Virome Sequencing in Patients With Myocarditis.

Area of Science:

• Virology
• Cardiology
• Immunology

Background:

• Viral sequences are detected in up to 67% of myocarditis cases using PCR on cardiac tissues.
• Viruses have not been implicated in giant cell myocarditis (GCM).
• Detecting myocarditis-associated viruses in peripheral blood has been unsuccessful.

Purpose of the Study:

• To investigate the presence of viruses in patients with myocarditis using a comprehensive screening method.
• To determine if viruses play a role in giant cell myocarditis (GCM) and fulminant myocarditis.
• To analyze viral presence in various sample types, including blood and cardiac tissues.

Main Methods:

• Utilized Virome Capture Sequencing for Vertbrate Viruses (VirCapSeq-VERT) for simultaneous screening of all known vertebrate viruses.
• Analyzed peripheral blood mononuclear cells, plasma, endomyocardial biopsies, and cardiac tissue samples from 33 myocarditis patients.
• Included patients with GCM (n=9) and fulminant myocarditis (n=4).

Main Results:

• Human endogenous retrovirus K (HERV-K) was detected in 100% of blood samples and all tissue samples from GCM and fulminant myocarditis.
• Epstein Barr virus (41%), anellovirus (56%), and human pegivirus (4%) were found in blood samples of myocarditis patients.
• No nucleic acids from previously implicated myocarditis viruses were found in GCM cardiac tissues or other myocarditis blood samples.

Conclusions:

• The findings suggest HERV-K is prevalent in GCM and fulminant myocarditis tissues.
• The absence of known viral pathogens in GCM cardiac tissue and other myocarditis blood samples challenges traditional viral etiology theories.
• While not excluding a viral role in GCM, the mechanism may be indirect, not direct cytotoxic infection.