Department of Neurology, Hospital Universitario Ramón y Cajal, Red Española de Esclerosis Múltiple (REEM), Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Universidad de Alcalá, Madrid, Spain.
Department of Immunology, Hospital Universitario Ramón y Cajal, Red Española de Esclerosis Múltiple (REEM), Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Universidad de Alcalá, Madrid, Spain.
Front Immunol. 2023 Oct 25;14:1288169. doi: 10.3389/fimmu.2023.1288169. eCollection 2023.
The immunoglobulin kappa free light chain (KFLC) index has been proposed as a potentially suitable alternative to oligoclonal IgG bands (OCGB) for diagnosing multiple sclerosis (MS), offering automation and reduced processing time. However, there is no consensus on the preferred approach or how to combine both techniques.
This prospective cohort study aimed to determine the best utilization of OCGB and KFLC index in patients with a clinically isolated syndrome (CIS) followed for at least two years. OCGB and KFLC were assessed using isoelectric focusing and immunoblotting and turbidimetry, respectively. Sensitivity, specificity, and accuracy for diagnosing MS were calculated for each method.
The study included 371 patients, with 260 (70.1 %) being women, and a median age of 34.9 (27.8 - 43.9) years. Using a cut-off value of 6.1, the KFLC index demonstrated a sensitivity and specificity of 86.3% and 93.9%, respectively. The sensitivity of OCGB (95.3%) was higher (p < 0.001 vs. KFLC index) and the specificity (100%) was comparable to that of the KFLC index (p = 0.5). The concordance between the methods was not uniform across all patients, with 97.8% agreement in patients with KFLC index ≥ 6.1 and 56.0 % in patients with KFLC index < 6.1. In patients with a KFLC index < 6.1, OCGB still identified 75.0 % of MS patients due to its higher sensitivity. An algorithm using the KFLC index as a screening tool and OCGB as an alternative for patients with a negative KFLC index result achieved an accuracy of 96.3 %.
Combining the KFLC index and OCGB can provide an easily reproducible and accurate method for diagnosing MS, with OCGB primarily reserved for patients with a KFLC index < 6.1.
免疫球蛋白 κ 轻链（KFLC）指数已被提出作为多发性硬化症（MS）诊断中替代寡克隆 IgG 带（OCGB）的潜在合适指标，具有自动化和缩短处理时间的优势。然而，目前对于哪种方法是首选方法或如何结合这两种技术尚未达成共识。
本前瞻性队列研究旨在确定在至少随访 2 年的临床孤立综合征（CIS）患者中，OCGB 和 KFLC 指数的最佳应用方法。OCGB 和 KFLC 分别采用等电聚焦和免疫印迹以及比浊法进行评估。为每种方法计算了诊断 MS 的敏感性、特异性和准确性。
本研究共纳入 371 例患者，其中 260 例（70.1%）为女性，中位年龄为 34.9（27.8-43.9）岁。使用 6.1 的截断值，KFLC 指数的敏感性和特异性分别为 86.3%和 93.9%。OCGB 的敏感性（95.3%）更高（p<0.001 与 KFLC 指数相比），特异性（100%）与 KFLC 指数相当（p=0.5）。这两种方法的一致性并非在所有患者中均一致，在 KFLC 指数≥6.1 的患者中有 97.8%的一致性，而在 KFLC 指数<6.1 的患者中有 56.0%的一致性。在 KFLC 指数<6.1 的患者中，OCGB 由于其更高的敏感性，仍能识别出 75.0%的 MS 患者。使用 KFLC 指数作为筛查工具和 OCGB 作为 KFLC 指数阴性患者的替代方法的算法，准确性达到 96.3%。
结合 KFLC 指数和 OCGB 可以提供一种易于重现且准确的 MS 诊断方法，OCGB 主要保留用于 KFLC 指数<6.1 的患者。
