In Nov there was a discussion here about a paralysed hand-cyclist who had a sudden miraculous recovery (in the comments after http://multiple-sclerosis-research.blogspot.com/2011/11/myelin-imaging.html )
Now there are doubts about whether she was paralysed at all when she won the Paralympic medals http://www.velonation.com/News/ID/12229/International-Paralympic-Committee-investigating-Van-der-Vorsts-claimed-paralysis.aspx
Good morning, I couldn't find much in the blog about this issue(maybe
I'm not so good in searching), but I would like to know how happens
that someone JC virus seropositive, become seronegative during
Natalizumab therapy (see 22 May 2012 post,"Research: JC Virus
seropositivity in MSers"). I suppose it's not related to Natalizumab
specifically, can you give me some information about that, and if
possible some research link? Thank You Francesco
Re: "I would like to know how happens that someone JC virus seropositive, become seronegative during Natalizumab therapy."
most common reason is analytical, i.e. the first test is a false
positive and the second test is correct. Or the first test is correct
and the second test is a false negative. These issues relate to the so
called positive and negative predictive value of the assay and are
related to the sensitivity and specificity of the assay. These flip-flop
results typically occur at the lower end of the assay, but can occur is
some assays when the titres or levels of antibody are very high.
a positive titre can disappear with immune senescence. As the immune
system ages it loses its memory and the antibodies to a virus disappear.
This is unlikely to occur with JCV as we believe that the virus
persists in the body and therefore it continues to stimulate the immune
system which overcomes this failing memory problem. I say believe as we
don't know if JCV persistence occurs in everyone; it is feasible that
some people clear the virus.
I see. As a matter of fact, I couldn't find any statistic about numbers
of people getting virus clear. Hope here in Italy hospital get this new
STRATIFY DxSelect by Biogen, just to be sure of the test. Thanks for the prompt reply.