AB0273 Assessment of serum levels of 14–3–3Η protein in rheumatoid arthritis: is it a specific marker for the disease?
Authors: M. Elshahaly, M. Saleh, H. Fahmy, M. Othman
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> 14–3–3η protein was suggested to be significantly higher in serum and synovial fluid of rheumatoid arthritis (RA) patients compared to healthy individuals and other diseases such as osteoarthritis (OA) and ankylosing spondylitis (AS).<sup>1</sup> Accordingly, 14–3–3η is now thought to be a diagnostic marker for early RA. Furthermore, some reports suggest that it correlates well with disease activity.<sup>2</sup> <h3>Objectives</h3> To assess the usefulness of serum levels of 14–3–3η protein in the diagnosis of RA in comparison with hands OA patients and healthy controls; furthermore, to correlate its levels with markers of inflammation in RA patients. <h3>Methods</h3> This study was carried out as a case control comparative study. Our sample consisted of three groups. Group 1 was made up of 30 RA patients fulfilling 2010 ACR–EULAR classification criteria for RA;<sup>3</sup> Group 2 made up of 30 hands OA patients according to OA ACR criteria<sup>4</sup> and group 3 of 30 healthy volunteers. Patients with other rheumatic and/or systemic diseases or infections were excluded. Patients were assessed using detailed clinical history and examination. Laboratory investigations included complete blood picture, ESR, CRP, RF, ACPA and serum levels of 14–3–3η protein using manual enzyme-linked immunosorbent assay (ELISA). <h3>Results</h3> Mean (SD) age of RA group was 45.5 (9.5) years old; for OA group was 50.3 (8.8) years old, and the control group was 46.2 (6.9) years old. Females represented 96.7% of group 1; 83.3% of group 2, and 86.7% of group 3. RF was positive in 78% of RA group, 6.7% in OA group and 6.3% of control group. Mean (SD) of RF titer was 123 (10.3), 15.3 (5.4) and 14.4 (5.2) IU/ml respectively. ACPA was positive in 96.7% of group 1 and was negative in groups 2 and 3. Mean (SD) ACPA was 64.4 (6.6) U/ml in RA group. Mean (SD) ESR was 32.5±8.2 in group 1, 22.0 (6.6) in group 2 and 16.1 (7.3) mm/hour in group 3. Mean (SD) CRP was 17.9 (5.04), 5.7 (2.8) in group 2 and 4.9 (2.4) mg/L in group 3. Mean (SD) levels of 14–3–3η protein were significantly higher among RA compared to OA and control groups (3.63 (1.35), 0.23 (0.14) and 0.28 (0.08) ng/ml, respectively) (p&lt;0.0001). The optimal cutoff point of 14–3–3η protein to diagnose RA was &gt;0.2 with a sensitivity of 80%, specificity of 87%, positive predicted value of 86% and negative predicted value of 81%. The eta protein also had high diagnostic odds ratio (26.1). No correlation was found between serum levels of 14–3–3 eta and CRP nor ESR (p&gt;0.05). <h3>Conclusions</h3> 14–3–3η is a specific marker for RA that should be used in conjunction with RF and ACPA for diagnosis of the disease. However, no correlation was found between 14–3–3η and markers of inflammation. <h3>References</h3> [1] Maksymowych WP, Landewe R, van der Heijde D. Serum 14–3–3η: a rheumatoid arthritis biomarker. Arthritis Rheum. 2011;63:358. [2] van Beers-Tas M, Marotta A, Maarten Boers M, Maksymowych W, van Schaardenburg D. Arthritis Research &amp; Therapy2016;18:7. [3] Aletaha D, Neogi T, Silman AJ, et al. Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis. 2010;69(9):1580–1588. [4] Altman R, Alarcón G, Appelrouth D, et al. The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hand. Arthritis Rheum. 1990;33(11):1601–10. <h3>Disclosure of Interest</h3> None declared