Detection of cytomegalovirus in paraffin-embedded lung tissue sections

Attempts were made to detect cytomegalovirus (CMV) in paraffin-embedded lung tissue sections from five patients with malignant disease by the immunofluorescence and immunoperoxidase methods with application of monoclonal antibodies against CMV and by localization of DNA by the method of in situ hybridization using a biotinylated probe. In the immunofluorescence method, the monoclonal antibody 1C6 stained a large number of CMV-infected cells. However, nonspecific staining of the bronchoepithelial cells was a disadvantage of this method. In the immunoperoxidase staining, the monoclonal antibodies E. 13 and CCH2 gave highly sensitive and specific results. These monoclonal antibodies stained the nuclei of the infected cells even in the absence of viral inclusions. In the viral DNA probe technique, three specimens were found to contain hybridizing cells. The DNA probe detected not only cytopathic cells but also normal-appearing infected cells. The number of cells stained by the DNA probe was much smaller than that stained by the immunoperoxidase method. The author concludes that the immunoperoxidase technique using monoclonal antibodies against CMV is useful for the diagnosis of CMV infection in the paraffin-embedded lung tissue. Localization of DNA by the method of in situ hybridization is not as useful as the immunoperoxidase method because of lower sensitivity.