HCMV DNA detection and quantitation in the plasma and PBL of lung transplant recipients: COBAS Amplicor HCMV monitor test versus in-house quantitative HCMV PCR.
BACKGROUND
Human cytomegalovirus (HCMV) reactivation may cause severe disease in immunosuppressed patients. Quantitation of HCMV viral load in the blood has been shown to be important in predicting for HCMV disease, however the particular blood compartment that should be tested, plasma versus peripheral blood leukocytes (PBL), has been subject to debate.


OBJECTIVE
To simultaneously compare HCMV viral loads in the PBL using an in-house quantitative HCMV polymerase chain reaction (PCR) assay and in the plasma using the commercially available COBAS Amplicor HCMV monitor test, in a cohort of lung transplant recipients (LTR).


METHODS
Sequential paired plasma and PBL samples were collected (n=98) from a total of 21 LTR during the first 6 months post lung transplantation. HCMV viral loads were assessed in the PBL using an in-house quantitative HCMV PCR assay and the plasma using the COBAS Amplicor HCMV monitor test. HCMV disease in LTR was defined as histopathologically proven HCMV pneumonitis.


RESULTS
HCMV deoxyribonucleic acid (DNA) was detected in 39/98 (40%) of total samples with excellent agreement between the two strategies. HCMV was detected in both the plasma and PBL in 38/39 (97%) of HCMV positive samples. HCMV viral loads were higher in patients with HCMV pneumonitis in both the PBL and plasma compared to patients without HCMV pneumonitis. Greater than 10-fold increases in HCMV DNA levels had a sensitivity of 88% and a specificity of 73% in the plasma for HCMV pneumonitis and a positive and negative predictive value of 70 and 89%, respectively. Greater that 10-fold increases in HCMV DNA levels in the PBL had a sensitivity of 88% and a specificity of 64%, for HCMV pneumonitis and a positive and negative predictive value of 64 and 88%, respectively.


CONCLUSIONS
Acknowledging the difference in assay methods used for HCMV DNA quantitation, the in-house PCR PBL assay and the COBAS Amplicor HCMV monitor plasma assay predicted equally well for HCMV pneumonitis in LTR.
Michaelides
Alexandra
A
Department of Microbiology and Infectious Diseases Unit, Alfred Hospital, Commercial Road, Prahran 3181, VIC, Australia.
Facey
David
D
Spelman
Denis
D
Wesselingh
Steven
S
Kotsimbos
Thomas
T
D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D003586:Cytomegalovirus Infections / Q000097:blood / Q000235:genetics / Q000517:prevention & control / Q000821:virology; D004279:DNA, Viral / Q000032:analysis / Q000097:blood* / Q000302:isolation & purification; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology*; D016040:Lung Transplantation; D016133:Polymerase Chain Reaction / Q000379:methods; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D019562:Viral Load; D014763:Viral Matrix Proteins / Q000097:blood*
D004279:DNA, Viral; D011933:Reagent Kits, Diagnostic; D014763:Viral Matrix Proteins