Quantitative CMV PCR in allogenic stem-cell transplant patients

Abstract number: 1733_136

Portocarrero N., Moriente A., Monclus D., Lomas E., Sanchez P., Sanchez C., Cardeñoso L.

Objective: To assess the clinical value of a commercial quantitative plasma CMV-PCR assay (COBAS AMPLICOR CMV MONITOR test, Roche Molecular System) in allogeneic SCT patients by comparing the results obtained with the PCR and the antigenaemia.

Methods: All patients were monitored weekly antigenaemia and PCR. A total of 1877 blood samples from 94 patients were tested prospectively. CMV seropositive patients (or negative with a seropositive donor < 9 received high dose of acyclovir as prophylaxis. PCR was considered positive when more or equal 400 DNA copies/mL were detected. Antigenaemia was considered positive when one or more positive cells were detected.

Result: All CMV seronegative patients with a seronegative donor were antigenaemia and PCR negative The total patients in study (94), 39 had a positive antigenaemia and/or PCR, with a total of 71CMV infection episodes. None developed CMV disease. PCR detected 49 out of 71 CMV episodes (69%). Overall there were 115 positive antigenaemia (belonging to 35 patients): 65 were PCR positive, 49 PCR negative and 1 PCR inhibited. Four patients (6 episodes) had a positive PCR with a negative antigenaemia. For samples with less than 600 copies/mL a manual calculation of the number of copies was retrospectively done (using a new cut-off). With this lower cut-off, PCR detected 62 out of 71 episodes (87, 4%).

Conclusion: Quantitative CMV PCR assay showed a lower sensibility for de detection of CMV infection in allogeneic SCT compared with antigenaemia. The PCR sensibility was increased without a decrease in the specifity, lowering the cut-off.