INFLUENCE OF FORMALIN FIXATION ON THE DETECTION OF CYTOMEGALOVIRUS BYPOLYMERASE CHAIN-REACTION IN IMMUNOCOMPROMISED PATIENTS AND CORRELATION TO IN-SITU HYBRIDIZATION, IMMUNOHISTOCHEMISTRY, AND SEROLOGICAL DATA

The possibility of detecting cytomegalovirus (CMV) in formalin-fixed t issues by polymerase chain reaction (PCR) was evaluated in necropsies from lung tissues in a total of 24 patients who either had received or gan transplants or were immunocompromised. PCR using two different pai rs of primers for amplification of the major immediate early antigen o f CMV was performed on fresh tissues and tissues fixed for 24, 48, and 72 h in neutral buffered formalin and compared to immunohistochemistr y (IHC) and in situ hybridization (ISH). The fresh tissues of nine pat ients with serological evidence for acute CMV infection were all posit ive for CMV by PCR. After formalin fixation, the majority of the patie nts failed to show distinct signals with one or both pairs of primers as measured by densitometry. In contrast to this, fresh tissues of 15 patients without signs of an acute CMV infection were found either neg ative or weakly positive by PCR. Using IHC or ISH, positive results we re observed only in five of nine and four of nine patients with acute CMV infection, respectively. These data demonstrate that, if only form alin-fixed tissue is available, PCR for CMV detection should be perfor med using two pairs of primers and should be supported by IHC. .