In situ hybridization for cytomegalovirus DNA in AIDS patients

Infection by cytomegalovirus (CMV) is a frequent cause of morbidity and mortality in patients with acquired immune deficiency syndrome (AIDS). The authors studied the distribution of CMV in 4 patients with AIDS using a commercially available, biotin-labeled CMV DNA probe for in situ hybridization and immunohistochemical staining for the detection of CMV antigen in formalin-fixed paraffin-embedded tissues. The sensitivity and specificity of the hybridization procedure was demonstrated by appropriate controls. The immunohistochemical test for the detection of CMV antigen in routine histologic sections was less sensitive than the in situ hybridization method. CMV DNA was detected not only in cytomegalic inclusion cells, but also in nuclei and cytoplasm of histologically normal-appearing cells such as endothelial cells, pneumocytes, hepatocytes, biliary epithelium, gastrointestinal epithelium, Langerhans islet cells, acinar and duct epithelium of pancreas, adrenal cortical and medullary cells, and prostate epithelium. In addition, CMV DNA, but not CMV antigen, was found in polymorphonuclear leukocytes. These cells may serve as intermediate host or reservoir of CMV and may transmit posttransfusion CMV infection. In situ hybridization on routine histologic sections with a biotinylated CMV DNA probe is a rapid, sensitive, and specific method for diagnostic and experimental pathology.