Early detection of human cytomegalovirus infection after kidney transplantation by nucleic acid sequence-based amplification.

BACKGROUND: The early detection of human cytomegalovirus infection after organ transplantation is a prerequisite for effective antiviral therapy. We evaluated the diagnostic value of monitoring the viral immediate-early (IE) 1 mRNA expression in blood leukocytes by nucleic acid sequence-based amplification (NASBA). METHODS: Nucleic acids were isolated from 489 blood samples collected from 42 kidney transplant recipients and subjected to amplification by IE NASBA. The IE NASBA results were compared to those from pp67 NASBA, pp65 antigenemia, cell culture (DEAFF and CPE), and serology. RESULTS: IE NASBA proved to be the most sensitive assay which detected the onset of both primary and secondary cytomegalovirus infection significantly earlier than the other assays. Conclusions: The early detection of cytomegalovirus infection with IE NASBA would enable the start of effective antiviral therapy at an early state of infection to prevent cytomegalovirus disease in patients at risk.     

巨细胞病毒即刻早期mRNA测定在肾移植后巨细胞病毒感染中的诊断价值

目的评价应用核酸基础序列扩增法(NASBA)检测巨细胞病毒(CMV)即刻早期(IE)mRNA对肾移植术后CMV活动性感染的诊断价值。方法采用NASBA法测定55例肾移植患者的外周血标本中CMVIE mRNA及pp67mRNA,免疫组化法检测CMV pp65抗原。结果55例患者中,发生有症状的CMV活动性感染者13例;IE mRNA阳性者20例,12例有CMV活动性感染,IE mRNA的敏感度、特异度、阳性预测值及阴性预测值分别为92.3%、80.9%、60.0%及97.1%。IE mRNA阳性结果出现最早,为术后(31.0±15.4)d,与pp67mRNA的(43.7±16.3)d和pp65抗原的(39.6±15.6)d相比,差异有统计学意义(P<0.05)。结论应用NASBA法检测CMV IEmRNA,能够早期、快速、准确的诊断CMV活动性感染,为临床抗病毒的治疗提供依据。     

A prospective study comparing cytomegalovirus antigenemia, DNAemia and RNAemia tests in guiding pre-emptive therapy in thoracic organ transplant recipients

We evaluated the usefulness of DNAemia and mRNAemia tests in guiding the pre-emptive therapy against cytomegalovirus (CMV) infections in thoracic organ transplant recipients using antigenemia test as the reference. Seven lung (LTR) and 14 heart (HTR) transplant recipients were prospectively monitored for CMV by antigenemia, DNAemia (Cobas Amplicor PCR Monitor) and pp67-mRNAemia (NASBA) tests. However, only the antigenemia test guided pre-emptive therapy with cut-off levels of >or=2 and >or=5-10 pp65-positive leukocytes/50 000 leukocytes in the LTRs and HTRs, respectively. CMV DNAemia was detected in 26/28 (93%) and RNAemia in 17/28 (61%) of the CMV antigenemias requiring antiviral therapy (P = 0.01). Optimal DNAemia levels (sensitivity/specificity) estimated from receiver-operating characteristic curve to achieve maximal sum of sensitivity and specificity were 400 (75.9/92.7%), 850 (91.3/91.3%) and 1250 (100/91.5%) copies/ml for the antigenemia of 2, 5 and 10 pp65-positive leukocytes, respectively. The sensitivities of nucleic acid sequence-based amplification (NASBA) were 25.9%, 43.5% and 56.3% in detecting the same cut-off levels of antigenemia. In thoracic organ transplant recipients, the Cobas PCR assay is comparable with the antigenemia test in guiding pre-emptive therapy against CMV infections when threshold levels of over 5 pp65-antigen-positive leukocytes are used as the reference. In contrast, the low sensitivity of NASBA limits its usefulness in the guidance of pre-emptive therapy.     

