question about HERV k18


Senior Member
Hey I am sure those of you in the know have already digested this and put it in its proper place but I was unaware of it, could anyone please explain to me where this fits in? I know the PA didnt like how Huber acted at the Invest in ME conference so I am assuming this isnt a big link but what I dont get is why herv-k18 is called a retrovirus when supposedly there are only 3 retrovirues, usually its hiv, xmrv and the htlvs I believe, anyway the info:

HHV-6 and CIHHV-6 may cause AIDS and Chronic Fatigue Syndrome by activating HERV-K18 which acts as a superantigen capable of bring down the whole immune system.

HHV-6A infection induces expression of HERV-K18-encoded superantigen
"The human endogenous retrovirus K-18 (HERV-K18) encodes a superantigen that causes deregulation of the immune system. This provirus is transcriptionally silent, but can be induced by Epstein–Barr virus (EBV) infection and IFN-α treatmen" --Albert K. Taia, Janos Lukab, Dharam Ablashic, Brigitte T. Huber


disjecta membra
Los Angeles, CA
Exogenous retrovirus = the contagious kind. Only three currently known to infect humans but there are a larger number known to infect various animals.

Endogenous retrovirus = the kind you're born with. Because a retrovirus copies itself into your DNA, occasionally throughout millions of years of evolution, retroviruses have gotten themselves into human genes and become heritable. It is not at all clear yet whether these 'leftover' retroviruses can actually cause disease. At the time this New Yorker article was written (2007), it didn't seem yet that they could, but research is ongoing and there is lots of controversy. (This article also doesn't mention XMRV, but it is a good explanation of what an "endogenous retrovirus" is.)



Senior Member
England (south coast)
Hi xrayspex,

I recently watched Brigitte Huber's presentation (which I thought was very interesting) on the Invest in ME 2010 conference DVD, so I know a bit about her research now.

Endogenous Retroviruses

An endogenous retrovirus was once an infectious exogenous retrovirus which, during the history of human evolution, managed to insert its own genetic code directly into the human genetic code (i.e. the virus permanently inserted its own DNA into our DNA). In order to achieve this, the retrovirus would have to infect human germline cells (cells that make a female's eggs or a male's sperm), and get transmitted to an infected person's offspring, and descendants, via the DNA in the germline cells (sperm or egg). These endogenous viruses are now part of our own genetic code, rather than being a separate infectious entity, so they are referred to as endogenous, not exogenous.

Retroviruses work by inserting their own genetic code directly into our DNA in the cells which they infect. If a virus manages to infect a sperm or egg cell, then this will transmit the virus DNA directly to the DNA of the embryo, just in the same way as our own genetic code is transmitted to the embryo (because the virus DNA is inserted into our own DNA in the sperm or egg cells). This means that every single cell of the embryo, and then the new-born baby, is infected with the virus DNA. Some embryos or babies won't survive this process as the virus DNA harms them, and this is the evolutionary process. The survivors of this process were the ones whose lives and health were not adversely affected by the virus DNA, because of their genetic resistance to it, and as such, they then directly transmitted the virus DNA to their descendants (us), along with their own genetic resistance. It is this process of evolution that means that only those who were not adversely affect by the virus DNA (the survivors) then passed down the virus DNA along with their own resistant human DNA. This is why endogenous retroviruses mostly do not cause disease. Also, over the years, the code of endogenous retroviruses has been broken up and weakened.

Endogenous retroviruses are thought to make 8% of our DNA. We all carry them as part of our genetic code. They are thought to be mainly inactive, and some of their DNA actually codes for beneficial mechanisms involving, for example, our immune system. They are part of our species' evolutionary journey.

There is ongoing research, by various researchers, to see if endogenous retroviruses can contribute, or cause, some diseases such as ME/CFS, MS and Schizophrenia (There maybe other diseases being looked at as well).

Brigitte Huber

Brigitte Huber is looking at how certain viral infections can upregulate a specific section of code of the HERV-K18 DNA. This section codes for the 'superantigen', which interferes with our immune system. She is currently looking at this process in CFS/ME patients who have the EBV virus. EBV is the Epstein-Barr virus which causes infectious mononucleosis, known as glandular fever in the UK.

She is looking at how upreguation of the HERV-K18 superantigen gene, in ME/CFS patients infected with EBV virus, might correspond to the severity of symptoms.

EBV is also known as the HHV-4 virus, but it appears that Huber has also worked on HHV-6 in the past, which I didn't know about.

HHV-6 and CIHHV-6 may cause AIDS and Chronic Fatigue Syndrome by activating HERV-K18 which acts as a superantigen capable of bring down the whole immune system.

I can't see where you got this quote from, so I don't know what context it is taken from, but it appears to be suggesting that HHV-6 can upregulate the HERV-K18 superantigen gene to such an extent that it may cause a person to suffer from ME/CFS, and a person with HIV to suffer from AIDS, due to its disruptive effect on the immune system.

xrayspex, this all became really complicated once I started writing it, so if I haven't explained it very clearly, then please feel free to ask me any questions, and I'll do my best to answer.

If you are interested, you can see my review of the Invest in ME conference DVD, which includes a more detailed review of Brigitte Huber's presentation, here:

Wikipedia article about Endogenous retroviruses: