Human herpesvirus 6 is thought to play a role in several neurological diseases. A recent technical report from the National Institutes of Health, Bethesda describes the development of novel techniques capable of detecting antibodies to HHV-6 infection, and the use of these techniques to examine blood serum samples from ME/CFS patients and healthy controls.

Overall, seropositive HHV-6A antibody responses were found in 13.5% of control samples and 9.7% of ME/CFS samples, while the equivalent figures for HHV-6B were 76 and 75%, respectively. There was, therefore, no evidence of increased infection with (or serum antibodies directed against) HHV-6 in CFS patients compared with healthy people, although immune responses to HHV-6B were highly prevalent in the general population.

Does this mean that we can exclude HHV-6 as a causal or maintaining factor in ME/CFS? Well, no – we’re still far from that stage. Results of studies can differ depending on whether testing is for active infection, for the presence of antibodies only, or for reactivation of latent infection. In fact, the real importance of HHV-6 might lie in how it associates with other co-infecting viruses, such as parvovirus B19, to impair the immune function of the patient, as Latvian researchers suggested in 2012.

Reference: No serological evidence for a role of HHV-6 infection in chronic fatigue syndrome. Burbelo et al., Am J Transl Res 2012; 4(4): 443-51.