Monitor Cytomegalovirus Infection Research Articles

Genetic Variants Associated with Drug Resistance of Cytomegalovirus in Hematopoietic Cell Transplantation Recipients.

Cytomegalovirus (CMV) infection is a serious complication in hematopoietic cell transplantation (HCT) recipients. Drug-resistant strains make it more challenging to treat CMV infection. This study aimed to identify variants associated with CMV drug resistance in HCT recipients and assess their clinical significance. A total of 123 patients with refractory CMV DNAemia out of 2271 HCT patients at the Catholic Hematology Hospital between April 2016 and November 2021 were analyzed, which accounted for 8.6% of the 1428 patients who received pre-emptive therapy. Real-time PCR was used to monitor CMV infection. Direct sequencing was performed to identify drug-resistant variants in UL97 and UL54. Resistance variants were found in 10 (8.1%) patients, and variants of uncertain significance (VUS) were found in 48 (39.0%) patients. Patients with resistance variants had a significantly higher peak CMV viral load than those without (p = 0.015). Patients with any variants had a higher risk of severe graft-versus-host disease and lower one-year survival rates than those without (p = 0.003 and p = 0.044, respectively). Interestingly, the presence of variants reduced the rate of CMV clearance, particularly in patients who did not modify their initial antiviral regimen. However, it had no apparent impact on individuals whose antiviral regimens were changed due to refractoriness. This study highlights the importance of identifying genetic variants associated with CMV drug resistance in HCT recipients for providing appropriate antiviral treatment and predicting patient outcomes.

Sequencing of Cell-Free DNA to Monitor Cytomegalovirus Infection After Liver Transplant.

In the present study, we investigated donor-derived cell-free DNA dynamics and assessed the diagnostic efficacy of 2 tests: the sequencing of cytomegalovirus-derived cell-free DNA and the quantitative nucleic acid amplification test in cytomegalovirus infection following liver transplant. We first examined 6 patients who were identified with active cytomegalovirus DNAemia by both quantitative nucleic acid amp-lification test and next-generation sequencing of cytomegalovirus-derived cell-free DNA and then performed a receiver operating characteristic analysis to evaluate the efficacy of cell-free DNA sequencing and establish a cutoff for this assay. Further validation of the next-generation sequencing method was also performed in 84 liver transplant recipients. The study protocol conformed to the ethical guidelines of the Declaration of Helsinki and the Declaration of Istanbul. In the first 6 patients, there was no significant correlation between the cytomegalovirus infection and donor-derived cell-free DNA. We determined that the levels of cytomegalovirus-derived cell-free DNA sequencing directly correlate with the results of the quantitative nucleic acid amplification test (area under the curve 0.982) and obtained a value of 0.015% as a cutoff for the cell-free DNA sequencing assay. In the validation cohort composed of 84 liver transplant recipients, next-generation sequencing of cell-free DNA revealed the occurrence of cytomegalovirus infection that remains otherwise undetected by the quantitative nucleic acid amplification test. Cytomegalovirus infections that do not cause direct graft injury (cytomegalovirus-related hepatitis) did not result in elevations of donor-derived cell-free DNA. Next-generation sequencing of cytomegalovirus-derived cell-free DNA provides a potential tool for detection of cytomegalovirus infection that remains undetected by the quantitative nucleic acid amplification test.

Cytomegalovirus Infection: comparison of methodologies for monitoring renal and cardiac transplants

Introduction: Cytomegalovirus (CMV) remains a major cause of morbidity and mortality among solid organ transplant recipients, despite remarkable advances in its diagnosis, prevention and treatment [1]. The two methods that are currently used to monitor CMV infection and disease in these patients are the pp65 antigenemia assay and the quantitative nucleic acid test (QNAT) [2]. The purpose of this study is to compare two different types of QNAT (the Roche COBAS AmpliPrep/COBAS TaqMan CMV test, which is available commercially, and a laboratory-developed RT-PCR test) and one CMV pp65 antigenemia assay. Materials and methods: A total of 49 samples from 32 transplant recipients (28 renal and 4 cardiac transplants) were submitted to these three methodologies. Results: The results showed a significant agreement (concordance rates between 81.6% and 71.4%, and Cohen’s kappa coefficient values between 0.456 and 0.602, p < 0.001) and a moderate to high, significant (p < 0.01), correlation between these methods (Spearman’s coefficient value of 0.769 for pp65 antigenemia and COBAS, 0.546 for pp65 antigenemia and RT-PCR “in-house”, and 0.736 for COBAS and RT-PCR “in-house” comparison). The unexpected good results obtained with antigenemia is a consequence of decades of laboratory’s and operators’ experience with this technique. In addition, one third (33.3%) of all antigenemia positive samples had 1 or 2 positive cells. Discussion and conclusions: The results from this study showed significant agreement and correlation between the three methodologies. Therefore, we conclude that these can be used successfully for monitoring solid organ transplant recipients.

