Human cytomegalovirus as a direct pathogen: correlation of multiorgan involvement and cell distribution with clinical and pathological findings in a case of congenital inclusion disease.

The human cytomegalovirus (HCMV), a member of the Herpesviridae, is the most frequent cause of congenital virus infections and a major cause of morbidity and mortality in immunocompromised patients. Due to the lack of an appropriate animal model, insight into the pathogenesis of HCMV infections originates primarily from in situ examination of HCMV-infected tissues. Although in immunocompromised adults such tests are complicated frequently by the presence of additional misleading pathogens, the absence of additional pathogens renders congenital inclusion disease the most suitable access for investigation of pathogenetic aspects of HCMV infections. Immunohistochemical examination of tissue sections from a boy with fatal congenital inclusion disease was undertaken to detect the extent of multiorgan and cell involvement. Adrenal gland, bone marrow, diencephalon, heart, kidney, liver, lung, pancreas, placenta, small bowel and spleen were included in this study. Detection of virus antigens from different phases of viral replication revealed that all investigated organs were infected by HCMV. Simultaneous detection of cell type specific marker molecules showed that a variety of cell types stained positive for HCMV antigens including endothelial cells, epithelial cells, smooth muscle cells, mesenchymal cells, hepatocytes, monocytes/macrophages and granulocytes. The lung, the pancreas, the kidneys and the liver were the major target organs with a high number of HCMV infected cells. This correlated with multiorgan failure as the cause of death and strongly indicates direct pathogenetic effects of HCMV.