实时定量PCR方法监测肾移植患者血浆巨细胞病毒DNA载量及其意义

目的 采用实时定量荧光PCR方法检测巨细胞病毒(CMV)DNA拷贝数,探讨病毒载量变化在诊断CMV活动性感染中的意义和指导抗病毒治疗中的作用.方法 对40例采用预排空治疗策略预防CMV病的肾移植受者同时进行CMV抗原血症(pp65)分析和病毒载量监测并进行随访,观察CMV-DNA载量和pp65在判断肾移植受者CMV活动性感染和指导抗病毒治疗中的价值.结果 264份样本中逆转录-聚合酶链反应(RT-PCR)检测57份阳性(21.59%),病毒载量水平2.648×101～5.273×105copy/ml;抗原血症分析检测48份阳性(18.18%),抗原指数1～18/5万WBC;Cohen,s-Kappa检验结果表明两种检测方法一致性良好(Kappa=0.762).25例(62.5%)患者PCR方法检测阳性,19例(47.5%)抗原血症分析阳性.病毒载量首次出现阳性时间为(13.22±14.78)d,pp65首次出现时间为(26.72±20.61)d,差异有统计学意义(P＜0.05).40例患者中4例出现CMV病,发病时间133～179 d,3例发病前pp65和CMV-DNA均为阳性,1例仅CMV-DNA阳性.结论 血浆CMV载量检测与抗原血症分析一致性良好,而敏感性较高,更准确反映肾移植术后CMV活动性,更适合用于肾移植术后预防CMV感染的预排空治疗策略.     

Monitoring of human cytomegalovirus infections in heart transplant recipients by pp65 antigenemia

BACKGROUND: Rapid diagnostic techniques offer the opportunity of early diagnosis of human cytomegalovirus (CMV) infection in immunocompromized patients at risk of developing CMV disease and syndrome. The use of CMV pp65 antigenemia as a predictor of CMV syndrome and disease in heart transplant recipient after induction therapy was studied retrospectively. METHODS: One hundred and nineteen consecutive heart transplant recipients treated with induction therapy who survived more then 14 d were monitored for CMV infection. Ninety-four recipients were seropositive for CMV. Twenty-five recipients were seronegative for CMV and received grafts from seropositive donors. Pre-emptive therapy was used in seropositive patients when CMV pp65 antigenemia was greater than 50 antigen-positive cells per 2 x 10(5) peripheral blood leukocytes (PBL); prophylactic therapy was done only in seronegative recipient matched with seropositive donor. RESULTS: High-level CMV pp65 antigenemia (50 antigen-positive cells 2 x 10(5) PBL) occurred in 34% (41 of 119) of patients at a median of 44 d following transplantation. In seropositive recipients, 16% (15 of 94) of patients developed CMV invasive disease or syndrome, and in seronegative recipients 20% (5 of 25) of patients developed CMV disease or syndrome. Sixty-six per cent (62 of 94) of CMV seropositive patients were identified as not requiring pre-emptive therapy. In seropositive and seronegative recipients, the sensibility and negative predictive value of the cut-off level of 50 antigen positive cell for CMV disease and syndrome was 100%. The specificity was 79% and positive predictive value was 49%. CONCLUSION: Because of the excellent sensibility and negative predictive value of the cut-off level of 50 antigen positive cell per 2 x 10(5) PBL, application of pre-emptive therapy guided by high level of CMV pp65 antigenemia in the context of induction therapy allow to omit antiviral therapy in many at risk patients. In the context of pre-emptive and prophylactic therapy, the cut-off level of 50 antigen positive cell do not allow to predict with accuracy the development of CMV disease or syndrome.     