Use of the Quantitative Karius® Plasma Next Generation Sequencing Cell-Free Pathogen DNA Test to Detect and Monitor Cytomegalovirus Infection in Allogeneic Stem-Cell Transplant Recipients

Background Allogeneic stem-cell transplant (allo-SCT) recipients are at risk of developing severe CMV infection. The pre-emptive approach to CMV prevention, weekly monitoring with CMV PCR with treatment for positive viral load (VL), is standard of care. The quantitative Karius plasma Next Generation Sequencing test (KT) can identify DNA from >1,000 human pathogens. We report on the clinical validation and utility of KT for detecting and monitoring CMV viremia in allo-SCT patients. Methods Plasma samples negative or positive by CMV PCR (COBAS® AmpliPrep/COBAS® TaqMan® CMV Test [CAP/CTM] or cobas 6800/8800 [cobas® CMV]) were tested with KT for analytical comparison. For KT, after cell-free DNA (cfDNA) was sequenced, human-derived reads were excluded bioinformatically, and remaining DNA sequences were aligned to a curated microbial pathogen database. KT results were reported as molecules per microliter (MPM). Linear regression was used to correlate log10 transformed CMV VL results within the overlapping quantifiable range of comparison assays. Using the regression equation to convert KT results from MPM to IU/mL, percent agreement was calculated and assay result agreement was analyzed with Bland-Altman plots. Allo-SCT recipients with CMV viremia were selected from the prospective observational DISCOVER trial (NCT02804464), and their plasma specimens were tested with KT. Mean differences in MPM between ≥7 days before start of antiviral treatment (D-7) and start of treatment (D0), and between D0 and ≥14 days after start of treatment (≥D14) were examined with Wilcoxon rank-sum tests. Results Among 125 residual samples tested by all 3 assays, 1 sample failed KT sequencing and was excluded from the analysis. Percent agreement between KT and cobas CMV (n = 124) was 94% using the cobas cut-off for negative samples (VL Conclusions High correlation was observed between KT and two FDA-approved CMV VL assays. KT identified significant increases in CMV VL at start of treatment and significant decreases at ≥14 post-treatment in allo-SCT recipients, showing potential clinical utility of KT as a monitoring assay, with the added value of detecting >1,000 pathogens in the same blood draw.

Enzyme-Linked Immunospot Assay as a Complementary Method to Assess and Monitor Cytomegalovirus Infection in Kidney Transplant Recipients on Pre-emptive Antiviral Therapy: A Single-Center Experience

BackgroundCytomegalovirus (CMV) disease represents a major cause of post-transplantation morbidity and mortality. To estimate the risk of infection and monitor response to antiviral therapy, current guidelines suggest combination of viral load monitoring with direct assessment of CMV-specific immune response. We used enzyme-linked immunospot (ELISpot) for the evaluation of CMV-specific T-cell response in kidney transplant recipients with CMV viremia and investigated how information gained could help manage CMV infection. MethodsSeventeen patients on pre-emptive antiviral therapy and CMV quantitative polymerase chain reaction (qPCR) ≥500 copies/mL (first episode after transplantation) were assessed using ELISpot and divided into Weak (9 patients with baseline ELISpot <25 spot-forming colonies [SFCs]/200,000 peripheral blood mononuclear cells [PBMCs]) and Strong Responders (8 patients with baseline ELISpot ≥25 SFCs/200,000 PBMCs). CMV-specific T-cell response, infection severity, viral load, and antiviral therapy were prospectively recorded and compared between groups at 1, 2, and 24 months of follow-up. ResultsDemographic and transplant characteristics of Weak and Strong Responders were similar. No episodes of CMV disease were observed. Weak Responders were more likely to experience CMV syndrome (56% vs 36.5%) and late virus reactivation (56% vs 25%) than Strong Responders. Weak Responders showed higher baseline median viral loads (19,700 vs 9265 copies/mL) and needed antiviral therapy for longer (179 vs 59.5 days). T-cell response showed 2 main patterns: early and delayed. ConclusionsELISpot provides prognostic information about infection severity, risk of late reactivation, and response to therapy. Randomized trials, evaluating the need for antiviral therapy in kidney transplant recipients with asymptomatic infection and effective virus-specific T-cell immune response, are warranted.

