Detection of viral and bacterial protein in endomyocardial biopsies of patients with inflammatory heart muscle disease?

Abstract

The development of highly sensitive molecular biological methods such as in-situ hybridization and polymerase chain reaction (PCR) made it possible to detect viral/bacterial nucleic acid in human endomyocardial biopsies. However, only a few investigations addressed the problem of latent persistence of viral and bacterial genome and the detection of the corresponding proteins, which could have important consequences for the clinical course of the disease. The purpose of this study was to determine whether protein of various viruses (adenovirus, enterovirus, cytomegalovirus, influenza A and B virus, herpes simplex virus 1 and 2) and bacteria (chlamydia pneumonia) can be detected in endomyocardial biopsies of patients with myocarditis and dilated cardiomyopathy with and without inflammation by use of an immunofluorescence assay and to compare the frequency of its detection with the results of PCR, immunohistology and serology. Thirty-nine patients with myocarditis and dilated cardiomyopathy with and without inflammation were examined by a direct immunofluorescence assay using the endomyocardial biopsy as antigen. Each of the samples was additionally studied by immunohistological methods and PCR for the detection of infiltrating cells and the genome of cardiotropic viruses or bacteria. Fourteen of patients were considered to have myocarditis (group 1), 9 dilated cardiomyopathy with inflammation (group 2), 10 dilated cardiomyopathy (group 3), 6 to have no myocarditis or dilated cardiomyopathy (group 4). Using a direct immunofluorescence assay we could show only that 1 patient without histological myocarditis or dilated cardiomyopathy (group 4) was positive for influenza B and chlamydia pneumonia antigens in the endomyocardial biopsy. In addition we have determined influenza B-specific antibodies, such as IgG (marginal titer) and IgA (high titer) and chlamydia pneumonia-specific antibodies, such as IgG (marginal titer) in serum of this patient. A second patient with dilated cardiomyopathy was found to be positive for protein of chlamydia pneumonia, who was shown to have chlamydia pneumonia-specific antibodies, such as IgG (high titer) in serum. There was no correlation with PCR results, but good correlation with influenza B and chlamydia pneumonia-specific antibodies in sera of these patients. In this investigation we have determined viral/bacterial-specific antibodies using serological methods and proteins of these agents using immunoflourescence. Despite the detection of virus or bacteria-specific antibodies in the sera and detection of viral and/or bacterial protein in the biopsies of some of the patients viral and/or bacterial genome was not found in the biopsy. This may be explained by the focal character of myocarditis and sampling error, because for technical reasons we use different biopsies for immunohistochemical and molecular biological investigations.