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.
More information on HERV-K18 here.
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
http://www.journalofclinicalvirology.com/article/S1386-6532%2809%2900194-2/abstract
Brigitte Huber on HERV-K18
Has HIV mistakenly been blamed for the HERV issues in AIDS, when HHV-6A is the culprit? This paper may be missing the forest for the trees:
The replicative activity of human endogenous retrovirus K102 (HERV-K102) with HIV viremia
Laderoute, Marian P; Giulivi, Antonio; Larocque, Louise; Bellfoy, Deana; Hou, Yangxun; Wu, Hong-Xing; Fowke, Keith; Wu, Jun; Diaz-Mitoma, Francisco
AIDS:30 November 2007 - Volume 21 - Issue 18 - p 2417-2424
Superantigens are proteins that are able to induce a strong undifferentiated T-cell response believed to deplete the immune system over time. They may be a serious problem for everyone who has an illness on the HHV-6 Spectrum, which includes AIDS, Chronic Fatigue Syndrome, Autism and many others.
The destructivenss of superantigens may be another reason that HHV-6 needs to be treated and controlled in AIDS, Chronic Fatigue Syndrome and autism.
Wikipedia Background on Superantigens
Superantigens: The Good, the Bad, and the Ugly
Barbara A. Torres, Scott Kominsky, George Q. Perrin, Amy C. Hobeika and Howard M. Johnson
Experimental Biology and Medicine 226:164-176 (2001)