JOURNAL OF CLINICAL MICROBIOLOGY, Nov. 2001, p. 3938–3941
0095-1137/01/$04.00⫹0 DOI: 10.1128/JCM.39.11.3938–3941.2001
Copyright © 2001, American Society for Microbiology. All Rights Reserved.
Vol. 39, No. 11
Qualitative Plasma PCR Assay (AMPLICOR CMV Test) versus pp65
Antigenemia Assay for Monitoring Cytomegalovirus Viremia
and Guiding Preemptive Ganciclovir Therapy in
Allogeneic Stem Cell Transplantation
CARLOS SOLANO,1 ISABEL MUÑOZ,2 ANTONIO GUTIÉRREZ,1 AMPARO FARGA,2 FELIPE PRÓSPER,1
JAVIER GARCÍA-CONDE,1 DAVID NAVARRO,2* AND CONCEPCIÓN GIMENO2
Department of Hematology and Medical Oncology1 and Department of Microbiology,2
University Clinic Hospital, Valencia, Spain
Received 25 May 2001/Returned for modification 18 July 2001/Accepted 21 August 2001
The performances of a commercially available qualitative plasma PCR assay (AMPLICOR CMV test; Roche
Diagnostics) and the pp65 antigenemia assay (AG) were evaluated for the monitoring of cytomegalovirus
(CMV) viremia in 43 allogeneic stem cell transplant recipients. In addition, the suitabilities of both assays for
triggering the initiation of preemptive ganciclovir therapy were assessed. A total of 37 CMV viremic episodes
were detected in 28 patients. Positivity of plasma PCR testing in one or more consecutive specimens was the
only marker of CMV viremia in 18 of the 37 episodes (PCR positive and AG negative, n ⴝ 50 specimens). Five
episodes were diagnosed on the basis of a single positive AG result (AG positive and PCR negative, n ⴝ 5
specimens); both assays were eventually positive (PCR positive and AG positive, n ⴝ 27 specimens) for 14
viremic episodes; for these episodes, conversion of the PCR assay result to a positive result occurred an average
of 1 week before conversion of the AG result. Overall, the concordance between the two methods was 90%, and
the sensitivities of the plasma PCR assay and AG for the detection of CMV viremic episodes were 86.5 and
51.3%, respectively. Two patients who tested positive by both assays simultaneously progressed to CMV
end-stage organ disease, despite the initiation of preemptive ganciclovir therapy. Conversion of the AG result
to a negative result upon administration of preemptive ganciclovir therapy occurred a median of 7.5 days
earlier than conversion of the plasma PCR assay result. Nineteen of the 28 patients with CMV viremia received
AG-guided preemptive ganciclovir therapy; had the positivity of the plasma PCR assay triggered the initiation
of preemptive therapy, 9 additional patients would have been unnecessarily treated since none of them
developed CMV end-stage organ disease. Although the AMPLICOR CMV assay is more sensitive than AG, the
latter appears to be more suitable both for guiding the initiation of preemptive therapy and for monitoring a
patient’s response to antiviral therapy.
Cytomegalovirus (CMV) infection remains a significant
cause of morbidity and mortality in allogeneic stem cell or
bone marrow transplant recipients (23, 24). The prevention of
CMV end-stage organ disease is therefore a major goal in the
clinical management of these patients. Three major therapeutic strategies have been developed to this effect: universal administration of ganciclovir (12, 27), selective use of ganciclovir
for patients displaying viremia before CMV end-stage organ
disease occurs (so-called preemptive therapy) (13, 25), and a
risk-adapted preemptive therapy by which only patients at the
highest risk of developing CMV end-stage organ disease (i.e.,
those with high-grade graft-versus-host disease or high-level
CMV antigenemia) receive ganciclovir upon detection of
CMV viremia (20). Of these, the last two approaches are the
most commonly used since the indiscriminate use of ganciclovir causes myelosuppression, resulting in an increased incidence of fungal and bacterial infections (12, 13, 27); delays
immune reconstitution; and predisposes the patient to the development of late CMV end-stage organ disease (17). A variety
of CMV diagnostic tests have been used for the surveillance of
CMV infection in allogeneic bone marrow transplant recipients and as triggers for the initiation of preemptive therapy,
including the leukocyte shell vial culture assay (4, 13, 15, 21),
the pp65 antigenemia assay (AG) (2, 3–6, 10, 15, 16, 19–22),
and more recently, several qualitative and quantitative PCR
and hybridization procedures that detect CMV DNA in either
blood leukocytes or plasma (1, 4, 6, 8, 9, 14–16, 18–20, 22). No
consensus as to which assay is optimal for such purposes has
been reached, however. A limited number of studies have
nevertheless directly compared the diagnostic utilities of qualitative plasma CMV DNA PCR assays and AG for the detection of CMV viremia and their suitability for guiding preemptive therapy in allogeneic stem cell or bone marrow transplant
recipients (4, 6, 15, 16, 19, 20, 22). Furthermore, most of these
studies (4, 15, 19, 20, 22) have used in-house PCR assays, which
complicates direct comparison of data and, thus, assessment of
the true clinical value of the methods. Here we report on the
experience of our group with a commercially available plasma
CMV DNA PCR assay (the AMPLICOR CMV test; Roche
Diagnostics, Branchburg, N.J.) and AG for the surveillance of
CMV viremia in allogeneic stem cell transplant recipients,
assessing their suitabilities for use in triggering the initiation of
preemptive ganciclovir therapy.
