Whole blood real-time quantitative PCR for cytomegalovirus infection follow-up in transplant recipients.
BACKGROUND
Cytomegalovirus (CMV) remains a major opportunistic agent among transplant recipients. While detection of CMV pp65-lower matrix protein (pp65Ag) is still widely used for monitoring CMV infection, real-time PCR assays have been recently developed for routine quantitation of CMV DNA. However, correlations are lacking between results of pp65Ag and quantitative PCR assays and there is no consensus yet as to the more appropriate blood compartment (whole blood (WB), leukocytes, plasma) to be tested with PCR assays.


OBJECTIVE
The aims of the study were to determine, in a population of transplant recipients: (i) the correlation between pp65Ag and CMV quantitative real-time PCR in our setting and (ii) the utility of plasma CMV DNA quantitation in comparison to WB quantitation.


METHODS
In 170 blood samples (from 61 solid organ or bone marrow transplant recipients) with pp65Ag results, CMV quantitation was performed in WB and plasma using an in-house real-time quantitative PCR.


RESULTS
Real-time PCR and pp65Ag results in WB were correlated: thresholds of 10 and 50(+) cells/200,000 cells were equivalent to 3.3 log(10)copies/mL (2,000 copies/mL) and 3.8 log(10)copies/mL (6,300 copies/mL), respectively. When WB viral load was >or=3.6 log(10)copies/mL, the risk to have a negative plasma CMV DNA result was <or=2.5%.


CONCLUSIONS
For the routine exploration of a single compartment, whole blood would represent a suitable compromise: easy processing for a sensitive assay. The 3.6 log(10)copies/mL threshold, which could help in identifying active CMV infection, deserves further evaluation.
Département de Virologie et d'Immunologie Biologique and Laboratoire EA 2968, Centre Hospitalo-Universitaire de Bordeaux, 33076 Bordeaux, France.
Isabelle
I
Garrigue
Sébastien
S
Boucher
Lionel
L
Couzi
Anne
A
Caumont
Claire
C
Dromer
Martine
M
Neau-Cransac
Reza
R
Tabrizi
Marie-Hélène
MH
Schrive
Hervé
H
Fleury
Marie-Edith
ME
Lafon
D000328:Adult; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000175:diagnosis* / Q000821:virology; D004279:DNA, Viral / Q000097:blood; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016377:Organ Transplantation / Q000009:adverse effects*; D010750:Phosphoproteins / Q000097:blood / Q000235:genetics; D012015:Reference Standards; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D019562:Viral Load; D014763:Viral Matrix Proteins / Q000097:blood / Q000235:genetics
D004279:DNA, Viral; D010750:Phosphoproteins; D014763:Viral Matrix Proteins; C065418:cytomegalovirus matrix protein 65kDa