Search

Chronic viral infections of the heart are considered one antecedent event leading to progressive dysfunction of the myocardium, often with an impaired prognosis due to a virus- or immune-mediated myocardial injury. Symptomatic treatment does not influence the viral cause of heart failure, and the effect of antiviral treatment has not been determined, yet.In this phase II study 143 patients with symptoms of heart failure and biopsy-based confirmation of the enterovirus (EV), adenovirus, and/or parvovirus B19 genomes in their myocardial tissue were randomly assigned to double-blind treatment, and received either placebo (n = 48) or 4 × 10(6) (n = 49) and 8 × 10(6) IU (n = 46) interferon beta-1b (IFN-β-1b) for 24 weeks, in addition to standard heart failure treatment. Patients with active myocarditis or other specific causes of heart failure were excluded. Compared to placebo, virus elimination and/or virus load reduction was higher in the IFN-β-1b groups (odds ratio 2.33, p = 0.048), similarly in both interferon groups and both strata. IFN-β-1b treatment was associated with favourable effects on NYHA functional class (p = 0.013 at follow-up week 12), improvement in quality of life (Minnesota Heart Failure score; p = 0.032 at follow-up week 24) and patient global assessment (follow-up week 12 to follow-up week 24; p = 0.039). The frequency of adverse cardiac events was not higher in the IFN-β-1b groups compared to the placebo group.Immunomodulatory IFN-β-1b treatment is a well-tolerated and safe treatment option, leading to effective virus clearance or reduction of the virus load in patients with chronic viral cardiomyopathy. Favourable clinical effects assess quality of life, NYHA functional class, and patient global assessment. ClinicalTrials.gov identifier: NCT001185250.

The role of endomyocardial biopsies in patients with clinically suspected acute myocarditis, myocarditis in the past, and dilated cardiomyopathy is discussed controversially. In fact, it is still under discussion whether information obtained from endomyocardial biopsies is relevant for further clinical decisions. Therefore this Critical Perspective will deal with the question, which patient should undergo endomyocardial biopsy investigations for an etiopathogenic differentiation of the disease and for the possible choice of immunomodulatory treatment strategies.

Severe combined immune deficiency (SCID) mice have been used as an animal model to study both the direct cytopathic effect of enteroviruses on the heart in the absence of an effective immune system and to investigate the role of immune mediated processes in the pathogenesis of human myocarditis. The infection of SCID mice with coxsackievirus B3 resulted in severe myocarditis with very high titers of the virus in the myocardium and severe necrosis of myocytes. This direct cytopathic effect caused an impairment of the myocardial function and resulted in a high mortality rate of the infected animals. For the study of the immune mechanisms in human myocarditis, peripheral blood leukocytes of patients with myocarditis, having an impaired left ventricular function without viral persistence in the myocardium, were transferred into SCID mice. As controls peripherals blood leukocytes of normal donors were used. At 60 days after transfer, human immunoglobulines could be demonstrated in the peripheral blood of the SCID mice, however, human autoantibodies against the adenine nucleotide translocator, a myocardial autoantigen, were only present in the animals receiving peripheral blood leukocytes from patients with myocarditis. Cellular infiltrates of human leukocytes in the myocardium and an impaired left ventricular function were also only observed in animals reconstituted with peripheral blood leukocytes from patients. These effects were T cell dependent as shown by differential transfer. These results are of interest for the treatment of human myocarditis, suggesting the avoidance of an immunosuppressive therapy in acute or chronic myocarditis with viral persistence to prevent a direct cytophatic effect in the absence of an effective immune system. However, in the setting of a chronic, (auto-)immunological myocarditis with the proven absence of entero- or adneoviral sequences an immunomodulatory therapy seems to be effective and safe.