Rapid immunodiagnosis of active cytomegalovirus infection by monoclonal antibody staining of blood leucocytes

The appearance of cytomegalovirus (CMV) antigen positive blood leucocytes (CMV antigenaemia) was investigated in 52 renal transplant recipients during the first three months after transplantation. Using a mixture of three monoclonal antibodies, CMV (immediate early) antigens were detected in cytocentrifuged blood leucocytes within 3-5 h after sampling. The results were related to virus isolation from buffy coats (CMV viraemia), serology with a sensitive enzyme-linked immunosorbent assay (ELISA), and clinical symptoms of CMV disease. The antigen test was positive in all 14 patients with CMV viraemia, in 25 out of 27 of patients with serological evidence of primary or secondary CMV infection, and in 2 out of 25 patients without active infection. In patients with a clinical CMV syndrome the presence of CMV antigen (CMV-Ag) positive blood cells correspond with the period of signs and symptoms. CMV antigens were not detected in 23 out of 25 patients without active infection, nor in healthy controls and patients with other herpesvirus infections. CMV-Ag positive blood cells appeared, on average, nine days before serological signs of active infection. This method provides a rapid and sensitive approach to CMV detection, enabling early clinical diagnosis and subsequent tapering of immunosuppression or commencement of antiviral therapy.     

Quantitation of cytomegalovirus DNA in lung tissue of bone marrow transplant recipients.

Five bone marrow transplant recipients who died of respiratory failure were retrospectively analyzed with polymerase chain reaction (PCR) assay for pulmonary cytomegalovirus (CMV) infection. Two patients had CMV interstitial pneumonitis according to the virus isolation and the histologic and immunofluorescent examinations of the lungs, while the other three patients had non-CMV diseases (ie, idiopathic interstitial pneumonitis, pulmonary aspergillosis, or Streptococcus mitis septicemia). Cytomegalovirus DNA was amplified from the postmortem lung tissue with PCR. The PCR assay showed apparent PCR signals specific to CMV DNA in the two patients with CMV pneumonitis. In contrast, CMV DNA was hardly detectable or undetectable in the three patients without CMV disease. With quantitative PCR assay the initial CMV copy number in the lung tissue of the two patients with CMV pneumonitis was more than 10(4) copies/micrograms DNA and was over 1,000-fold more than that of the three patients without CMV pneumonitis. These results show that quantitative PCR assay could be useful as a diagnostic measure for pulmonary CMV infection.     

Comparison of quantitative cytomegalovirus (CMV) PCR in plasma and CMV antigenemia assay: clinical utility of the prototype AMPLICOR CMV MONITOR test in transplant recipients

The correlation between the prototype AMPLICOR CMV MONITOR test (Roche Molecular Systems), a quantitative PCR assay, and the cytomegalovirus (CMV) pp65 antigenemia assay was evaluated in transplant recipients. Sequential blood specimens were collected on 29 patients (491 specimens), the leukocyte fraction was tested by CMV antigenemia, and quantitative PCR was performed on plasma specimens. None of the 15 patients (242 specimens) who were antigenemia negative were positive for CMV DNA by PCR, and none of these patients developed active CMV disease. There were 14 antigenemia-positive patients, 8 of whom developed active CMV disease. In all patients, there was a good association between the antigenemia and PCR assays. Ganciclovir-resistant virus was isolated from three patients with active CMV disease. These three patients had persistently elevated levels of antigenemia and CMV DNA by PCR when resistance to ganciclovir developed. This standardized, quantitative CMV PCR assay on plasma has clinical utility for the diagnosis of active disease and in monitoring the response to antiviral therapy in transplant recipients.     

Evaluation of the COBAS AMPLICOR CMV MONITOR test for detection of viral DNA in specimens taken from patients after liver transplantation

Detection of cytomegalovirus (CMV) DNA in blood by PCR is a sensitive method for the detection of infection in patients posttransplantation. The test, however, has low specificity for the identification of overt CMV disease. Quantitative CMV PCR has been shown to overcome this shortcoming. The COBAS AMPLICOR CMV MONITOR test was evaluated by using consecutive serum and peripheral blood mononuclear cell (PBMN) samples from liver transplant patients. Twenty-five patients had CMV viremia (by shell vial cell culture assay) and/or tissue-invasive disease (by biopsy); 20 had no active infection. A total of 262 serum and 62 PBMN specimens were tested. Of 159 serum specimens from patients with overt CMV infection, the COBAS assay detected CMV DNA in 21 patients (sensitivity, 84%). Only 1 of 103 samples from patients with no evidence of active infection had detectable CMV DNA (341 copies/ml). By comparison of 62 matching serum and PBMN samples by the same assay, 12 PBMN samples were exclusively positive, whereas only 2 serum samples were exclusively positive (P < 0.05). At the time of clinical CMV infection, viral copy numbers were higher in PBMNs than serum from four of five patients. The COBAS AMPLICOR CMV MONITOR test is a sensitive and specific test for the quantitative detection of CMV DNA in blood. Clinical applications of the assay will require further validation with samples from a larger population of transplant patients.     

