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HHV-6A Found in 22% of ME/CFS Patients' PBMCs, but in Only 4% of Healthy Controls'


Senior Member
In 2012, the International Committee on Taxonomy of Viruses classified HHV-6A and HHV-6B as separate viruses (prior to that they were considered subtypes of HHV-6). Ref: 1

However, even though HHV-6A is a distinct and separate virus, since nearly all HHV-6 tests cannot distinguish between HHV-6A and HHV-6B, and since HHV-6 is found in nearly everybody (so nearly all HHV-6 tests are going to come back positive for having the virus), by standard labs tests, it is hard to know whether you might have HHV-6A or not.

According to the HHV-6 Foundation, testing laboratories that can detect HHV-6A include:

• Viracor-IBT Laboratories — HHV-6 Quantitative Real-time PCR

• Focus Diagnostics

• Wisconsin Viral Research, who have now become Coppe Labs.

HHV-6A seems to be a significant virus for ME/CFS:

One study of 36 ME/CFS patients and 24 healthy controls found HHV-6A in the peripheral blood mononuclear cells (PBMC) of 22% of ME/CFS patients, but only in 4% of healthy controls.

This study of 13 ME/CFS patients and 13 healthy controls found HHV-6A in the PBMCs of 31% of patients, HHV-6B in the PBMCs of 23% of patients, and no HHV-6A nor HHV-6B found in the PBMCs of healthy controls.

However, although the above studies found little to no HHV-6A or HHV-6B in the PBMCs of healthy controls, somewhat confusingly, this study of healthy individuals found HHV-6A in 16% of subjects' PBMCs, and HHV-6B in 98% of subjects' PBMCs.

Some HHV-6A Info

HHV-6A is a more neurotropic virus than HHV-6B.

HHV-6A is acquired later in life, usually without clinical symptoms, except in Africa where HHV-6A is more prevalent than HHV-6B in children. Ref: 1

HHV-6A may act a cofactor with HIV in the progression to AIDS, since progression to full-blown AIDS is dramatically accelerated by HHV-6A. Ref: 1

HHV-6A is more prevalent in multiple sclerosis, an autoimmune disorder. Ref: 1

HHV-6A is associated with Hashimoto's thyroiditis, an autoimmune disorder. Ref: 1

It is only possible to differentiate HHV-6A from HHV-6B using a PCR DNA test. Ref: 1

HHV-6A may gain entry into the brain via the olfactory pathway. Ref: 1

HHV-6A has been found to persist in the spinal fluid long after it has disappeared from the plasma. Ref: 1

HHV-6A is more likely to be found in the spinal fluid or serum, whereas HHV-6B is more likely to be found in the white blood cells and in the saliva. Ref: 1

HHV-6A is not found in the saliva, ref: 1 2 (although this study says it is).
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Senior Member
One additional point:

Almost all of us will have picked up HHV-6B by the age of 2. This means that HHV-6B is very unlikely to be a triggering virus for ME/CFS. This is because most people come down with ME/CFS later in life, in their teens, 20s, 30s and 40s typically, long after we have caught HHV-6B as an infant.

By contrast, HHV-6A when caught is picked up later in life. So this means that HHV-6A might be a candidate for a triggering virus of ME/CFS. By a triggering virus, we mean a virus that gives you an acute infection, soon after which you come down with ME/CFS.

Of course, even though HHV-6B is already in most of us by the age of 2, it could still play a causal role in the development of ME/CFS; however, because we already have in our body from the age of 2, HHV-6B cannot be a triggering virus of ME/CFS.

So this makes HHV-6A more interesting from the ME/CFS perspective: because it is found in much higher prevalence in the PBMCs of ME/CFS patients; and because as it is caught later in life, it might be triggering ME/CFS.


Senior Member
I know that Dr. Peterson is able to identify a subset of his ME patients (around 20%) who really just have a very active HHV6A infections. This group tends to have dramatic clinical improvements. However he checks blood, CSF, and tissue for confirmation.


Senior Member
I really wish we had better testing and drugs for this. I really want to try this avenue of attack for my moderate CFS. My dad had bell's palsy and I had very light bell's palsy symptoms. He's not my genetic dad but I was with him since I was a baby. I get hives with light exercise/heat. Might be HHV.

Will that super fast virus testing thing be helpful here? Anyone have any updates on that?

This one: http://www.cortjohnson.org/forums/t...-test-to-find-all-known-viruses-at-once.3060/