Clinical Utility of Viral Load in the Management of Cytomegalovirus Infection in Solid Organ Transplant Patients in Kuwait

BackgroundInfection with human cytomegalovirus (CMV) in solid organ transplant patients remains an unresolved challenge, despite improvements in immunosuppressive therapy, post-transplantation care, viral prevention, and therapy. MethodsWe conducted quantitative real-time polymerase chain reaction (PCR) assays of CMV on plasma samples of 1,168 patients in Kuwait who received solid organ transplants from 2012 to 2014 to detect and monitor CMV DNA viral load. ResultsOf the 1,168 patients, 180 (15.4%) were positive for CMV DNA. Among the CMV DNA–positive patients, 119 (66.1%) remained without symptoms and 61 (33.9%) developed CMV-related symptoms. During the follow-up period, peak viral loads were significantly (P < .05) higher in symptomatic patients (mean 970 copies/mL; range, 15–625,000 copies/mL) than in asymptomatic patients (<150 copies/mL; range, 67–2,650 copies/mL). Many symptomatic patients (n = 57) were successfully treated, and their viral loads declined. However, some symptomatic patients had irregular viral-load kinetics, with prolonged periods of symptoms despite CMV treatment; we excluded the possibility of drug resistance in these patients, because there was no evidence of clinical resistance to treatment. ConclusionsQuantitative real-time PCR of CMV DNA is useful in monitoring CMV infection and the effectiveness of CMV treatment in renal transplant recipients in Kuwait.

Methodology for monitoring cytomegalovirus infection after renal transplantation

The aim of this study was to evaluate the diagnostic value of different detection methods for cytomegalovirus (CMV) infection after renal transplantation and also to establish a system to monitor therapy for CMV infection. We retrospectively studied 1516 renal transplant recipients from June 1994 to December 2006. All patients were screened for CMV-DNA. A total of 1402 patients had received CMV-IgG/IgM detection since June 1996 and 660 had received CMV antigen detection since June 2000. A total of 664 (43.8%) recipients developed CMV infection. The sensitivity, specificity and Youden index of the three methods, respectively, were 18.84%, 100% and 0.1884 for ELISA, 91.86%, 82.98% and 0.7484 for PCR, and 88.06%, 96.95% and 0.8501 for the CMV-pp65 antigenemia test. The sensitivity and specificity of the two combined detection methods (CMV-DNA and CMV-pp65) for post-operation CMV infection were 93.49% and 99.06%; the two detection methods had significant dependability (p<0.05) in diagnosis of CMV infection and in evaluation of therapeutic effect of antiviral drugs. Only ELISA can be used as a screening index in order to distinguish whether the donors or recipients are infected with CMV or not. CMV-pp65 antigenemia can help guide clinical therapy for CMV infection. CMV-pp65 and CMV-PCR combined together provide a more effective method to monitor CMV infection and predict its outcome.

Concurrent Genotyping and Quantitation of Cytomegalovirus gB Genotypes in Solid-Organ-Transplant Recipients by Use of a Real-Time PCR Assay

