EBNA-1 titer gradient in families with multiple sclerosis indicates a genetic contribution

Area of Science:

• Immunogenetics
• Neuroimmunology
• Virology

Background:

• Epstein-Barr virus (EBV) infection is linked to multiple sclerosis (MS) pathogenesis.
• Humoral immune responses, specifically immunoglobulin G (IgG) titers to EBV nuclear antigen 1 (EBNA-1), are implicated in MS.
• Genetic factors, including HLA loci, may influence immune responses to EBV in MS.

Purpose of the Study:

• To determine Epstein-Barr virus nuclear antigen 1 (EBNA-1)-specific immunoglobulin G (IgG) titers in multiplex MS families.
• To investigate the role of specific genetic loci, including HLA-DRB1*1501 and HLA-A*02, in modulating antiviral IgG titers.
• To assess the association between genetic polymorphisms and EBNA-1 IgG levels in patients with MS, their siblings, and unrelated spouses.

Main Methods:

• Measurement of IgG levels against EBNA-1 and varicella zoster virus (VZV) as a control.
• Genotyping of single-nucleotide polymorphisms (SNPs) for HLA-DRB1*1501 and HLA-A*02.
• Statistical assessment of associations between identified SNPs and measured antiviral IgG titers.

Main Results:

• Elevated EBNA-1 IgG titers were observed in MS patients, intermediate in their siblings, and lowest in unrelated spouses.
• The HLA-DRB1*1501 genotype was confirmed to be associated with higher EBNA-1 IgG levels.
• Even after accounting for HLA-DRB1*1501, a significant gradient in EBNA-1 IgG levels persisted between MS patients and siblings compared to spouses; HLA-A*02 showed no such association. No associations were found for VZV IgG.

Conclusions:

• A familial genetic contribution to EBNA-1 IgG levels exists in MS families, independent of, but partially explained by, HLA-DRB1*1501.
• The observed gradient in EBNA-1 IgG titers suggests a complex interplay between genetics and environmental factors (like EBV exposure) in MS.
• Further research is warranted to identify additional genetic factors influencing EBNA-1 immunity in the context of MS.