Yang Kun, Li Sixing, Zheng Leting, Dong Fei, Wen Jing, He Zhendong, Wen Jiale, Qin Fang
Department of Rheumatology and Immunology, First Affiliated Hospital of Guangxi Medical University, Nanning, P. R. China.
Int J Rheum Dis. 2025 Aug;28(8):e70393. doi: 10.1111/1756-185x.70393.
This study aimed to evaluate the diagnostic accuracy and prognostic value of the Rheumatoid Arthritis Citrullinated Peptides (RACP) assay in a real-world cohort, assessing its performance both independently and in combination with established biomarkers such as anti-cyclic citrullinated peptide (anti-CCP), rheumatoid factor (RF), and anti-keratin antibodies (AKA).
A single-center retrospective analysis included 2632 patients who underwent serological testing between September 2022 and September 2023. Of these, 644 patients met ACR/EULAR classification criteria for rheumatoid arthritis (RA), while 1988 patients served as non-RA controls, including an osteoarthritis (OA) subgroup. RACP, anti-CCP, RF, and AKA levels were measured by enzyme-linked immunosorbent assay (ELISA). Diagnostic sensitivity, specificity, and combination strategies were assessed using chi-square and t-tests.
RACP alone demonstrated a sensitivity of 76.86% and a specificity of 89.94%, closely comparable to anti-CCP (70.87% sensitivity and 89.92% specificity). Area under the curve (AUC) values were 0.805 for RACP, 0.783 for RF, 0.799 for anti-CCP, and 0.623 for AKA. Combining RACP with RF improved sensitivity (85.36%), while dual positivity (RACP + AKA) optimized specificity (96.61%). In the OA subgroup, biomarker positivity remained minimal, confirming strong discriminatory capacity. Patients positive for RACP or anti-CCP exhibited significantly higher tender joint counts, correlating biomarker positivity with clinical disease severity.
RACP is a robust biomarker for RA diagnosis, offering sensitivity and specificity comparable to or exceeding traditional assays. Combinations with RF or anti-CCP enhance diagnostic accuracy, supporting its utility in early RA detection, differential diagnosis from OA, and potentially reflecting disease activity. Prospective studies are warranted to confirm these findings.
本研究旨在评估类风湿关节炎瓜氨酸化肽（RACP）检测在真实世界队列中的诊断准确性和预后价值，独立评估其性能，并与抗环瓜氨酸化肽（抗CCP）、类风湿因子（RF）和抗角蛋白抗体（AKA）等既定生物标志物联合评估其性能。
一项单中心回顾性分析纳入了2022年9月至2023年9月期间接受血清学检测的2632例患者。其中，644例患者符合美国风湿病学会/欧洲抗风湿病联盟（ACR/EULAR）类风湿关节炎（RA）分类标准，而1988例患者作为非RA对照，包括骨关节炎（OA）亚组。采用酶联免疫吸附测定（ELISA）法检测RACP、抗CCP、RF和AKA水平。使用卡方检验和t检验评估诊断敏感性、特异性和联合策略。
单独的RACP检测显示敏感性为76.86%，特异性为89.94%，与抗CCP（敏感性70.87%，特异性89.92%）相近。RACP的曲线下面积（AUC）值为0.805，RF为0.783，抗CCP为0.799，AKA为0.623。将RACP与RF联合可提高敏感性（85.36%），而双阳性（RACP + AKA）可优化特异性（96.61%）。在OA亚组中，生物标志物阳性率仍然很低，证实了其强大的鉴别能力。RACP或抗CCP阳性的患者压痛关节计数显著更高，表明生物标志物阳性与临床疾病严重程度相关。
RACP是RA诊断的一种可靠生物标志物，其敏感性和特异性与传统检测方法相当或更高。与RF或抗CCP联合可提高诊断准确性，支持其在早期RA检测、与OA的鉴别诊断以及潜在反映疾病活动方面的应用价值。有必要进行前瞻性研究以证实这些发现。
