Treatment Options in Pediatric Behçet's Disease.

Behçet's disease is a rare and poorly understood vasculitis affecting blood vessels of all types and sizes. Uveitis and oral and genital ulcers represent the typical clinical triad. Populations along the ancient trading route connecting the Mediterranean basin with the Middle and Far East are most affected. Up to a quarter of the cases has a pediatric onset, typically around puberty. The aim of the treatment is early intervention to control inflammation, with symptom relief and prevention of relapses, damage, and complications. The heterogeneous clinical presentation often requires a multidisciplinary and tailored approach. Ocular, neurological, gastrointestinal, and vascular involvement is associated with a worse prognosis and needs more aggressive treatments. In young patients with expected prolonged disease, treatment should also focus on preventive measures and lifestyle advice. In recent years, the pharmacological armamentarium has grown progressively, although only a limited number of drugs are currently authorized for pediatric use. Most evidence for these drugs still derives from adult studies and experience; these are prescribed as off-label medications and are only available as adult formulations. Corticosteroids frequently represent the mainstay for the management of the initial acute phases, but their potential serious adverse effects limit their use to short periods. Different conventional disease-modifying anti-rheumatic drugs have long been used. Many other biologic drugs targeting different cytokines such as interleukin-1, interleukin-6, and interleukin-17 and treatments with small molecules including the phosphodiesterase 4 and Janus kinase inhibitors are emerging as novel promising therapeutic agents. In recent years, a growing interest has developed around anti-tumor necrosis factor agents that have often proven to be effective in severe cases, especially in those with a gastrointestinal and ocular involvement.

Semiquantitative classification (SQC) and Oxford classifications predict poor renal outcome better than The International Study of Kidney Disease in Children (ISKDC) and Haas in patients with IgAV nephritis: a multicenter study.

INTRODUCTION: Several histologic classifications are used in the evaluation of IgA vasculitis nephritis (IgAVN), however, to date, no studies have determined which one has the strongest association with the severity of IgAVN and, as a consequence, its outcomes. MATERIALS AND METHODS: Patients included in the study were diagnosed with IgAV and IgAVN in seven tertiary university medical centers in Croatia, Italy and Israel. The International Study of Kidney Disease in Children (ISKDC), Haas, Oxford, and Semiquantitative classification (SQC) classifications were used in the analysis and description of renal biopsy. Time from biopsy to outcome evaluation was a statistically significant factor in outcome prediction that was used to define the base model, and was a covariate in all the tested models. RESULTS: Sixty-seven patients were included in this study. The SQC classification proved to be the best one in outcome prediction, followed by the Oxford classification. The ISKDC and Haas classifications could not predict renal outcome. The Oxford parameters for mesangial hypercellularity and tubular atrophy, as well as the SQC parameters for cellular crescents showed an independent statistically significant contribution to outcome prediction. High level of twenty-four hour protein excretion was associated with a higher grade in the Oxford, SQC and ISKDC classifications. Endocapillary proliferation was positively associated with the Pediatric Vasculitis Activity Score (PVAS) at diagnosis, while tubular atrophy was negatively associated. CONCLUSION: The SQC, followed by the Oxford classification were found to provide the best classifications of renal biopsy analysis in patients to predict the outcome in patients with IgAVN. Cellular crescents, mesangial hypercellularity and tubular atrophy showed significant contributions, indicating that active and chronic variables should be included in the estimation.

New Insights and Challenges Associated With IgA Vasculitis and IgA Vasculitis With Nephritis-Is It Time to Change the Paradigm of the Most Common Systemic Vasculitis in Childhood?