* Corresponding author. Mailing address: Departamento de Microbiologı́a, Hospital Clı́nico Universitario, Blasco Ibañez 17, 46010Valencia, Spain. Phone: 34(96)3864657. Fax: 34(96)3864173. E-mail:
David.Navarro@uv.es.
3938
VOL. 39, 2001
CMV INFECTION IN ALLOGENEIC STEM CELL TRANSPLANTATION
MATERIALS AND METHODS
Patients. Forty-three consecutive patients undergoing allogeneic stem cell
transplantation at the Bone Marrow Transplantation Unit of the Department of
Hematology and Medical Oncology of the University Clinic Hospital in Valencia,
Spain, between June 1997 and December 2000 were included in the study. All
patients received stem cells from related donors. The CMV serostatus (as determined by a commercial immunoassay [Biokit, Barcelona, Spain]) of the transplant recipients and donors were as follows: donor positive and recipient positive,
n ⫽ 35; donor positive and recipient negative, n ⫽ 3; donor negative and
recipient positive, n ⫽ 3; donor negative and recipient negative, n ⫽ 2. From the
time of hospital admission onwards, patients were given standard prophylaxis for
bacterial (ciprofloxacin at 500 mg twice daily orally [p.o.]), fungal (fluconazole at
200 mg twice daily p.o.), and viral (acyclovir at 800 mg three times daily p.o.)
infections. In addition, all patients received immunoglobulins intravenously (i.v.)
at a dose of 400 mg/kg of body weight weekly until day ⫹100 and then monthly
until day ⫹360.
Monitoring and management of CMV viremia. Patients were monitored
weekly (in some cases the patients were monitored twice a week after a positive
AG result) by AG for evidence of CMV viremia. Preemptive ganciclovir therapy
was initiated at the time of a single positive AG result. Preemptive therapy
consisted of the i.v. administration of ganciclovir at 5 mg/kg two times daily for
15 days or until the patient was negative by AG, followed by 1 month of
maintenance therapy (ganciclovir at 5 mg/kg/day for 5 days/week). In addition,
plasma specimens were aliquoted and frozen at ⫺70°C. Plasma specimens collected over a 1-week period were tested by a commercially available CMV DNA
PCR assay (Roche Diagnostics) at the end of the week (in a single run). Patients
with CMV end-stage organ disease were treated with i.v. ganciclovir (at 5 mg/kg
two times daily for 21 days, followed by 5 mg/kg/day for 5 days/week for 1 month)
and i.v. human immunoglobulin (at 400 mg/kg/day every 48 h for 15 days and
weekly thereafter for 1 month).
Criteria for the diagnosis of CMV viremia and CMV end-stage organ disease.
A patient was diagnosed as having an episode of CMV viremia when either AG
or the plasma PCR assay (or both) proved positive. CMV pneumonitis was
diagnosed on the basis of the clinical condition, the presence of interstitial
infiltrates on chest X rays, and the histological demonstration of CMV inclusions
in tissue samples obtained at biopsy or necropsy.
