Incidence of human herpesvirus 6 in clinical samples from Swedish patients with demyelinating diseases.

BACKGROUND

Human herpesvirus 6 (HHV-6) has been reported to be associated with multiple sclerosis (MS) and Guillain-Barré syndrome (GBS).

METHODS

We analyzed cell-free HHV-6 DNA as an indication of active infection in the peripheral blood and cerebrospinal fluid (CSF) of Swedish patients with GBS, patients with chronic inflammatory demyelinating polyradiculoneuropathy, treatment-naïve patients with possible MS, interferon-β treated MS patients [with or without neutralizing antibodies (NAbs)], and control patients with headache.

RESULTS

One of 14 GBS patients and one of eight patients with chronic inflammatory demyelinating polyradiculoneuropathy were positive for HHV-6 DNA in serum. Of the 27 treatment-naïve possible MS patients, two were positive in plasma and one in CSF. HHV-6 DNA was detected in the serum of three of 79 NAb+ patients and one of 102 NAb-interferon-β treated MS patients. HHV-6 DNA could not be detected in the plasma or CSF of any of the 33 controls, although the differences were not statistically significant.

CONCLUSION

Our results do not suggest active HHV-6 infection to be a common phenomenon in any of the patient groups studied.