Demortiere Sarah, Stolowy Natacha, Perriguey Marine, Boutiere Clemence, Rico Audrey, Hilezian Frederic, Ndjomo-Ndjomo Blaise-Roger, Durozard Pierre, Stellmann Jan-Patrick, Marignier Romain, Boucraut José, Pelletier Jean, Maarouf Adil, Audoin Bertrand
Department of Neurology, University Hospital of Marseille, France.
Department of Ophtalmology, University Hospital of Marseille, France.
Neurol Neuroimmunol Neuroinflamm. 2025 May;12(3):e200386. doi: 10.1212/NXI.0000000000200386. Epub 2025 Mar 14.
A simple, quick, and reproducible procedure for distinguishing multiple sclerosis (MS), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and neuromyelitis optica spectrum disorder (NMOSD) at inaugural optic neuritis (ION) could be highly valuable in guiding early management.
We included all adults admitted to the MS center of Marseille for ION between March 2016 and April 2024, with CSF analysis including the kappa free light chain (K-FLC) index. Receiver operating characteristic curves were used to measure the diagnostic ability of the K-FLC index.
Two hundred twenty-seven adults were admitted for ION; 210 (93%) had a K-FLC index measurement. MS was diagnosed in 84 (40%); clinically isolated syndrome suggestive of MS in 77 (36.5%), including 20 with future conversion to MS (CISwc); MOGAD in 26 (12.5%); NMOSD in 13 (6%); and other inflammatory disorders in 10 (5%). A K-FLC index ≥6.7 differentiated MS/CISwc from other diagnoses with specificity 86% and sensitivity 95% (area under the curve [AUC] 0.94). A K-FLC index <4.9 differentiated MOGAD from other diagnoses with specificity 63% and sensitivity 92% (AUC 0.78) and MOGAD from MS/CISwc with specificity 96% and sensitivity 92% (AUC 0.97). Among all patients, 93 (44%) had a K-FLC index <4.9: 24 of these (26%) had MOGAD and 5 (5.5%) MS/CISwc. Among the remaining patients with a K-FLC index ≥4.9 (n = 117), 2 (1.7%) had MOGAD (K-FLC index of 7.9 and 16.2) and 99 (85%) MS/CISwc. Among patients with normal MRI (n = 96), 73 (76%) had a K-FLC index <4.9: 22 of these (30%) had MOGAD, and none showed conversion to MS. Among the remaining patients with a K-FLC index ≥4.9 (n = 23), 2 (8.5%) had MOGAD and 7 (30.5%) showed conversion to MS. The K-FLC index did not differentiate NMOSD from other diagnoses and only moderately differentiated NMO from MS/CISwc (AUC 0.80).
The K-FLC index is an accessible biomarker to guide early diagnosis in patients with ION. The probability of MOGAD in patients with ION and a K-FLC index ≥4.9 is low even in case of normal brain/spinal cord MRI.
This study provides Class II evidence that for patients with ION, the K-FLC index can distinguish between MS/CISwc and MOGAD.
在首发视神经炎（ION）时，一种简单、快速且可重复的区分多发性硬化（MS）、髓鞘少突胶质细胞糖蛋白抗体相关疾病（MOGAD）和视神经脊髓炎谱系障碍（NMOSD）的方法，对于指导早期治疗可能具有极高价值。
我们纳入了2016年3月至2024年4月间因ION入住马赛MS中心的所有成年患者，并进行了包括κ游离轻链（K-FLC）指数在内的脑脊液分析。采用受试者工作特征曲线来衡量K-FLC指数的诊断能力。
227名成年患者因ION入院；210名（93%）进行了K-FLC指数测量。84名（40%）被诊断为MS；77名（36.5%）为临床孤立综合征提示MS，其中20名后来转变为MS（CISwc）；26名（12.5%）为MOGAD；13名（6%）为NMOSD；10名（5%）为其他炎症性疾病。K-FLC指数≥6.7可将MS/CISwc与其他诊断区分开来，特异性为86%，敏感性为95%（曲线下面积[AUC]为0.94）。K-FLC指数<4.9可将MOGAD与其他诊断区分开来，特异性为63%，敏感性为92%（AUC为0.78），并将MOGAD与MS/CISwc区分开来，特异性为96%，敏感性为92%（AUC为0.97）。在所有患者中，93名（44%）的K-FLC指数<4.9：其中24名（26%）患有MOGAD，5名（5.5%）患有MS/CISwc。在其余K-FLC指数≥4.9的患者（n = 117）中，2名（1.7%）患有MOGAD（K-FLC指数分别为7.9和16.2），99名（85%）患有MS/CISwc。在MRI正常的患者（n = 96）中，73名（76%）的K-FLC指数<4.9：其中22名（30%）患有MOGAD，且无一人转变为MS。在其余K-FLC指数≥4.9的患者（n = 23）中，2名（8.5%）患有MOGAD，7名（30.5%）转变为MS。K-FLC指数无法将NMOSD与其他诊断区分开来，仅能中度区分NMO与MS/CISwc（AUC为0.80）。
K-FLC指数是一种可获取的生物标志物，可用于指导ION患者的早期诊断。即使脑/脊髓MRI正常，ION且K-FLC指数≥4.9的患者患MOGAD的概率也较低。
本研究提供了II类证据，表明对于ION患者，K-FLC指数可区分MS/CISwc和MOGAD。
