POLYMERASE CHAIN-REACTION ASSAYS FOR THE DETECTION OF CYTOMEGALOVIRUSIN ORGAN AND BONE-MARROW TRANSPLANT RECIPIENTS

Cytomegalovirus (CMV) infection is ubiquitous and results in a wide sp ectrum of clinical manifestations ranging from asymptomatic infection to severe life threatening disease, Infection in normal children and a dults usually causes no symptoms but in the immunocompromised host, CM V may result in severe opportunistic infections with high morbidity an d mortality. Historically, virus detection was dependent on culture of the virus or on a centrifugation culture system referred to as a shel l vial assay. The shell vial assay frequently lacked sensitivity and w as unable to detect infection in its early phase. Also, as with cultur e assays, the results were affected by antiviral therapy. The CMV anti genemia assay was developed to provide more rapid results and has gain ed wide usage. This assay is limited to detection of the virus in whit e blood cells and is more sensitive than culture or the shell vial ass ay. Application of the polymerase chain reaction (PCR) to these proble ms has resulted in the development of assays for CMV which are more se nsitive than previously available methods. This method employs liquid hybridization with P-32 labeled probes and gel retardation analysis fo r detection of amplified DNA specific for each virus. A comparison of the detection of CMV by an antigenemia assay or the PCR method in the leukocytes of renal transplant patients revealed that the PCR assay de tects cytomegalovirus earlier and more consistently than the antigenem ia assay. Finally, the application of a fluorescent dye detection syst em and image analysis of the acrylamide gel with a laser scanner provi des additional sensitivity to the detection of cytomegalovirus, as wel l as avoiding the use of radioactivity, making the assay more adaptabl e to the clinical laboratory.