Determination of anti-cyclic citrullinated peptide antibodies in the sera of patients with juvenile idiopathic arthritis.
Determination of anti-cyclic citrullinated peptide antibodies in the sera of patients with juvenile idiopathic arthritis.
复制标题
幼年特发性关节炎患者血清中抗环瓜氨酸肽抗体的测定。
作者：
J. Low;A. Chauhan;D. Kietz;U. Daud;P. Pepmueller;T. Moore
目的
抗环瓜氨酸肽（anti-CCP）抗体在76%的类风湿关节炎（RA）患者血清中检出，主要见于类风湿因子（RF）阳性患者，特异性为96%。我们评估了青少年特发性关节炎（JIA）患者抗CCP抗体的存在，并评估了合成瓜氨酸肽作为JIA抗原决定簇的可能性。
方法
使用3种合成瓜氨酸化肽变体和2种商业试剂盒（Inova Diagnostics和Axis-Shield Diagnostics）确定抗CCP抗体的存在，这些试剂盒经优化用于通过基于ELISA的测定法检测血清中的JIA特异性抗体。我们评估了66例JIA患者（16例RF阳性多关节炎，18例RF阴性多关节炎，19例少关节炎和13例全身性关节炎）。我们还测试了9例成人RA患者，34例系统性红斑狼疮（SLE）患者，25名健康人作为对照。
结果
在大多数RF阳性的多发性关节炎JIA患者中检测到显着浓度的抗CCP抗体。使用2种合成线性肽，12/16（75%）为阳性; 9/12（75%）为Inova试剂盒阳性，9/10（90%）为Axis-Shield试剂盒阳性。然而，利用合成的线性肽，在51/66（77%）JIA患者中检测到显著浓度的抗CCP抗体，包括15/18（83%）RF阴性多关节炎、16/19（84%）少关节炎和8/13（62%）全身性关节炎患者。没有健康对照显示抗体水平升高。相反，4/9（44%）例成人RA和2/6（33%）例SLE患者的抗CCP水平升高。合成的环状变体cfc-1-cyc在13/14（93%）RF阴性多关节炎患者、6/10（60%）少关节炎患者、3/7（43%）系统性关节炎患者和8/9（88%）RF阳性患者中产生显著的抗CCP水平。没有健康对照组的抗CCP水平升高。然而，发现4/9（44%）成人RA和9/34（26%）SLE患者具有升高的抗CCP水平。使用Inova和Axis-Shield试剂盒，在RF阴性患者中发现的百分比要小得多，使用Inova试剂盒的少关节炎和RF阴性多关节炎患者中仅为4/16（25%），使用Axis-Shield试剂盒的患者为0/25（0%）。Inova试剂盒显示5/9（56%）成人RA患者和8/34（24%）SLE患者的抗CCP抗体升高。没有健康对照组的抗CCP抗体升高。然而，Axis-Shield试剂盒在成人RA（0/9）或SLE（0/34）患者中未检测到抗CCP抗体。此外，0/25（0%）健康个体表现出抗CCP水平。抗CCP抗体的存在与RF的存在更频繁地相关。
结论
这项研究通过所有基于ELISA的方法证实了JIA患者中存在抗CCP抗体，尤其是RF阳性多关节炎患者。使用合成肽也显示抗CCP抗体在RF阴性的多关节炎，少关节炎和全身性关节炎患者的百分比;有特异性的损失，但敏感性增加。这些结果表明，这些抗原肽的抗体可能是JIA的标志物，并表明在JIA的发病机制中的瓜氨酸含表位的可能作用。
OBJECTIVE
Anti-cyclic citrullinated peptide (anti-CCP) antibodies have been found in sera of 76% of patients with rheumatoid arthritis (RA), mainly in rheumatoid factor (RF) positive patients, with a specificity of 96%. We evaluated the presence of anti-CCP antibodies in patients with juvenile idiopathic arthritis (JIA) and assessed the possibility of synthetic citrullinated peptides as antigenic determinants in JIA.
METHODS
The presence of anti-CCP antibodies was determined using 3 synthetic citrullinated peptide variants and 2 commercial kits (Inova Diagnostics and Axis-Shield Diagnostics) optimized for detecting JIA-specific antibodies in serum by an ELISA based assay. We evaluated 66 patients with JIA (16 RF positive polyarthritis, 18 RF negative polyarthritis, 19 oligoarthritis, and 13 systemic arthritis). We also tested 9 adult RA patients, 34 patients with systemic lupus erythematosus (SLE), and 25 healthy persons as controls.
RESULTS
Significant concentrations of anti-CCP antibodies were detected in the majority of RF positive JIA patients with polyarthritis. Using the 2 synthetic linear peptides, 12/16 (75%) were positive; 9/12 (75%) were positive with the Inova kit and 9/10 (90%) were positive with the Axis-Shield kit. However, utilizing the synthetic linear peptides, significant concentrations of anti-CCP antibodies were detected in 51/66 (77%) JIA patients, including 15/18 (83%) RF negative polyarthritis, 16/19 (84%) oligoarthritis, and 8/13 (62%) systemic arthritis patients. No healthy control showed elevated antibody levels. In contrast, 4/9 (44%) patients with adult RA and 2/6 (33%) with SLE had elevated anti-CCP levels. The synthetic cyclic variant cfc-1-cyc yielded significant anti-CCP levels for 13/14 (93%) patients with RF negative polyarthritis, 6/10 (60%) with oligoarthritis, and 3/7 (43%) with systemic arthritis, and 8/9 (88%) RF positive patients. No healthy control had increased anti-CCP levels. However, 4/9 (44%) adult RA and 9/34 (26%) SLE patients were found to have elevated anti-CCP levels. Using the Inova and Axis-Shield kits, much smaller percentages were found in the RF negative patients, with only 4/16 (25%) in the oligoarthritis and RF negative polyarthritis patients with the Inova kits and 0/25 (0%) by the Axis-Shield kits. The Inova kit revealed elevated anti-CCP antibodies in 5/9 (56%) adult RA patients and in 8/34 (24%) SLE patients. No healthy control had elevated anti-CCP antibodies. However, the Axis-Shield kits did not detect anti-CCP antibodies in adult RA (0/9) or SLE (0/34) patients. Moreover, 0/25 (0%) healthy individuals exhibited anti-CCP levels. The presence of anti-CCP antibodies correlated more frequently with the presence of RF.
CONCLUSION
This study confirms the presence of anti-CCP antibodies in patients with JIA, especially those with RF positive polyarthritis, by all ELISA based methods. Use of synthetic peptides also revealed anti-CCP antibodies in a percentage of RF negative patients with polyarthritis, oligoarthritis, and systemic arthritis; there was a loss in specificity, but an increase in sensitivity. These results suggest that antibodies to these antigenic peptides may be markers for JIA, and indicate a possible role of citrulline-containing epitopes in the pathogenesis of JIA.