Epstein-Barr Virus Antibodies and Autoimmune Diseases: A Bidirectional Mendelian Randomization Analysis.

This study aims to evaluate the estimate of causal relationship between Epstein-Barr virus (EBV) antibody levels and autoimmune diseases (AIDs), such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), through bidirectional two-sample Mendelian randomization (MR) analysis. Despite 50 years of research into the link between EBV infection and AIDs, inconsistent results persist due to the complex mechanisms of EBV within the body. We utilized large-scale genome-wide association studies (GWAS) data from the Integrative Epidemiology Unit (IEU) Open GWAS Project database to conduct rigorous MR analysis, incorporating various sensitivity analyses to assess potential impacts and ensure robustness. EBV antibodies (including VCA-IgG, ZEBRA-IgG, EBNA-1-IgG, and EA-D-IgG) were used as exposure variables, whereas RA and SLE served as outcome variables. In the reverse analysis, RA and SLE were treated as exposure variables and EBV antibodies as outcome variables. When EBV antibodies are designated as the exposure variables, the random-effects inverse-variance weighted (IVW) analysis indicated a significant negative genetic causal relationship between EBV EA-D antibody levels and RA (p = 0.007, odds ratio [OR] = 0.700, 95% confidence interval [CI] = [0.539-0.907]). No significant genetic causal relationship was found between SLE and EBV antibody levels. When RA and SLE are designated as the exposure variables, the random-effects IVW analysis revealed significant positive genetic causal relationships between SLE and EBV ZEBRA antibody levels (p = 0.009, OR = 1.028, 95% CI = [1.007-1.050]) and EBV EA-D antibody levels (p = 0.005, OR = 1.032, 95% CI = [1.009-1.054]). No significant genetic causal relationship was observed between RA and EBV antibody levels. This study offers compelling evidence of a causal relationship between EBV antibody levels and AIDs through MR analysis. Our findings lay a new foundation and perspective for future research directions, clinical prognosis, and treatment.