The Increased Levels of Fecal Calprotectin in Children With Active Enthesitis Related Arthritis and MRI Signs of Sacroiliitis: The Results of a Single Center Cross-Sectional Exploratory Study in Juvenile Idiopathic Arthritis Patients.

Enthesitis related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA), often regarded as an undifferentiated form of juvenile spondyloarthritis (jSpA). While gut is increasingly recognized as origin and/or target of inflammation in adult onset spondyloarthritis (SpA), the incidence of gut involvement in ERA patients is largely unknown. The aim of this study was to measure the concentration of fecal calprotectin (fCAL), a surrogate marker of gut inflammation, in patients with different subtypes of JIA, as well as to correlate the results with various demographic, clinical, laboratory, imaging, and treatment characteristics. The cross-sectional exploratory study involving 71 patients with ERA, other forms of JIA and children complaining musculoskeletal symptoms was therefore conducted. Along with fCAL assessment, a detailed clinical and laboratory examination was performed, including the calculation of a composite disease activity scores. Moreover, MRI of the sacroiliac joints was performed in all ERA and other patients complaining of low back pain. The median concentration of fCAL was highest in ERA patients (33.2 mg/kg, p = 0.02), with a significant difference between those with inactive and active disease (20.0 vs. 57.4, p = 0.01), as well as those with and without MRI signs of sacroiliitis (22.6 vs. 54.3, p = 0.04). The fCAL did not differ depending on the NSAID use (23 vs. 20, p = 0.18), although weak correlation was observed with the treatment duration (r = 0.25, p = 0.03). In conclusion, our findings indicate that a parallel inflammation in musculoskeletal system and gut can occur not just in adults with SpA, but in children with ERA as well.

Beyond the guidelines management of juvenile idiopathic arthritis: a case report of a girl with polyarticular disease refractory to multiple treatment options and Leri Weill syndrome.

BACKGROUND: The last two decades brought new treatment options and high quality guidelines into the paediatric rheumatologic practice. Nevertheless, a number of patients still present a diagnostic and therapeutic challenge due to combination of vague symptoms and unresponsiveness to available treatment modalities. CASE PRESENTATION: We report a case of sixteen years old girl suffering from polyarticular type of juvenile idiopathic arthritis refractory to multiple treatment options. She first presented at the age of 4 with swelling and contractures of both knees. Her symptoms were initially unresponsive to nonsteroidal anti-inflammatory drugs and progressed despite treatment with intraarticular and systemic glucocorticoids and methotrexate. Throughout the years, she received several biologics together with continuous administration of nonsteroidal anti-inflammatory drugs and disease modifying anti-rheumatic drugs as well as intraarticular and systemic glucocorticoids in disease flares. However, none of this options  provided a permanent remission, so various other modalities, as well as other possible diagnoses were constantly being considered. Eventually she became dependent on a daily dose of systemic glucocorticoids. In 2018, the treatment with Janus kinase inhibitor tofacitinib was initiated, which led to gradual amelioration of musculoskeletal symptoms, improvement of inflammatory markers and overall well-being, as well as to the weaning of systemic glucocorticoids. As the swelling of the wrists subsided for the first time in many years, Madelung's deformity was noticed, first clinically, and later radiographically as well. Genetic analysis revealed short-stature homeobox gene deficiency and confirmed the diagnosis of Leri Weill syndrome. CONCLUSIONS: This case report emphasizes the need for reporting refractory, complicated cases from everyday clinical practice in order to build-up the overall knowledge and share experience which is complementary to available guidelines. Individual reports of difficult to treat cases, especially when additional diagnoses are involved, can be helpful for physicians treating patients with common rheumatological diseases such as juvenile idiopathic arthritis.

The Croatian version of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR).

The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) is a new parent/patient reported outcome measure that enables a thorough assessment of the disease status in children with juvenile idiopathic arthritis (JIA). We report the results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Croatian language. The reading comprehension of the questionnaire was tested in 10 JIA parents and patients. Each participating centre was asked to collect demographic, clinical data and the JAMAR in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents. The statistical validation phase explored descriptive statistics and the psychometric issues of the JAMAR: the 3 Likert assumptions, floor/ceiling effects, internal consistency, Cronbach's alpha, interscale correlations, test-retest reliability and construct validity (convergent and discriminant validity). A total of 100 JIA patients (7% systemic, 38% oligoarticular, 19% RF negative polyarthritis, 36% other categories) and 100 healthy children, were enrolled in the paediatric rheumatology centres of the Clinical Hospital Center Sestre Milosrdnice and Childen's Hospital Srebrnjak in Zagreb. The JAMAR components discriminated well healthy subjects from JIA patients. All JAMAR components revealed satisfactory psychometric performances. In conclusion, the Croatian version of the JAMAR is a valid tool for the assessment of children with JIA and is suitable for use both in routine clinical practice and clinical research.

