EBV and MS
The cause of MS (multiple sclerosis) has long been sought. Although many factors are felt to predispose to it, genetics and environment top the lists. For instance, the illness is much more common in Europe and North America than in the rest of the world.
Viral infections have long been suspects. Now there is mounting evidence that the Epstein Barr Virus (EBV) may be the culprit. Two recently published research studies lend credence to this possibility.
The first study was done on service members on active duty who came down with MS. Over the study period 801 patients developed MS and all but one of them had evidence of active EBV infection. Now, don’t over interpret this finding. Evidence for prior EBV infection (the main cause for Mono, although CMV can also cause Mono) can be found in 90 plus percent of young adults and MS is a comparatively rare disease.
But the other recent study done by immunologists at Stanford University found that 25% of the MS patients they studied had a blood antibody that reacted to both EBNA1 protein and GlialCAM (glial cell adhesion molecule) protein. These two proteins are very similar in their chemical structure even though one is a viral protein and the other is a protein found in myelin sheaths. This is a phenomenon called molecular mimicry. Long story short what seems to be happening is the immune systems attempt to irradicate the virus via the anti-EBNA1 antibody ends up attacking the GlialCAM protein in the myelin sheath of nerves. The myelin sheath can be thought of as the plastic or rubber insulation on an electric wire. Damage to the sheath leads to altered nerve conduction and hence the numbness and muscle weakness found in MS.
The Stanford scientists extended their research in a mouse model. In one group of mice they injected EBNA-1 protein into their brains and in the control group a non-viral protein of similar size. A handful of the EBNA-1 injected mice developed neurologic disorders whereas none of the control group did.