University College London scientists have revealed that a simple blood test may soon help predict the severity of multiple sclerosis (MS).
Lead researcher Rachel Farrell says that a biological marker in blood appears to be linked to a patient's prognosis after the first MS attack.
If a blood test based on the biomarker can be validated, it could be used with MRI scans and other methods to improve accuracy and assess an individual's likely prognosis.
Almost everybody with MS has been infected with EBV, and adults who get it are at an increased risk.
This has led scientists to question whether a reactivation of latent EBV might be a factor in the onset of MS.
"It's very interesting that people who are negative for EBV don't get MS. The question is: do you need EBV to develop MS, or is there something about the immune system of people without EBV that also means they don't get MS?" Times Online quoted Farrell as saying.
The scientists looked for antibodies to EBV in 50 people who had had an attack with MS-type symptoms but had not had MS diagnosed, 25 people with relapsing-remitting MS, and 25 people with primary progressive MS.
"We wanted to see if reactivation of the virus triggered relapses, but we found no evidence of that," she said.
"But when we looked at the pattern of antibody response, we found people with a higher level of antibodies had more lesions. The suggestion is that a higher antibody load is indicative of a quicker progression of MS.
"We have identified something that may be used as a biomarker. This may be useful in identifying those who are going to go on and develop MS," she added.
The blood test could be particularly useful in deciding whether to prescribe drugs like beta interferon and glatiramer acetate (Copaxone) to people who have had an initial MS-type attack.
They can reduce the frequency and intensity of relapses, but they are burdensome because they must be injected daily.
The new research has been published in the journal Neurology.