Intraarticular infliximab therapy in patients with juvenile idiopathic arthritis: the role of musculoskeletal ultrasound and disease activity scores in monitoring therapy response.

OBJECTIVES: Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in children, with heterogeneous clinical features. Although therapeutic options are wide and in the majority of children symptoms improve with the combination of non-steroidal anti-inflammatory and disease-modifying drugs, there are a number of patients who do not respond to conventional therapy and who do not meet the criteria for systemic biologics, namely anti TNF-alpha. Those patients are potential candidates for intraarticular therapy with biologics and in this report we present the results of intra-articular infliximab treatment in a series of patients diagnosed with oligoarticular subtype of JIA. METHODS: Twenty patients (30 joints) were treated with intraarticular infliximab and monitored by power Doppler musculoskeletal ultrasound according to the OMERACT and Juvenile Arthritis Disease Activity Score (JADAS 10) before intraarticular application and during the follow-up period of 18 months (0, 1, 12, 18 months). RESULTS: The results showed statistically significant improvement in PD-MSUS measures and JADAS in both B mode and power Doppler mode scores (p<0.001, p<0.001, respectively) in patients treated with i.a. infliximab with persistent response in fifteen patients. The JADAS score, as well as the ultrasound scores, were significantly reduced during the follow-up period. CONCLUSIONS: This study showed promising results, good safety and potential for the clinical benefit of intraarticular infliximab treatment in a selected group of patients with oligoarticular subtype of JIA.

[THE IMPORTANCE OF TRANSITION IN RHEUMATOLOGY].

Rheumatic diseases are among the most common chronic diseases of childhood. Between 30 and 70% of pediatric rheumatology patients reach adulthood with some disease activity, functional limitations, or psychosocial problems. Transition is the purposeful, planned move of chronic pediatric patients from pediatric to adult care. It is a process in which adolescents with chronic conditions prepare for independent care for their health and life in general. Th e establishment of transitional services will ensure better disease control, limit long-term complications, work loss, and unnecessary health care costs, and increase quality of life.

[MICROARRAY AND GENE EXPRESSION ANALYSIS]. / SITNOPOLJE I ANALIZA GENSKOG IZRAZAJA.

Microarray gene expression analysis is high-throughput method in which many different sized DNA molecules are attached to solid surface in designated spots. These molecules are used for the discovery of specific RNA molecules isolated from various biological samples of interest. Core principle of this method is hybridization of complementary nucleotides (A-T and G-C), which leads to creation of double stranded nucleic acids. Gene expression differences in two groups of samples are discovered and quantificated by comparison of signal intensity values in microarray spots. Systemic analysis of data gathered in microarray gene expression measurement is performed by various bioinformatic methods such as group analysis, annotation analysis as well as network and pathway analysis. Expression comparison of all genes in different cells of the same individual or same cells of different individuals provides an insight into the mechanism responsible for development of a certain condition or disease.

Single nucleotide polymorphism of toll-like receptor 4 (TLR4) is associated with juvenile spondyloarthritis in Croatian population.

Single nucleotide polymorphisms (SNP) of toll-like and NOD-like receptors have been associated with altered receptor activity and modified production of proinflammatory cytokines leading to a number of diseases. Our aim was to determine whether SNP of TLR2 (Arg753Gln), TLR4 (Asp299Gly, Thr399Ile), and NLRP3 (Q705K) influence susceptibility to juvenile spondyloarthrtis (jSpA) and juvenile idiopathic arthritis (JIA). After the DNA extraction, 26 patients with jSpA, 11 with oligoarticular, polyarticular, or systemic JIA, and 40 healthy controls were genotyped for Arg753Gln, Asp299Gly, Thr399Ile, and Q705K SNP using real-time PCR-SNP analysis. Statistically significant difference in genotype frequency for Thr399Ile SNP of TLR4 was observed in the jSpA (χ2 = 6.705, p = 0.035) and not in the JIA group (χ2 = 3005, p = 0.223). Regarding Asp299Gly SNP, no significant difference in genotype frequency was found; however, allele frequency was significant in both jSpA and JIA patients. No significant difference in genotype or allele frequency was observed for Arg735Gln and Q705K SNP. The399Ile polymorphism of TLR4 may be responsible for altered immune response to microbial infection in variant carriers and represent a mechanism of triggering overproduction of proinflammatory cytokines and long-term inflammation in jSpA. SNP of TLR2, NLRP3, and TLR4 (Asp299Gly) were not associated with jSpA or JIA.

