Negative bloodwork - a showstopper?
Hi @ Lady, you raised an excellent point about whether one can have virus in tissues, but not in blood:
what if the virus is only in the CNS and brain and is gone from the blood?...can that happen?
From what I can discern of the available research, we just don't know that yet for XMRV. BUT we sure as heck do for some of the opportunistic viruses. Dr Ablashi, Scientific Director of the HHV-6 Foundation writes an excellent precis on the dangers of assuming that bloodwork is THE answer. He cites several specific instances of where tissue investigations are required (eg. PCR, immunohistochemistry) in lieu of bloodwork, in his letter to CFSAC:
http://www.hhs.gov/advcomcfs/meetings/presentations/ablashi_1009.pdf
One of his key points:
"The CDC has made several assumptions that we believe will prove to be in error:
1. The CDC has assumed that if a pathogen exists, it can be found in the serum"
Also:
"It is imperative that the CDC study biopsy samples from the gut, and brain as well as heart tissues, and
that they look at spinal fluid. Most of the studies done by the CDC have been on serum. However, many
pathogens cannot be found in the serum because they do not circulate in the peripheral blood after the
initial infection."
This diagnostic oversight is
absolutely vital for us patients to understand, because we're talking about chronic, years/decades long infections. Namely, when is bloodwork adequate, and when does it yield false negative results? Despite all the vampire hype in the media, blood isn't always all it's cracked up to be. Because false negative in bloodwork = no treatment.
Here are a few tidbits from my digging through the chronic Parvovirus B19 research, another known virus associated with ME, which is known to present diagnostic challenges with bloodwork:
Over-reliance on unreliable bloodwork: The Dangers
- From Harvard: In some low viremic states, parvovirus B19 DNA is detectable by nested PCR in plasma but not in serum. S. Kim Jacobson, Jennifer S. Daly, Grace M. Thorne, and Kenneth McIntosh. Chronic Parvovirus B19 Infection Resulting in Chronic Fatigue Syndrome: Case History and Review (From the Division of Infectious Diseases, Department of Pediatrics, Harvard Medical School). Clinical Infectious Diseases 1997; 24:104851 : http://www.journals.uchicago.edu/doi/pdf/10.1086/513627
- The diagnosis (of PVB19) is based on serology, bone marrow examination to demonstrate pure red cell aplasia, and PCR tests to demonstrate the presence of parvovirus B19 DNA in clinical specimens. Use of serology is limited due to failure to mount immune response in some patients. Schlossberg, David. Clinical Infectious Diseases. Part XI: The Susceptible Host, pp. 620-621. Cambridge University Press, May 2008. http://books.google.ca/books?id=-wW...m=23#v=onepage&q=acyclovir parvovirus&f=false
- immunocompetent individuals who have evidence of current or recent infection may lack detectable levels of B19 DNA in their blood when tested by PCR. Evidence to support this came from a study of 40 immunocompetent individuals, who were tested for B19 DNA by PCR. All had shown evidence of seroconversion, B19 IgM and B19 IgG positive. Of these 40, only 45%(18/40) contained B19 DNA using non-nested PCR, whereas the remaining 55% of samples were negative by PCR for B19V DNA. It is suggested that based on this data, PCR should not be used to detect B19V acute infection in immunocompetent persons. Diagnosing human Parvovirus B19 infection: Guidelines for test selection. Jordan J. Molecular Diagnosis 2001:6:307-312. See page 3 of URL: http://www.fifthdisease.org/cmsFiles/fifthdisease_human_literature_reveiw.pdf
- It is well known that the B19 genome can be detected in tissue without concurrent viremia as well as that negative serological test results during acute B19 infection can be seen in the first months after HSCT (hematopoietic stem cell transplantation) and It has to be noted that not all assays are capable of detecting the B19 genotypes 2 and 3. F Beske, S Modrow, J Srensen, H Schmidt, S Kriener, R Allwinn, T Klingebiel, D Schwabe and T Lehrnbecher , Parvovirus B19 pneumonia in a child undergoing allogeneic hematopoietic stem cell transplantation. Bone Marrow Transplantation (2007) 40, 8991; doi:10.1038/sj.bmt.1705693; published online 30 April 2007. http://www.nature.com/bmt/journal/v40/n1/full/1705693a.html
Here's an example of how this plays out for patients with ME and chronic PVB19. The reality emerges that legions of chronic PVB19 patients are denied proper diagnosis and further investigation as a result of flawed emphasis on bloodwork which may itself be flawed! To whit: my PCR for PVB19 was
negative in Canada, but my clinical presentation was
exactly like that of Kerr's PVB19 chronic fatigue patients. So while it may be well known in German cardiology circles that B19 genome can be detected in tissue without concurrent viremia, this is certainly not my experience in Canada, where it took 10 years of bull-headed insistence and a trip to Germany for a biopsy to prove that I had chronic PVB19.