What are the challenges ahead and how have we responded so far when it comes to the non-granulomatous systemic vasculitis, characterized mainly by deposits of IgA immune complexes in the endothelium of small blood vessels-IgA vasculitis (IgAV)? That is the question to which we tried to answer. We summarized existing knowledge about epidemiology, pathogenesis, genetics, diagnostic tests and therapy in this somewhat neglected entity in pediatric rheumatology. Since etiopathogenesis of IgA vasculitis is complex, with factors other than galactose-deficient IgA1-containing immune complexes also being important, and may involve numerous interactions between environmental and genetic factors, genomics alone cannot explain the entirety of the risk for the disease. The incidence of IgAV and nephritis varies worldwide and may be a consequence of overlapping genetic and environmental factors. In addition to the role of the HLA class II genes, some studies have pointed to the importance of non-HLA genes, and modern geostatistical research has also indicated a geospatial risk distribution, which may suggest the strong influence of different environmental factors such as climate, pathogen load, and dietary factors. The application of modern geostatistical methods until recently was completely unknown in the study of this disease, but thanks to the latest results it has been shown that they can help us a lot in understanding epidemiology and serve as a guide in generating new hypotheses considering possible environmental risk factors and identification of potential genetic or epigenetic diversity. There is increasing evidence that an integrative approach should be included in the understanding of IgA vasculitis, in terms of the integration of genomics, proteomics, transcriptomics, and epigenetics. This approach could result in the discovery of new pathways important for finding biomarkers that could stratify patients according to the risk of complications, without an invasive kidney biopsy which is still the gold standard to confirm a diagnosis of nephritis, even if biopsy findings interpretation is not uniform in clinical practice. Ultimately, this will allow the development of new therapeutic approaches, especially important in the treatment of nephritis, for which there is still no standardized treatment.

Serum calprotectin (S100A8/9), clinical and ultrasound assessment in patients with juvenile idiopathic arthritis.

OBJECTIVES: To explore the association between serum S100A8/9 (calprotectin), clinical and ultrasound (US) assessment in juvenile idiopathic arthritis (JIA) patients. METHODS: A total of 30 well-characterised consecutive patients (18 female) with non-systemic JIA and 20 age-matched healthy controls were included. Serum and plasma samples obtained the same day of the clinical and sonographical assessment were tested for calprotectin levels by ELISA. Clinical status was defined using Wallace criteria. Ultrasonographic B-mode and power Doppler (PD) assessment of 44 joints for each subject was performed. RESULTS: Clinically active disease was present in 14 patients, while 16 patients were active according to US evaluation. We found no differences in the serum/plasma calprotectin levels in clinically active disease group [29.6 (5.4-198.1) ng/ml; 12.6 (2.8-65.8) ng/ml] as compared with inactive disease group [24.8 (14.1-204.3); 12.7 (3.4-65.1)] (p=0.73; p=0.29). There was also no difference between US active disease [29.8 (5.4-204.3); 12.9 (2.8-65.8)] and US inactive disease [24.8 (12.1-197.1); 11.7 (3.4-44.2)] with regard to the serum/plasma calprotectin levels (p=0.83; p=1.0). Serum/plasma calprotectin levels correlated moderately with C-reactive protein (CRP) (Spearman r=0.44, p=0.01; Spearman r=0.56, p=0.0021). CONCLUSIONS: To our knowledge, this is the first study to simultaneously examine the correlation between serum/plasma calprotectin levels, clinical and US assessment in JIA. Calprotectin was not associated with the disease status in JIA patients with low number of active joints and its levels were moderately correlated with CRP. Our preliminary study needs to be extended with a larger number of patients.

Whole-body MRI in pediatric undefined inflammatory conditions.

BACKGROUND: Whole-body magnetic resonance imaging (WBMRI) is a multiregional imaging technique suitable for investigating the extent of multisystemic diseases without exposure to radiation, with a high sensitivity to bone alterations. The aim of our study was to evaluate the role of WBMRI in the workup of children with non-specific musculoskeletal features and non-indicative laboratory and instrumental data, who were suspected to have a rheumatologic disease. METHODS: We retrospectively analyzed medical records, including laboratory tests and radiological data of 34 children who had been evaluated due to non-specific musculoskeletal manifestations, for which a WBMRI was prescribed. RESULTS: We included 34 children, 19 females and 15 males, mean age 10 years (range 2-16 years), with the following clinical features: diffuse arthralgia (12 children), persistent fever (2 children), persistent fever and diffuse arthralgia (20 children). Serologic inflammatory markers were increased in 29/34 patients. Twenty-five children had already received X-ray and / or ultrasound before WBMRI, with a negative / uninformative result. WBMRI was performed 3-6 weeks (median, 3.5 weeks) after the initial presentation of symptoms. In 22/34 (65%) children, WBMRI revealed some abnormalities that supported the final diagnosis. Twelve out of 34 children (35%) were be affected by chronic recurrent multifocal osteomyelitis. CONCLUSIONS: WBMRI is helpful in pediatric rheumatology for the differential diagnosis of undefined inflammatory conditions. It appears to be a promising tool, especially in the detection of multifocal bone lesions. The diagnosis that mainly benefits from WBMRI in our series is chronic recurrent multifocal osteomyelitis. WBMRI can also help in excluding neoplastic diseases.

