Potential viral causes
Objective: To investigate Epstein-Barr virus (EBV) oral shedding frequency and EBV genetic diversity in pediatric patients with multiple sclerosis (MS).
Methods: This was a prospective case-control study. We used PCR-based assays to detect viral DNA in the monthly mouth swabs of 22 pediatric patients with MS and 77 age- and sex-matched healthy controls. EBV-positive samples were further analyzed for sequence variation in the EBV BCRF1 (ebvIL-10) gene using direct DNA sequencing methods, and in the EBV LMP1 gene by mass spectrometry.
Results: Nineteen of the 22 (86.4%) children with MS were seropositive for remote EBV infection compared to 35 out of 77 (45.5%) healthy controls (p = 0.008). Baseline analysis of mouth swabs revealed a higher proportion of EBV-positive samples from EBV-seropositive patients with MS compared to EBV-seropositive healthy controls (52.6% vs 20%, p = 0.007). Longitudinal analysis of monthly swabs revealed average EBV detection rates of 50.6% in patients with MS and 20.4% in controls (p = 0.01). The oral shedding frequencies of Herpesviruses herpes simplex virus–1, cytomegalovirus, human herpesvirus (HHV)-6, and HHV-7 did not differ between groups. Changes in the predominant EBV genetic variants were detected more frequently in patients with MS; however, no specific EBV genetic variant was preferentially associated with MS.
Conclusion: Children with MS demonstrate abnormally increased rates of EBV viral reactivation and a broader range of genetic variants, suggesting a selective impairment in their immunologic control of EBV.
Carmen Yea, MSc, Raymond Tellier, MD, Patrick Chong, PhD, Garrett Westmacott, PhD, Ruth Ann Marrie, MD, PhD, Amit Bar-Or, MD, Brenda Banwell, MD; On behalf of the Canadian Pediatric Demyelinating Disease Network
Source: Neurology © 2013 American Academy of Neurology (30/10/13)