Cytomegalovirus infection in organ-transplant recipients: diagnostic value of pp65 antigen test, qualitative polymerase chain reaction (PCR) and quantitative Taqman PCR

BACKGROUND: The human cytomegalovirus (CMV) is a major cause of morbidity and mortality in transplant patients. In this study, we compared the diagnostic value of pp65 antigen test, qualitative nested polymerase chain reaction (PCR), and quantitative Taqman PCR in predicting the clinical outcome of CMV infection. METHODS: A total of 169 samples derived from 59 organ-transplant recipients (kidney n= 46, liver n= 11, kidney and pancreas n= 2) were analyzed. Peripheral blood leukocytes (PBL) were isolated using dextran gradient centrifugation, and 2 x 10 cells were analyzed for pp65 antigen by immunofluorescence. A crude DNA extract obtained from the same number of cells was used for qualitative nested PCR and quantitative Taqman PCR analysis. RESULTS.: The correlation coefficient of pp65 antigen test and Taqman PCR was R= 0.699 (P = 0.001). With cut-off values for pp65 antigen test set at greater than 10 positive nuclei per 2 x 10 PBL, sensitivity was 91%, and positive predictive value (PPV) was 70%. When the corresponding cut-off value for Taqman PCR was applied (>125000 genome copies per 2 x 10 PBL), a sensitivity of 83% and a PPV of 68% were found. Both assays allowed for the monitoring of successful antiviral therapy. Although qualitative nested PCR was highly sensitive (95%), it was less useful in predicting CMV disease (PPV 47%) and in therapy control. CONCLUSION: Our data show that pp65 antigen test and Taqman PCR are almost equivalent in the monitoring of CMV infection and disease when identical cell numbers are used for both assays.     

Antigenemia for cytomegalovirus in renal transplantation: choosing a cutoff for the diagnosis criteria in cytomegalovirus disease

Cytomegalovirus (CMV) infection is a frequent complication in transplant recipients, causing a high level of morbidity and mortality. We studied 203 consecutive renal transplant recipients performed between January 2000 and December 2001. Patients underwent weekly measurements of CMV pp65 antigen to assess CMV activity from the 4th to the 12th week posttransplantation. The results were reported as number of cells positive for the pp65 antigen among 10(5) granulocytes. In order to define a best cutoff to diagnose CMV disease with desirable sensitivity and specificity, we used a receiver operator characteristics (ROC) curve. The cutoff of four positive cells corresponded to a sensitivity of 93% and specificity of 60% (AUC = 0.87) for the diagnosis of CMV disease. The chosen cutoff for starting antiviral treatment was 10 cells, since this was associated with a sensitivity of 92% and specificity of 70% (AUC = 0.90). In conclusion, the highly sensitive cutoff points for the diagnosis of antigenemia was four cells and 10 cells for initiation of antiviral therapy.     

Preemptive Therapy in Adult Liver Transplant Recipients in CMV-Endemic Area

Cytomegalovirus (CMV) infection is not only a common complication after liver transplantation but also a significant contributing factor to morbidity and mortality. We investigated whether preemptive therapy can prevent CMV syndrome or tissue-invasive CMV disease in an endemic area. Preemptive therapy was initiated when more than 10 positive CMV pp65 antigen-positive cells per 400,000 white blood cells were detected, regardless of clinical manifestations. Intravenous ganciclovir as preemptive therapy was administered daily for 10 to 14 days until negative results were achieved. The incidence of initial CMV antigenemia and CMV syndrome during the posttransplantation period was 49.7% (353/710) and 5.2% (37/710), respectively. One hundred eight-two patients (51.6%) received ganciclovir as preemptive therapy. Patients with CMV antigenemia who received preemptive therapy had high Model for End-Stage Liver Disease score, repeat operation, renal dysfunction, infection, low hemoglobin concentration, low platelet count, low albumin concentration, high international normalized ratio, high total bilirubin value, high aspartate transaminase concentration, and high CMV peak titer. Cytomegalovirus syndrome and tissue-invasive CMV disease were more common in these patients. The survival curve in patients without CMV syndrome was better than that in those with CMV syndrome (P = .000). Patients with more than 10 pp65 antigen-positive cells per 400,000 white blood cells should be treated aggressively with an antiviral agent as preemptive therapy because CMV infection is common in CMV-endemic areas and patients with CMV syndrome demonstrate poor survival rates.     

