ORLANDO – Epstein-Barr virus exposure and vitamin D insufficiency, which are some of the known risk factors for multiple sclerosis in children and adults, appear not to be associated with transverse myelitis, a small study has shown.
"What we found was that MS risk factors are specific for multiple sclerosis, and not necessarily for all autoimmune demyelinating diseases," said Kelley M. Weinfurtner, a third-year medical student at the University of California, San Francisco (UCSF), who presented a poster detailing the study at the fifth Cooperative Meeting of the Consortium of Multiple Sclerosis Centers and the Americas Committee for Treatment and Research in Multiple Sclerosis.
Kelley M. Weinfurtner
Transverse myelitis (TM) has substantial clinical overlap, especially at early stages, with autoimmune diseases such as multiple sclerosis and neuromyelitis optica, according to Ms. Weinfurtner.
Risk factors for TM are not known, and finding what they are "could be helpful in terms of stratifying when patients come in with TM," and deciding whether the patients would be at risk of MS further down the line, she said.
Ms. Weinfurtner and her colleagues collected blood samples from patients with TM (16), neuromyelitis optica (34), and MS (184) at early stages of disease, and from neurologic controls (95) through the Stony Brook Pediatric MS Center and the Accelerated Cure Project for MS Guthy Jackson Biobank.
They measured serum 25-hydroxyvitamin D levels and checked the blood samples for Epstein-Barr virus, cytomegalovirus, herpes simplex virus (HSV), and HLA-DRB1 allele status.
The median ages at disease onset were 12 years for TM, 11 years for neuromyelitis optica, and 14 years for MS; the median ages at sampling were 30, 16, and 16 years, respectively. The median age of healthy controls at the time of sampling was 16 years.
The majority of the patients were female (61%-70%) and white (all TM patients were white).
The results showed that TM patients were less likely to have been exposed to Epstein-Barr virus, compared with MS patients (odds ratio = 0.021; P less than .001), neuromyelitis optica patients (OR = 0.154; P = .054), and controls (P = .001). TM patients were more likely to have been exposed to HSV-1, although the data did not reach statistical significance.
TM patients also had higher levels of 25-hydroxyvitamin D, compared with MS patients (P = .037) and healthy controls (P = .01).
Meanwhile, there were no significant differences in the frequency of the HLA-DRB1*1501 allele or exposure to cytomegalovirus among TM patients, compared with MS and neuromyelitis optica patients and neurologic controls.
TM patients were significantly older and further from disease onset at the time of the blood draw, but the findings were adjusted for age at the time of the draw. The discrepancy in age "could explain the trend toward higher HSV-1 exposure in TM patients, but only strengthens the findings that TM patients have a lower prevalence of [Epstein-Barr virus] exposure than MS patients," she reported in the poster.
The difference in age could also explain the higher levels of 25-hydroxyvitamin D in TM patients, because they may have been on vitamin D supplementation after diagnosis.
The sample size for the study was small, and TM patients were not stratified by etiology or extent of cord involvement, although they all met criteria for TM, Ms. Weinfurtner said. The investigators were not able to adjust for race or ethnicity, because all TM patients were white.
Her study is not published and she said there’s a need for larger studies to confirm the findings.
Her research was supported by a grant from the Dean’s Office Medical Student Research Program at UCSF. The study is an offshoot of a large, multicenter study conducted by the Pediatric MS Network, which is in the third year of its 5-year period.
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