Epstein-Barr Virus Antibodies to Differentiate Multiple Sclerosis From Other Neuroinflammatory Diseases

Importance: Differentiating multiple sclerosis (MS) from myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and neuromyelitis optica spectrum disorder (NMOSD), especially in seronegative cases, remains challenging due to overlapping clinical and imaging features. High-level Epstein-Barr virus (EBV)-derived Epstein-Barr nuclear antigen 1 (EBNA-1) peptide antibody titers may be an MS-specific biomarker that could the improve differential diagnosis. Objective: To determine whether longitudinal EBNA-1 peptide antibodies can distinguish MS from MOGAD and NMOSD. Design, Setting, and Participants: This was a retrospective, multicenter, longitudinal, case-control study with patients from Austria, Germany, and the US. This study assessed samples from 2 independent retrospective cohorts. A test cohort and a validation cohort assessed longitudinal plasma samples from patients with MS, MOGAD, or NMOSD. Patients were recruited between 2001 and 2023 and followed up for 2 years. A combined analysis of both cohorts was conducted in January 2025. Exposures: Plasma EBNA-1 peptide immunoglobulin G (IgG) titers measured by enzyme-linked immunosorbent assay after diagnosis and in 3 follow-up samples. Main Outcomes and Measures: Diagnostic utility of persistent EBNA-1 peptide antibody levels across 4 time points in patients with MS compared with patients with MOGAD and NMOSD. Results: This study included the plasma samples of 2091 patients (mean [SD] age, 31.0 [16.9] years; 1137 female [54.4%]) with neuroinflammatory disease and 1976 healthy controls (mean [SD] age, 39.8 [16.2] years; 1120 male [56.7%]) recruited between 2001 and 2023. The test cohort (310 patients; 54.8% female) included 184 patients with MS, 65 with MOGAD, and 61 with NMOSD (including 12 who were seronegative for aquaporin 4 [AQP4] IgG). The validation cohort (183 patients; 126 female [68.8%]) included 142 patients with MS, 24 with MOGAD, and 17 with NMOSD. In the test cohort, 177 patients with MS (96.2%) had high-level titers in 2 or more of 4 follow-up samples compared with 5 patients (7.7%) with MOGAD (odds ratio [OR], 303.4; 95% CI, 94.4-908.6) and 11 patients (18.0%) with NMOSD (OR, 114.9; 95% CI, 43.0-280.0). Among patients with NMOSD who were seronegative for AQP4-IgG, only 1 (11.1%) had persistent high-level EBNA-1 peptide antibody titers compared with 61 matched patients (96.7%) with MS (OR, 236.0; 95% CI, 18.6-2588.0). In the validation cohort, 135 patients (95.1%) with MS had high-level titers in 2 or more of 4 follow-up samples compared with 4 patients (16.7%) with MOGAD (OR, 96.4; 95% CI, 26.6-293.0) and 3 patients (17.6%) with NMOSD (OR, 90.0; 95% CI, 19.7-319.7). Conclusions and Relevance: Results of this case-control study reveal that persistent high-level EBNA-1 peptide antibody titers may serve as a reliable biomarker for differentiating MS from MOGAD, and NMOSD.