Response similarity assessment between polyarticular juvenile idiopathic arthritis and adult rheumatoid arthritis for biologics

Background:Idiopathic juvenile arthritis (JIA) is a heterogeneous group of pathologies whose origin remains unknown at present (1). They are characterised by a systemic inflammatory and joint disease affecting children under 16 years of age. The current classification groups the different forms of JIA into 7 distinct entities (systemic forms, polyarticular forms with or without rheumatoid factors, oligoarticular forms, inflammatory arthritis associated with enthesopathies (ERA), arthritis associated with psoriasis and unclassifiable arthritis). Exact etiology of JIA is still unknown. To date, the various hypotheses put forward on the occurrence of JIAs integrate the genetic and environmental framework.The link between periodontal disease and rheumatoid arthritis (RA) is largely reported. Recently, Porphyromonas gingivalis (P. gingivalis) infection explained the occurrence of arthritis in rodent and in RA (2). Several studies mention the beneficial effect of P. gingivalis treatment on disease activity.Currently, there are very few studies on the prevalence of P. gingivalis in patients with JIA and the possible involvement of the germ in the development of inflammatory joint diseases in the pediatric population(3)(4).Objectives:The objective of our study is to determine presence of high IgG antibodies against P. gingivalis and Prevotella Intermedia in a cohort of patients with JIA compared to a control population and to determine variation of level according to sub-classes of JIA.Methods:Sera were obtained from 101 patients satisfying the ILAR classification criteria for JIA and in 25 patients with two other dysimmune disorders (type 1 diabetes and juvenile inflammatory bowel disease). Level of IgG antibodies against P. gingivalis and Prevotella Intermedia were obtained by homemade ELISA already used previously (5).Results:In the JIA group, major children were oligarthritis (47.5%), polyarthritis represents 31.7% of JIAs, ERA and systemic forms of JIA are respectively 9 and 11%. For the control group, 10 (40%) children had diabetes and 15 (60%) had IBD.Levels of anti-P. gingivalis anti-Prevotella Intermedia antibodies were higher in AJI group compared at control groups (P<0.01, P<0.05). Theses difference are mainly related to oligoarthritis and ERA subsets for both P. gingivalis and Prevotella Intermedia.Figure 1.Relative titer of antibodies to P. gingivalis and anti Prevotella intermedia. *: P<0.05; **: P<0.01; ***: P<0.001. P. gingivalis (control vs oligoarthritis p= 0.0032. control vs ERA p= 0.0092). Prevotella intermedia (control vs oligoarthritis p= 0.0194. control vs ERA p= 0.0039).Conclusion:We confirmed high level of anti-P. gingivalis and anti-Prevotella intermedia antibodies in JIA compared to other inflammatory disorders. For the first time, we observed that this high level was mainly in oligoarthritis and ERA. Further investigations are required to investigate involvement of oral dysbiosis in AJI pathogenesis. As observed in RA, it could be a new way to integrate in JIA therapy management.References:[1]Thatayatikom A, De Leucio A. Juvenile Idiopathic Arthritis (JIA). StatPearls Publishing; 2020[2]Cheng Z, Meade J, Mankia K, Emery P, Devine DA. Periodontal disease and periodontal bacteria as triggers for rheumatoid arthritis. Best Pract Res Clin Rheumatol. 2017;31(1):19–30.[3]Romero-Sánchez C, Malagón C, Vargas C, Fernanda Torres M, Moreno LC, Rodríguez C, et al. Porphyromonas Gingivalis and IgG1 and IgG2 Subclass Antibodies in Patients with Juvenile Idiopathic Arthritis. J Dent Child Chic Ill. 2017 May 15;84(2):72–9.[4]Lange L, Thiele GM, McCracken C, Wang G, Ponder LA, Angeles-Han ST, et al. Symptoms of periodontitis and antibody responses to Porphyromonas gingivalis in juvenile idiopathic arthritis. Pediatr Rheumatol Online J. 2016 Feb 9[5]Rinaudo-Gaujous M, Blasco-Baque V, Miossec P, Gaudin P, Farge P, Roblin X, et al. Infliximab Induced a Dissociated Response of Severe Periodontal Biomarkers in Rheumatoid Arthritis Patients. J Clin Med. 2019 May 26;8(5).Disclosure of Interests:None declared.

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Association analysis of juvenile idiopathic arthritis genetic susceptibility factors in Estonian patients

Clinical Rheumatology ◽

10.1007/s10067-021-05756-x ◽

2021 ◽

Author(s):

Tiit Nikopensius ◽

Priit Niibo ◽

Toomas Haller ◽

Triin Jagomägi ◽

Ülle Voog-Oras ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Juvenile Idiopathic Arthritis ◽

Autoimmune Diseases ◽

Genetic Risk ◽

Association Studies ◽

Control Sample ◽

Case Control ◽

Genome Wide Association ◽

Genome Wide Association Studies ◽

Genome Wide

Abstract Background Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic condition of childhood. Genetic association studies have revealed several JIA susceptibility loci with the strongest effect size observed in the human leukocyte antigen (HLA) region. Genome-wide association studies have augmented the number of JIA-associated loci, particularly for non-HLA genes. The aim of this study was to identify new associations at non-HLA loci predisposing to the risk of JIA development in Estonian patients. Methods We performed genome-wide association analyses in an entire JIA case–control sample (All-JIA) and in a case–control sample for oligoarticular JIA, the most prevalent JIA subtype. The entire cohort was genotyped using the Illumina HumanOmniExpress BeadChip arrays. After imputation, 16,583,468 variants were analyzed in 263 cases and 6956 controls. Results We demonstrated nominal evidence of association for 12 novel non-HLA loci not previously implicated in JIA predisposition. We replicated known JIA associations in CLEC16A and VCTN1 regions in the oligoarticular JIA sample. The strongest associations in the All-JIA analysis were identified at PRKG1 (P = 2,54 × 10−6), LTBP1 (P = 9,45 × 10−6), and ELMO1 (P = 1,05 × 10−5). In the oligoarticular JIA analysis, the strongest associations were identified at NFIA (P = 5,05 × 10−6), LTBP1 (P = 9,95 × 10−6), MX1 (P = 1,65 × 10−5), and CD200R1 (P = 2,59 × 10−5). Conclusion This study increases the number of known JIA risk loci and provides additional evidence for the existence of overlapping genetic risk loci between JIA and other autoimmune diseases, particularly rheumatoid arthritis. The reported loci are involved in molecular pathways of immunological relevance and likely represent genomic regions that confer susceptibility to JIA in Estonian patients. Key Points• Juvenile idiopathic arthritis (JIA) is the most common childhood rheumatic disease with heterogeneous presentation and genetic predisposition.• Present genome-wide association study for Estonian JIA patients is first of its kind in Northern and Northeastern Europe.• The results of the present study increase the knowledge about JIA risk loci replicating some previously described associations, so adding weight to their relevance and describing novel loci.• The study provides additional evidence for the existence of overlapping genetic risk loci between JIA and other autoimmune diseases, particularly rheumatoid arthritis.

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