Virological assays. Blood samples were drawn into EDTA-treated tubes and
were processed within 2 h. Polymorphonuclear leukocytes (PMNLs) and plasma
were separated by the standard dextran sedimentation method. AG was carried
out by a recent optimization of a standard immunofluorescence procedure (11).
Briefly, PMNLs containing supernatants were transferred to a 15-ml conical
centrifuge tube and were centrifuged at 300 x g for 10 min. Supernatants were
discarded and cell pellets were resuspended in phosphate-buffered saline (PBS)
to a final concentration of 1.0 ⫻ 106 PMNLs/ml; then, 0.2 ml of the cell suspensions (2 ⫻ 105 PMNLs) were spotted onto a glass slide by using a cytocentrifuge
(500 ⫻ g for 3 to 4 min). Two slides were prepared per specimen. The slides were
air dried, fixed in a solution containing 5% formaldehyde and 2% sucrose in PBS
(10 min at room temperature), and then washed twice with PBS. The cells were
permeabilized by immersing the slides in a PBS solution containing 2% sucrose
and Nonidet P-40 (5 min at room temperature). The slides were then washed in
PBS, rinsed in distilled water, and air dried. The cells were incubated with a
pp65-specific monoclonal antibody and then with an anti-mouse immunoglobulin
G-fluorescein isothiocyanate conjugate (both immunoglobulin G and fluorescein
isothiocyanate were obtained from Chemicon International, Temecula, Calif.).
The presence of one or more pp65-positive cells/2 ⫻ 105 PMNLs was considered
a positive result. Qualitative detection of CMV DNA in plasma was carried out
by the AMPLICOR PCR assay (Roche Diagnostics), according to the instructions of the manufacturer. Standard precautions for avoiding PCR contamination were adopted.
Data analysis. Comparison of data was performed by the nonparametric
Mann-Whitney U test with the assistance of commercially available software
(Instat, San Diego, Calif.). By this test, the average ranks of two independent
samples are statistically compared. Two-tailed P values are given, and those of
⬍0.05 were considered to be of statistical significance.
RESULTS
Detection of CMV viremia by plasma CMV DNA PCR assay
and AG. Sequential blood samples from 43 patients were analyzed in the study. A total of 543 blood specimens were tested
by both methods; 5 additional samples were tested only by
3939
TABLE 1. Performances of plasma CMV PCR assay and
AG in monitoring CMV viremia in allogeneic
stem cell transplant recipients
Plasma PCR assay
result
Positive
Negative
No. (%) of specimens with the
following AG result:
Positive
Negative
27 (4.9)
5 (0.9)
50 (9.1)
466 (85.0)
PCR due to severe neutropenia. A total of 37 episodes of CMV
viremia were detected in 28 patients, and most of these episodes (n ⫽ 30) occurred before day ⫹100. Seven of the 28
patients had several consecutive episodes of viremia (5 patients
had two episodes and 2 patients had three episodes). A positive
plasma PCR result was the only evidence of CMV viremia in
18 episodes (10 of the 18 episodes were defined by the positivity of a single specimen; for the remaining 8 episodes, two or
more sequential samples [up to four sequential samples] were
found to be positive). To rule out a false-positive result of the
plasma PCR due to cross-contamination, a number of these
specimens were retested by using a different aliquot. All of
these samples were found to be repeatedly positive. AG was
the only test positive for five viremic episodes (only one sample
from each episode was positive). One or more sequential blood
specimens drawn during 14 episodes of CMV viremia were
found to be positive by both assays; for 8 of these episodes, the
PCR test and AG became positive simultaneously, while for
the remaining 6 episodes the onset of positivity of the plasma
PCR test preceded that of AG by an average of 7.1 days.
The performances of the two assays are summarized in Table 1. Overall, the concordance between the methods was 90%,
and the sensitivities of the PCR assay and AG for the detection
of episodes of CMV viremia were 86.5 and 51.3%, respectively.
Clinical outcomes for patients with CMV viremia and performances of plasma PCR assay and AG in patients who developed CMV end-stage organ disease. Nineteen of the 28
patients with laboratory evidence of CMV viremia received
AG-guided preemptive ganciclovir therapy. Of these, two patients progressed to CMV end-stage organ disease; one of the
two patients developed biopsy-proven CMV pneumonitis by
day ⫹57. Blood specimens drawn from one of the patients 1
and 2 weeks before the clinical manifestations of CMV disease
became apparent tested positive by both assays. The other
patient developed necropsy-proven CMV pneumonitis by day
⫹50. Both tests became positive 5 days before diagnosis of the
disease. In both cases, the patients died (of respiratory failure)
shortly after the diagnosis of CMV end-stage organ disease
and despite the initiation of i.v. ganciclovir inductive therapy.
