Increased detection of serum HHV-6 DNA sequences during multiple sclerosis (MS) exacerbations and correlation with parameters of MS disease progression

Abstract
In recent years, human herpesvirus 6 (HHV-6) has been investigated as a possible causative agent for MS. To determine if the detection of HHV-6 DNA in the serum of MS patients correlates with clinical parameters of MS disease progression, a total of 215 serum samples was obtained from 59 MS patients followed prospectively for a 5-month period. These samples were analyzed for the presence of HHV-6 DNA by nested PCR and compared in parallel to MS disease activity. HHV-6 DNA was amplified in 22% (4/18) of samples obtained during a period of clinical exacerbation. Significantly fewer (P = 0.008) sera, 5.6% (11/197), obtained from MS patients during clinical remission tested positive for the presence of HHV-6 DNA. This work demonstrates that the detection of serum HHV-6 DNA is significantly correlated with clinical exacerbations in MS. Moreover, the findings presented in this study have confirmed previous reports supporting an association between MS and HHV-6 and suggest a role for this human herpesvirus in the pathogenesis of MS.