We have developed a real-time genotyping and quantitative PCR (RT-GQ-PCR) assay to genotype cytomegalovirus (CMV) and quantify viral loads simultaneously in solid organ transplant (SOT) recipients. Special minor-groove DNA-binding probes were designed based on sequence polymorphism in the gB gene to increase genotyping specificity for gB1 to gB4. For validation, 28 samples with known genotypes determined by restriction fragment analysis (RFA) and 121 with unknown genotypes were tested. All samples were from SOT patients with CMV viremia. A 100% concordance for genotyping was achieved by using the RT-GQ-PCR with known genotypes determined by RFA. The RT-GQ-PCR identified more cases of CMV infections with mixed genotypes than RFA did. No cross-reaction between genotypes was observed. All four gB genotypes were detected in the 121 samples of unknown genotype. gB1 was the predominant single genotype (n = 61, 50.4%), followed by gB2 (n = 26, 21.0%), gB3, (n = 11, 9.1%), and gB4 (n = 3, 2.5%). Mixed-genotype infections were detected in 17% (20/121) of the samples. Patients with mixed-genotype infections had significantly higher CMV viral loads than those with single-genotype infections (P = 0.019). The RT-GQ-PCR assay was found to be highly sensitive and specific, with a wide dynamic range (2.7 to 10.7 log(10) copies/ml) and very good precision (coefficient of variation, approximately 1.78%). With the prominent feature of concurrent CMV gB genotyping and quantitation in a single reaction, the new assay provides a rapid and cost-effective method for monitoring CMV infection in SOT recipients.

Relationship of cytomegalovirus load assessed by real-time PCR to pp65 antigenemia in organ transplant recipients

Background Cytomegalovirus (CMV) infection in immunocompromised patients can lead to viremia associated with morbidity and mortality. Monitoring of viral loads in blood is critical for initiating and monitoring antiviral treatment. Objectives Validate quantitative real-time PCR assay targeting the US17 and UL54 regions of the CMV genome for automated DNA and extraction and amplification. Study design 3422 blood specimens from organ transplant recipients, including longitudinal specimens from 12 organ transplant recipients, were tested by CMV PCR and pp65 antigenemia. Results CMV PCR for both US17 and UL54, was more sensitive and detected CMV DNA earlier and for longer than the CMV pp65 antigenemia test. Using antigenemia results as a reference standard, an optimal cutoff of 500 normalized copies was calculated for both US17 and UL54 PCR targets based on high sensitivity, specificity, and positive and negative predictive values. CMV DNA levels tracked well with clinical symptoms, response to treatment, and antigenemia. Conclusions Detection of persistent increases in CMV DNA levels above 500 normalized copies by this real-time PCR assay is indicative of symptomatic CMV disease in organ transplant recipients. Quantitative real-time PCR for CMV DNA can be used in lieu of antigenemia for monitoring CMV infection and determining when to initiate preemptive treatment.

A prospective study comparing quantitative Cytomegalovirus (CMV) polymerase chain reaction in plasma and pp65 antigenemia assay in monitoring patients after allogeneic stem cell transplantation

BackgroundLow levels of Cytomegalovirus (CMV) viral load are frequently detected following allogeneic stem cell transplantation (SCT) and CMV disease may still develop in some allogeneic SCT patients who have negative pp65-antigenemia (pp65-Ag) or undetectable DNA. Pp65Ag is a sensitive method to diagnose CMV infection. Quantitative CMV-DNA PCR assay in plasma has been proposed to monitor CMV infection in SCT patients. We evaluated the clinical utility of pp65Ag and PCR assay in plasma of SCT recipients.MethodsIn a prospective longitudinal study, 38 consecutive patients at risk of CMV infection (donor and/or recipient CMV seropositive) were weekly monitored for CMV infection by both quantitative CMV-PCR in plasma (COBAS AMPLICOR CMV MONITOR) and pp65 Ag, during the first 100 days after SCT.ResultsA total of 534 blood samples were simultaneously analysed for pp65Ag and PCR. Overall, 28/38 patients (74%) had active CMV infection within 100 days from SCT. In 16 patients, CMV was first detected by pp65 Ag alone; in 5 patients by both methods and in 6 by PCR assay alone; one patient had CMV biopsy-proven intestinal disease without pp65Ag and PCR assays positivity before CMV disease. Overall, three patients developed intestinal CMV disease (7.9%): one had negative both pp65Ag and PCR assays before CMV disease, one had disease and concomitant positivity of both methods, while in the remaining patient, only pp65Ag was positive before CMV disease.ConclusionPlasma PCR(COBAS AMPLICOR CMV MONITOR) and pp65Ag assays were effective in detecting CMV infection, however, discordance between both methods were frequently observed. Plasma PCR and pp65Ag assays may be complementary for diagnosis and management of CMV infection.