Of the nine patients with CMV viremia (detected by plasma
PCR assay) who were not receive preemptive ganciclovir therapy, none went on to develop CMV end-stage organ disease.
Finally, 1 of the 19 patients who received preemptive ganciclovir therapy presented with a clinically silent secondary episode of CMV viremia (diagnosed on the basis of a single
positive plasma PCR assay result).
Performances of plasma PCR assay and AG test in monitoring resolution of ongoing CMV viremia. The analysis of the
14 episodes of CMV viremia in which both assays eventually
3940
SOLANO ET AL.
J. CLIN. MICROBIOL.
TABLE 2. Performances of plasma CMV PCR assay and
AG in monitoring clearance of CMV viremia
after initiation of preemptive therapy
Patient
no.
Time (day after transplant)
of initiation of preemptive therapy
Time (day) of negative conversion after start of preemptive
ganciclovir therapy
Plasma PCR assay
AG
7
11
14
21
25
⫹67
⫹47
⫹39
⫹59
⫹187
⫹7
⫹14
⫹57
⫹20
⫹12
⫹7
⫹7
⫹29
⫹13
⫹12
26
27
30
31
36
⫹447
⫹48
⫹60
⫹48
⫹34
⫹7
⫹21
⫹23
⫹7
⫹20
⫹7
⫹21
⫹13
⫹7
⫹11
37
38
40
42
⫹82
⫹37
⫹48
⫹55
⫹19
⫹22
⫹25
⫹45
⫹19
⫹22
⫹25
⫹5
became positive (Table 2) revealed that, overall, conversion to
a negative result by AG upon administration of preemptive
ganciclovir therapy occurred earlier than that by the plasma
PCR test (a median of 12.5 days for AG versus a median of 20
days for the plasma PCR test), although the difference did not
reach statistical significance (P ⫽ 0.164). The time of conversion to a negative result by the two assays was simultaneous in
eight episodes; in the remaining six episodes, the plasma PCR
test result continued to be positive after conversion of the AG
result to a negative result. Earlier conversion of the PCR test
result to a negative result with respect to the time of conversion of the AG result to a negative result was not observed.
DISCUSSION
In the present study, the plasma PCR assay proved to be
more sensitive than AG in detecting CMV viremia in allogeneic stem cell transplant recipients. In effect, by the plasma
PCR assay, 32 of 37 episodes of CMV viremia could be diagnosed, while the AG test was able to detect only 19 episodes.
If the specificities of both assays are considered to be 100%,
the sensitivities of the plasma PCR assay and AG were found
to be 86.5 and 51.3%, respectively. In addition, the analysis of
CMV viremic episodes in which the results of both tests eventually turned positive revealed that the time of onset of a
positive plasma PCR assay result preceded that of a positive
AG result by an average of 1 week, indicating that a positive
plasma PCR test result is an earlier marker of CMV viremia
than a positive AG result. The sensitivity rates reported in the
present study are lower than those published by Hiyoshi et al.