Successful preemptive cidofovir treatment for CMV antigenemia after dose-reduced conditioning and allogeneic blood stem cell transplantation

BACKGROUND: Cidofovir (CDV) is a nucleotide analogue with proven in vitro effects against cytomegalovirus (CMV) and adenovirus and has been successfully used in the treatment of CMV retinitis in AIDS patients. METHODS: We performed a prospective study to evaluate the efficacy of CDV in 17 patients with hematological malignancies after allogeneic blood stem cell transplantation from related (n=3) and unrelated (n=14) donors. Dose-reduced conditioning (DRC) regimen consisted of busulfan (Bu)/fludarabine (Flu) (n=9) and idarubicin/cytosine arabinoside/Flu (n=1). Myeloablative conditioning (MC) was performed with Bu/cyclophosphamide (Cy)/etoposide (Eto) (n=4), Bu/Cy (n=2), and total body irradiation (TBI)/Cy/Eto (n=1). Antithymocyte globulin (ATG) was used in seven patients with DRC and in six patients with MC. In all patients, either the donor, host, or both were CMV IgG positive pretransplant. Indication for therapy was preemptive treatment of primary CMV antigenemia defined as two consecutive positive tests of pp65 antigenemia assay after transplant. In case of response with a decreasing number of pp65-positive leukocytes, CDV was scheduled in a dosage of 5 mg/kg body weight once a week for 2 weeks followed by maintenance therapy every 2 weeks in an outpatient setting. All patients received probenecid and prehydration as recommended. Patients were monitored using an immunostaining assay for pp65 antigen and a qualitative and quantitative CMV polymerase chain reaction (PCR). Success of treatment was defined as negativity for the pp65 antigen. RESULTS: After DRC, nine of ten patients (90%) showed a response with seven of nine revealing a complete clearance of the virus (pp65 negative, qualitative PCR negative). In the remaining two responders, treatment was changed to ganciclovir because of either renal impairment or slow clearance of antigenemia. Only one of seven patients in the MC group experienced a temporary clearance of pp65 antigen. After MC, two patients experienced CMV disease. Treatment-related toxicity rate was moderate with four patients developing reversible renal impairment (creatinine 133-180 micromol/L); one patient with proteinuria and three patients with complaints of nausea and vomiting. CONCLUSION: Our data suggest the feasibility of CDV administration in patients after allogeneic transplantation. In the recommended dose, it might be used successfully for low-risk patients, e.g., after DRC or organ transplantation, in an outpatient setting.     

A prospective study of the natural course of cytomegalovirus infection and disease in renal allograft recipients

BACKGROUND: Cytomegalovirus (CMV) infection is the single most frequent infectious complication in renal transplant recipients. Because no CMV-prophylaxis is given and ganciclovir is used only as deferred therapy for CMV disease at our center, we have been able to study the natural course of CMV infections. The aim was to assess risk factors for CMV infection and disease and thus identify subgroups of patients likely to benefit from CMV prophylaxis or preemptive therapy. METHODS: Between October 1994 and July 1997, 477 consecutive renal transplant recipients (397 first transplants and 80 retransplants) were included in the study. The patients were followed prospectively for 3 months with serial measurements of CMV pp65 antigen for monitoring activity of CMV infections. RESULTS: The incidence of CMV infections in first transplants was 68% in D+R- and D+/-R+ serostatus groups, whereas the incidence of CMV disease was higher in D+R- (56%) than in D+/-R+ (20%, P<0.001). No difference in severity of CMV disease in D+R- and D+/-R+ was seen except for an increased incidence of hepatitis in primary infections. One of 14 deaths could be associated with CMV disease in a seropositive recipient. Cox regression analysis showed that rejection (RR 2.5, P<0.01) and serostatus group D+R- (RR 3.9, P<0.001) were significant risk factors for development of CMV disease. The maximum CMV pp65 antigen count had significant correlation to disease only in CMV seropositive recipients, P<0.001. Conclusion. Renal transplant recipients can safely be given deferred ganciclovir therapy for CMV disease if they are intensively monitored for CMV infection. Patients with primary CMV infection (D+R-), CMV infected patients undergoing anti-rejection therapy and R+ patients with high CMV pp65 counts seem to have a particular potential for benefit from preemptive anti-CMV-therapy.     

Pre-emptive therapy of CMVpp65 antigen positive renal transplant recipients with oral ganciclovir: a randomized, comparative study.

