A new study from Italy indicates that HHV-6 reactivation is selectively increased among patients suffering from autoimmune connective tissue diseases (ACTD). Low levels of HHV-6 DNA were detected in the serum of 26% of ACTD patients, which was significantly greater than that observed amongst controls (P < 0.0002). The authors used a highly sensitive assay and the median viral load for these patients was under 100 copies/ml, which would fall below the current level of detection at most clinical laboratories. The group also found a significant association between HHV-6 reactivation and the active disease state for lupus erythematosus (P = 0.021). By contrast, the rate of EBV viremia was similar in patients and controls groups, while CMV, HHV-8, and parvovirus B19 viremia was not detected in any subject.
In the paper, published in the Journal of Medical Virology this month, the group evaluated samples from 115 patients affected by different autoimmune connective tissue disorders. They found HHV-6 viremia in systemic sclerosis (27%), systemic lupus (36%), discoid lupus (32%). The prevalence for rheumatoid arthritis and dermatomyositis was between 10-20%, compared to 6.6% of 105 healthy controls and patients with other inflammatory diseases. In addition, HHV-6 and anti-EBV early antigen IgG titers were both significantly elevated among ACTD patients as compared to healthy controls.
The group previously published a study linking HHV-6A to Hashimoto’s Thyroiditis (HT), an autoimmune disorder that is the most common of all thyroid diseases (Caselli 2012). The authors conclude that their data does not offer a definitive answer on whether HHV-6 acts as a pathogenic factor predisposing patients to the development of some prominent autoimmune diseases or, conversely, or if these disorders may predispose patients to HHV-6 reactivation.
For more information, read the full paper.