A novel serum calprotectin (MRP8/14) particle-enhanced immuno-turbidimetric assay (sCAL turbo) helps to differentiate systemic juvenile idiopathic arthritis from other diseases in routine clinical laboratory settings.

BACKGROUND: Differential diagnosis in children with signs of unprovoked inflammation can be challenging. In particular, differentiating systemic juvenile idiopathic arthritis (SJIA) from other diagnoses is difficult. We have recently validated the complex of myeloid-related proteins 8/14 (MRP8/14, also known as S100A8/A9 complex or serum calprotectin) as a helpful biomarker supporting the diagnosis of SJIA. The results were subsequently confirmed with a commercial ELISA. However, further optimization of the analytical technology is important to ensure its feasibility for large-scale use in routine laboratory settings. METHODS: To evaluate the accuracy in identifying children with SJIA, the performance of a particle-enhanced immuno-turbidimetric assay for serum calprotectin (sCAL turbo) on an automated laboratory instrument was analyzed. Samples from 615 children were available with the diagnoses SJIA (n = 99), non-systemic JIA (n = 169), infections (n = 51), other inflammatory diseases (n = 126), and acute lymphoblastic leukemia (ALL, n = 147). In addition, samples from 23 healthy controls were included. RESULTS: The sCAL turbo assay correlated well with the MRP8/14 ELISA used in previous validation studies (r = 0.99, p < 0.001). It could reliably differentiate SJIA from all other diagnoses with significant accuracy (cutoff at 10,500 ng/ml, sensitivity 84%, specificity 94%, ROC area under curve 0.960, p < 0.001). CONCLUSIONS: Serum calprotectin analyses are a helpful tool supporting the diagnosis of SJIA in children with prolonged fever or inflammatory disease. Here, we show that an immuno-turbidimetric assay for detection of serum calprotectin on an automated laboratory instrument can be implemented in clinical laboratory settings to facilitate its use as a diagnostic routine test in clinical practice.

Biologic switching patterns among children with non-systemic juvenile idiopathic arthritis.

BACKGROUND: In juvenile idiopathic arthritis (JIA) clinical remission is unattainable in some patients despite modern biologic disease-modifying antirheumatic drugs (bDMARD) therapy and switching bDMARD is required. The best choice of second-line bDMARD remains unclear. This retrospective observational study aims to describe the pattern, timing, frequency, and reasons for bDMARD switching among children diagnosed with non-systemic JIA. METHODS: Patients were identified by combining unique personal identification numbers, the International Code of Diagnosis (ICD10) for JIA and biologic therapy. Clinical characteristics were collected retrospectively from the electronic medical records. Included were 200 children diagnosed with non-systemic JIA initiating their first biologic drug between January 1st, 2012, and March 1st, 2021. We compared characteristics of non-switchers vs switchers and early switchers (≤ 6 months) vs late switchers (> 6 months). RESULTS: The median age at diagnosis was 7.7 years. We found that 37% switched to a different bDMARD after a median age of 6.3 years after diagnosis. In total, and 17.5% of patients switched at least twice, while 6% switched three or more times. The most common reason for switching was inefficacy (57%) followed by injection/infusion reactions (15%) and uveitis (13%). 77% were late switchers, and switched primarily due to inefficacy. All patients started a tumor necrosis factor inhibitor (TNFi) as initial bDMARD (Etanercept (ETN): 49.5%, other TNFis: 50.5%). The patients who started ETN as first-line bDMARD were more likely to be switchers compared to those who started another TNFi. CONCLUSION: During a median 6.3-year follow-up biologic switching was observed in more than one third, primarily due to inefficacy.

Inflammatory Biomarkers Can Differentiate Acute Lymphoblastic Leukemia with Arthropathy from Juvenile Idiopathic Arthritis Better Than Standard Blood Tests.

