Objective: The possible role of Human Herpes Virus-6 in cardiac disorders in childhood was explored in a retrospective study on archival specimens of explanted hearts.
Methods: 16 children (median age at transplantation 11.0 years) with idiopathic dilated cardiomyopathy (DCM) and 19 children (median age at transplantation 1.0 year) with congenital heart disease (CHD), previously found negative for other cardiotropic viruses such as Enteroviruses, Adenovirus, Parvovirus B19, CMV, and EBV, were tested for HHV-6 by quantitative Real-Time PCR and by genotyping. In addition, HHV-7/8 infection was investigated by qualitative PCR.
Results: HHV-6 B variant was detected in 11 out of 35 samples (31.4%) with a mean viral load of 3.15 x102 copies/µg of cellular DNA. When assessed by heart disorder, the prevalence was different in the two groups (i.e. 43.7% in DCM and 21% in CHD) while the mean viral loads were similar. In a logistic multivariate analysis HHV-6 was independently associated with DCM taking CHD as reference and adjusting for age (best estimate: OR 6.94, 95% C.I.: 1.00-49.76, p=0.05).
Conclusions: Although the clinical significance of our finding is unknown, we frequently detected HHV-6 B genome in explanted hearts from children with DCM and to a lesser extent with CHD, thus adding evidence of the HHV-6 cardiac involvement.