Accumulation of Epstein-Barr virus–induced cross-reactive immune responses is associated with multiple sclerosis

To the Editor: Multiple sclerosis (MS) is a chronic autoinflammatory and demyelinating disease of the central nervous system (CNS).The individual risk of developing MS substantially increases after a primary infection with the ubiquitous EBV (1).MS pathogenesis was associated earlier with the development of high-level antibodies directed against the EBV nuclear antigen-1 (EBNA-1), which cross-reacts with distinct CNS-derived proteins and may result in autoreactive immune responses (1).Recent studies have already identified a conserved sequence in the EBNA-1 region, EBNA 381-452 , as a main factor for potential molecular mimicry and autoreactivity (1).However, it is unknown whether potent EBNA 381-452 -specific immune responses may in fact trigger MS pathogenesis in the individual host.The aim of this study was thus to investigate whether a distinct antibody signature against EBNA 381-452 is associated with high cross-reactive autoimmune responses that further evolve into MS.Therefore, we recruited a study cohort of 270 EBV-seropositive MS patients that were matched to 270 healthy controls regarding age, sex, and time point of EBV seroconversion (Supplemental Table 1; supplemental material available online with this article; https://doi.org/10.1172/JCI184481DS1).From all study participants, plasma samples were available at the time point of primary EBV infection as well as at MS diagnosis and, in controls, at a matched time point after EBV seroconversion, respectively.We first analyzed the fine specificity of the EBNA 381-452specific antibody responses of all MS patients and controls using an EBNA 381-452 -derived peptide library.MS patients had during MS diagnosis, in comparison with controls at a matched time point, significantly higher EBNA-specific antibody responses against epitopes that exhibit recently identified cross-reactive immune responses to the CNS-derived glial cell adhesion molecule (GlialCAM) (2), -crystallin B chain (CRYAB) (3), myelin basic protein (MBP) (4), and anoctamin 2 (ANO2) (5) (Figure 1A).Hence, we further quantified the individual antibody responses against all four EBNA-derived and all four associated cross-reactive CNS-derived peptides (EBNA 386-405 / GlialCAM 370-389 , EBNA 393-412 /CRYAB 2-21 , EBNA 409-428 /MBP 205-224 , EBNA 426-445 /ANO2 135-154 ) in the individual MS patients and controls.Neither MS patients nor controls had detectable EBNA 381-452specific antibody responses at the time point of primary EBV infection (Figure 1B).At the time point of MS diagnosis, overall higher EBNA-and CNS-derived peptide-specific antibody titers were observed in MS patients than in controls (Figure 1B).However, a substantial part (33.8%-53%) of controls had peptide-specific antibody titers against individual EBNA-and CNS-derived peptides that were comparable to titers found in MS patients.Neither in MS patients nor in healthy controls were a particular combination