Monitoring of cytomegalovirus infection in solid-organ transplant recipients by an ultrasensitive plasma PCR assay

Early and accurate monitoring of cytomegalovirus (CMV) infection in solid-organ transplant recipients is of major importance. We have assessed the potential benefit of an ultrasensitive plasma-based PCR assay for renal transplant recipients. The pp65 CMV antigen (pp65 Ag) assay using leukocytes was employed as a routine test for the monitoring of CMV in 23 transplant recipients. We compared the pp65 antigenemia with the CMV load quantified by an ultrasensitive PCR (US-PCR) with a limit of detection of 20 CMV DNA copies/ml of plasma. CMV infection was detected in 215 (67%) of 321 plasma samples by the US-PCR compared with 124 (39%) of 321 samples by the pp65 Ag assay. The US-PCR assay permitted the detection of CMV infection episodes following transplantation a median of 12 days earlier than the pp65 Ag assay. Moreover, during CMV infection episodes, DNA detection by the US-PCR was consistently positive, whereas false negative results were frequently observed with the pp65 Ag assay. We found a good correlation between the two assays, and the peak viral loads were significantly higher in patients with CMV-related complications (median, 5000 DNA copies/ml) than in those without symptoms (1160 DNA copies/ml) (P = 0.048). In addition, patients that did not require preemptive therapy based on the results of the pp65 assay had CMV loads significantly lower (median, 36 DNA copies/ml) than those that needed treatment (median, 4703 DNA copies/ml) (P < 0.001). These observations provided cutoff levels that could be applied in clinical practice. The ultrasensitive plasma-based PCR detected CMV infection episodes earlier and provided more consistent results than the pp65 Ag assay. This test could improve the monitoring of CMV infection or reactivation in renal transplant recipients.     

Monitoring levels of human cytomegalovirus DNA in blood after liver transplantation.

We evaluated a semiquantitative PCR assay prospectively in 40 liver transplant recipients as an aid in making a prompt diagnosis of cytomegalovirus (CMV) infection. For 2 months after transplantation, clinical specimens from patients were tested weekly by PCR, virus isolation from peripheral blood and urine, and CMV serology. The incidence of active CMV infection was 70%. The levels of CMV DNA determined by hybridization of PCR samples and densitometric scanning of blots were assigned a score of 1 to 4 by comparison with four external standards amplified in parallel and corresponding to a range of 80 to 80,000 genomes. The first detection of CMV in blood by PCR occurred at a mean of 15 days, and high-level PCR scores of 3 or 4 were obtained 21 days after transplantation, whereas viremia occurred 33 days after transplantation. Significantly higher levels of CMV DNA were seen in patients with CMV disease (P < 0.05) than in asymptomatic patients. The prevalence of symptomatic CMV infection was 30%. The positive predictive value of PCR was 48%, while the negative predictive value was 100%. After treatment, the clearance of CMV DNA was always observed and the disappearance of symptoms occurred concomitantly with undetectable PCR signals.     

Detection of cytomegalovirus in urine specimens from renal transplant recipients using polymerase chain reaction]

Human cytomegalovirus (CMV) in this study, a polymerase chain reaction (PCR) assay was developed to detect human cytomegalovirus (CMV) from urine specimens taken from renal transplant patients and one congenital CMV infection. Twenty eight urine specimens of 20 renal transplant patients were analyzed by the PCR. CMV infection was detected in 11 specimens (8 recipients). The incidence (40.0%) of PCR positive in the renal transplant patients was highest among the other conventional methods including fluorescent antibody study, anti-IgM EIA and complement fixation test. In two cases, CMV infection could be identified by PCR before antibody development. The PCR procedure is more sensitive and rapid than conventional methods for the diagnosis of CMV. Rapid diagnosis of CMV infection using PCR may be useful in clinical diagnosis and have therapeutic value.     

