OBJECTIVE:We analyzed the Epstein-Barr nuclear antigen 2 (EBNA2) gene, which
contains the most variable region of the viral genome, in persons with
multiple sclerosis (MS) and control subjects to verify whether virus
genetic variants are involved in disease development.
METHODS:A seminested PCR approach and Sanger sequencing were used to analyze
EBNA2 in 53 patients and 38 matched healthy donors (HDs).
High-throughput sequencing by Illumina MiSeq was also applied in a
subgroup of donors (17 patients and 17 HDs). Patients underwent
gadolinium-enhanced MRI and human leucocyte antigen typing.
risk significantly correlated with an excess of 1.2 allele (odds ratio
[OR] = 5.13; 95% confidence interval [CI] 1.84-14.32; p = 0.016) and
underrepresentation of 1.3B allele (OR = 0.23; 95% CI 0.08-0.51; p =
0.0006). We identified new genetic variants, mostly 1.2 allele- and
MS-associated (especially amino acid variation at position 245; OR =
9.4; 95% CI 1.19-78.72; p = 0.0123). In all cases, the consensus
sequence from deep sequencing confirmed Sanger sequencing (including the
cosegregation of newly identified variants with known EBNA2 alleles)
and showed that the extent of genotype intraindividual variability was
higher than expected: rare EBNA2 variants were detected in all HDs and
patients with MS (range 1-17 and 3-19, respectively). EBNA2 variants did
not seem to correlate with human leucocyte antigen typing or
CONCLUSIONS:Our study unveils a strong association between Epstein-Barr virus genomic
variants and MS, reinforcing the idea that Epstein-Barr virus
contributes to disease development.