SAPHO syndrome: the supposed trigger by isotretinoin, the efficacy of adalimumab and the specter of depressive disorder: a case report.

BACKGROUND: SAPHO (synovitis, acne, pustolosis, hyperostosis and osteitis) syndrome is a rare autoinflammatory chronic disorder, presenting with non-infectious osteitis, sterile joint inflammation and skin manifestations including palmoplantar pustolosis and severe acne. It could be often misdiagnosed for its heterogeneous clinical presentation. Treatment is challenging and, due to the rarity of this syndrome, no randomized controlled clinical trials have been conducted. Empirical treatments, including non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antibiotics and bisphosphonates and disease-modifying anti-rheumatic drugs (DMARDs) could be quite effective. Anti-tumor necrosis factor-alpha (anti-TNF-α) agents and interleukin-1 (IL-1) antagonists have shown promising results in refractory patients. Isotretinoin, commonly used for severe acne, has been rarely described as possible trigger of osteo-articular manifestations, in particular sacroiliitis. CASE PRESENTATION: The case of a boy, affected by acne fulminans and depression, who presented with sacroiliitis after a 10-week treatment with isotretinoin is presented. After SAPHO diagnosis, NSAIDs therapy was started but the onset of bilateral gluteal hidradenitis suppurativa required the switch to a TNF-α antagonist (Adalimumab) with the achievement of a good control of the disease. Despite specific therapy with sertraline, the patient continued to complains severe depression. CONCLUSIONS: Our case reports a temporal association between the onset of osteo-articular symptoms and the introduction of isotretinoin, as previously described. However, this timeline is not sufficient to establish a causal role of this drug into the pathogenesis of sacroiliitis. At this regard, further studies are required. The occurrence of hidradenitis suppurativa during SAPHO course supported the introduction of TNF-α blockers with a favourable result, as reported in a few cases in literature. The association between SAPHO syndrome and depressive mood disorders is already reported. Our patient experienced severe depression whose trend seems to be independent from the course of the main disease. Currently, it is not clarified if depression could be considered reactive to the underling disease or if it forms an integral part of the autoinflammatory disorder.

Pharmacotherapy for juvenile spondyloarthritis: an overview of the available therapies.

INTRODUCTION: Spondyloarthropathies (SpA) represent a heterogeneous group of inflammatory arthritides with autoimmune pathogenesis that can affect both adults and children with peculiar features such as enthesitis, sacroiliac joint, and axial involvement. Since juvenile onset of SpA (JSpA) is not well codified by the current juvenile idiopathic arthritis classification, studies in this field are restricted to single categories and therefore cannot be exhaustive. This review aims to report recent advances in the treatment of JSpA. AREAS COVERED: In order to assess the available therapies for JSpA, the authors have analyzed data obtained from retrospective and prospective studies, case reports, and case series, as well as from controlled trials. EXPERT OPINION: Given the challenging classification of JSpA, research in this field has been restricted to single subcategories. Little is known of which patients are more likely to develop axial involvement leading to severe spinal damage. Whether TNF inhibitors are capable to prevent or stop disease progression, once started, is yet to be ascertained with structural damage still a matter for research. Therefore, trials on the efficacy of TNF inhibitors in JSpA are strongly advocated since they may help to elucidate their place as a treatment option.

Usefulness of magnetic resonance enterography in detecting signs of sacroiliitis in young patients with inflammatory bowel disease.

