[Enteroviral myocarditis and dilated cardiomyopathy]

Proteome alterations in human host cells infected with coxsackievirus B3

Coxsackievirus B3 (CVB3) is a common factor in human myocarditis. The interplay between host factors and virus components is crucial for the fate of the infected cells. Despite that, host protein responses, which characterize CVB3-induced diseases, have not yet been determined in detail. To investigate the nature of modified protein patterns in infected human cells compared with uninfected cells, two-dimensional gel electrophoresis in combination with matrix-assisted laser desorption/ionization-mass spectrometry were used. The regulated proteins, e.g. nucleophosmin (nucleolar protein B23), lamin, the RNA-binding protein UNR and the p38 mitogen-activated protein kinase, were sorted according to their functional groups and interpreted in the context of the myocarditis process.

Lympho-monocytic enteroviral myocarditis: traditional, immunohistological and molecularpathological methods for diagnosis in a case of suspected sudden infant death syndrome (SIDS)

A 7-month-old boy was found lifeless in his bed by his grandfather. Near the mouth there were some blood and chyme on the bedlinen. His mother reported a chill during the last 8 days. Autopsy revealed multiple petechia under the capsule of the thymus, subepicardially and subpleurally, the cause of death was tentative supposed to be a sudden infant death. Histologically parts of the myocardium showed a lympho-monocytic myocarditis according to the DALLAS-criteria. Immunohistological investigations demonstrated an enhanced expression of MHC class II antigens, an increased number of leucocytes as well as T-lymphocytes. In situ hybridization and immunohistochemistry revealed myocardial enterovirus infection. Considering that there were regions in the myocardium without the traditional findings of myocardial necrosis and inflammation but with distinct expression of the above mentioned immunohistologic markers, immunohistological investigations turn out to be an appropriate tool to examine infant fatalities with uncertain cause of death for early stages of myocarditis.

Mechanisms and consequences of enterovirus persistence in cardiac myocytes and cells of the immune system

In humans and experimental murine models enteroviruses, and in particular coxsackieviruses of group B (CVB), may induce chronic myocarditis associated with a persistent type of heart muscle infection. Persistent myocardial infection has been characterized by restricted viral replication and gene expression, which is capable of sustaining chronic inflammation. Altered replication and transcription of the virus, in addition to an immune response insufficient to recognize and clear infected cells entirely, are essential mechanisms for initiation and maintenance of persistent heart muscle infection. Viral cytotoxicity was found to be crucial for organ pathology both during acute and persistent infection, indicating that enterovirus myocarditis is a virus-induced rather than an immune-mediated disease. Notably, resistance to the development of persistent heart muscle infection is not linked to the H-2 haplotype of the host. In addition to persistently infected myocytes, detection of the replicative minus-strand RNA intermediate provided evidence for virus replication in lymphoid cells of the spleen, predominantly in splenic B lymphocytes, during the course of the disease. Whereas viral RNA was also detected in certain CD4+ helper T cells and Mac1+ macrophages, no enteroviral genomes were identified in CD8+ T cells. Detection of infected activated B lymphocytes both in heart tissue of CVB3-infected immunocompetent mice and syngenic SCID mice receiving splenocytes from CVB3-infected donors support the concept that B cell traffic may contribute to maintenance of chronic disease. Dissection of the diversity of viral and host-specific determinants in susceptible and resistant hosts will allow us to define the protective mechanisms that mediate resistance to the development of life-threatening acute and chronic enterovirus myocarditis.