Evaluation of the AmpliSensor PCR and the SHARP signal detection system for the early prediction of symptomatic CMV infection in solid transplant recipients

Background: Cytomegalovirus (CMV) is associated with high morbidity and mor tality in transplant patients. Specific antiviral treatment at an early sta ge of CMV infection may effectively ameliorate, but not eliminate CMV disea se in these patients. Presently, the pp65 antigenemia test on peripheral le ukocytes is the method most widely used for predicting and monitoring trans plant patients for active CMV infection. Nucleic acid amplification methods are less well defined since they lack standardisation. Objective: A seminested fluorometric PCR assay (AmpliSensor-CMV, BAG, Germa ny) and a one-step PCR with a signal-amplification step (SHARP, Abbott, Ger many) specific for the fragments of the CMV UL 122 and UL 123 genes, respec tively, were evaluated for the early diagnosis of CMV infection. Design: A total of 26 recipients of heterogeneous solid organs were monitor ed prospectively for a median of 99 days after transplantation. By testing 371 clinical samples parallel with the pp65-antigen assay and IgM and IgG E IA assays the sensitivity, specificity, correlation and quantitation potent ial of both PCRs was evaluated. Results: Eight out of 26 patients developed active CMV infection. A total o f 48 samples of these patients exceeded a CMV-DNA load threshold of 15 geno me equivalents/10(5) leukocytes (AmpliSensor-CMV) and 41 samples exceeded t he critical cut-off for the SHARP system. The AmpliSensor PCR exceeded its threshold consistently before the clinical onset of CMV disease (median 8 d ays). There was very good agreement between symptomatic CMV infection in pa tients and AmpliSensor-PCR, SHARP PCR, and pp65-antigen results (k-coeffici ent > 0.900). IgM and Ige EIA showed moderate agreement (k-coefficient = 0. 591 and 0.552, respectively). Conclusion: Both PCRs and pp65 antigen assay correlated significantly bette r with CMV disease than serodiagnosis. The AmpliSensor PCR allowed more pre cisely than the SHARP system a quantitative determination of viral load and an early and reliable prediction of active CMV infection. The use of Ampli Sensor PCR may improve the diagnosis and management of active CMV infection in organ transplant recipients. (C) 1999 Elsevier Science B.V. All rights reserved.