The performance of a plasma real-time PCR (cytomegalovirus [CMV] PCR kit; Abbott Diagnostics) was compared with that of the antigenemia assay for the surveillance of active CMV infection in 42 allogeneic hematopoietic stem cell transplantation (Allo-SCT) recipients. A total of 1,156 samples were analyzed by the two assays. Concordance between the two assays was 82.2%. Plasma DNA levels correlated with the number of pp65-positive cells, particularly prior to the initiation of preemptive therapy. Fifty-seven episodes of active CMV infection were detected in 37 patients: 18 were defined solely by the PCR assay and four were defined on the basis of the antigenemia assay. Either a cutoff of 288 CMV DNA copies/ml or a 2.42-log 10 increase of DNAemia levels between two consecutive PCR positive samples was an optimal value to discriminate between patients requiring preemptive therapy and those not requiring therapy on the basis of the antigenemia results. The real-time PCR assay allowed an earlier diagnosis of active CMV infection and was a more reliable marker of successful clearance of CMV from the blood. Analysis of the kinetics of DNAemia levels at a median of 7 days posttreatment allowed the prediction of the response to CMV therapy. Two patients developed CMV colitis. The PCR assay tested positive both before the onset of symptoms and during the disease period. The plasma real-time PCR from Abbott is more suitable than the antigenemia assay for monitoring active CMV infection in Allo-SCT recipients and may be used for guiding preemptive therapy in this clinical setting.Preemptive antiviral therapy based on the detection of cytomegalovirus (CMV) in blood has been shown to significantly reduce the incidence of CMV disease in the early posttransplant period following allogeneic hematopoietic stem cell transplantation (Allo-SCT) (2, 7). The pp65 antigenemia assay has been adopted by many transplant centers as the "gold standard" for monitoring active CMV infection and guiding preemptive therapy in this clinical setting. The antigenemia assay, however, requires rapid processing of specimens, is labor-intensive, cannot be automated, is subjective in reading, and is unfeasible during periods of severe neutropenia. In addition, it does not reflect the viral load in the blood compartment accurately (12) and sometimes displays negative results in the presence of CMV disease (2,31,32,36).Quantification of CMV DNA in blood by PCR is emerging as an alternative to the antigenemia assay and may soon become the standard for the surveillance of CMV infection in Allo-SCT recipients. Viral load quantification in blood allows early detection of active CMV infection, close monitoring of the response to antivirals, prediction of the risk of viremic relapse, emergence of resistant strains, and eventual development of CMV disease (8,31). In addition, it may be safely used for guiding preemptive therapy (11,16,23,24,32,37). Nevertheless, there is some controversy as to which is the optimal clinical specimen (plasma, whole blood, or leukoc...

Threshold levels of CMV-specific T-cell populations presumably affording protection from active CMV infection in allo-SCT recipients have been proposed, but lack extensive validation. We quantified CMV pp65 and immediate-early 1-specific IFN-c CD8 þ and CD4 þ and CD4 þ T-cell markers were 68.1 and 61.8%, respectively. Recipients of grafts from CMV seropositive, related or HLA-matched donors, or receiving non-myeloablative conditioning had nonsignificant tendencies to reach more frequently protective levels of both T-cell subsets at early and late (day þ 365) times after transplantation. The use of antithymocyte globulin and umbilical cord blood transplantation were associated with impaired CMV-specific T-cell reconstitution. CMV-specific IFN-c CD8 þ and CD4 þ T-cell recovery occurred irrespective of detectable CMV DNAemia.

Cytomegalovirus (CMV) reactivation occurs frequently in critically ill patients. The natural course of CMV infection and the interaction between CMV and the adaptive immune system in this setting remain poorly defined. Fifty‐three CMV‐seropositive patients in a surgical and trauma intensive care unit were included in this study. The CMV DNA load in tracheal aspirates (TA) and plasma (PL) was monitored by qPCR. CMV‐specific T‐cell immunity was assessed by intracellular cytokine staining. Plasma TNF‐α levels were determined by ELISA. CMV reactivation occurred in 39.7% of patients (23% had CMV DNA detected only in TA). The analysis of TA allowed an earlier diagnosis in 28% of patients. Clearance of CMV DNAemia preceded that of CMV DNA in TA in some episodes. Peak CMV DNA levels were significantly higher in TA than in PL (P = 0.02). CMV reactivation developed in the presence of CMV‐specific T cells. Termination of CMV reactivation was associated with an expansion of functional CMV‐specific T cells. Plasma levels of TNF‐α did not allow for the prediction of the occurrence of CMV reactivation. CMV‐specific T‐cell immunity is preserved in most critically ill patients experiencing CMV reactivation. Analysis of respiratory specimens is imperative for an optimal monitoring of CMV reactivation in this setting. J. Med. Virol. 82:1384–1391, 2010. © 2010 Wiley‐Liss, Inc.

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Rising levels of cytomegalovirus (CMV) DNAemia and/or pp65 antigenemia have been observed during pre-emptive ganciclovir therapy in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-SCT). We assessed the incidence of this event in our series, and investigated whether its occurrence was associated with an impairment in the CMV-specific T-cell response. A total of 36 allo-SCT recipients experienced one or more episodes of active CMV infection (n ¼ 68) that were preemptively treated with val(ganciclovir). Rising levels of antigenemia and DNAemia, and an isolated increase in antigenemia, were observed in 39.7 and 2.9% of all episodes, respectively. Receipt of corticosteroids was associated with rising levels of antigenemia and DNAemia. Median increases of 12-and 6.8-fold of IFNc CD8 þ T and IFNc CD4 þ T cells, respectively, were observed at a median of 16.5 days after initiation of therapy in episodes with decreasing levels in antigenemia and DNAemia. In contrast, the numbers of both T-cell subsets at a median of 13.5 days after initiation of therapy did not differ significantly from those of pre-treatment samples in episodes with rising levels of antigenemia and DNAemia. Lack of prompt expansion of CMV pp65 and IE-1-specific IFNc CD8 þ and CD4 þ T cells is associated with rising levels in antigenemia and DNAemia during pre-emptive therapy.