Section of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Arthritis Rheumatol. 2023 Jul;75(7):1110-1119. doi: 10.1002/art.42463. Epub 2023 Apr 27.
This study was undertaken to develop and characterize a multiplex immunoassay for detection of autoantibodies against peptides derived from proteins known to play a role in development of arthritis and that are also expressed in joints.
We selected peptides from the human counterpart of proteins expressed in the joints, based on mouse models that showed these to be targeted by pathogenic or regulatory antibodies in vivo. Using bead-based flow immunoassays measuring IgG antibodies, we selected triple helical or cyclic peptides, containing the epitopes, to avoid collinear reactivity. We characterized the analytical performance of the immunoassay and then validated it in 3 independent rheumatoid arthritis (RA) cohorts (n = 2,110), Swedish age- and sex-matched healthy controls, and patients with osteoarthritis (OA), patients with psoriatic arthritis (PsA), and patients with systemic lupus erythematosus (SLE).
Screening assays showed 5 peptide antigens that discriminated RA patients from healthy controls with 99% specificity (95% confidence interval [CI] 98-100%). In our validation studies, we reproduced the discriminatory capacity of the autoantibodies in 2 other RA cohorts, showing that the autoantibodies had high discriminatory capacity for RA versus OA, PsA, and SLE. The novel biomarkers identified 22.5% (95% CI 19-26%) of early RA patients seronegative for anti-cyclic citrullinated peptide and rheumatoid factor. The usefulness of the biomarkers in identifying seronegative RA patients was confirmed in validation studies using 2 independent cohorts of RA patients and cohorts of patients with OA, PsA, and SLE.
A multiplex immunoassay with peptides from disease-related proteins in joints was found to be useful for detection of specific autoantibodies in RA serum. Of note, this immunoassay had high discriminatory capacity for early seronegative RA.
本研究旨在开发和鉴定一种多重免疫分析方法，用于检测来自已知在关节炎发生中起作用且在关节中表达的蛋白质的肽段的自身抗体。
我们根据体内存在致病性或调节性抗体靶向这些蛋白质的小鼠模型，从关节中表达的蛋白质的人类对应物中选择肽段。我们使用基于珠的流免疫分析测量 IgG 抗体，选择包含表位的三螺旋或环状肽段，以避免共线性反应。我们对免疫分析的分析性能进行了特征描述，然后在 3 个独立的类风湿关节炎（RA）队列（n=2110）、瑞典年龄和性别匹配的健康对照者以及骨关节炎（OA）、银屑病关节炎（PsA）和系统性红斑狼疮（SLE）患者中进行了验证。
筛选试验显示，有 5 种肽抗原能够以 99%的特异性（95%置信区间[CI] 98-100%）区分 RA 患者和健康对照者。在我们的验证研究中，我们在另外 2 个 RA 队列中重现了自身抗体的区分能力，表明这些自身抗体对 RA 与 OA、PsA 和 SLE 具有很高的区分能力。新的生物标志物在识别抗环瓜氨酸肽和类风湿因子阴性的早期 RA 患者方面具有高的预测能力，分别占 22.5%（95% CI 19-26%）。在使用两个独立的 RA 患者队列和 OA、PsA 和 SLE 患者队列进行的验证研究中，证实了该生物标志物在识别抗阴性 RA 患者中的有用性。
一种来自关节中疾病相关蛋白质的肽段的多重免疫分析被发现对 RA 血清中特定自身抗体的检测有用。值得注意的是，该免疫分析对早期抗阴性 RA 具有很高的区分能力。
