In situ detection of enteroviral genomes in myocardial cells by nucleic acid hybridization: an approach to the diagnosis of viral heart disease

We have developed an in situ hybridization assay capable of detecting enteroviral RNA in myocardial cells, using molecularly cloned coxsackievirus B3 cDNA as a diagnostic probe. Because of the high degree of nucleic acid sequence homology among the numerous enteroviral serotypes, including the group A and B coxsackieviruses and the echoviruses, detection of these various agents commonly implicated in human viral heart disease is possible in a single hybridization assay. We demonstrate the considerable potential of this method for an unequivocal diagnosis of enteroviral heart disease as well as for pathogenicity studies. Using athymic mice persistently infected with coxsackievirus B3 as a model system, we show that the myocardium is affected in a disseminated, multifocal manner.

[Primary and secondary chylopericardium]

Primary chylopericardium proved to be the (rare) cause of chronic, symptom-poor pericardial effusion in a 19-year-old man. Echocardiography and pericardiocentesis provided a firm diagnosis. Lymphography demonstrated extravasation into the mediastinum but no direct connection into the pericardial sac. Ligation of the thoracic duct at diaphragmatic level and pericardiostomy achieved a cure. Secondary chylopericardium requires treatment of the underlying disease, e.g. mediastinal tumor. Chylopericardium after thoracic or cardiac operation without signs of tamponade is preferably treated conservatively by pericardiocentesis and diet.

Coxsackie B3 virus can replicate in cultured human foetal heart cells and is inhibited by interferon

Coxsackie B viruses (types 1 to 5) are the most frequent reported cause of acute viral myocarditis. To study the pathogenesis of the disease at the cellular level, we simulated an infectious situation by infecting cultured human foetal heart cells with Coxsackie B3 (CB3) virus. Successful replication of this virus could be demonstrated by the presence of virus particles inside cultivated foetal myocytes together with high titres of progeny virus of 10(8) plaque-forming units (PFU) per millilitre culture medium. Within 9 h of infection networks of myocytes lost their ability to contract spontaneously followed by disintegration and replacement by overgrowing fibroblasts which survived the infection. These cells produced CB3 virus continuously over several months, indicating carrier state infection of human myocardial fibroblasts. Human fibroblasts interferon (IFN-beta) was found to act as a potent inhibitor of the replication of this virus. Virus yields could be reduced from 1.2 x 1.8 x 10(5) PFU/ml culture medium when human heart cells were incubated with IFN-beta 20 h prior to challenge with a high input multiplicity of 50 PFU of CB3 virus per cell, demonstrating the major protective role of IFN-beta in CB3 viral infection. It thus appear that IFN-beta might become useful as an antiviral agent in the treatment of Coxsackie myocarditis.