Posted 2/2/2016 9:02 PM (GMT 0)
IgM antibodies in most diseases indicate a recent or acute infection. But Lyme is different. Because the Lyme borrelia practises many tricks to evade the immune system, eg antigenic variation, your body can produce IgM antibodies to proteins on the surface of the organism even though you have had the infection for years. These tricks can make the Borrelia appear "new" to your immune system.
In short, the Denialists claim that if you have only IgM positive results and not IgG, and have been ill for a long time, that it can't be Lyme. This is nonsense - the Denialists themselves long ago admitted that IgM can appear late in the illness. Then they just quietly didn't mention ithat fact anymore.
Also, please bear in mind that Bb sensu stricto is a lab strain which may be very different to what is actually in people's bodies. None of the serology tests in common use detect Borrelia miyamotoi, and in general serology is an insensitive method that cannot rule out Lyme.
Elena