(16) (97.1 and 79.4% for the plasma PCR test and AG, respectively), although the superior sensitivity of the plasma PCR test
was also evident in the present study. Our data also seem to be
in agreement with those published by Hebart et al. (15), who
used an in-house-designed PCR test to detect CMV DNA in
plasma in a number of allogeneic bone marrow transplant
recipients. In that study, although the sensitivities of the assays
were not calculated, the concordance between the two tests
was reported to be 92% (versus 90% in our study); moreover,
as in our own experience, most of the samples with discordant
results were found to be plasma PCR assay positive and AG
negative. Likewise, a superior sensitivity of plasma PCR assays
in comparison with the sensitivity of AG has been reported in
different transplant settings (26). Our data are nevertheless
discrepant from those recently reported by Boivin et al. (6) for
a comparable cohort of patients; in the latter study the number
of subjects with a positive test result was significantly higher for
AG than for the qualitative plasma PCR assay and the AG
result tended to turn positive earlier than the PCR assay result
did. The reasons for such a discrepancy are not clear since the
protocol used to perform AG appeared not to be substantially
different from that followed in our study and, moreover, the
same commercial PCR was used. The sole difference between
the two studies is the time during which plasma specimens
were kept frozen: a few days in our case versus several months
in the other study (6); it is not clear, however, whether this
variation could account for such a discrepancy. Our data are
also in contrast to those reported by Boeckh et al. (4), who
found the sensitivity of the plasma PCR test to be similar to
that of AG. That study, however, used an in-house-designed
PCR assay whose sensitivity might not have been optimal. In
agreement with previous reports (6), the AG result globally
tended to turn negative earlier than the plasma PCR test result
(a median of 7.5 days earlier) after the initiation of preemptive
ganciclovir treatment. Since patients who continued to be
CMV DNA PCR assay positive after conversion of the AG
result to a negative result did not progress to CMV end-stage
organ disease, the latter assay appears to be more suitable than
PCR for monitoring of the efficiency of anti-CMV therapy.
In our cohort, the AG-guided strategy for the triggering of
preemptive therapy resulted in an incidence of CMV end-stage
organ disease before day ⫹100 of 4.8%, which is comparable to
that reported by Boeckh et al. (3), who also started preemptive
therapy upon a positive (any level) AG result, and to that
reported by Einsele et al. (9), who initiated ganciclovir treatment when two consecutive whole-blood samples became positive by PCR. Our CMV end-stage organ disease-preventing
strategy also resulted in a low incidence of secondary episodes
of CMV viremia (only one) and in a zero incidence of late
CMV end-stage organ disease. In the two patients who progressed to CMV disease despite the initiation of preemptive
ganciclovir therapy, the results of both tests turned positive
concomitantly; therefore, PCR-guided preemptive therapy
would not have resulted in more favorable clinical outcomes
for these patients. In accordance with our CMV end-stage
organ disease-preventing strategy, 19 of 43 (44.1%) patients
studied received preemptive ganciclovir therapy. Had either a
single positive plasma PCR test result or two consecutive positive plasma PCR test results triggered the initiation of preemptive therapy, nine and six additional patients, respectively,
would have received preemptive ganciclovir therapy that would
have been unnecessary, since all these patients remained free
of CMV end-stage organ disease during the study period.
In summary, the AMPLICOR CMV commercial plasma
PCR assay is more sensitive than AG for the detection of CMV
viremia in allogeneic stem cell transplant recipients. Nevertheless, we find AG to be more suitable both for guiding the
initiation of preemptive therapy and for monitoring the efficacy
VOL. 39, 2001
CMV INFECTION IN ALLOGENEIC STEM CELL TRANSPLANTATION
of ganciclovir treatment. Several drawbacks are associated with
the use of AG, however: the need for rapid processing in order
not to lose sensitivity and the impossibility of using the test
during severe neutropenia. Perhaps the quantitative version of
the presently evaluated PCR assay (the COBAS AMPLICOR
CMV MONITOR assay) will prove useful once the procedure
is sufficiently evaluated and the threshold for the initiation of
preemptive therapy is clearly defined. Several studies seem to
support this view (6, 7).
REFERENCES
1. Barrett-Muir, W. Y., C. Aitken, K. Templeton, M. Raftery, S. M. Kelsey, and
J. Breuer. 1998. Evaluation of the Murex hybrid capture cytomegalovirus
DNA assay versus plasma PCR and shell vial assay for diagnosis of human
cytomegalovirus viremia in immunocompromised patients. J. Clin. Microbiol. 36:2554–2556.
2. Boeckh, M., R. A. Bowden, J. Goodrich, M. Pettinger, and J. D. Meyers.
1992. Cytomegalovirus antigen detection in peripheral blood leucocytes after
allogeneic bone marrow transplantation. Blood 80:1358–1364.
3. Boeckh, M., R. A. Bowden, T. Gooley, D. Myerson, and L. Corey. 1999.
Successful modification of a pp65 antigenemia-based early treatment strategy for prevention of cytomegalovirus disease in allogeneic marrow transplant recipients. Blood 93:1781–1782.
4. Boeckh, M., G. M. Gallez-Hawkins, D. Myerson, J. Zaia, and R. A. Bowden.
1997. Plasma polymerase chain reaction for cytomegalovirus DNA after
allogeneic bone marrow transplantation. Transplantation 64:108–113.
