Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
Department of Immunology and Rheumatology, Medical University Hannover, Hannover, Germany.
Arthritis Res Ther. 2018 Mar 1;20(1):38. doi: 10.1186/s13075-018-1535-x.
Anti-CD74 IgG antibodies are reported to be elevated in patients with axial spondyloarthritis (axSpA). This study assessed the diagnostic value of anti-CD74 antibodies in patients with early axSpA.
Anti-CD74 IgG and IgA antibodies were first measured in an exploratory cohort of patients with radiographic axSpA (138 patients with ankylosing spondyloarthritis (AS)) and 57 healthy controls and then were measured in patients with early axSpA (n = 274) and with non-SpA chronic back pain (CBP) (n = 319), participating in the spondyloarthritis caught early (SPACE) prospective cohort study of patients under 45 years old with early back pain (for ≥ 3 months, but ≤ 2 years).
In the exploratory cohort, anti-CD74 IgG antibodies were present in 79.7% of patients with AS vs. 43.9% of healthy controls (p < 0.001). Anti-CD74 IgA antibodies were present in 28.5% of patients with AS vs. 5.3% of healthy controls (p < 0.001). In the SPACE cohort, anti-CD74 IgG antibody levels were present in 46.4% of the patients with axSpA vs. 47.9% of the patients with CBP (p = 0.71). Anti-CD74 IgA antibodies were present in 54.7% of the patients with axSpA and 37.0% of the patients with CBP (p < 0.001). This resulted in a positive predictive value of 58.8% (compared to a prior probability of 46.2%) and a negative predictive value of 59.1% (compared to a prior probability of 53.8%). In a regression model, total serum IgA was associated with axSpA odds ratio (OR) 1.19, p < 0.001) whereas anti-CD74 IgA was not (OR) 1.01, p = 0.33). Furthermore, anti-CD74 IgA was associated with sacroiliitis on magnetic resonance imaging (MRI) (OR) = 2.50, p = 0.005) and heel enthesitis (OR) = 2.56, p = 0.002).
Albeit anti-CD74 IgA is elevated in patients with early axSpA, this elevation is not sufficiently specific to yield significant diagnostic value in patients under 45 years old presenting with early back pain.
抗 CD74 IgG 抗体在患有中轴型脊柱关节炎（axSpA）的患者中被报道升高。本研究评估了抗 CD74 抗体在早期 axSpA 患者中的诊断价值。
首先在放射学 axSpA（138 例强直性脊柱炎（AS）患者）和 57 名健康对照者的探索性队列中测量抗 CD74 IgG 和 IgA 抗体，然后在早期 axSpA 患者（n=274）和非 SpA 慢性背痛（CBP）患者（n=319）中进行测量，这些患者参加了年龄在 45 岁以下的早期背痛（≥3 个月，但≤2 年）的早期脊柱关节炎（SPACE）前瞻性队列研究。
在探索性队列中，79.7%的 AS 患者存在抗 CD74 IgG 抗体，而健康对照组为 43.9%（p<0.001）。28.5%的 AS 患者存在抗 CD74 IgA 抗体，而健康对照组为 5.3%（p<0.001）。在 SPACE 队列中，axSpA 患者中抗 CD74 IgG 抗体水平为 46.4%，CBP 患者为 47.9%（p=0.71）。抗 CD74 IgA 抗体在 axSpA 患者中为 54.7%，在 CBP 患者中为 37.0%（p<0.001）。这导致阳性预测值为 58.8%（与先前的概率 46.2%相比），阴性预测值为 59.1%（与先前的概率 53.8%相比）。在回归模型中，总血清 IgA 与 axSpA 比值比（OR）为 1.19，p<0.001），而抗 CD74 IgA 则不然（OR）为 1.01，p=0.33）。此外，抗 CD74 IgA 与 MRI 上的骶髂关节炎（OR）=2.50，p=0.005）和足跟腱炎（OR）=2.56，p=0.002）相关。
尽管抗 CD74 IgA 在早期 axSpA 患者中升高，但这种升高在年龄在 45 岁以下出现早期背痛的患者中特异性不足，无法产生显著的诊断价值。
