Shi Jing, van Steenbergen Hanna W, van Nies Jessica A B, Levarht E W Nivine, Huizinga Tom W J, van der Helm-van Mil Annette H M, Toes René E M, Trouw Leendert A
Department of Rheumatology, Leiden University Medical Center, C1-R, LUMC, PO Box 9600, 2300, RC Leiden, The Netherlands.
Arthritis Res Ther. 2015 Nov 24;17:339. doi: 10.1186/s13075-015-0860-6.
Anti-carbamylated protein (anti-CarP) antibodies have been described in rheumatoid arthritis (RA) and arthralgia patients at risk of developing RA. To what extent these autoantibodies are specific for RA is unknown. Therefore, we investigated the diagnostic performance of the presence of anti-CarP antibodies for RA in a setting of early arthritis.
Anti-CarP antibodies were detected using carbamylated fetal calf serum as substrate. Anti-CCP2 antibodies were measured using enzyme-linked immunosorbent assay and immunoglobulin M (IgM) rheumatoid factor (RF) as part of routine care. Sera were derived from patients in the Leiden Early Arthritis Clinic cohort obtained at inclusion. Test characteristics were determined using the fulfillment of the 2010 RA criteria after 1 year as outcome.
In total 2086 early arthritis patients were studied regarding the presence of anti-CarP antibodies. We observed that the sensitivity and specificity of the presence of anti-CarP antibodies for RA were 44 % and 89 %, respectively. As a reference, sensitivity and specificity of the presence of anti-CCP2 antibodies were 54 % and 96 %, respectively, and of IgM-RF 59 % and 91 %. Patients harboring anti-CarP antibodies not classified as RA were mainly diagnosed with undifferentiated arthritis and less frequently reactive arthritis and psoriatic arthritis.
Anti-CarP antibodies are predominantly present in RA but can also be detected in other forms of arthritis.
在类风湿关节炎（RA）患者以及有患RA风险的关节痛患者中已发现抗氨甲酰化蛋白（anti-CarP）抗体。这些自身抗体对RA的特异性程度尚不清楚。因此，我们在早期关节炎背景下研究了anti-CarP抗体对RA的诊断性能。
以氨甲酰化胎牛血清为底物检测anti-CarP抗体。作为常规检查的一部分，采用酶联免疫吸附测定法检测抗环瓜氨酸肽2（anti-CCP2）抗体和免疫球蛋白M（IgM）类风湿因子（RF）。血清来自莱顿早期关节炎诊所队列中纳入时的患者。以1年后符合2010年RA标准作为结局来确定检测特征。
总共对2086例早期关节炎患者进行了anti-CarP抗体检测。我们观察到，anti-CarP抗体对RA的敏感性和特异性分别为44%和89%。作为对照，anti-CCP2抗体的敏感性和特异性分别为54%和96%，IgM-RF的敏感性和特异性分别为59%和91%。携带anti-CarP抗体但未被归类为RA的患者主要被诊断为未分化关节炎，较少被诊断为反应性关节炎和银屑病关节炎。
anti-CarP抗体主要存在于RA患者中，但也可在其他形式的关节炎中检测到。