BACKGROUND: About one-quarter of renal transplant patients will suffer from symptomatic cytomegalovirus (CMV) disease if no preventive therapeutic measures are taken. In this prospective, randomized single-centre study pre-emptive therapy with oral ganciclovir is compared with conventional deferred treatment. METHODS: Renal transplant recipients (n= 455) over 18 years of age were screened weekly for CMV pp65 antigenaemia during the first 12 weeks post-transplantation. If CMV pp65 antigen in leukocytes appeared within 8 weeks post-transplantation patients were randomized and included in the study. Five patients developed CMV disease before positive CMV pp65, and 14 patients with a positive antigen test developed CMV disease before randomization could take place, all these representing a limitation of the applicability of the results in the overall renal transplant population. Altogether 179 patients were not randomized for various reasons. Eighty patients completed the study, 42 were randomized to receive pre-emptive oral ganciclovir therapy and 38 to conventional deferred treatment (control group). RESULTS: Time from transplantation to start of ganciclovir capsules was 36 (12-60) days and duration of oral ganciclovir therapy was 49 (27-70) days, median (range). No patient in the pre-emptive treatment group, but nine of 38 patients (23.7%) in the control group, developed CMV disease during the first 12 weeks post-transplantation (P= 0.0009). In the period from 3 months to 1 year post-transplantation, two patients in each group developed CMV disease. There were no significant differences in acute rejection or renal function between treatment groups during the first post-transplant year. CONCLUSIONS: Pre-emptive oral ganciclovir therapy in renal transplant recipients during the first 12 weeks post-transplantation effectively prevents CMV disease during this time period. The incidence of late CMV disease (3 months to 1 year after transplantation) was similar in the two groups, indicating that pre-emptive therapy does not result in late onset of CMV disease.     

Prospective randomized trial to assess the value of preemptive oral therapy for CMV infection following liver transplantation

BACKGROUND: With the development of sensitive tests to detect cytomegalovirus (CMV) viremia, preemptive approaches become a reasonable alternative to general CMV prophylaxis. We performed a randomized trial comparing pp65-antigenemia guided preemptive therapy using oral ganciclovir with symptom-triggered intravenous ganciclovir treatment. METHODS: Eighty-eight of 372 liver transplant recipients developed antigenemia early after orthotopic liver transplantation. Twenty-eight symptomatic patients with antigenemia were excluded from randomization and treated with intravenous ganciclovir. Sixty pp65-antigen-positive asymptomatic patients were randomized to receive either oral ganciclovir 3x1 g/day for 14 days (group 1) or no preemptive treatment (group 2). Patients that developed CMV disease were treated with intravenous ganciclovir 2x5 mg/kg body weight for 14 days. The high-risk (Donor+/Recipient-) patients were equally distributed in the two study groups. RESULTS: Three of 30 (10%) patients on oral ganciclovir developed mild to moderate CMV disease compared with 6/30 (20%) patients in the control group. In the Donor+/Recipient- patients, the incidence of CMV disease was 1/6 and 3/7. All disease episodes resolved after intravenous treatment. The 1- and 3-year patient and organ survival was the same in the study groups and in the patients with or without CMV infection. No deaths related to CMV occurred. CONCLUSIONS: The positive predictive value of pp65-antigenemia for the development of CMV disease was very low, and, in 28/88 patients (32%), antigenemia did not precede symptoms. Therefore, pp65-antigenemia is of limited value in deciding on the timing and need for ganciclovir therapy after liver transplantation.     

Cytomegalovirus disease latent and active infection rates during the first trimester after kidney transplantation

Cytomegalovirus (CMV) infection is the single most frequent infectious complication in renal transplant recipients. The aim of this study was to determine the incidence of latent and active infections with CMV during the first 3 months after kidney transplantation. From January 2000 to December 2001, 203 consecutive adult renal transplant recipients underwent weekly measurements of pp65 CMV antigen from the 4th to the 12th posttransplantation week. Latent infection (seropositivity) was found in 92% of the population. Primary infection occurred in 4.9% (10 of 203), among whom 66% were previously seronegative patients. Among the primary infection patients, 70% (7 of 10) developed severe disease. The overall incidence of viremia was 69.5%, being more frequent among cadaver recipients (79% vs 59%; P =.02). The overall incidence of CMV disease was 38.4% (78 of 203) with 24.6% classified as severe disease requiring antiviral therapy. In conclusion, our population showed a high prevalence of latent infection with viremia. Not all patients developed clinical disease. Most subjects experienced a mild spectrum of symptoms, probably due to the prospective search for active infection during the major risk period after kidney transplantation.     