Quantitative detection of cytomegalovirus DNA by real-time PCR in transplant recipients

目的 评价实时荧光定量聚合酶链反应(PCR)检测移植后受者的巨细胞病毒感染情况.方法应用定性PCR检测59例骨髓移植受者和9例肝移植受者的150份外周血标本中的巨细胞病毒DNA,比较外周血白细胞和血浆的检出差异;应用实时荧光定量PCR检测上述150份血浆样本和54份对照血浆中巨细胞病毒DNA载量.结果以实时荧光定量PCR为参照,定性PCR检测白细胞的敏感度和特异度分别为62.5%和95.5%;检测血浆的敏感度和特异度分别为57.5%和99.1%.所检测的150份血浆样本中,定量PCR阳性率为26.7%,阳性者其病毒拷贝数介于5.065×102～3.570×105/ml之间;对照组仅1例阳性,且拷贝数小于103/ml.临床调查显示病毒拷贝数大于5×103的患者具有较高的机会发展为巨细胞病毒病.结论实时荧光定量PCR是一个快速、敏感、特异的,可用于监测移植后患者巨细胞病毒感染的方法,帮助临床及早治疗,缩短治疗时间。

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. Objectives 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 (2000 copies/mL) and 3.8 log 10 copies/mL (6300 copies/mL), respectively. When WB viral load was ≥3.6 log 10 copies/mL, the risk to have a negative plasma CMV DNA result was ≤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.

Rapid Quantitative Analysis of Human Cytomegalovirus DNA by the Real-Time Polymerase Chain Reaction Method

Human cytomegalovirus (CMV) infection is a progressive and life-threatening complication in immunocompromised patients even now. Therefore, early and accurate treatment based on rapid and certain detection is needed to prevent fatal CMV infection diseases. To study a quicker, simpler, and less expensive method of quantitative analysis using real-time polymerase chain reaction based on the SYBR Green I method of CMV detection for appropriate treatment of CMV infection in immunocompromised patients. We quantified 50 samples tested by direct immunoperoxidase staining of leukocytes with peroxidase-labeled monoclonal antibody (C7-HRP test), 30 samples from healthy persons, and 47 samples from 7 patients suspected of having CMV infection diseases. We used the primer set in the pp65 gene of CMV and whole blood without a preparatory process. The setting for the study was the First Department of Pathology, Kurume University School of Medicine, St Mary's Hospital, and the Gene Section of the Clinical Laboratory at St Mary's Hospital, Fukuoka, Japan. The results obtained with this method corresponded well with conventional C7-HRP tests and demonstrated excellent reproduction. Additionally, the results were better correlated with the clinical course than were C7-HRP tests. This method was more useful than the C7-HRP test as a rapid diagnostic test for early treatment of CMV infection. This test also demonstrated its usefulness for monitoring CMV infection during treatment using ganciclovir. Moreover, it was quicker, simpler, and cheaper than other real-time polymerase chain reaction methods.

Diagnostic implications of human cytomegalovirus immediate early-1 and pp67 mRNA detection in whole-blood samples from liver transplant patients using nucleic acid sequence-based amplification.

Nucleic acid sequence-based amplification (NASBA) was used for detection of the human cytomegalovirus (CMV) immediate early-1 (IE) and the late pp67 mRNA in 353 blood samples collected from 34 liver transplant patients. The diagnostic value of these assays was compared to that of the pp65 antigenemia assay. Overall, 95 and 42% of the antigenemia-positive samples were IE NASBA and pp67 NASBA positive, respectively. Although the results from pp67 NASBA and the antigenemia assay appeared to correspond poorly, a clear correlation was seen between pp67 NASBA-negative results and low numbers of pp65 antigen-positive cells. Twenty patients (59%) were treated with ganciclovir after the diagnosis of symptomatic CMV infection. Before initiation of the antiviral therapy, the antigenemia assay detected the onset of symptomatic infection in all patients, whereas 95 and 60% of these patients were IE NASBA and pp67 NASBA positive, respectively. Although the sensitivity of IE NASBA was very high, the positive predictive value (PPV) of this assay for the onset of a symptomatic infection was only 63%. The PPV of the antigenemia assay as well as pp67 NASBA was considerably higher (80 and 86%, respectively). Thus, the detection of IE mRNA using NASBA appears to be particularly useful as a marker for early initiation of antiviral therapy in patients at high risk for the development of a symptomatic infection. Also, IE NASBA was found to be more sensitive than the antigenemia assay for monitoring CMV infection during antiviral therapy. On the contrary, pp67 NASBA did not appear to have additional diagnostic value compared to the antigenemia assay.

