Hey Amanda,
Demyelinating diseases like MS cause 2+ or 4+ (depending on the lab) unique oligoclonal bands which represent immune response to an inflammatory process 'inside' the CNS.
From my understanding of what youve posted, if the results showed only 1 paired oband, so in the CSF and the serum, these results would be pointing away from demyelinating diseases like MS is and towards a causation that is 'outside' the CNS.
Hope that helps.......JJ