5. Boeckh, M., T. A. Gooley, D. Myerson, T. Cunningham, G. Schoch, and R. A.
Bowden. 1996. Cytomegalovirus pp65 antigenemia-guided early treatment
with ganciclovir versus ganciclovir at engraftment after allogeneic marrow
transplantation—a randomized double-blind study. Blood 88:4063–4071.
6. Boivin, G., R. Bèlanger, R. Delage, C. Bèliveau, C. Demers, N. Goyette, and
J. Roy. 2000. Quantitative analysis of cytomegalovirus (CMV) viremia using
the pp65 antigenemia assay and the COBAS AMPLICOR CMV MONITOR PCR test after blood and marrow allogeneic transplantation. J. Clin.
Microbiol. 38:4356–4360.
7. Caliendo, A. M., K. St. George, S.-Y. Kao, J. Allega, B.-H. Tan, R. LaFontaine, L. Bui, and C. R. Rinaldo. 2000. Comparison of quantitative cytomegalovirus (CMV) PCR in plasma and CMV antigenemia assay: clinical utility
of the prototype AMPLICOR CMV MONITOR test in transplant recipients. J. Clin. Microbiol. 38:2122–2127.
8. Einsele, H., G. Ehninger, H. Hebart, K. M. Wittkowsky, U. Schuler, G. Jahn,
P. Mackes, M. Herter, M. Klingebiel, J. Loffler, S. Wagner, and C. A. Müller.
1995. Polymerase chain reaction monitoring reduces the incidence of cytomegalovirus disease and the duration of side effects of antiviral therapy after
bone marrow transplantation. Blood 86:2815–2820.
9. Einsele, H., C. H. Hebart, C. Kauffmann-Schneider, C. Sinzger, G. Jahn, P.
Bader, T. Kinglebiel, K. Dietz, J. Löffler, C. Bokemeyer, C. A. Müller, and L.
Kanz. 2000. Risk factors for treatment failures in patients receiving PCRbased preemptive therapy for CMV infection. Bone Marrow Transplant.
25:757–763.
10. Gerna, G., F. Baldanti, D. Lilleri, M. Parea, E. Alessandrino, A. Pagani, F.
Locatelli, J. Middletorp, and M. G. Revello. 2000. Human cytomegalovirus
immediate-early mRNA detection by nucleic acid sequence-based amplification as a new parameter for preemptive therapy in bone marrow transplant
recipients. J. Clin. Microbiol. 38:1845–1853.
11. Gerna, G., M. G. Revello, E. Percivalle, and F. Morina. 1992. Comparison of
different immunostaining techniques and monoclonal antibodies to lower
matrix phosphoprotein (pp65) for optimal quantitation of human cytomegalovirus antigenemia. J. Clin. Microbiol. 30:1232–1237.
12. Goodrich, J. M., R. A. Bowden, L. Fisher, C. Keller, G. Schoch, and J. D.
Meyers. 1993. Ganciclovir prophylaxis to prevent cytomegalovirus disease
3941
after allogeneic marrow transplant. Ann. Intern. Med. 118:173–178.
13. Goodrich, J. M., M. Mori, C. A. Gleaves, C. Du Mond, M. Cays, D. F.
Ebeling, W. C. Buhles, B. DeArmond, and J. D. Meyers. 1991. Early treatment with ganciclovir to prevent cytomegalovirus disease after allogeneic
bone marrow transplantation. N. Engl. J. Med. 325:1601–1607.
14. Hebart, H., D. Gamer, J. Loeffler, C. Mueller, C. Sinzger, G. Jahn, P. Bader,
T. Klingebiel, L. Kanz, and H. Einsele. 1998. Evaluation of Murex CMV
DNA hybrid capture assay for detection and quantitation of cytomegalovirus
infection in patients following allogeneic stem cell transplantation. J. Clin.
Microbiol. 36:1333–1337.
15. Hebart, H., C. Müller, J. Löffler, G. Jahn, and H. Einsele. 1996. Monitoring
of CMV infection: a comparison of PCR from whole blood, plasma-PCR,
pp65 antigenemia and virus culture in patients after bone marrow transplantation. Bone Marrow Transplant. 17:861–868.