Qualitative and semiquantitative polymerase chain reaction testing for cytomegalovirus DNA in serum allows prediction of CMV related disease in liver transplant recipients

AIM: To identify cytomegalovirus (CMV) infection in liver transplant recipients by polymerase chain reaction (PCR) techniques and to separate the cases in which CMV related disease will occur, for whom treatment is indicated, from those in whom infection will remain innocuous. METHODS: The combination of qualitative and semiquantitative PCR of serum and urine was assessed to determine whether these assays can identify those at risk of CMV related disease and compared their performance with conventional approaches to diagnosis. RESULTS: Qualitative PCR of serum had superior specificity, sensitivity, and positive and negative predictive values compared with urine DEAFF (detection of early antigen fluorescent foci) and PCR of urine. All episodes of CMV related disease were associated with the presence of CMV DNA by PCR in serum or urine; CMV was detected before clinical onset in 70% and 60% of cases, respectively. The period over which CMV DNA could be detected was not correlated with CMV related disease. Both peak viral load and cumulative viral load estimated using a semiquantitative PCR method on serum samples positive by the qualitative method could be used to distinguish asymptomatic infection from CMV related disease with 100% specificity and sensitivity. In contrast semiquantitative PCR of urine was of little value. CONCLUSIONS: An approach based on PCR testing with a combination of qualitative and subsequently semiquantitative serum samples would improve the diagnosis of CMV infection and aid identification of those patients at risk of CMV related disease, allowing treatment to be targeted specifically.     

Human cytomegalovirus DNA in plasma and serum specimens of renal transplant recipients is highly fragmented

Quantitation of cytomegalovirus (CMV) DNA in plasma and serum by PCR is increasingly used to identify patients at risk for developing CMV disease and to monitor the efficacy of antiviral therapy. Although CMV DNA levels are generally interpreted as viral loads, the exact nature of the viral DNA in these specimens is unknown. We studied the state of CMV DNA in plasma and serum specimens obtained from three renal transplant recipients at peak viral DNA levels during primary CMV infection. For this purpose, DNA isolated from these specimens was fractionated by size, and CMV DNA levels in the resulting DNA fractions were measured by quantitative PCR targeted at large (578-bp) and small (134-bp) amplicons. These experiments showed that the molecular sizes of DNA fragments from which CMV DNA is amplified were small (<2,000 bp), indicating that CMV DNA in plasma and serum is highly fragmented. Furthermore, CMV DNA levels were consistently higher when targeted at the smaller amplicon, providing additional evidence for the fragmentation of viral DNA. In conclusion, the first results with three patients have shown that CMV DNA in plasma and serum is highly fragmented and does not necessarily reflect the amount of infectious virus. These observations have potential consequences for understanding CMV pathogenesis and interpreting CMV DNA levels in individual patient management.     

Comparison of PCR and pp65 antigenemia assay with quantitative shell vial culture for detection of cytomegalovirus in blood leukocytes from solid-organ transplant recipients.

This study compared PCR and an assay for cytomegalovirus (CMV) pp65 antigenemia (CMV-vue; INCSTAR Corp.) with a quantitative shell vial culture (QSVC) technique for the detection of CMV in serial blood specimens from 46 solid-organ transplant recipients. In a comparison based on 535 specimens tested by PCR and QSVC, CMV was detected by PCR in 41 and by QSVC in 37 of 43 recipients at risk of CMV infection. The mean number of days after transplantation of initial detection of CMV was 29.9 for PCR and 34.0 for QSVC (P = 0.01). The antigenemia assay was performed on 395 specimens, including 304 of those also tested by PCR. In these specimens, CMV was detected by the antigenemia assay, QSVC, and PCR in 30, 32, and 35 (respectively) of 38 patients at risk, with no statistically significant difference in the time to detection. Each of the assays detected CMV in similar proportions of patients with and without clinically significant CMV infection. PCR stayed positive longer after transplantation than the other assays but frequently returned to negative when more than 6 months had elapsed after transplantation. The antigenemia assay and PCR stayed positive longer after institution of antiviral therapy than QSVC. PCR can provide highly sensitive detection of CMV viremia, but a PCR assay for CMV is not yet available in kit form. The pp65 antigenemia assay and shell vial culture are quantifiable and comparable in sensitivity. Either is recommended for rapid detection of CMV in blood specimens from solid-organ transplant recipients.     