Human cytomegalovirus pp67 mRNAemia versus pp65 antigenemia for guiding preemptive therapy in heart and lung transplant recipients: a prospective,randomized, controlled,open-label trial

BACKGROUND: Preemptive therapy of human cytomegalovirus (HCMV) infections has gained popularity in transplantation centers. However, standardized protocols are not available. In particular, whether a qualitative molecular assay for detection of a late (pp67) HCMV mRNA represents a valuable alternative to quantitative antigenemia remains to be defined. METHODS: Overall, 82 heart (HTR) and lung (LTR) transplant recipients were randomized into two arms, where therapy was guided by qualitative pp67 mRNA NASBA (40 patients) or quantitative antigenemia (42 patients). In the NASBA arm, both primary and recurrent infections were treated upon first confirmed positive NASBA result. In the antigenemia arm, primary infections were treated upon first confirmed positive result, while recurrent infections were treated upon cutoff of 100 pp65-positive leukocytes. In both arms, therapy was stopped upon virus disappearance. Primary endpoint was duration of therapy. RESULTS: The number of treated/infected patients was significantly higher in the NASBA arm (25/30 vs. 15/39; P=0.015), as was the number of treated/relapsing patients (5/8 vs. 1/11; P=0.040), whereas the number of HCMV-infected/total number of patients was significantly higher in the antigenemia arm (39/42 vs. 30/40; P=0.026). Thus, in the NASBA arm, although the median duration of therapy was shorter compared to antigenemia (17 vs. 21 days, P>0.05), the overall number of days of therapy was significantly higher. No patient developed HCMV disease. CONCLUSION: pp67 mRNA NASBA can safely replace antigenemia, with some apparent advantages (semiautomation and objectivity of test results) and disadvantages (overtreatment of patients and greater duration of overall treatment).     

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.     

Pretransplant Immediately Early‐1‐Specific T Cell Responses Provide Protection for CMV Infection After Kidney Transplantation

Cytomegalovirus (CMV) infection is still a major complication after kidney transplantation. Although cytotoxic CMV‐specific T cells play a crucial role controlling CMV survival and replication, current pretransplant risk assessment for CMV infection is only based on donor/recipient (IgG)‐serostatus. Here, we evaluated the usefulness of monitoring pre‐ and 6‐month CMV‐specific T cell responses against two dominant CMV antigens (IE‐1 and pp65) and a CMV lysate, using an IFN‐γ Elispot, for predicting the advent of CMV infection in two cohorts of 137 kidney transplant recipients either receiving routine prophylaxis (n = 39) or preemptive treatment (n = 98). Incidence of CMV antigenemia/disease within the prophylaxis and preemptive group was 28%/20% and 22%/12%, respectively. Patients developing CMV infection showed significantly lower anti‐IE‐1‐specific T cell responses than those that did not in both groups (p < 0.05). In a ROC curve analysis, low pretransplant anti‐IE‐1‐specific T cell responses predicted the risk of both primary and late‐onset CMV infection with high sensitivity and specificity (AUC > 0.70). Furthermore, when using most sensitive and specific Elispot cut‐off values, a higher than 80% and 90% sensitivity and negative predictive value was obtained, respectively. Monitoring IE‐1‐specific T cell responses before transplantation may be useful for predicting posttransplant risk of CMV infection, thus potentially guiding decision‐making regarding CMV preventive treatment.     

A longitudinal prospective study of cytomegalovirus pp65 antigenemia in renal transplant recipients

