Detection of the human cytomegalovirus gene in placental chronic villitis by polymerase chain reaction.

Placental chronic villitis was observed in 44 cases (2.12%) of 2,073 histologically examined placentas. Infiltrating lymphocytes in chronic villitis were determined by immunohistochemistry to be predominantly helper/inducer T cells. Detection of the cytomegalovirus (CMV) gene was performed on paraffin-embedded sections by polymerase chain reaction (PCR) using two different primers (CMV immediate early gene and CMV late antigen gp 64). Both CMV immediate early gene and late antigen gp 64 gene were detected in one case. Cytomegalovirus late antigen gp 64 gene was observed in only three cases. Among these four cases, the cytomegalic inclusion body was observed only in a single case with light microscopic examination. In two cases generalized CMV infection was manifested during the early infantile period and the patient died of the disease. The other two cases were asymptomatic. Our data suggest that approximately 9% of the cases of chronic villitis are caused by CMV infection, and most of them are difficult to detect morphologically. Detection of CMV gene by PCR using primers, especially late antigen gp 64 gene, is very useful for assessing the cause of placental chronic villitis.