16. Hiyoshi, M., S. Tagawa, T. Takubo, K. Tanaka, T. Nakao, Y. Higeno, K.
Tamura, M. Shimaoka, A. Fujii, M. Higashihata, Y. Yasui, T. Kim, A.
Hiraoka, and N. Tatsumi. 1997. Evaluation of the Amplicor CMV test for
direct detection of cytomegalovirus in plasma specimens. J. Clin. Microbiol.
35:2692–2694.
17. Li, C. R., P. D. Greenberg, M. J. Gilbert, J. M. Goodrich, and S. Riddell.
1994. Recovery of HLA-restricted cytomegalovirus (CMV)-specific T cell
responses after allogeneic bone marrow transplant: correlation with CMV
disease and effect of ganciclovir prophylaxis. Blood 83:1971–1979.
18. Ljungman, P., K. Lore, J. Aschan, S. Klaesson, I. Lewensohn-Fuchs, B.
Lonnqvist, O. Ringden, J. Winiarski, and A. Ehrnst. 1996. Use of semiquantitative PCR for cytomegalovirus DNA as a basis for preemptive antiviral
therapy in allogeneic bone marrow transplant patients. Bone Marrow Transplant. 17:583–587.
19. Machida, U., M. Kami, T. Fukui, Y. Kazuyama, M. Kinoshita, Y. Tanaka, Y.
Kanda, S. Ogawa, H. Honda, S. Chiba, K. Mitani, Y. Murto, K. Osumi, S.
Kimura, and H. Hirai. 2000. Real-time automated PCR for early diagnosis
and monitoring of cytomegalovirus infection after bone marrow transplantation. J. Clin. Microbiol. 38:2536–2542.
20. Mori, T., S. Okamoto, S. Matsuoka, T. Yajima, R. Watanabe, A. Ishida, Y.
Iwao, M. Mukai, T. Hibi, and Y. Ikeda. 2000. Risk-adapted therapy for
cytomegalovirus disease in patients undergoing allogeneic bone marrow
transplantation. Bone Marrow Transplant. 25:765–769.
21. Nicholson, V. A., E. Whimbey, R. Champlin, D. Abi-Said, D. Przepiorka, J.
Tarrand, K. Chan, G. P. Bodey, and J. M. Goodrich. 1997. Comparison of
cytomegalovirus antigenemia and shell vial culture in allogeneic marrow
transplantation recipients receiving ganciclovir prophylaxis. Bone Marrow
Transplant. 19:37–41.
22. Preiser, W., S. Brauninger, R. Schwerdtfeger, U. Ayliffe, J. A. Garson, N. S.
Brink, S. Franck, H. W. Doerr, and H. F. Rabenau. 2001. Evaluation of
diagnostic methods for the detection of cytomegalovirus in recipients of
allogeneic stem cell transplants. J. Clin. Virol. 20:59–70.
23. Prentice, H. G., and P. Kho. 1997. Clinical strategies for the management of
cytomegalovirus infection and disease in allogeneic bone marrow transplantation. Bone Marrow Transplant. 19:135–142.
24. Reusser, P. 1996. The challenge of cytomegalovirus after bone marrow
transplantation: epidemiology, prophylaxis, and therapy. Bone Marrow
Transplant. 18(Suppl. 2):107–109.
25. Schmidt, G. M., D. A. Horak, J. C. Niland, S. R. Duncan, S. J. Forman, and
J. A. Zaia. A randomized controlled trial of prophylactic ganciclovir for
cytomegalovirus pulmonary infection in recipients of allogeneic bone marrow transplants. N. Engl. J. Med. 324:1005–1011.
26. Weinberg, A., T. N. Hodges, S. Li, G. Cai, and M. R. Zamora. 2000. Comparison of PCR, antigenemia assay, and rapid blood culture for detection
and prevention of cytomegalovirus disease after lung transplantation. J. Clin.
Microbiol. 38:768–772.
27. Winston, D. J., W. G. Ho, K. Bartoni, C. Du Mond, D. F. Ebeling, W. C.
Buhles, and R. E. Champlin. Ganciclovir prophylaxis of cytomegalovirus
infection and disease in allogeneic bone marrow transplant recipients. Results of a placebo-controlled, double-blind trial. Ann. Intern. Med. 118:179–
184.