Cytomegalovirus (CMV)-encoded pp65 antigen in peripheral blood leukocytes (CMV antigenemia) was investigated in 1017 serial samples from 64 patients for 16 weeks after renal transplantation in a prospective study. In 110 samples from 24 patients, at least one antigen-positive leukocyte was identified. The median number of stained cells was 4 (range 1–1000) per 4×10⁵ leukocytes. Twenty-one of 24 patients with serological signs of an active CMV infection were antigen-positive (sensitivity 87.5%), whereas 3 patients with antigenemia did not show serological signs of infection during the observation period (specificity 92.5%). Positive results were obtained 19 days (median) before serological response and 9 days (median) before the onset of CMV syndrome. The sensitivity in defining a CMV syndrome was 100% (n=8). In all patients who presented with CMV syndrome, antigenemia was present prior to the onset of symptoms or on the same day. In contrast, serological monitoring rendered the diagnosis of CMV infection possible at the onset of clinical symptoms in only two of eight patients. We conclude that (1) insufficient results obtained with the CMV antigenemia assay by other investigators are mainly due to technical problems that can easily be overcome by the protocol presented and (2) the detection of CMV pp65 antigen in peripheral blood leukocytes is an excellent tool for rapid and early diagnosis of CMV infection.     

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.     

HHV‐6 reactivation is often associated with CMV infection in liver transplant patients

Abstract Human herpesvirus 6 (HHV‐6) infection has been recently reported in liver transplant patients. HHV‐6 is closely related to cytomegalo‐virus (CMV), and some interaction between the viruses has been suggested. In this study, the post‐transplant HHV‐6 antigenemia was investigated in relation to symptomatic CMV infections in adult liver transplant patients. CMV infections were diagnosed by the pp65 antigenemia test and by viral cultures. HHV‐6 infections were demonstrated by the HHV‐6 antigenemia test and by serology. Significant symptomatic CMV infection was diagnosed in 42 of 75 patients during the first 6 months after transplantation. All CMV infections were successfully treated with ganciclovir. Concurrent HHV‐6 antigenemia was detected in 21 (50%) of 42 patients with CMV infection. All HHV‐6 infections were reactivations. HHV‐6 also responded to the antiviral treatment, but with less clear effect. In conclusion, HHV‐6 reactivation is often associated with CMV infection in liver transplant patients. The results support the suggestion that CMV and HHV‐6 may have interactions.     

Therapeutic implication of quantitative pp65 antigen assay in living renal transplant in a high seroendemic population

Various methods have been used to diagnose cytomegalovirus (CMV) infection/disease; however, pp65 antigenemia assay has emerged as a good marker for CMV disease in a high seroendemic population. We studied the role of quantitative pp65 antigen assay in live related renal transplant recipients in a high seroendemic population. Between November 1998 and May 2003, a total of 350 blood samples from 250 symptomatic patients were tested by quantitative pp65 antigen assay; 14% of the patients tested positive. There were 5 (14%) low-positive and 30 (86%) high-positive patients. All high-positive patients had CMV disease. The response to antiviral therapy monitored by the assay was dramatic, and one low-positive patient responded to reduction in immunosuppression. In conclusion, pp65 antigen assay is a good test for diagnosing CMV disease and monitoring response to antiviral therapy in a high seroendemic population.     

An animal model of human cytomegalovirus infection

To develop a rat model that allowed in vivo progressive human cytomegalovirus (HCMV) infection, allogeneic liver transplantation was performed across a rat combination of Dark Agouti (DA) to Brown Norway (BN). AD169, a well-characterized laboratory strain of HCMV, was used to establish a rat model of HCMV infection by injection of 0.4 mL (30.0 logTCID50) supernate into the rat peritoneum. Histological and blood specimens were obtained from animals sacrificed at predetermined timepoints. We performed immunohistochemical staining in liver, heart, kidney, spleen, and lung for HCMV immediate-early antigen (IE), lower matrix protein (pp65) detection in peripheral blood leukocytes, and HCMV early antigen (EA) and late antigen (LA). We compared survival rates. Our results showed positive HCMV IE and pp65 antigenemia detected in peripheral blood leukocytes in transplanted recipients from day 1 to day 30. Positive HCMV EA and LA staining cells were only detected in sections 10 days after liver transplantation, namely, in hepatocytes, mononuclear cells, bile duct epithelial cells, and endothelial cells. Successful HCMV replication was due to the combination of liver transplantation and cyclosporine (CsA) immunosuppression. Survival analysis showed no significant differences between the HCMV-infected group and HCMV-uninfected group. This new rat model of HCMV infection may be helpful to understand immune system modulation of HCMV infection.     

