Quantitative Real-Time PCR Compared with pp65 Antigen Detection for Cytomegalovirus (CMV) in 1122 Blood Specimens from 77 Patients after Allogeneic Stem Cell Transplantation: Which Test Better Predicts CMV Disease Development?

Abstract

Cytomegalovirus (CMV) can compromise the life of patients who are immunosuppressed after organ transplantation or who have acquired immunodeficiency syndrome. CMV infections or reactivations can be successfully treated, provided treatment is instituted early in the course of developing disease. Current assays to detect the CMV pp65 antigen in peripheral blood leukocytes or CMV DNA by qualitative PCR of leukocytes or plasma can be slow and tedious (1)(2)(3). Antigen detection is limited by the availability of sufficient white blood cell numbers and is impossible to perform on leukopenic patients. In addition, blood for antigen detection cannot be stored for long periods because white blood cells need to be intact for staining procedures (4)(5). PCR techniques detect relatively stable double-stranded DNA present in the plasma or whole blood regardless of storage conditions or cell integrity, but qualitative PCR assays are not useful for follow-up studies of patients, and they do not allow the determination of viral load, which is useful for prognosis. In this study we compared quantitative real-time PCR (6)(7) with conventional pp65 antigen staining among 77 patients (1122 blood samples) surviving more than 30 days after stem cell transplantation (see Table 1 in the Data Supplement that accompanies the online version of this Technical Brief at http://www.clinchem.org/content/vol49/issue10/). In a retrospective study, results of the two assays were compared, and their sensitivity and specificity for predicting CMV disease were calculated. All patients were transplanted in the Virchow Klinikum (Berlin, Germany) between January 1998 and March 2001 (see Table 1 in the online Data supplement). Five patients developed CMV organ disease, which included pneumonitis and hepatitis (n = 1), hepatitis (n = 1), enteritis (n = 2), and retinitis (n = 1). Seven additional patients developed thrombo- and leukopenia not explained by other conditions. …