OBJECTIVE: To evaluate the predictive value of biomarkers of inflammation like phagocyte-related S100 proteins and a panel of inflammatory cytokines in order to differentiate the child with acute lymphoblastic leukemia (ALL) from juvenile idiopathic arthritis (JIA). STUDY DESIGN: In this cross-sectional study, we measured S100A9, S100A12, and 14 cytokines in serum from children with ALL (n = 150, including 27 with arthropathy) and JIA (n = 236). We constructed predictive models computing areas under the curve (AUC) as well as predicted probabilities in order to differentiate ALL from JIA. Logistic regression was used for predictions of ALL risk, considering the markers as the respective exposures. We performed internal validation using repeated 10-fold cross-validation and recalibration, adjusted for age. RESULTS: In ALL, the levels of S100A9, S100A12, interleukin (IL)-1 beta, IL-4, IL-13, IL-17, matrix metalloproteinase-3, and myeloperoxidase were low compared with JIA (P < .001). IL-13 had an AUC of 100% (95% CI 100%-100%) due to no overlap between the serum levels in the 2 groups. Further, IL-4 and S100A9 had high predictive performance with AUCs of 99% (95% CI 97%-100%) and 98% (95% CI 94%-99%), respectively, exceeding both hemoglobin, platelets, C-reactive protein, and erythrocyte sedimentation rate. CONCLUSIONS: The biomarkers S100A9, IL-4, and IL-13 might be valuable markers to differentiate ALL from JIA.

Management of Orofacial Manifestations of Juvenile Idiopathic Arthritis: Interdisciplinary Consensus-Based Recommendations.

Involvement of the temporomandibular joint (TMJ) is common in juvenile idiopathic arthritis (JIA). TMJ arthritis can lead to orofacial symptoms, orofacial dysfunction, and dentofacial deformity with negative impact on quality of life. Management involves interdisciplinary collaboration. No current recommendations exist to guide clinical management. We undertook this study to develop consensus-based interdisciplinary recommendations for management of orofacial manifestations of JIA, and to create a future research agenda related to management of TMJ arthritis in children with JIA. Recommendations were developed using online surveying of relevant stakeholders, systematic literature review, evidence-informed generation of recommendations during 2 consensus meetings, and Delphi study iterations involving external experts. The process included disciplines involved in the care of orofacial manifestations of JIA: pediatric rheumatology, radiology, orthodontics, oral and maxillofacial surgery, orofacial pain specialists, and pediatric dentistry. Recommendations were accepted if agreement was >80% during a final Delphi study. Three overarching management principles and 12 recommendations for interdisciplinary management of orofacial manifestations of JIA were outlined. The 12 recommendations pertained to diagnosis (n = 4), treatment of TMJ arthritis (active TMJ inflammation) (n = 2), treatment of TMJ dysfunction and symptoms (n = 3), treatment of arthritis-related dentofacial deformity (n = 2), and other aspects related to JIA (n = 1). Additionally, a future interdisciplinary research agenda was developed. These are the first interdisciplinary recommendations to guide clinical management of TMJ JIA. The 3 overarching principles and 12 recommendations fill an important gap in current clinical practice. They emphasize the importance of an interdisciplinary approach to diagnosis and management of orofacial manifestations of JIA.

[Biological therapy in juvenile idiopathic arthritis].

During the past 20 years of the biologic era, remission has become a realistic goal when treating children and adolescents with juvenile idiopathic arthritis (JIA). Studies describing long-term effects and safety are now available for several biologic agents, overall being well tolerated and with acceptable adverse events. No significant association between treatment with biologics and malignancy has been detected. This review finds that although biologics have been a success for most JIA patients, some fail to respond leaving the need for new treatment options and optimal switching between biologics most relevant.

Anakinra in Patients With Systemic Juvenile Idiopathic Arthritis: Long-term Safety From the Pharmachild Registry.

OBJECTIVE: To evaluate the long-term safety profile of anakinra in patients with systemic juvenile idiopathic arthritis (sJIA). METHODS: Data from patients with sJIA enrolled in the Pharmachild registry (ClinicalTrials.gov: NCT03932344) prior to September 30, 2018, and treated with anakinra were analyzed. The study endpoints were the occurrence of non-serious adverse events (SAEs) of at least moderate severity and SAEs, including macrophage activation syndrome (MAS), and the duration of anakinra treatment with reasons for discontinuation. All endpoints were analyzed overall by 6-month time windows, and in different treatment sets represented by those patients treated continuously with anakinra for at least 12, 18, and 24 months (set-12, -18, and -24, respectively). RESULTS: Three hundred six patients were enrolled. Of these patients, 46%, 34%, and 28% had been treated for at least 12, 18, and 24 months, respectively. Two hundred and one AEs, mostly represented by infections, were reported for 509.3 patient-years (PY) with an overall incidence rate (IR) of 39.5 per 100 PY. Among 56 SAEs (IR 11.0/100 PY), 23.2% were infections and 19.6% MAS episodes. The IR of AEs was higher during the first 6 months of anakinra treatment, followed by decreasing IRs in the long-term treatment sets. Treatment discontinuation occurred in 76% of patients, most frequently in the first 6 months, because of inefficacy (43%), remission (31%), or AEs/intolerance (15%). No deaths or malignancies occurred during anakinra treatment. CONCLUSION: The results of the present study confirm the long-term safety profile of anakinra in patients with sJIA and demonstrate an overall decreasing incidence of AEs over time. [ClinicalTrials.gov: NCT01399281 and NCT03932344].

