CELL-TYPES INFECTED IN HUMAN CYTOMEGALOVIRUS PLACENTITIS IDENTIFIED BY IMMUNOHISTOCHEMICAL DOUBLE STAINING

Chronic villitis is almost always present in intrauterine infection wi th human cytomegalovirus (HCMV). The inflammatory response to this vir us has been described in detail. However, little is known about the ty pes of placental cells that may be infected by HCMV and six cases of H CMV placentitis were thus investigated to identify the vulnerable cell types. Immunohistochemical double staining analyses were performed us ing antibodies to HCMV immediate early antigens and to specific cellul ar marker proteins. Fixed connective tissue cells could be demonstrate d to be the predominantly infected cell type in each placental tissue. Endothelial cells and macrophages were also found to be infected in a ll six cases, whereas evidence of trophoblast infection was obtained i n four cases. It is concluded that release of infectious virus by conn ective tissue cells, macrophages and endothelial cells may play a crit ical role in transplacental transmission of HCMV. The findings further suggest that the cytopathic effect of HCMV infection on these cells m ight be involved in the pathogenesis of intrauterine HCMV disease.