Evaluation of Murex CMV DNA Hybrid Capture Assay for Detection and Quantitation of Cytomegalovirus Infection in Patients following Allogeneic Stem Cell Transplantation

Murex hybrid capture DNA assay (HCS) is a solution hybridization antibody capture assay for detection and quantitation of cytomegalovirus (CMV) DNA in leukocytes. To determine whether CMV HCS is sensitive enough to initiate and monitor antiviral therapy after allogeneic stem cell transplantation (SCT), 51 consecutive SCT recipients were prospectively screened for the appearance of CMV infection by HCS, PCR, and culture assays from blood samples. Preemptive antiviral therapy was initiated after the second positive PCR result in all patients, as previously reported, and HCS was not considered for clinical decision making. A total of 417 samples were analyzed. Of these, 21 samples were found to be positive by PCR and HCS, 88 samples were PCR positive but HCS negative, and 308 were negative by both assays. Concordance of results between PCR and HCS and between HCS and blood culture was observed in 78.9 and 95.9% of the samples assayed, respectively. PCR was found to be more sensitive than HCS, and HCS was more sensitive than the blood culture assay (P < 0.0001). Four patients with symptomatic CMV infection were PCR positive prior to the onset of CMV-related symptoms, whereas HCS detected CMV DNA in three patients prior to and one at onset of CMV disease. The numbers of genomes per milliliter of blood were higher in patients with symptomatic CMV infection than in those with asymptomatic CMV infection (P = 0.06). None of the HCS-negative patients developed CMV disease. Thus, all patients with CMV disease were correctly identified by HCS; however, the lower sensitivity limit of the HCS assay may still be insufficient to allow diagnosis of CMV infection early enough to prevent CMV disease in patients following allogeneic SCT.     

Cytomegalovirus diagnosis in renal and bone marrow transplant recipients: the impact of molecular assays.

BACKGROUND: Cytomegalovirus (CMV) infections are a major threat in transplant recipients. In recent years, new assays for routine CMV diagnosis, based on molecular techniques, have become available. OBJECTIVE: The impact of molecular assays for CMV diagnosis in transplant recipient was evaluated. STUDY DESIGN: A total of 51 transplant recipients were screened for CMV infection. Serological (AxSYM CMV IgG and recombinant CMV IgM assays), antigenemia, CMV DNA (qualitative in house PCR and the quantitative COBAS AMPLICOR CMV MONITOR Test), and CMV mRNA (NucliSens CMV pp67 Test) tests were compared. RESULTS: In 11/20 bone marrow transplant (BMT) recipients and 10/31 renal transplant (RTX) recipients there was no evidence of active CMV infection. Ten RTX recipients and one BMT recipient were antigenemia positive, 21 RTX and seven BMT recipients were PCR positive (qualitative CMV PCR). There were more BMT recipients CMV DNA positive in serum (7/21) than antigenemia positive (1/21). CMV mRNA was found positive in two BMT recipients (one case with no other evidence of CMV infection, the other one CMV DNA positive and antigenemia negative). The only antigenemia positive BMT recipient was found negative for CMV mRNA, but positive in all other tests. Eight RTX recipients were found positive for CMV mRNA. Six of them were also antigenemia positive and five of those were also found positive for CMV IgM. One CMV mRNA positive RTX recipient was CMV IgM positive but antigenemia negative and the other one CMV mRNA positive RTX recipient was found negative in all other tests. Two antigenemia positive RTX recipients were found negative for mRNA and CMV IgM. CONCLUSION: Antigenemia was found to be a good screening test for CMV infection in RTX recipients. In BMT recipients, tests based on molecular techniques appeared to be superior compared to antigenemia.     

Use of Laboratory Assays To Predict Cytomegalovirus Disease in Renal Transplant Recipients

Eight laboratory assays, viz., the pp65 direct antigenemia test, a quantitative cytomegalovirus (CMV)-specific immunoglobulin G (IgG) assay (Biomerieux VIDAS), a CMV-specific IgM assay (Biomerieux VIDAS), the Hybrid Capture system (Murex), an in-house PCR with plasma (P-PCR) and leukocytes (L-PCR), and a commercial PCR (Roche AMPLICOR) with plasma (P-AMP) and leukocytes (L-AMP), were compared for their abilities to predict CMV disease before the onset of illness in a prospective study of 37 renal transplant recipients. By using an expanded criterion for active infection (two or more of the markers positive) and a clinical definition of disease, 22 (59%) patients were identified as having active CMV infection and 13 (35%) were identified as having CMV disease. Of the 13 CMV-seronegative recipients who received seropositive kidneys (R− group), 8 had active infection and disease. All assays were 100% specific and 100% predictive of CMV disease in the R− group. The leukocyte PCRs (L-PCR and L-AMP) were the most sensitive assays, had positive results an average of between 8 and 13 days before the onset of illness, and were the assays of choice. The performance of the assays was less satisfactory for the 24 patients who were CMV seropositive before transplantation (R+ group). A negative result was more useful for this group. Overall, P-AMP had the best results, and it could be the assay of choice for monitoring R+ patients. The non-PCR-based methods generally had high specificities but often gave late positive results and were not sensitive enough for use as prediction tools for either group of patients.     