M-ficolin: a valuable biomarker to identify leukaemia from juvenile idiopathic arthritis.

OBJECTIVE: Distinction on clinical grounds between acute lymphoblastic leukaemia presenting with arthropathy (ALLarthropathy) and juvenile idiopathic arthritis (JIA) is difficult, as the clinical and paraclinical signs of leukaemia may be vague. The primary aim was to examine the use of lectin complement pathway proteins as markers to differentiate ALLarthropathy from JIA. The secondary aims were to compare the protein levels at baseline and follow-up in a paired number of children with ALL and to examine the correlation with haematology counts, erythrocyte sedimentation reaction (ESR), C-reactive protein (CRP), blasts, relapse and death. STUDY DESIGN: In this observational study, we measured M-ficolin, CL-K1 and MASP-3 in serum from children with ALL (n=151) and JIA (n=238) by time-resolved immunofluorometric assays. Logistic regression was used for predictions of ALL risk, considering the markers as the respective exposures. We performed internal validation using repeated '10-fold cross-validation' with 100 repetitions computing the area under the curve (AUC) as well as positive and negative predictive values in order to evaluate the predictive performance. RESULTS: The level of M-ficolin was higher in JIA than ALLtotal and the ALLarthropathy subgroup. The M-ficolin level normalised after remission of ALL. M-ficolin could differentiate ALL from JIA with an AUC of 94% and positive predictive value (PPV) of 95%, exceeding CRP and haemoglobin. In a dichotomised predictive model with optimal cut-offs for M-ficolin, platelets and haemoglobin, AUC was 99% and PPV 98% in detecting ALL from JIA. CONCLUSION: M-ficolin is a valuable marker to differentiate the child with ALL from JIA.

Initial radiological signs of dentofacial deformity in juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood and the temporomandibular joint (TMJ) is often involved. TMJ arthritis in growing individuals can cause deformation of facial skeleton (dentofacial deformity) and TMJ components (TMJ deformity). Treatment outcome hinges on early initiation of anti-inflammatory treatment and orthopaedic treatment with dental splints. The aim of the present study was to characterize the radiological signs of dentofacial deformity in patients with a JIA-induced need for orthopaedic treatment. We retrospectively studied 96 patients with JIA and 20 non-JIA controls to identify the initial radiological signs of JIA-induced dentofacial deformity leading to initiation of orthopaedic treatment. We found that initial radiological signs of dentofacial deformities were subtle and characterized by minor mandibular asymmetry and occlusal plane steepening. Radiological findings of TMJ deformity associated with initial dentofacial deformity were frequent and characterized by condylar articular surface flattening (OR 8.42), condylar subcortical cyst (OR 5.94), condylar surface erosion (OR 5.38) and condylar deviation in form (OR 25.39). Radiological signs of TMJ deformity were also documented in TMJs considered "healthy" during initial clinical and radiological examination. This study presents new knowledge of importance for early diagnosis of dentofacial deformity in JIA. Early diagnosis of dentofacial deformity is important as treatment outcome is greatly influenced by timely initiation.

Identifying acute lymphoblastic leukemia mimicking juvenile idiopathic arthritis in children.

