HHV-6 and HHV-7 in Cardiovascular Diseases and Cardiomyopathies

Human herpesvirus 6 (HHV-6) and HHV-7 are ubiquitous human pathogens with lymphotropic and neurotropic potential. Both viruses infect cells that express the CD46 complement receptor. Based on their biological properties and their receptor-dependent cellular tropism, HHV-6 and HHV-7 are detected in cells of different organs and consequently associated with various diseases. In addition to modulation of immune responses, HHV-6 and HHV-7 can directly infect endothelial cells and subsequently enter adjacent tissues. If the cardiovascular system is affected, HHV-6 and HHV-7 infections can be causative for myocarditis, vasospastic endothelial dysfunction, and development of post-infectious or post-inflammatory cardiomyopathies. Reactivation of HHV-6 is often associated with a higher percentage of chest pain, while inhibition of viral RNA is associated with clinical improvement of treated patients. This may be a therapeutic option for HHV-6-positive patients with unexplained cardiac symptoms.