Role of antigenemia assay in the early diagnosis and treatment of CMV infection in renal transplant patients

AIM: CMV antigenemia by direct pp65 antigen detection and quantification was monitored on a weekly basis during the first 3 months after kidney transplantation. SUBJECTS AND METHODS: Preemptive therapy with ganciclovir was started according to the following criteria: any positive antigemia in CMV-NEG subjects, a single determination > or = 30 cell or a two fold increase of positive cells in two consecutive specimens in CMV-POS and continued until pp65 was cleared. Overall, 109 patients were monitored. RESULTS: Among the 24 CMV-NEG patients, 13 (54%) developed a pp65 positive assay without symptoms and were treated. Ten patients remained CMV-infection free and one patient developed late onset (7 months) CMV disease (hepatitis). Among the 85 POS patients 15 (17%) developed a pp65 positive assay and were treated. Two of them developed CMV disease within 7 days of the onset of positive antigenemia and 13 were asymptomatic. The other 70 patients remained CMV-infection free. The interval between transplant and the onset of CMV infection was 39 +/- 13 days in the CMV-NEG group and 64 +/- 20 days in the CMV-POS group (p < 0.001). The peak antigenemia level was 193 +/- 175 cells in the CMV-NEG group and 55+/- 78 cells in the CMV-POS group (p < 0.001). The duration of treatment did not differ in the two groups (22 +/- 7days). A second course of therapy, due to a relapse of asymptomatic infection was performed in 11/13 (85%) treated CMV-NEG patients and in 2/15 (13%) treated CMV-POS patients. CONCLUSIONS: Among the total 28 treated patients, we observed only 6 episodes of mild creatinine increase and 9 episodes of mild neutropenia. In the overall population, we observed 8 systemic infections not related to CMV.     

An Assessment of Herpesvirus Co-infections in Patients with CMV Disease: Correlation with Clinical and Virologic Outcomes

The effect of herpesvirus co-infections (HHV-6, HHV-7) on cytomegalovirus (CMV) disease and its response to therapy is unknown. We prospectively analyzed herpesvirus co-infections in transplant recipients with CMV disease. All patients received 3 weeks of antiviral therapy. Samples were collected at baseline (day 0) and then day 3, 7, 14 and 21 poststart of therapy. Viral load testing for CMV, HHV-6 and HHV-7 was done using quantitative PCR assays in 302 patients of whom 256 had documented symptomatic CMV viremia. In this subset, day 0 HHV-6 co-infection was present in 23/253 (9.1%) and HHV-7 in 17/253 (6.7%). Including those positive at any time point raised the prevalence to 79/256 (30.9%) for HHV-6 and 75/256 (29.3%) for HHV-7. Viral co-infection did not influence the response of CMV disease to antiviral therapy. Baseline CMV viral loads, time to eradication and risk of recurrence were similar in patients with and without HHV-6 or HHV-7 co-infection. Ganciclovir and valganciclovir had no clear effect on HHV-6 and HHV-7 viremia. In conclusion, herpesvirus co-infections are common in patients with CMV disease but with standard antiviral therapy, no clear clinical effects are discernable. Routine monitoring for viral co-infection in patients with CMV disease is not indicated.     

Clinical validation of a novel enzyme‐linked immunosorbent spot assay‐based in vitro diagnostic assay to monitor cytomegalovirus‐specific cell‐mediated immunity in kidney transplant recipients: a multicenter,longitudinal, prospective,observational study

