AB0724 CANDIDATE PREDICTIVE BIOMARKERS OF POOR TREATMENT RESPONSE IN OLIGOARTICULAR ONSET JUVENILE ARTHRITIS TO EARLY STEROID INJECTIONS

Abstract

Background:Intra-articular corticosteroid injections are the first-line antirheumatic drugs of oligoarticular onset juvenile arthritis. Despite significant advances in treatment (anti-TNF, block IL6) this choice of pediatric chronic joint disease still remains relevant. Pediatric rheumatologists and to this day there are no consensus on the best modality for treatment.Objectives:The aim of this study was to search of biomarkers ineffective of early intra-articular steroid injections of oligoarticular onset juvenile arthritis.Methods:Clinical, imaging, laboratory data (blood and synovial fluid), and effect of early isolated intra-articular injections (is-IAI) of triamcinolone acetonide 92 children (89% girls) aged median (IQR) 4,2 (1,6 – 7,6) years with oligoarticular onset juvenile arthritis without extra-articular manifestations (oligo-JA) were collected retrospectively and analyzed. All children were met ILAR criteria. Triamcinolone acetonide (TA) was administered intra-articular at a dose of 20-40 mg with an injection interval of 3-6-12 months which was depended on the activity of the disease. All children were divided into two groups: active / inactive arthritis based on the effectiveness of local corticosteroid treatment. The average follow-up was 48 [38; 62] months.Results:32 children (35%; all girls) were achieved remission oligo-JA after is-IAI of TA with mean of 2 [1,75; 2] injection per joint (inactive arthritis > 24 months). The mean interval between two consecutive is-IAI was 7 [5,25; 10] months. Other children did not achieve inactive oligo-JA after is-IAI of TA with mean of 3 [2; 4] injection per joint. The mean interval between first two consecutive injection was 5,5 [4,25; 7] months and other injections - 2 [2; 3] months. All children who did not achieve remission oligo-JA for is-IAI were treated by DMARDs. Statistical analyses were performed to determine the relationships between clinical, instrumental, laboratory signs and efficacy is-IAI of TA. Measures included the number of swollen or tender joints [active joint counts]; biological inflammatory markers [erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), serum and synovial fluid level of interleukin 6 (IL6) and tumor necrosis factor alfa (TNF-α)]; autoimmunity [titer of antinuclear factor (ANF)] and physicians’ assessment of JIA disease activity [clinical Juvenile Arthritis Disease Activity Score including maximal 10 joints (cJADAS10)]. Efficacy is-IAI of TA was no associated significantly with number of active joint of onset oligo-JA, cJADAS10, serum level of CRP mg/ml, ESR mm/h, IL6 pg/ml and TNF-α pg/ml, titer of ANF. The mean inflamed synovial fluid of IL6 levels 2208 [710; 4564] / 3234 [1265; 16902] pg/ml and TNF-α levels 3,3 [2,5; 3,8] / 1,1 [0,6; 3,7] pg/ml at onset of inactive and active oligo-JA were not significantly differ. The analysis revealed a correlation between a short phase of beneficial effect after is-IAI of TA and risk of activity disease (with an inactive phase of arthritis less than 3 months, the risk activity was OR = 2.09, p <0.001; with an inactive phase less than 2 months - OR = 8.9, p <0.001).Conclusion:TA is an effective and safe treatment in children with oligo-JA. Research was revealed that about a third of children with oligo-JA achieved inactive arthritis of average after two intra-articular injections of TA (all girls). There are no biomarkers for prediction of poor treatment response in oligo-JA to early steroid injections. But a short phase of beneficial effect after is-IAI of TA may be sign of risk activity disease. In addition boys with oligoarticular onset juvenile arthritis may be considered like potentially ineffective for local steroid therapy.