I have a high IgG titre (1:1280) for HHV-6 but have proved negative by PCR. I have plenty of neurocognitive and immunosuppression symptoms (brainfog, poor memory, poor concentration, dysgraphia, dyscalculia, frequent infections), which are consistent (as I understand it) with active or reactivated HHV-6. I've read on the HHV-6 Foundation site that it's possible to have an active infection, including one in the brain, without being positive by PCR. I'd like some published evidence/rationale on this to discuss with my doctor. I've been listening to the pre-FDA workshop recordings and at the end of the third recording (28 minutes), Nancy Klimas says that one of Konnie Knox's papers showed that in relation to HHV-6, spinal fluid didn't correlate with blood so if you had it in your brain the virus (not antibody) didn't necessarily show up in your blood, and vice versa. She also said that Konnie's early papers showed that HHV-6 was a 'here and gone, here and gone' thing and that if you looked at people once about half were PCR positive but if you looked at them longitudinally, over 3-4 blood draws you could bring that up to 85% or so. Can anyone refer me to the relevant papers by Konnie (or anyone) on these issues? Also, a question (from the medically pig-ignorant): If there's an infection in the brain, wouldn't it be in the circulating blood in the brain and hence also measurable in the blood in the body? Isn't blood all one big circulating system?