Lakos G, Soós L, Fekete A, Szabó Z, Zeher M, Horváth I F, Dankó K, Kapitány A, Gyetvai A, Szegedi G, Szekanecz Z
Laboratory of Immunology, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary.
Clin Exp Rheumatol. 2008 Mar-Apr;26(2):253-60.
Anti-cyclic citrullinated peptide (anti-CCP) antibodies of IgG isotype are specific diagnostic markers of rheumatoid arthritis (RA). Recent evidence also points to their direct involvement in the pathophysiology. Little information is available, however, regarding the isotype distribution of anti-CCP antibodies and the characteristics of IgA and IgM anti-CCP.
IgG, IgA and IgM anti-CCP2 and rheumatoid factor (RF) levels were measured in the sera of 119 RA patients and 118 controls, including patients with other rheumatic diseases and healthy subjects. We analyzed the diagnostic performance of IgA and IgM anti-CCP2 antibodies and their relationship with IgG anti-CCP2, RFs, disease duration and the presence of HLA-DRB1 shared epitope (SE) alleles.
Patients with RA had significantly higher serum IgA and IgM anti-CCP2 antibody levels than healthy subjects and patients with other rheumatic diseases (p<0.0001). IgG, IgA and IgM anti-CCP2 antibodies were present in 74.8%, 52.9% and 44.5% of RA patients, and their diagnostic specificity was 95.8%, 95.8% and 91.6%, respectively. The presence of anti-CCP2 antibodies was significantly associated with SE alleles (p=0.03). The frequency of IgM anti-CCP2 positivity was lower in longstanding disease compared to early RA (p=0.03).
IgA and IgM anti-CCP2 antibodies are present in RA patients, and they are similarly specific for RA as IgG anti-CCP2. The higher frequency of IgM anti-CCP2 antibodies in early RA suggests that they are mostly generated during the first phase of immune response; nonetheless, their production seems to be sustained in some patients. Further analysis of IgM and IgA anti-CCP2 antibodies may provide insights into the pathogenesis of RA.
IgG 同种型抗环瓜氨酸肽（anti-CCP）抗体是类风湿关节炎（RA）的特异性诊断标志物。近期证据还表明它们直接参与了病理生理学过程。然而，关于抗 CCP 抗体的同种型分布以及 IgA 和 IgM 抗 CCP 的特征，目前所知甚少。
检测了 119 例 RA 患者以及 118 例对照（包括其他风湿性疾病患者和健康受试者）血清中的 IgG、IgA 和 IgM 抗 CCP2 以及类风湿因子（RF）水平。我们分析了 IgA 和 IgM 抗 CCP2 抗体的诊断性能及其与 IgG 抗 CCP2、RF、病程以及 HLA-DRB1 共享表位（SE）等位基因存在情况的关系。
RA 患者血清中 IgA 和 IgM 抗 CCP2 抗体水平显著高于健康受试者和其他风湿性疾病患者（p<0.0001）。74.8%的 RA 患者存在 IgG 抗 CCP2 抗体，52.9%存在 IgA 抗 CCP2 抗体，44.5%存在 IgM 抗 CCP2 抗体，它们的诊断特异性分别为 95.8%、95.8%和 91.6%。抗 CCP2 抗体的存在与 SE 等位基因显著相关（p=0.03）。与早期 RA 相比，长期患病患者中 IgM 抗 CCP2 阳性频率较低（p=0.03）。
RA 患者体内存在 IgA 和 IgM 抗 CCP2 抗体，它们对 RA 的特异性与 IgG 抗 CCP2 相似。早期 RA 中 IgM 抗 CCP2 抗体频率较高，表明它们大多在免疫反应的第一阶段产生；尽管如此，在一些患者中其产生似乎持续存在。对 IgM 和 IgA 抗 CCP2 抗体的进一步分析可能有助于深入了解 RA 的发病机制。
