Anti-Epstein-Barr virus antibodies as serological markers of multiple sclerosis: a prospective study among United States military personnel

Abstract

Background: Elevated Epstein-Barr virus (EBV) antibody titers are risk factors for multiple sclerosis (MS), but the strength and consistency of this association are not well characterized.

Objectives: The objectives of this study were to determine whether this association is confounded by vitamin D or modified by gender or race, and the usefulness of EBV nuclear antigen (EBNA) antibodies as a marker for MS.

Methods: We conducted a prospective study among US military personnel. Antibody titers against EBV antigens were measured in serum samples from 222 individuals who developed MS and 444 age, sex, and race/ethnicity matched controls. Conditional logistic regression was used to estimate relative risks.

Results: MS risk increased with increasing titers of anti-EBNA complex (p < 10(-9)) and anti-EBNA-1 (p = 5.8 × 10(-9)) titers. MS risk was 36-fold higher among individuals with anti-EBNA complex IgG titers ≥320 than among those with titers <20 (95% confidence interval [CI] 9.6-136), and 8-fold higher among those with anti-EBNA-1 ≥320 than among those with anti-EBNA-1 <20 (95% CI 2.6-23). These associations were consistent across gender and race/ethnicity groups and independent from 25-hydroxyvitamin D levels. Areas under the receiver operating characteristic (ROC) curves were 0.67 for EBNA complex and 0.65 for EBNA-1.

Conclusions: Serum titers of pre-onset anti-EBNA antibodies are strong, robust markers of MS risk and could be useful in an MS risk score.

Figure 1

RR of MS by levels of EBV IgG antibody titers A. EBNAc: 217 cases/422 controls; excludes 5 cases and 4 controls missing average EBNAc, 17 controls negative for EBV infection in all samples, and 1 control deleted due to suspect lab values; B. EBNA-1; C: EBNA-2 EBNA-1 and EBNA-2 IgG antibodies were not measured in 56 cases and 112 controls. Both include 161 cases/313 controls: excluded from analysis were 5 cases and 4 controls missing EBNA-1 and EBNA-2, and 15 controls negative for EBV infection in all samples. D. VCA: 218 cases/ 421 controls; excludes 4 cases and 5 controls missing average VCA, 17 controls negative for EBV infection in all samples, and 1 control deleted due to suspect lab values.

Figure 2

Receiver Operating Characteristic curves for EBV IgG antibodies in the sample collected most recently before MS symptom onset. A) anti-EBNAc IgG antibodies (C=0·67); B) anti-EBNA-1 IgG antibodies (C=0·65)