BACKGROUND: Arthritis is often an underestimated extraintestinal manifestation in pediatric inflammatory bowel disease (IBD), including sacroiliitis, whose early signs are well detectable at magnetic resonance imaging (MRI). Magnetic resonance enterography (MRE) is an accurate imaging modality for pediatric IBD assessment. We studied the possibility to detect signs of sacroiliac inflammation in a group of children with IBD who underwent MRE for gastrointestinal disease evaluation. METHODS: We retrospectively reviewed MRE scans performed in pediatric patients with IBD. We looked for signs of sacroiliitis taking the ASAS (Assessment of SpondyloArthritis international Society) criteria as a model. Presence of bone marrow edema (using T2W sequences with fat suppression), diffusion restriction in Diffusion Weighted Imaging (DWI) or Diffusion Weighted Imaging with Background Suppression (DWIBS), and dynamic contrast enhancement were evaluated. Each SI joint was divided into 4 quadrants: upper iliac, lower iliac, upper sacral, and lower sacral. Two blinded observers with experience in pediatric and skeletal imaging independently evaluated the images. Cases upon which there was a disagreement were evaluated by the two reviewing radiologists and a third radiologist with similar experience together. RESULTS: We enrolled 34 patients (24 males and 10 females, with mean age at scanning 14.3 years, median 15.3 years; 2 affected by ulcerative colitis, 32 by Crohn's disease) for a total of 59 examinations performed at the time of their first diagnosis or at symptom exacerbations. No patient complained of musculoskeletal symptoms, neither had pathological findings at articular examination. At the time of MRE 25 patients were under treatment for their IBD. Five patients had radiological signs of SI inflammation at MRE, albeit of mild degree. All patients with SI joint edema also had a restricted diffusion in DWIBS or DWI and almost everyone had contrast media uptake. CONCLUSIONS: Sacroiliitis is one of the extraintestinal manifestation associated with IBD; it is often asymptomatic and clinically underdetected, with an unrelated progression with respect to the underlying IBD. MRE offers the possibility to study SI joints in young patients with IBD who undergo MRE for the investigation of their intestinal condition. Furthermore, we observed that gadolinium enhancement does not improve diagnostic specificity in sacroiliiitis detection.

COVID-19 and what pediatric rheumatologists should know: a review from a highly affected country.

On March 11th, 2020 the World Health Organization declared COVID-19 a global pandemic. The infection, transmitted by 2019 novel coronavirus (2019-nCov), was first discovered in December 2019, in Wuhan, Hubei Province, and then rapidly spread worldwide. Italy was early and severely involved, with a critical spread of the infection and a very high number of victims. Person-to-person spread mainly occurs via respiratory droplets and contact. The median incubation period is 5 days. The spectrum of respiratory symptoms may range from mild to severe, strictly depending on the age of the patient and the underlying comorbidities.In children COVID-19 related disease is less frequent and less aggressive. In Italy 1% of positive cases are under 18 years of age, and no deaths have been recorded before 29 years of age. For patients affected by rheumatic disease, despite the concerns related to the imbalance of their immune response and the effect of immunosuppressive treatments, there are still few data to understand the real consequences of this infection. Major scientific societies have issued recommendations to help rheumatologists in caring their patients. Interestingly, some of the drugs mostly used by rheumatologists appear to be promising in critical COVID-19 infected patients, where the hyperinflammation and cytokine storm seem to drive to the multiorgan failure.Pediatric rheumatologists are expected to play a supporting role in this new front of COVID-19 pandemic, both as general pediatricians treating infected children, and as rheumatologists taking care of their rheumatic patients, as well as offering their experience in the possible alternative use of immunomodulatory drugs.

Common variable immunodeficiency presenting as sarcoidosis in a 9-year-old child.

BACKGROUND: Granulomatous diseases are a heterogeneous group of conditions characterized by an inflammatory infiltrate with a core of macrophages, epithelioid, giant cells and a corona of fibroblasts and lymphocytes. They are associated with a wide range of disorders such as mycobacterial and fungal infections, neoplasms, immunodeficiencies and systemic inflammatory disorders as sarcoidosis. CASE REPORT: We report the case of a previously healthy 9-year-old male child who presented with persistent cough, diffuse lymphadenopathy, enlargement of liver and spleen and protracted fever. Anemia, lymphopenia and reduced platelet count was reported, with an increase of inflammatory markers. High levels of Angiotensin-converting enzyme and chitotriosidases were noted. A PET-CT scan showed increased uptake of 18 F-FDG glucose in multiple lymph nodes in thorax and abdomen and in the spleen. Biopsy of inguinal and bronchial nodes showed nodal granulomatous inflammation. The child was diagnosed with sarcoidosis and treated with corticosteroids with only transient efficacy. Further tests reported panhypogammaglobulinaemia and a reduced pool of B-memory lymphocytes. Thus, the diagnosis was revised to common variable immunodeficiency (CVID). CONCLUSION: Common variable immunodeficiency is a heterogeneous condition with a highly variable clinical phenotype and a strong association with autoimmune disorders. The presence of noncaseating granuloma and pulmonary lesions, along with extrapulmonary features required a step by step approach to differentiate between CVID and sarcoidosis. This enables early introduction of immunoglobulin replacement therapy and decreases the morbidity and mortality of CVID.

Alagille Syndrome and Chronic Arthritis: An International Case Series.