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.     

Factors influencing the occurrence of active cytomegalovirus (CMV) infections after organ transplantation.

In this study, several factors influencing the occurrence of active CMV infection after organ transplantation (Tx) are analysed. For this purpose, 105 heart, kidney and lung transplant recipients who were CMV-positive or had a CMV-positive donor, were closely monitored for active CMV infection by antigenaemia, cultures, CMV serology and lymphocyte proliferation (LP) to CMV. Univariate and multivariate regression analysis were performed. As pretransplant risk factors the HLA-type and numbers of HLA mismatches between recipients and their donors, and the CMV serology of the recipient and donor were analysed. A new finding was that recipients of donors positive for HLA-B7 were especially at risk for developing active CMV infection (P = 0.03) and CMV disease (P = 0.03). This was not due to increased rejection treatment in these patients. Post-transplant risk factors for development of active CMV infection were absence of detectable cellular immunity to CMV (lymphocyte proliferation) after Tx (P < 0.01) and rejection treatment with OKT3 or ATG (P = 0.05). High levels of IgG anti-CMV did not prevent occurrence of active CMV infection or CMV disease in the CMV+ recipients.     

Comparison of three PCR techniques for detecting cytomegalovirus (CMV) DNA in serum, detection of early antigen fluorescent foci and culture for the diagnosis of CMV infection.

Three PCR assays were developed for detection of cytomegalovirus (CMV) DNA in serum and were evaluated with samples from organ transplant recipients. The Qiamp Blood Kit was efficient for extraction of DNA from sera. Single-round PCR of a 293-bp region of CMV DNA was sensitive and highly specific for CMV targets and was more sensitive than detection of early antigen fluorescent foci (DEAFF) testing or isolation of CMV from buffy coat by cell culture. The results of a significant proportion of buffy coat samples were not interpretable because of toxicity in conventional culture or DEAFF tests. A non-competitive quantitative PCR test and semi-quantitative PCR test for the detection of CMV DNA in serum yielded comparable results for samples taken serially from three bone marrow transplant recipients. Single-round PCR was superior to conventional techniques for the diagnosis of CMV infection, was simple to perform and was completed rapidly. The semi-quantitative technique has added advantages where quantification is important.     

Monitoring of leukocyte cytomegalovirus DNA in bone marrow transplant recipients by nested PCR.

A nested PCR assay for the detection of human cytomegalovirus (CMV) DNA was evaluated by weekly monitoring of blood samples taken from 101 bone marrow transplant (BMT) recipients. When peripheral blood leukocytes were used as the source of CMV DNA, even a modified assay with stringent temperature-cycling conditions was as sensitive as the standard assay. The sensitivity, specificity, and positive predictive value of two consecutively positive leukocytic PCR results with this modified assay in predicting CMV disease of 101 patients submitting 1,441 peripheral blood leukocyte samples were found to be 92.1, 63.5, and 60.3%, respectively. The positive predictive value of patients' seropositivity for CMV was 40%, while that of viremia was 72%. However, viremia followed CMV disease by a median of 1.5 days, while the first leukocytic positive PCR assay preceded disease by a median of 14 days. By use of the criteria of two consecutively positive PCR results instead of recipient CMV seropositivity for starting preemptive ganciclovir treatment, 38 of the 43 recipients with isolated single positive or negative assays (groups I and II) would be spared unnecessary ganciclovir treatment. Moreover, two other findings support the use of antiviral prophylaxis before engraftment in high-risk cases and subsequent preemptive treatment of patients with two consecutively positive PCR assays. First, for 7.9% of 76 patients with positive assays (groups II and III), the first positive PCR assay occurred before engraftment, which implied the presence of viral DNA in the blood (DNAemia) soon after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of PCR, antigenemia assay, and rapid blood culture for detection and prevention of cytomegalovirus disease after lung transplantation