[PATHOGENESIS OF UNDIFFERENTIATED SPONDYLOARTHRITIS]. / PATOGENEZA NEDIFERENCIRANOG SPONDILOARTRITISA.

Spondyloarthritis or spondyloarthropathy (SpA) is a multifactorial disease in which a disturbed interplay occurs between the immune system and environmental factors on a predisposing genetic background, which leads to inflammation and structural damage of target tissue. Many recent researches on development of SpA showed important role of innate and adaptive immunity as well as of prominent bone tissue remodeling which leads to osteoproliferation and ankylosis. It is believed that possible sites of inflammation in SpA are entheses, sinovium and gut. Current knowledge on inflammation and tissue destruction leads to conclusion that SpA is disease characterized by disorders on different levels. Disorder on the first level is disturbed pathogen recognition and immune response activation, on second level disturbed inflammatory cells migration and on third level disturbed immune response regulation. As follows, disease progress depends on range of disturbances: disease course can be short, as in reactive arthritis, or long-lasting with substantial structural damage, as in ankylosing spondylitis. Unfortunately, there are still no confident markers of disease progression, so at the mere beginning disease is often described as undifferentiated.

Aberrant expression of shared master-key genes contributes to the immunopathogenesis in patients with juvenile spondyloarthritis.

Association of juvenile spondyloarthritis (jSpA) with the HLA-B27 genotype is well established, but there is little knowledge of other genetic factors with a role in the development of the disease. To date, only a few studies have tried to find those associated genes by obtaining expression profiles, but with inconsistent results due to various patient selection criteria and methodology. The aim of the present study was to identify and confirm gene signatures and novel biomarkers in highly homogeneous cohorts of untreated and treated patients diagnosed with jSpA and other forms of juvenile idiopathic arthritis (JIA) according to ILAR criteria. For the purposes of the research, total RNA was isolated from whole blood of 45 children with jSpA and known HLA genotype, 11 children with oligo- and polyarticular forms of JIA, as well as 12 age and sex matched control participants without diagnosis of inflammatory disease. DNA microarray gene expression was performed in 11 patients with jSpA and in four healthy controls, along with bioinformatical analysis of retrieved data. Carefully selected differentially expressed genes where analyzed by qRT-PCR in all participants of the study. Microarray results and bioinformatical analysis revealed 745 differentially expressed genes involved in various inflammatory processes, while qRT-PCR analysis of selected genes confirmed data universality and specificity of expression profiles in jSpA patients. The present study indicates that jSpA could be a polygenic disease with a possible malfunction in antigen recognition and activation of immunological response, migration of inflammatory cells and regulation of the immune system. Among genes involved in these processes TLR4, NLRP3, CXCR4 and PTPN12 showed almost consistent expression in study patients diagnosed with jSpA. Those genes and their products could therefore potentially be used as novel biomarkers, possibly predictive of disease prognosis and response to therapy, or even as a target for new therapeutic approaches.

[Genetic predisposition for various forms of spondyloarthritis]. / Genetska podloga razlicitih oblika spondiloartritisa.

In addition to the long-established association of HLA-B27 antigen and spondyloarthritis, several studies have shown a similar association with HLA-B7 antigen. But since the whole MHC region carries less than half of the risk for the development of the disease, the main goal of many recently performed researches, which implemented various high-throughput methods, was to discover the influence of genes outside the MHC region on disease development. The results showed that genes closely linked to spondyloarthritis participate in antigen processing and coding of various cytokines. This can lead to the conclusion that diseases from the spondyloarthritis group are polygenic, affected by both autoinflammatory and autoimmune mechanisms.

[Guidelines on biologic drugs for the treatment of children with juvenile idiopathic arthritis (JIA)]. / Smjernice za primjenu bioloske terapije u djece s juvenilnim idiopatskim artritisom (JIA).

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in children, and one of the major causes of short-term or long-term disability, and impairment of quality of life in childhood. Without early and adequate treatment the disease will progress and result with irreparable joint damage. The choice of therapy depends on the JIA subtype, disease activity index, prognostic factors, and prooven efficacy and probable side-effects of the drugs. The goal of modern JIA therapy is the achievement of complete disease remission, and not only the improvement of symptoms and temporarily inflammation control. The implementation of biologics significantly altered therapeutic approach to children with resistant JIA. We present Croatian guidelines on biologic drugs for the treatment of patients with JIA.