We describe 10 children with Alagille syndrome and inflammatory arthritis. In our centers, the prevalence of chronic arthritis in patients with Alagille syndrome is approximately 50 times higher compared with the general population. Arthritis was refractory to most treatment. Patients with Alagille syndrome should routinely be screened for musculoskeletal symptoms.

Risks associated with use of TNF inhibitors in children with rheumatic diseases.

Introduction: Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine involved in the pathogenesis of many inflammatory diseases. Several drugs blocking TNF-α are employed in clinical practice in pediatrics. Given their action on the immune system, TNF-α inhibitors have raised concerns on their safety profile since their introduction. A broad spectrum of side effects related to TNF inhibition has been reported: immunogenicity, infectious diseases, malignancies, and others. Areas covered: In order to assess the risk related to the use of anti-TNF-α agents in children with rheumatic diseases we analyzed data obtained from retrospective and prospective safety studies, case reports and case series, and controlled trials. Expert commentary: Anti-TNF-α agents have shown a remarkably good safety profile in the pediatric population so far. However, there are lots of questions to be answered and maintaining active surveillance on these drugs is necessary in order to not overlook any possible unexpected adverse effects.

Common symptoms for a rare disease in a girl with sarcoidosis: a case report.

BACKGROUND: Sarcoidosis in pediatric age is uncommon and challenging diagnosis, because manifestations can be significantly variable and non-specific since it is a multisystem disease, and virtually any organ system may be involved. CASE PRESENTATION: In this report, we describe the case of a 12-year-old girl presenting with fatigue and weight loss, with a painless hepato-splenomegaly without additional clinical signs on physical examination. In our patient, once we had ruled out infections, malignancies and granulomatous diseases of childhood, we made diagnosis of sarcoidosis, finding suggestive histological features in two different tissues (liver and lymph nodes) with lung involvement. CONCLUSIONS: Our case points out that pediatricians should consider sarcoidosis in the differential diagnosis in case of systemic symptoms, even in absence of other specific clinical clues, because they represent the most common clinical manifestations on presentation in children, in order to refer promptly the young patient to specialist evaluation.

Glucocorticoids in the management of systemic juvenile idiopathic arthritis.

Glucocorticoids have been the mainstay of treatment for many years in systemic-onset juvenile idiopathic arthritis (sJIA), causing important side effects and some difficulties in the management of this disease. Until the introduction of biologic agents, oral glucocorticoids were used to control fever and other systemic features for several months or even years if systemic manifestations persisted. Nowadays, clinicians have valid alternatives that have revolutionized the natural history of sJIA. Biologic agents, such as the interleukin-1 inhibitors anakinra and the more recent canakinumab, or the interleukin-6 inhibitor tocilizumab, have improved the prognosis of this debilitating disease. Glucocorticoids still have to be considered at the onset of disease when a non-steroidal anti-inflammatory drug therapy fails or when there are life-threatening complications such as severe anemia or pericarditis, or macrophage activation syndrome. Local (intra-articular) triamcinolone hexacetonide is the treatment of choice for arthritis limited to one joint or a few joints in patients without systemic activity. To date, there is still great heterogeneity in the management of sJIA patients, but in recent years there have been attempts to design algorithms and treatment protocols for glucocorticoids, disease-modifying anti-rheumatic drugs, and biologic agents. This review provides an overview of the current knowledge of glucocorticoid therapy in sJIA, comments on recently published recommendations, and gives practical support to the clinician for management of this disease.

Osteoprotegerin serum levels in Kawasaki disease: an additional potential marker in predicting children with coronary artery involvement.

OBJECTIVE: Emerging evidence from in vitro studies and mouse genetics attributes to osteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, an important role in vascular biology. We evaluated serum levels of OPG in a group of children with Kawasaki disease (KD), before immunoglobulin (IVIG) infusion and at 3-month followup. METHODS: Fifty patients (38 boys, 20 girls, median age 3.6 yrs, range 4 mo-7.4 yrs) fulfilling criteria for the diagnosis of KD, 30 febrile controls with infectious diseases, 18 patients with juvenile systemic lupus erythematosus (JSLE), and 40 healthy controls were enrolled. All KD patients received IVIG treatment within the first 10 days of illness, and aspirin. Coronary artery abnormalities (CAA) were reported in 6 out of 58 patients; all were male and younger than 5 years. Serum OPG was measured by ELISA in patients with KD before IVIG and at 3-month followup (median time 3.2 mo, range 3-3.5). RESULTS: At baseline and at the 3-month followup, KD patients had significantly higher OPG serum levels than febrile controls (p < 0.001 and p < 0.004, respectively), JSLE patients (p < 0.0001), and healthy controls (p < 0.0001). At baseline, KD patients who developed CAA had higher OPG serum levels than those without CAA (p = 0.0001); this difference was not present at 3-month followup. The optimal OPG cutoff value of 123.2 pg/ml was a significant predictor for CAA, with a sensitivity of 100% (6/6), a specificity of 96% (50/52), and a positive predictive value of 75% (6/8). CONCLUSION: High OPG levels might be the result of compensatory production during acute and subacute phases of KD. OPG assay might be an additional clinically useful marker to monitor and differentiate patients who develop, from those who do not develop, such coronary artery abnormalities.