The goal of this study was to evaluate serial cytomegalovirus (CMV) blood culture, antigenemia testing, and qualitative and quantitative plasma CMV PCR for their ability to predict CMV disease and thus to direct preemptive therapy after lung transplantation. Forty-one patients provided 414 samples for blood culture, 290 samples for antigenemia testing, and 432 samples for PCR. Seven patients developed 11 episodes of CMV disease. CMV PCR had sensitivity, specificity, and positive predictive and negative predictive values of 79, 99, 84, and 99%, respectively, compared with 48, 99, 85, and 98%, respectively, for antigenemia testing, and 8, 100, 100, and 97%, respectively, for culture. Only quantitative CMV PCR correlated with disease stage: asymptomatic patients had a mean of 1,500 CMV DNA copies/ml, whereas patients who developed CMV disease had 5,087 copies/ml 12 to 4 weeks before symptoms and 32,000 copies/ml at diagnosis. Furthermore, CMV PCR-measured DNA increased 5- to 10-fold immediately preceding symptoms. PCR and antigenemia test values decreased with anti-CMV therapy. CMV DNA (as detected by PCR), but not antigenemia, persisted in patients who later developed recurrent CMV disease. The data indicate that lung transplant recipients will benefit from monitoring of CMV disease by plasma CMV PCR.     

Evaluation of diagnostic methods for the detection of cytomegalovirus in recipients of allogeneic stem cell transplants.

BACKGROUND: Although several diagnostic methods are available for the surveillance of patients at risk of human cytomegalovirus (CMV) infection and disease, little data is available on their comparative performances in the diagnostic setting. OBJECTIVES: To compare different assays for CMV detection, especially assays based on (quantitative) DNA and mRNA detection. STUDY DESIGN: Eight allogeneic bone marrow and stem cell transplant recipients at high risk for developing CMV disease (donor CMV-negative, recipient positive) were regularly tested for 7-20 weeks post-transplant by spin-amplification rapid culture from urine (viruria), antigenemia (pp65 assay), pp67 mRNA in whole blood (NASBA), and CMV DNA both qualitatively (in-house PCR, whole blood) and quantitatively (in-house PCR, plasma; Cobas Amplicor CMV Monitor Test, plasma and whole blood; Hybrid Capture, whole blood). RESULTS: Four patients (50%) suffered CMV reactivation during follow-up. Out of 104 sample dates, 41 (39.4%) yielded a positive CMV result in at least one assay. Out of the 28 samples tested by all assays, the highest percentage of positive results was obtained with the in-house quantitative PCR (60.7%), followed by the Hybrid Capture system (39.3%), the Cobas Amplicor CMV Monitor Test, plasma version (35.7%), the Cobas Amplicor CMV Monitor Test, whole blood version (32.1%), in-house qualitative PCR (28.6%), and the mRNA assay (21.4%). Viruria was positive in one sample and pp65 antigenemia was found in two samples. CONCLUSIONS: Despite a considerable incidence of CMV reactivations, pre-emptive anti-CMV chemotherapy prevented the development of CMV disease with the exception of one case. The molecular assays had superior sensitivity to conventional ones. The antigenemia assay proved unsuitable for the surveillance of hematological transplant patients. However, none of the tests recognized all timepoints with CMV reactivation. Further comparative studies are needed to determine their respective diagnostic values.     

Antibodies to cytomegalovirus in renal allograft recipients: correlation with isolation of virus.

A cohort of 47 renal transplant recipients was studied prospectively for up to one year after transplantation. Cytomegalovirus (CMV) was isolated from 21 of the patients. The first time the virus was isolated seven patients were IgM positive, nine showed a significant rise in IgG titres, and 12 had a four-fold or greater rise in complement fixation titre. There was no significant difference in the time at which virus was first detected following transplantation between patients with primary CMV infection and those with reinfection or recurrent infection. In general, patients with primary infection shed virus consistently over long periods. Those with reinfection or recurrent infection shed virus intermittently or not at all. There were considerable differences between individual patients in the timing and pattern of the immune response. Taken overall, a four-fold rise detected by the complement fixation test correlated best with the onset of CMV shedding in primary infection. There was more variation in the pattern of antibody response in cases of reinfection or recurrent infection, with no single serological test correlating better than the others. It is concluded that serology is of limited value in the detection of active CMV infection after renal transplantation.