Antibody index (cerebrospinal fluid/serum) of the Epstein-Barr virus in patients with demyelinating disease.

Demyelinating diseases (DD) encompass disorders characterized by varying and nonspecific triggers of both infectious and autoimmune origins, leading to varied signs and symptoms. These complexities necessitate a multifaceted diagnostic approach. In 2022, Bjornevik et al. established a correlation between multiple sclerosis (main DD) and the Epstein-Barr virus (EBV), setting the stage for further investigation into this association. Given this context, this study aimed to measure the levels of IgG antibodies specific to EBV viral capsid antigen (VCA) in the cerebrospinal fluid (CSF) and serum to calculate the specific antibody index (SAI), correlating it with other diagnostic measures such as oligoclonal bands (OCB), the Reibergram, and clinical laboratory findings in patients with DD treated at the University Hospital of Santa Maria and the Institute of Neurology of Goiania, both in Brazil, from March 2022 to March 2024. The study included sixty-one patients, ranging in age from 28 days to 84 years, divided into two groups: 34 patients with DD and 27 patients without demyelinating diseases (NDD). The assessments performed were OCB, total IgG and albumin in serum and CSF, Reibergrams, and activity for EBV VCA IgG, from which the SAI was calculated. Most DD patients were women, who demonstrated a higher incidence of EBV VCA IgG antibody activity in both serum and CSF as compared to NDD patients. OCB presence was identified in 7 (33.3 %) of MS patients. The presence of intrathecal synthesis, assessed by Reibergrams, was concordant in 88.9 % of patients with OCB detection. The SAI for EBV VCA IgG remained below 2.5 in 96.9 % of DD patients, even when OCB was present and the Reibergram indicated intrathecal synthesis. These findings suggest that the majority of DD patients, despite demonstrating intrathecal synthesis and reactivity to EBV VCA IgG in both serum and CSF, exhibited an SAI within normal ranges.