Bizzaro N, Mazzanti G, Tonutti E, Villalta D, Tozzoli R
Laboratorio di Patologia Clinica, Ospedale Civile, 30027 S. Donà di Piave (VE), Italy.
Clin Chem. 2001 Jun;47(6):1089-93.
Rheumatoid arthritis (RA) is the most common autoimmune rheumatic disease, but specific and practicable tests for its diagnosis are lacking. We evaluated the diagnostic accuracy of a new commercial ELISA in detecting anti-cyclic citrullinated peptide (CCP) antibodies for the diagnosis of RA.
Anti-CCP antibodies were determined in 330 serum samples: 98 from RA patients and 232 from controls, including patients with connective tissue diseases, other rheumatic diseases, viral infections, Lyme disease, autoimmune thyroiditis, cancer, and monoclonal gammopathy, and sex- and age-matched healthy subjects. Intra- and interassay CVs were 5-13% and 9-17%, respectively. Rheumatoid factor (RF) was also assayed in every sample, and results were compared to anti-CCP for sensitivity and specificity.
At a cutoff value of 50 units, sensitivity was 41% (confidence interval, 31-50%) and specificity was 97.8% (95-100%). Anti-CCP-positive RA patients had a mean antibody concentration of 1100 units (range, 57-3419 units), and anti-CCP-negative RA patients and controls had mean values of 7.6 and 6.8 units, respectively (range, 1-39 units). The area under the ROC curve was 0.71 (95% confidence interval, 0.63-0.78). RF had a higher sensitivity (62%) and a lower specificity (84%) than anti-CCP. When the two antibodies were used together, specificity was 99.6%.
Anti-CCP antibody testing may be useful if performed concomitantly with RF assay to diagnose patients with suspected early RA.
类风湿关节炎（RA）是最常见的自身免疫性风湿性疾病，但缺乏用于其诊断的特异性且实用的检测方法。我们评估了一种新型商用酶联免疫吸附测定（ELISA）在检测抗环瓜氨酸肽（CCP）抗体以诊断RA方面的诊断准确性。
在330份血清样本中测定抗CCP抗体：98份来自RA患者，232份来自对照，包括结缔组织病、其他风湿性疾病、病毒感染、莱姆病、自身免疫性甲状腺炎、癌症和单克隆丙种球蛋白病患者以及性别和年龄匹配的健康受试者。批内和批间变异系数分别为5 - 13%和9 - 17%。每个样本也检测类风湿因子（RF），并将结果与抗CCP进行敏感性和特异性比较。
在临界值为50单位时，敏感性为41%（置信区间，31 - 50%），特异性为97.8%（95 - 100%）。抗CCP阳性的RA患者平均抗体浓度为1100单位（范围，57 - 3419单位），抗CCP阴性的RA患者和对照的平均值分别为7.6和6.8单位（范围，1 - 39单位）。ROC曲线下面积为0.71（95%置信区间，0.63 - 0.78）。RF的敏感性（62%）高于抗CCP，特异性（84%）低于抗CCP。当两种抗体联合使用时，特异性为99.6%。
如果与RF检测同时进行，抗CCP抗体检测对于诊断疑似早期RA患者可能有用。