Neprilysin levels in plasma and synovial fluid of juvenile idiopathic arthritis patients.

OBJECTIVE: Neprilysin (neutral endopeptidase, 3:4:24:11, CD10) (NEP) is a Zn metallopeptidase linked to controlling inflammation through the degradation of neuropeptides involved in neurogenic inflammation of chronic rheumatic diseases. The aim of our study was to evaluate circulating activity and cellular expression of NEP in the plasma of 58 children with juvenile idiopathic arthritis (JIA) and 52 controls. In 20 subjects requiring local steroid injection, NEP was measured in synovial fluid. METHODS: Plasma and synovial NEP were evaluated using a fluorimetric technique. Neprilysin, expressed as the antigen CD10, was determined on circulating and synovial fluid cells as mean fluorescence intensity (MFI) and as percentage of positive cells by two-color immunofluorescence. RESULTS: Circulating NEP levels were lower in JIA patients than in controls (42.0+/-16.6 vs 76.5+/-24 pmol/ml per min, P<0.001), while synovial fluid NEP values were higher than circulating levels (241.4+/-86.2 vs 40+/-15.3 pmol/ml per min, P<0.001). In monocytes, the percentage of CD10-positive circulating cells and the MFI in JIA were lower than in controls (11.6+/-5.2% vs 41.4+/-13%, P<0.001 and 18.1+/-7.5 vs 31.2+/-5.4, P<0.05, respectively). On synovial monocytes, the percentage of CD10-positive cells and the MFI were higher than on circulating monocytes (35.2+/-14.6% vs 9.1+/-2.4%, P<0.001 and 66.4+/-5.4 vs 22.8+/-14.7, P<0.001, respectively). CONCLUSIONS: The downregulation of CD10 expression in monocytes and the reduction in NEP activity may be linked to the enzyme's role in the control of peptides involved in the inflammation. The increased levels of NEP, MFI, and CD10-positive monocytes in synovial fluid, even though in plasma, might reflect a reactive effort to control synovial proliferation.

Osteoprotegerin (OPG)/RANK-L system in juvenile idiopathic arthritis: is there a potential modulating role for OPG/RANK-L in bone injury?

OBJECTIVE: To evaluate serum levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kB-ligand (RANK-L) in patients with juvenile idiopathic arthritis (JIA); to correlate these values with disease activity variables, radiological bone damage, and bone mass; and to correlate OPG gene polymorphisms with bone mass. METHODS: Eighty-four patients (66 girls and 18 boys) with JIA and 40 sex and age-matched controls were enrolled. Serum OPG and RANK-L were measured using an enzyme-linked immunosorbent assay. OPG genotyping was performed by polymerase chain reaction. RESULTS: Patients with JIA had significantly higher levels of serum OPG than controls (p = 0.001) and lower levels of RANK-L in comparison with controls (p = 0.0003). The OPG/RANK-L ratio in patients was higher than in controls (p = 0.004). No significant correlations were found between disease duration, erythrocyte sedimentation rate, and C-reactive protein values with either OPG or RANK-L serum levels. A significant difference in serum OPG levels (but not in RANK-L) was found between patients with and without erosions (p = 0.008). No correlation was found between OPG and RANK-L levels and bone mass (DXA Z scores). A higher prevalence of OPG CC genotype was found in both patients (65.4%) and controls (82.5%) (p = 0.006). Subjects with CC genotype had a higher lumbar spine bone mineral density (LS-BMD). CONCLUSION: We evaluated for the first time levels of OPG and RANK-L in children with JIA. The higher OPG/RANK-L ratio in JIA might be the result of a compensatory production of OPG. The presence of the T allele of the OPG gene appears to be associated with low BMD.