Impaired cytomegalovirus (CMV)‐specific cell‐mediated immunity (CMV‐CMI) is a major cause of CMV reactivation and associated complications in solid‐organ transplantation. Reliably assessing CMV‐CMI is desirable to individually adjust antiviral and immunosuppressive therapy. This study aimed to evaluate the suitability of T‐Track^® CMV, a novel IFN‐γ ELISpot assay based on the stimulation of peripheral blood mononuclear cells with pp65 and IE‐I CMV proteins, to monitor CMV‐CMI following kidney transplantation. A prospective longitudinal multicenter study was conducted in 86 intermediate‐risk renal transplant recipients. CMV‐CMI, CMV viral load, and clinical complications were monitored over 6 months post‐transplantation. Ninety‐five percent and 88–92% ELISpot assays were positive pre‐ and post‐transplantation, respectively. CMV‐specific response was reduced following immunosuppressive treatment and increased in patients with graft rejection, indicating the ability of the ELISpot assay to monitor patients' immunosuppressive state. Interestingly, median pp65‐specific response was ninefold higher in patients with self‐clearing viral load compared to antivirally treated patients prior to first viral load detection (P < 0.001), suggesting that reactivity to pp65 represents a potential immunocompetence marker. Altogether, T‐Track^® CMV is a highly sensitive IFN‐γ ELISpot assay, suitable for the immunomonitoring of CMV‐seropositive renal transplant recipients, and with a potential use for the risk assessment of CMV‐related clinical complications (ClinicalTrials.gov Identifier: NCT02083042).     

The use of consensus guidelines for management of cytomegalovirus infection in renal transplantation

Cytomegalovirus (CMV) infection imposes a significant economic burden on susceptible patients after renal transplantation. Our study was conducted to determine the prediction, probability, consequences, and treatment costs of CMV infection under Canadian consensus guidelines in 270 sequential transplant patients. Transplant patients from donors positive (D(+)) for CMV into recipients negative (R(-)) for CMV received antiviral prophylaxis for 14 weeks and all but donor negative (D(-))/R(-) patients were monitored weekly for the CMVpp65 marker expression. Marker-positive patients and patients with CMV infection or disease received antiviral treatment. Within the first 6 months, 27% of the 270 patients tested had incidences of asymptomatic CMV infection, while 9% had CMV syndrome or disease. Only 1% of patients had infection after 6 months. The CMVpp65 marker levels were significantly greater in patients with syndrome or disease; but post-test probabilities and predictive value of the marker assay were low. Mean direct costs for care were $2256 and ranged from $927 for D(-)/R(-) patients to $7069 in the D(+)/R(-) patients. Extension of antiviral prophylaxis to D(+) or D(+)/R(+) patients significantly increased the estimated mean costs for an absolute reduction to 4% in CMV syndrome or disease. Our studies show that current guidelines for treatment enable effective control of CMV infection; however, alternative strategies have different economic impact.     

Comparison of cytomegalovirus viral load measure by real-time PCR with pp65 antigenemia for the diagnosis of cytomegalovirus disease in solid organ transplant patients

Cytomegalovirus (CMV) infection is the most frequent complication in solid organ transplant recipients. Currently, the antigenemia assay is widely used to detect this infection, although its success is being questioned to a great extent nowadays. The aim of our study is to compare a quantitative real time PCR to measure CMV DNA to the antigenemia assay, for the diagnosis to CMV disease. For our research, we prospectively processed 1198 samples (plasma and peripheral blood leukocytes [PBMC]), which belonged to 158 transplant recipients. In every sample the detection of the pp65 antigen in PBMC was carried out, as well as the quantification of CMV DNA by PCR (Light Cycler, LC-PCR). For this process, FRET probes, which detect a 254-bp fragment from the CMV gB gene, were used. The dynamic range of the LC-PCR was 500 to 5.10(7) copies/mL plasma and from 62 to 6.10(6) copies/10(6) PBMC. Twenty-three episodes of cytomegalovirus (CMV) disease occurred in 22 out of 158 patients and PCR displayed levels of sensitivity and specificity of 100% and 67%, respectively. The antigenemia assay obtained values of 91% and 57%. We established a cutoff value of 10(3) copies/mL plasma and 315 copies/10(6) cells. According to these cutoff values, PCR showed levels of sensitivity, specificity, VPN and VPP of 95.6%, 81.6%, 99%, and 53% respectively. Moreover, the LC-PCR assay anticipated the antigenemia assay in 10 patients out of 22 who developed CMV disease and the appearance of any clinical symptoms in 12 out of 22 patients. In conclusion, we believe that the quantification of CMV DNA by LC-PCR is a superior assay to pp65 antigenemia test regarding the early diagnosis of CMV disease in solid organ transplant recipients.     