Best Tests To Predict and Monitor CMV Infection

Cytomegalovirus (CMV) infection in renal transplant patients may contribute to graft rejection. How best to distinguish such infection from asymptomatic viral shedding is contingent upon the efficacy of available detection methods. These French investigators compared 6 CMV assays in 30 renal transplant patients to ascertain which were the most useful in determining the …

Nucleic acid sequence-based amplification: a new technique for monitoring cytomegalovirus infection in transplant recipients

HE MAJORITY of the adult human population is infected with cytomegalovirus (CMV), a member of the b-herpesvirus family. Normally, infection of immunocompetent individuals does not cause disease. In contrast, infection of immunocompromised individuals, such as neonates, patients with AIDS, and transplant recipients, can cause severe complications and can even lead to death. Therefore, early detection of active CMV infection is necessary to start effective antiviral treatment. Nucleic acid sequence-based amplification (NASBA) has been developed for the specific amplification of RNA. 1 We evaluated the diagnostic value of monitoring the expression of the CMV immediate early (IE) 1 mRNA using NASBA, in peripheral blood cells of kidney and liver transplant patients. The IE 1 mRNA is expressed directly after entrance of the virus into a cell. NASBA results were compared to the techniques which are routinely being used for the detection of CMV: pp65-antigenemia, virus culture, and serology.

Definitions of cytomegalovirus disease after heart transplantation: antigenemia as a marker for antiviral therapy.

In this prospective study, cytomegalovirus (CMV) antigenemia was defined as the marker for initiation and episodes of antigenemia as the indicator for the duration of antiviral therapy (CMV hyperimmune globulin and ganciclovir). The CMV antigenemia assay and CMV-specific IgM and IgG antibody tests were used to monitor CMV infection in 22 heart transplant recipients who, between October 1992 and July 1994, were followed up for 6 months. A total of 178 out of 627 antigenemia assays tested positive. The highest number of positive cells was greater after primary infection than after either reactivation (43.3 vs 0.3; P < 0.01) or reinfection (43.3 vs 9.3; P = NS). Sixty episodes of antigenemia were observed. More episodes of antigenemia were seen after primary infection than after either reactivation (4.6 vs 0.2; P < 0.01) or reinfection (4.6 vs 2.2; P = NS). The detection of antigenemia indicated the initiation of antiviral therapy within 24 h after the blood sample was harvested. Therapy was stopped immediately after a subsequent negative result became available. Our experience indicates that antigenemia directed antiviral therapy prevents CMV disease after primary and secondary infection in heart transplant recipients.

Definitions of cytomegalovirus disease after heart transplantation: Antigenemia as a marker for antiviral therapy

Abstract In this prospective study, cytomegalovirus (CMV) antigenemia was defined as the marker for initiation and episodes of antigenemia as the indicator for the duration of antiviral therapy (CMV hy-perimmune globulin and ganciclovir). The CMV antigenemia assay and CMV-specific IgM and IgG antibody tests were used to monitor CMV infection in 22 heart transplant recipients who, between October 1992 and July 1994, were followed up for 6 months. A total of 178 out of 627 antigenemia assays tested positive. The highest number of positive cells was greater after primary infection than after either reactivation (43.3 vs 0.3; P < 0.01) or reinfection (43.3 vs 9.3; P = NS). Sixty episodes of antigenemia were observed. More episodes of antigenemia were seen after primary infection than after either reactivation (4.6 vs 0.2; P< 0.01) or reinfection (4.6 vs 2.2; P = NS). The detection of antigenemia indicated the initiation of antiviral therapy within 24 h after the blood sample was harvested. Therapy was stopped immediately after a subsequent negative result became available. Our experience indicates that antigenemia directed antiviral therapy prevents CMV disease after primary and secondary infection in heart transplant recipients.