Sequence Variation of Epstein-Barr Virus EBNA-1 Gene in Central Nervous System Inflammatory Demyelinating Diseases in Pakistan.

CNS inflammatory demyelinating diseases (CNS-IDDs), including multiple sclerosis and related conditions, have increasingly been associated with Epstein-Barr virus (EBV). However, data on EBV genetic diversity, particularly regarding EBNA-1 gene variants, across different CNS-IDD subtypes in South Asian populations remain limited. This study examined EBV DNA prevalence and EBNA-1 sequence variation in 40 patients with CNS-IDD and 40 healthy controls from Pakistan. EBV DNA was found in 21 of 80 samples (26%), with a significantly higher occurrence in CNS-IDD patients (16/40, 40%) compared to healthy controls (5/40, 13%) (p = 0.005, OR = 4.667). All EBV-positive samples clustered within the P-thr EBNA-1 variant, carrying consistent amino acid substitutions P476Q, A487T, S492C, and T524I, suggesting these are conserved features of the regionally circulating strain. These findings provide a foundation for further studies to explore the pathogenic significance of EBNA-1 variation linked with CNS-IDDs in the region.