OBJECTIVE: Acute lymphoblastic leukemia (ALL) may present with arthritis implying the risk of being misdiagnosed as juvenile idiopathic arthritis (JIA). The aim of this study was to identify predictors for ALL based on clinical and laboratory information. METHODS: This cross-sectional, retrospective study compared clinical presentation and laboratory results of 26 children with ALL and arthritis versus 485 children with JIA (433 non-systemic, 52 systemic JIA). Using a Bayesian score approach the findings were evaluated by calculating odds ratios (OR) and lnOR as a measure of diagnostic weight. RESULTS: Distinction on clinical grounds was difficult, as even a high number of joints involved did not exclude ALL. One or more hematologic cell counts were low (Hb <10 g/dL, platelet count <100 x 109/L, neutrophil count < 1.0 x 109/L) in 92% with ALL, 25% with systemic JIA and 10% with non-systemic JIA. Neutropenia and thrombocytopenia had the highest ORs of 128 (95% CI 43-387) and 129 (95% CI 26-638), each giving a diagnostic weight of 4. The estimated risks of ALL were 0.2% with normal cell counts and 9%, 67% and 100% when one, two or three cell lines were affected. CONCLUSION: A simple count of cell lines with low counts can serve as a basic diagnostic strategy. Children with tri- or bilinear involvement should be referred to a bone marrow, and those with unilinear involvement a thorough screen for further evidence of ALL (organomegaly, ESR, LDH, uric acid, and blood smear).

Systemic juvenile idiopathic arthritis and recurrent macrophage activation syndrome due to a CASP1 variant causing inflammasome hyperactivation.

OBJECTIVES: We investigated a patient with systemic juvenile idiopathic arthritis (sJIA) and recurrent macrophage activation syndrome (MAS) to discover genetic and immunological contributing factors. METHODS: Severe recurrent MAS motivated whole exome sequencing (WES) to identify genetic variants potentially involved in disease pathogenesis. In vitro peripheral blood mononuclear cell (PBMC) stimulations for cytokine expression and caspase-1 activity assays as well as NF-κB reporter luciferase assays were performed to functionally characterize variants. RESULTS: WES revealed an extremely rare heterozygous missense variant, c.482G>A, p.R161H in the CASP1 gene encoding pro-caspase-1. Lipopolysaccharide (LPS) stimulation of patient PBMCs induced high levels of IL-6 compared to controls, and activation of the NLRP3 inflammasome resulted in increased production of IL-1ß and IL-18 as well as significantly elevated caspase-1 activity. Constitutive and inducible levels of IL-18 and IFNγ in whole blood were markedly elevated. Expression of the CASP1 variant in an NF-κB reporter luciferase assay induced increased NF-κB activation in a RIP2-dependent manner. The disease course of the patient was complicated by severe recurrent MAS. However, dual IL-1 and IL-6 blockade caused disease remission. CONCLUSION: For the first time, we demonstrate the involvement of a CASP1 variant in sJIA and recurrent MAS. This variant is gain-of-function for both inflammasome and NF-κB activation leading to increased production of IL-6, IL-1ß and IL-18. Although dual IL-1 and IL-6 blockade may be beneficial in patients, in whom single treatment is not sufficient to control MAS, caution should be practiced, since interstitial lung disease may progress despite apparent clinical and biochemical remission.

Tubulointerstitial nephritis in a patient with probable autoimmune lymphoproliferative syndrome.

Autoimmune lymphoproliferative syndrome (ALPS) is caused by a nonmalignant defective Fas-mediated apoptosis. The main clinical manifestations are chronic lymphadenopathy, splenomegaly, and autoimmune cytopenia. Most patients with ALPS have a FAS germline mutation. ALPS has occasionally been associated with glomerulonephritis and we present the first report of tubulointerstitial nephritis associated with probable ALPS. A 5-year-old girl presented with fever, vomiting, hypertension, and azotemia. No autoantibodies, viral, or streptococcal antibodies were detected. A renal biopsy showed small-vessel vasculitis with normal glomeruli and inflammation in the interstitium. The patient responded to prednisolone treatment and obtained a full renal recovery. Symptoms of connective tissue disorder supervened and after the development of more pronounced splenomegaly, a diagnosis of ALPS was confirmed.

Splenectomy in two children with autoimmune lymphoproliferative syndrome and massive splenomegaly.

Treatment of patients with ALPS has varied but presently there is no consensus about the optimal therapy. Splenectomy is an option but data regarding the postsplenectomy outcome in pediatric ALPS patients remain very limited. We present two children who suffered from anemia and physical discomfort from the large spleen. Both patients underwent uneventful splenectomy and experienced significant improvement in cytopenia, daily activity and well-being. Furthermore the youngest patient showed a significant catch-up growth. We conclude that in selected patients with marked splenomegaly and ALPS, splenectomy may be considered a treatment option.