Meier survival and logistic regression analyses.

RESULTS

One hundred fifty-one ERA patients (male 86%; Chinese 81%) were included. The median age at onset was 11.9 years (IQR: 9.4-13.9), and disease duration was 5.3 years (IQR: 2.9-8.4). At diagnosis, 39% of the patients had sacroiliitis. HLA-B27 was positive in 83%, and biologics were used in 72% of the patients. Clinical inactive disease (CID) was achieved in 92% of the patients, of which 27% achieved within 6 months. Sacroiliitis at diagnosis is an unfavorable predictor of early CID at 6 months. Medication was discontinued in one-third of the patients. Favorable predictor of medication withdrawal includes male gender, while unfavorable predictors include positive HLA-B27 and ANA. Two-thirds of the patients with CID had at least one disease flare. Sacroiliitis at diagnosis is a protective predictor of flare after stopping medication.

CONCLUSION

Despite a high proportion of ERA patients achieving CID, only one-third could stop medication with high rates of disease flare. Unfavorable predictors include older age at onset, HLA-B27, and ANA positivity. While sacroiliitis at diagnosis is a negative predictor of CID at 6 months, it is associated with less disease flare after discontinuing medication.

Associations between HLA-B27 subtypes and outcomes in Thai children with enthesitis-related arthritis

OBJECTIVE

Expression of human leukocyte antigen B27 (HLA-B27) has been identified as a predictor of severe disease in enthesitis-related arthritis (ERA) patients. However, the associations between HLA-B27 subtypes and outcomes of this disease are still unclear. Here, we examined the distributions of HLA-B27 subtypes among ERA patients and the associations with disease outcomes.

METHODS

This was a historical cohort study of ERA patients. Patients were followed from diagnosis to the most recent visit. Relationships between outcomes and the HLA-B27 subtype were assessed by mixed-effect regression, Kaplan-Meier survival, and Cox proportional hazards regression analyses.

RESULTS

Of the 66 ERA patients, 50 HLA-B27-positive (86% male) and 16 HLA-B27-negative (69% male) patients were included in this study. Patients with HLA-B27-positive were classified into HLA-B*27:04-positive (84%), including combined HLA-B*27:04 and HLA-B*27:07 (2%), and HLA-B*27:04-negative (16%), including HLA-B*27:05 (10%), HLA-B*27:06 (2%), HLA-B*27:07 (2%), and HLA-B*27:15 (2%). HLA-B*27:04-positive (83.3%) and HLA-B*27:04-negative patients (100%) had refractory disease more than HLA-B27-negative patients (37.5%, p = 0.001). HLA-B*27:04-negative patients (57%, 1.73 years) had relapsing disease more and earlier than HLA-B*27:04-positive (35%, 5.54 years) and HLA-B27-negative patients (40%, 6.92 years; p < 0.001). Furthermore, HLA-B*27:04-negative was predictors of refractory disease (HR 4.56, 95%CI 1.40-14.87; p = 0.012) and relapsing disease (HR 3.80, 95% CI 1.18-12.30; p = 0.026). The duration before anti-tumor necrosis factor treatment initiation > 1 year was also a predictor of refractory disease (HR 116.08, 95% CI 14.67-918.26; p < 0.001).

CONCLUSION

HLA-B*27:04 was the most common HLA-B27 subtype in Thai ERA patients. HLA-B*27:04-negative was associated with more unfavorable outcomes than HLA-B*27:04-positive and HLA-B27-negative patients. Key Points • Most ERA patients in Thailand had HLA-B27-positive, and HLA-B*27:04 was the most common HLA-B27 allele in these patients. • The outcomes of ERA were associated with the presence of HLA-B27 and its subtypes. • HLA-B*27:04-negative patients had unfavorable outcomes, including refractory and relapsing disease, compared to HLA-B*27:04-positive and HLA-B27-negative patients.