Rheumazentrum Ruhrgebiet Herne, , Herne, Germany.
Ann Rheum Dis. 2014 Jun;73(6):1079-82. doi: 10.1136/annrheumdis-2012-202177. Epub 2013 May 3.
The pathogenesis of axial spondyloarthritis (axSpA) is still unclear. There is a strong association with HLA-B27 and other genes. Recently, anti-CD74 antibodies with specificity to a class II-associated invariant chain peptide (anti-CLIP-ABs) were found in axSpA patients. We examined the prevalence, sensitivity and specificity of anti-CLIP-ABs in axSpA in comparison with controls.
Sera of axSpA and non-SpA patients were analysed for IgG-antibodies against CD74 by ELISA with specificity for CLIP developed in cooperation with AESKU Diagnostics (Germany). A cut-off of ≥4 SDs of arbitrary units (AU) from mean serum levels was used to differentiate the results. The laboratory workers were completely blinded for clinical data.
We analysed 145 sera from 94 axSpA and 51 non-SpA patients. AxSpA patients were more often male and younger. HLA-B27 status was available in 72 patients. Anti-CLIP-ABs were detected in 85.1% in axSpA but in only 7.8% in non-SpA patients (p≤0.0001). AxSpA patients showed higher levels of anti-CLIP-ABs versus non-SpA: mean 14.5 versus 0.8 AU (p≤0.0001). The sensitivity of anti-CLIP-ABs for diagnosing axSpA was 85.1%, specificity 92.2%, likelihood ratio (LR) LR+ was 10.8 and LR- was 0.08. Anti-CLIP-ABs and HLA-B27 were positive in 87.5% patients with axSpA, but only 14.9% were anti-CLIP-negative, while 23.6% were HLA-B27-negative.
Anti-CLIP antibodies were strongly associated with axSpA. The LR for confirming axSpA by using anti-CLIP was even higher than by using HLA-B27. More studies using this promising new method in patients with non-radiographic axial SpA or peripheral SpA are needed to establish its usefulness in clinical practice.
轴性脊柱关节炎（axSpA）的发病机制仍不清楚。它与 HLA-B27 和其他基因有很强的关联。最近，在 axSpA 患者中发现了针对 II 类相关不变链肽的抗 CD74 抗体（抗 CLIP-ABs）。我们比较了 axSpA 患者与对照组中抗 CLIP-ABs 的患病率、敏感性和特异性。
通过 ELISA 分析 axSpA 和非 SpA 患者血清中的 IgG 抗体对与 AESKU Diagnostics（德国）合作开发的 CLIP 的特异性。使用均值血清水平的≥4 个标准差（AU）的截断值来区分结果。实验室工作人员对临床数据完全不知情。
我们分析了 94 例 axSpA 和 51 例非 SpA 患者的 145 份血清。axSpA 患者更多为男性和年轻人。72 例患者提供了 HLA-B27 状态。在 axSpA 中检测到 85.1%的抗 CLIP-ABs，但在非 SpA 患者中仅为 7.8%（p≤0.0001）。axSpA 患者的抗 CLIP-ABs 水平高于非 SpA 患者：均值 14.5 与 0.8 AU（p≤0.0001）。抗 CLIP-ABs 诊断 axSpA 的敏感性为 85.1%，特异性为 92.2%，优势比（LR）LR+为 10.8，LR-为 0.08。在 87.5%的 axSpA 患者中，抗 CLIP-ABs 和 HLA-B27 均为阳性，但只有 14.9%的患者抗 CLIP 为阴性，而 23.6%的患者 HLA-B27 为阴性。
抗 CLIP 抗体与 axSpA 强烈相关。使用抗 CLIP 确认 axSpA 的 LR 甚至高于使用 HLA-B27。需要更多使用这种有前途的新方法在非放射性轴性 SpA 或周围 SpA 患者中的研究，以确定其在临床实践中的有用性。
