Diagnosing infections in myocardial biopsies: Interview with Cardiologist Uwe Kühl and IKDT Lab Director Dirk Lassner

In All, Featured, Heart Disease by hhv6foundation

The cardiology clinic at the Campus Benjamin Franklin, Charité – University Medicine Berlin is recognized as leading center for using state-of-the art mRNA analysis to diagnose active infections the biopsy tissue of myocarditis and heart failure patients. Uwe Kühl has published a number of important papers on the subject of viral persistence in progressive cardiac dysfunction, including a recent paper demonstrating that heart failure patients with active ciHHV-6 improved on antiviral therapy. Dirk Lassner is laboratory director of IKDT, the lab that performs their virology testing.

Q: Of the patients you treat for pathogen-triggered myocarditis at your clinic, approximately what percentage improve?

Interferon-beta treatment of patients with myocardial infections by adenoviruses or enteroviruses results in a nearly 100% elimination of virus associated with an improved short and long-term outcome. Treatment of erythrovirus infection by type I interferon or replication inhibitors do not eliminate the virus. Despite limited data, improvement of clinical symptoms has been reported in about 20-30% of treated patients. Our patients with chromosomally integrated ciHHV-6 (n=10) improved clinically upon ganciclovir treatment with rapid recurrence of symptoms (within days) after interruption of treatment.

Q: At your clinic, what is the rate of serious complications from endomyocardial biopsies in patients with myocarditis?

In an earlier publication from our clinic (Holzmann 2008) we have shown that endomyocardial biopsy (EMB) is safe if performed by well-trained cardiologists. During an 11-year-period (1995-2005) we performed 3,048 EMBs from 2,415 patients (26,025 biopsies, 8.2+/-0.8 EMBs/patient). No patient died, no emergency treatment. The major complication rate was very low ( 0,12% tamponade and AV-block with permanent defibrillator support) and a minor complication rate included 0.20% PE, conduction disorder, or arrhythmias). In another corresponding paper from an Italian group Frustaci and colleagues also reported their experience from about 4,000 left and/or right ventricular biopsies that EMB is a safe procedure (Frustaci 2013).

Q: Why have other countries been so slow to adopt your approach of using a biopsy to diagnose myocarditis infections and treat with the appropriate therapy (IVIG for parvovirus B19, interferon for enterovirus, ganciclovir for CMV or HHV-6, etc)?

Acceptance of EMB to diagnose myocarditis and dilated cardiomyopathy has been low due to missing therapeutic options and missing data on clinical consequences. In the last 5-8 years, different treatment approaches have been established and several papers have been published on improved outcome after successful treatment. Today at least one therapeutic option for the most frequent cardiotropic viruses exists (HHV-6, ciHHV-6, enterovirus, adenovirus) .

Consequently, the international consensus on EMBs has changed in the recent past. Since 2007 we have an international recommendation for diagnostic biopsies in patients with non-ischemic myocardial diseases (Cooper, 2007). In 2013 the European Society of Cardiology (ESC) published a statement for the diagnosis of myocarditis citing EMB as the gold standard to confirm viral or inflammatory heart diseases (Carforio, 2013).

Q: Your HHV-6 mRNA test is unique in Europe. To our knowledge, no other center offers a test that can distinguish active from latent HHV-6 infection, which is critical information for making a decision to treat a patient with inherited ciHHV-6. Does IKDT offer this test to other physicians and hospitals in Europe? If yes, can you describe the procedure to send a sample?

IKDT offers its EMB diagnostics (accredited by the College of American Pathologists) including molecular biological virus analyses in tissues, blood or other body fluids to a number of hospitals and centers in Germany, Europe and overseas.

For fixation of tissues or cells we recommend RNAlater as fixative (PAX tubes for whole blood). EDTA tubes for whole blood cells, transported overnight by mail or express services are also suitable for most diagnostic question. For serum, plasma, or cell culture supernatants (especially for virus genome analyses) we recommend sample preparation in the submitting institution and transport of samples on dry ice to IKDT lab.

Q: In your recent paper, you described treating patients with ciHHV-6 and active HHV-6 infections with valganciclovir. Have you treated non-ciHHV6 patients for active HHV-6 infection?

We have not treated non-ciHHV6 patients with valganciclovir.

Q: In a case report, Leveque et al describe a patient who died of HHV-6 myocarditis , in spite of no abnormal findings in the peripheral blood. They concluded that frozen cardiac tissues are required to identify pathogens in chronic myocarditis. They found that the DNA was too degraded to be reliable in paraffin embedded samples. Do you agree with this?

Today we recommend fixation of myocardial tissue in fixative RNAlater directly after taking endomyocardial biopsies (EMB). The former standard was shock freezing of EMB in liquid nitrogen, but this approach is not very suitable for daily clinical routine EMB in catheritization laboratories.

We tested different recommended tests for extraction of DNA from paraffin embedded biopsies, but if DNA was isolated, there was no correlation of virus load between native heart muscle tissue and DNA extracted from paraffin embedded samples. FFPE extracted DNA contains only minute amount of DNA and virus detection is impossible even in tissue samples with extremely high genome numbers.