Human herpesvirus 6-induced inflammatory cardiomyopathy in immunocompetent children

Area of Science:

• Cardiology
• Virology
• Pediatrics

Background:

• Human herpesvirus 6 (HHV-6) is increasingly linked to pediatric myocarditis and dilated cardiomyopathy (DCM).
• The precise role and pathogenic significance of HHV-6 in the heart remain under investigation.
• HHV-6 is detected in both affected children and healthy controls, complicating etiological determination.

Purpose of the Study:

• To review the literature on HHV-6 in pediatric inflammatory cardiomyopathy.
• To analyze cases of HHV-6 associated pediatric myocarditis and DCM.
• To discuss the diagnostic challenges and potential pathogenetic role of HHV-6 in the myocardium.

Main Methods:

• Literature review of pediatric cases with HHV-6 and myocarditis/DCM.
• Electron microscopy analysis of endomyocardial biopsy samples for HHV-6 particles.
• Discussion of diagnostic techniques like quantitative PCR and mRNA testing.

Main Results:

• Eleven published cases of pediatric myocarditis/DCM associated with HHV-6 were reviewed.
• Electron microscopy detected HHV-6 particles in the vascular endothelium of affected biopsy tissues.
• The viral load and presence of HHV-6 in cardiac tissue are controversial due to findings in healthy individuals.

Conclusions:

• HHV-6 should be considered a potential causative agent in pediatric inflammatory cardiomyopathy, particularly in primary infections in young children.
• Distinguishing between latent and active HHV-6 infection is crucial for understanding its role.
• Further studies are required to establish diagnostic thresholds and investigate the impact of coinfections with other cardiotropic viruses.