S100A12 Is Associated with Response to Therapy in Juvenile Idiopathic Arthritis

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Monitoring S10012 serum concentration helps physician decision-making

Expert opinion

When considering arthritis, many people assume that chronic joint inflammation is an aged-related condition predominantly found in the elderly population. Unfortunately, that is not entirely true. Arthritis also affects children. From infants to teenagers, more than 300,000 patients in the United States have some form of arthritis. Juvenile Idiopathic Arthritis (JIA) is the most common type of arthritis described in children.
Therapies already exist. Treatment seeks to relieve inflammation, control pain, and improve the quality of life for these young patients. Remission is possible thanks to aggressive early treatment. Common therapies either use antirheumatic drugs such as methotrexate (MTX), or biologicals such as anti-Tumor Necrosis Factor (anti-TNF) antibodies.
These therapies have significant side effects, so it is essential to identify the best responders as early as possible. JIA diagnosis is based on patient history and findings during physical examination. However, for effective treatment, JIA must be further documented by complementary laboratory analysis.
Are you looking for a predictive biomarker to predict therapy responses in young patients suffering from JIA? A comprehensive analysis was performed on three prospective groups of patients, with results provided in this interesting article by Faekah Gohar from University of Münster (Germany).
You will see that measuring baseline serum S100A12 can help physicians decide which therapy is the most suitable for helping patients suffering from JIA. The article also explains how a proven biomarker monitors treatment efficacy just by measuring S100A12 serum concentration with a simple ELISA assay.

Abstract

Around one-third of patients with juvenile idiopathic arthritis (JIA) fail to respond to first-line methotrexate (MTX) or anti-tumor necrosis factor (TNF) therapy, with even fewer achieving ≥ American College of Rheumatology Pediatric 70% criteria for response (ACRpedi70), though individual responses cannot yet be accurately predicted. Because change in serum S100-protein myeloid-related protein complex 8/14 (MRP8/14) is associated with therapeutic response, we tested granulocyte-specific S100-protein S100A12 as a potential biomarker for treatment response.
S100A12 serum concentration was determined by ELISA in patients treated with MTX (n = 75) and anti-TNF (n = 88) at baseline and follow-up. Treatment response (≥ ACRpedi50 score), achievement of inactive disease, and improvement in Juvenile Arthritis Disease Activity Score (JADAS)-10 score were recorded.
Baseline S100A12 concentration was measured in patients treated with anti-TNF [etanercept n = 81, adalimumab n = 7; median 200, interquartile range (IQR) 133-440 ng/ml] and MTX (median 220, IQR 100-440 ng/ml). Of the patients in the anti-TNF therapy group, 74 (84%) were also receiving MTX. Responders to MTX (n = 57/75) and anti-TNF (n = 66/88) therapy had higher baseline S100A12 concentration compared to non-responders: median 240 (IQR 125-615) ng/ml versus 150 (IQR 87-233) ng/ml, p = 0.021 for MTX, and median 308 (IQR 150-624) ng/ml versus 151 (IQR 83-201) ng/ml, p = 0.002, for anti-TNF therapy. Follow-up S100A12 could be measured in 44/75 MTX-treated patients (34/44 responders) and 39/88 anti-TNF-treated patients (26/39 responders). Responders had significantly reduced S100A12 concentration (MTX: p = 0.031, anti-TNF: p < 0.001) at follow-up versus baseline. Baseline serum S100A12 in both univariate and multivariate regression models for anti-TNF therapy and univariate analysis alone for MTX therapy was significantly associated with change in JADAS-10.
Responders to MTX or anti-TNF treatment can be identified by higher pretreatment S100A12 serum concentration levels.

Details

The Journal of Rheumatology. 2018 Jan 15, 45:3. doi: 10.3899/jrheum.170438

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