In situ hybridization analysis for cytomegalovirus in chronic villitis

Chronic villitis with villous lymphoplasmacytic, histiocytic infiltrate and stromal necrosis may have various etiologies. Infection with cytomegalovirus (CMV) is a frequent cause of such villitis, but the nuclear and cytoplasmic inclusions diagnostic of CMV are often not apparent. In this study placentas with chronic villitis were analyzed for CMV DNA by means of in situ hybridization. Of the eight cases of chronic villitis studied, three demonstrated inclusions diagnostic of CMV infection. On in situ hybridization, three additional cases had detectable CMV DNA. CMV was detected in endothelial, histiocytic, and fibroblastic cells and occasionally in the trophoblast. In cases with characteristic CMV inclusions, CMV DNA was often present in cells that lacked inclusions. CMV DNA was not detected in unremarkable placental tissue obtained from normal deliveries. It is concluded that CMV is commonly found in lymphoplasmacytic and histiocytic villitis and that in situ analysis for CMV is a rapid, easy, and sensitive way to detect the virus in placentas.