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.     

肝移植术后巨细胞病毒再感染的预防与治疗

目的　探讨肝移植术后巨细胞病毒(CMV)再感染的预防、诊断及治疗。方法　回顾性分析44例原位肝移植患者的临床资料。结果　44 例中,术前43 例(97.7 %)有CMV潜伏性感染,其中6例(14.0 %)术后发生CMV再感染。6例CMV再感染患者的CMV pp65抗原均为阳性,3例CMV IgM阳性,均为无临床症状的CMV活动性感染,其中5例治愈,无一例发展为CMV病,1 例因上消化道大出血死亡。43例中,仅有7例CMV再感染高危病例接受了抗CMV感染的预防性治疗,患者在生存期内未发生CMV再感染。结论　在我国,肝移植患者术前CMV潜伏性感染的发生率较高,测定CMV pp65抗原可以早期诊断CMV再感染;对CMV再感染的高危患者进行预防性治疗可以降低术后CMV再感染的发生率;对无临床症状的CMV再感染者进行及时、规范的治疗是防止CMV病发生的关键。     

Rapid detection of cytomegalovirus DNA and RNA in blood of renal transplant patients by in vitro enzymatic amplification.

Cytomegalovirus infection causes significant morbidity and mortality in renal transplant patients. The only marker of CMV infection that appears to correlate with the development of symptomatic illness is viremia. However, CMV grows slowly in tissue culture, requiring 2-6 weeks of incubation for detection of characteristic cytopathic effect. The efficacy of antiviral therapy for CMV may be improved by earlier detection of viremia and institution of antiviral therapy. We performed amplification of CMV DNA and RNA from peripheral blood of renal transplant patients using the polymerase chain reaction (PCR) technique. We consistently detected CMV DNA by PCR earlier than CMV was detected by culture. Detection of CMV RNA in one patient confirmed the presence of actively replicating virus in peripheral blood. Amplification of peripheral blood from healthy CMV-seropositive and seronegative individuals, and from seropositive renal transplant patients without evidence of active CMV disease, was consistently negative. These preliminary data indicate that PCR may provide a means for earlier diagnosis of CMV viremia. Future prospective studies should determine if early detection of CMV DNA by PCR in peripheral blood does predict viremia and symptomatic illness, and if earlier institution of antiviral therapy based on PCR results improves outcome for the CMV-infected transplanted patient.     

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.     

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.     

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 antigenemia as a useful marker of symptomatic cytomegalovirus infection after renal transplantation--a report of 130 consecutive patients

In earlier work we demonstrated that CMV immediate early antigens can be detected in peripheral blood leukocytes of patients with active CMV infection. We now report a comparison of the antigenemia assay and an anti-CMV ELISA in a prospective longitudinal study of 130 renal transplant recipients who were monitored for active CMV infection during the first 3 months after transplantation. Active CMV infection developed in 56 patients. The antigenemia assay had a sensitivity of 89% and a specificity of 93% in the diagnosis of active CMV infection; for the ELISA these figures were 95 and 100%, respectively. In 22 of the 56 patients a CMV syndrome occurred. Antigenemia was demonstrated in all 22 patients while an antibody response occurred in 21 of them. The antigenemia assay became positive 8 +/- 7 days before the onset of symptoms while the antibody response was observed 4 +/- 9 days after the onset of symptoms. The pattern of antigenemia was helpful for monitoring the course of the infection. The maximum level of antigenemia was significantly higher and its duration significantly longer in symptomatic than asymptomatic infection. We conclude that CMV antigenemia is a sensitive, specific, and early marker of CMV infection. The antigenemia assay is of great value in monitoring patients with a high risk of CMV infection.