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.

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.

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.

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the best of our knowledge, never described in the literature before.

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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.

Juvenile spondyloarthritis (jSpA) is a complex disease with both genetic and environmental factors contributing to etiology. Multiple studies have shown that epigenetic mechanisms could link the environment and gene expression and thus provide a potential explanation for external contribution in the pathogenesis of numerous diseases, including rheumatic. Previously obtained gene signatures in jSpA patients revealed distinctive expression of important immune-related genes, though the mechanism(s) responsible for those alterations remained unknown. The purpose of this study was to evaluate the methylation levels of the TLR4, CXCR4, NLRP3, and PTPN12 gene promoter, along with the expression of several non-coding microRNAs (miR-150, miR-146a, miR-181a, and miR-223) in jSpA patients. Peripheral blood samples were obtained from 19 patients newly diagnosed with jSpA according to ILAR classification criteria for enthesitis-related arthritis (ErA) and seven gender-and age-matched subjects without any symptoms or signs of inflammatory disease. The expression of specific microRNAs was analyzed using qRT-PCR with predeveloped microRNA assays. DNA promoter region methylation status of selected genes was assessed by methylated DNA immunoprecipitation (MeDIP) analysis. Fold enrichment of immunoprecipitated DNA differed significantly for NLRP3 promoter site, while the expression analysis of selected microRNAs showed no significant difference in fold change between jSpA patients and healthy controls. The results indicated that epigenetic modifications in the initial phase of the disease could be responsible for some of the expression alterations in jSpA patients. Since NLRP3 has a crucial role in inflammasome assembly and inflammasomes have been shown to shape microbiota, it is tempting to assume that dysbiosis in jSpA patients can at least partially be explained by reduced NLRP3 expression due to hypermethylation, stressing for the first time the epigenetic contribution to jSpA pathophysiology.