Cytomegalovirus infection in a seroendemic renal transplant population: a longitudinal study of virological markers

BACKGROUND/AIMS: The detection of viremia by polymerase chain reaction (PCR) in cytomegalovirus (CMV) infection in renal allograft recipients has been shown to have a predictive value for disease. However, its diagnostic utility in a population with high background seropositivity has not been defined. This prospective study was undertaken to assess the relationship of CMV DNAemia, and/or IgM seropositivity to CMV disease in a seroendemic transplant population. METHODS: Consecutive patients undergoing renal transplantation between August 1997 and February 1998 were enrolled. Blood was sampled before transplantation from the donors and recipients for CMV serology and nested PCR for CMV DNA, and after transplantation from the recipients only at monthly intervals until 6 months. Patients were observed for the development of any CMV-like illness during follow-up. CMV DNA was quantitated using limiting dilution PCR on samples obtained from symptomatic patients at the time of illness and from asymptomatic patients at the end of their 6-month follow-up. RESULTS: A total of 57 recipient-donor pairs were recruited. Immunosuppression was cyclosporine-based in 55 of 57 (95. 6%). The CMV serologic status was D+R+ in 55 of 57 and D+R- in 2 of 57 pairs. PCR positivity indicating viremia increased from 5% before transplantation to 95% at 6 months after transplantation. Similarly IgM positivity reached 80% at 3 months and thereafter; positivity for any marker was 100% by 6 months. Viremia was sustained in over half the patients. The incidence of CMV-attributable disease peaked at 3 months, and was predominantly mild and self-limiting. Tissue-invasive disease appeared later in 4 patients (7%). Asymptomatic viremia was seen in 60-70% of patients at each sampling point. The positive predictive value (PPV) of PCR positivity for disease was 35-40%, and the negative predictive value (NPV), 90-100%. However, the high NPV was of use only in the early post-transplant period, negativity for markers declining rapidly with time. Quantitative assay showed significantly higher levels of CMV DNA in symptomatic patients (p = 0.01). A cutoff of 0.001 microg had a specificity of 95% and a PPV of 92.3% for symptomatic CMV disease. CONCLUSION: Qualitative tests to detect CMV DNAemia and IgM, although useful markers of viremia and active infection, have limited utility for the diagnosis of disease in a seroendemic transplant population. Quantitation of CMV DNAemia may play an important role in diagnosis in such a setting.     

Evaluation of a new method for early detection of active cytomegalovirus infections. A study in kidney transplant recipients

Abstract Early detection of active cytomegalovirus (CMV) infection after organ transplantation is necessary to start effective antiviral treatment. In the present study, blood specimens of kidney transplant recipients ( n = 38) were monitored for the expression of CMV immediate early (IE) and late (L) mRNA using nucleic acid sequence-based amplification (NASBA). Results were compared with virus isolation, pp65 antigenemia and serology. In patients developing active CMV infection, pp65 antigen and L mRNA were detected simultaneously. At the same time, positive cell culture results could be reported to the clinic. CMV was detected significantly earlier with IE NASBA than with the other assays. However, the specificity of IE NASBA is lower than that of antigenemia, late NASBA and cell culture. Early detection of IE mRNA is especially useful for patients at high risk of developing symptomatic CMV infection in order that early, adequate antiviral therapy may be started. Late NASBA can be used to monitor further development of CMV infection, comparable to antigenemia.     

Fatal cytomegalovirus pneumonia after preemptive antiviral therapy in a renal transplant recipient

Cytomegalovirus (CMV) infections occur with an incidence of up to 70% in renal transplant patients and mortality is low due to effective antiviral drugs. We report here the case of a patient who suffered from an uncommonly severe and therapy-resistant pulmonary CMV infection. During the disease course, CMV-PCR from alveolar cells and lung biopsy material was repeatedly negative despite high CMV pp65 antigenemia. CMV pneumonia was finally diagnosed from a biopsy obtained by open thoracotomy revealing positive CMV immunostaining of lung tissue. The patient died of respiratory failure though double-treatment using both ganciclovir and foscavir was administered. Post mortem, the clinically suspected resistance to both antiviral drugs, but not to cidofovir, could be proven by bioassay testing of in vitro growth responses using viral cultures. CMV pneumonia may thus not be diagnosed by standard PCR techniques in rare cases and may be resistant to the available antiviral therapy. Severe CMV pneumonia may benefit from novel antiviral drugs such as cidofovir, which is currently used in the treatment of CMV retinitis in HIV patients.