[Hematopoietic stem cell transplantation in treatment of autoimmune diseases]. / Transplantacija krvotvornih maticnih stanica u lijecenju autoimunosnih bolesti.

Hematopoietic stem cell transplantation (HSCT) has become an effective therapeutic option for the treatment of severe cases of autoimmune diseases (AD). Hematopoietic stem cells (HSC) can be collected from the patient (autologous), identical twin (syngenic) or HLA identical donor (allogenous). In allogenous transplantation autoagressive immunological effector cells are substituted with non-autoagressive cells of the donor. Possible graft versus host reaction (GVHD) makes this type of transplantation less attractive. On the other hand, autologous transplantation can induce the >>resetting<< of immunological clock without any fear of GVHD, but it requires previous conditioning. As an alternative option, transplantation ofmesenchymal stem cells (MSS) was developed. MSS has a strong immunosuppressive effect, while it doesn't require previous conditioning, nor does it induce GVHD. Due to the treatment related mortality, these therapeutic option should remain reserved for the most severe cases of AD. Nevertheless, they present a great opportunity for these patients, and even a chance for full recovery.

Familial antiphospholipid syndrome presenting as bivessel arterial occlusion in a 17-year-old girl.

This article presents a case of a 17-year-old girl with primary antiphospholipid syndrome developing subacute signs of hand and leg ischaemia caused by radiologically verified radial and popliteal artery occlusion. She is successfully treated with a thrombolytic agent (alteplase) and recovers completely. Her laboratory results came positive for all three subtypes of antiphospholipid antibodies. This kind of antiphospholipid syndrome presentation is a very rare entity in itself. Shortly afterwards her mother is diagnosed with primary antiphospholipid syndrome as well. A familial form of antiphospholipid syndrome is suspected. Combination of a familial antiphospholipid syndrome presenting as bivessel arterial thrombosis is a unique case, to the best of our knowledge, never described in the literature before.

[Juvenile dermatomyositis]. / Juvenilni dermatomiozitis.

Juvenile dermatomyositis is the most common idiopathic inflammatory myopathy in children, and presents a heterogeneous group of subacute, chronic and acute diseases of skeletal muscles. Its unique presentation is marked with characteristic skin rushes and progressive muscle weakness. JDM is clinically distinct from adult dermatomyositis, because it is a systemic vasculopathy not associated with malignancy and it often overlaps with other chronic childhood inflammatory diseases. Although immunopathology of JDM is complex, new studies are completing our knowledge of disease pathogenesis. Corticosteroids represent the first line therapy, afterwards combined with immunomodulatory drugs and biological agents. Better knowledge of the disease combined with modem treatment modalities resulted in reduced mortality rates and in much improved quality of life in patients with JDM.

The 'head-to-head' comparison of etanercept and infliximab in treating children with juvenile idiopathic arthritis.

OBJECTIVES: Our aim was to assess long-term efficacy and tolerability of etanercept and infliximab in patients with JIA. METHODS: This was an observational, retrospective study of 41 patients treated with anti-TNF therapy. We assessed clinical remission, flare, ACR improvement, improvement of DAS28, and JADAS. Some patients with polyarticular JIA were scored according to the modified SHARP criteria. RESULTS: Twenty-four weeks after beginning of therapy 35 patients (92.1%) achieved ACR 20, 33 patients (86.8%) ACR 30, 31 patients (81.6%) ACR 50, 28 patients (73.7%) ACR 70 and 20 patients (52.6%) ACR 90. In the same period 19 patients (50%) had good DAS28 response, 12 patients (31.6%) had moderate response, and 5 patients (13.2%) did not respond to therapy. Statistically significant difference was shown in the average value of JADAS-71 before the beginning and 24 weeks after introduction of anti-TNF therapy. Eleven patients had a flare in the study period (28.9%); five on etanercept (13.1%), three on infliximab (7.9%), and three flared on both of the medications (7.9%). After 12 months, fifteen patients fulfilled criteria for clinical remission on medications. Seven of them were on infliximab and eight on etanercept. Eleven patients have fulfilled criteria for clinical remission off of medications: three were taking etanercept, seven infliximab, and one was switched from etanercept to infliximab. CONCLUSIONS: In our patient cohort, both etanercept and infliximab performed well, since we found no significant difference in the duration, response, flare, resistance or adverse effects between both drugs, however long term remissions are rare.