The role of PCR in the diagnosis and management of CMV in solid organ recipients: what is the predictive value for the development of disease and should PCR be used to guide antiviral therapy?

Metagenomic Next-Generation Sequencing for Identification and Quantitation of Transplant-Related DNA Viruses

Infections with DNA viruses are frequent causes of morbidity and mortality in transplant recipients.

Infections with DNA viruses are frequent causes of morbidity and mortality in transplant recipients. This study describes the analytical and clinical performance characteristics of the Arc Bio Galileo Pathogen Solution, an all-inclusive metagenomic next-generation sequencing (mNGS) reagent and bioinformatics pipeline that allows the simultaneous quantitation of 10 transplant-related double-stranded DNA (dsDNA) viruses (adenovirus [ADV], BK virus [BKV], cytomegalovirus [CMV], Epstein-Barr virus [EBV], human herpesvirus 6A [HHV-6A], HHV-6B, herpes simplex virus 1 [HSV-1], HSV-2, JC virus [JCV], and varicella-zoster virus [VZV]). The mNGS 95% limit of detection ranged from 14 copies/ml (HHV-6) to 191 copies/ml (BKV), and the lower limit of quantitation ranged from 442 international units (IU)/ml (EBV) to 661 copies/ml (VZV). An evaluation of 50 residual plasma samples with at least one DNA virus detected in prior clinical testing showed a total percent agreement of mNGS and quantitative PCR (qPCR) of 89.2% (306/343), with a κ statistic of 0.725. The positive percent agreement was 84.9% (73/86), and the negative percent agreement was 90.7% (233/257). Furthermore, mNGS detected seven subsequently confirmed coinfections that were not initially requested by qPCR. Passing-Bablok regression revealed a regression line of y = 0.953x + 0.075 (95% confidence interval [CI] of the slope, 0.883 to 1.011; intercept, −0.100 to 0.299), and Bland-Altman analysis (mNGS − qPCR) showed a slight positive bias (0.28 log₁₀ concentration; 95% limits of agreement, −0.62 to 1.18). In conclusion, the mNGS-based Galileo pipeline demonstrates analytical and clinical performance comparable to that of qPCR for transplant-related DNA viruses.

Performance of an in-house real-time PCR assay for detecting Cytomegalovirus infection among transplant patients from a tertiary care centre

Background

Quantitative Cytomegalovirus (CMV) polymerase chain reactions are increasingly being used for monitoring CMV DNAemia in haematopoietic stem cell transplants and solid organ transplants.

Objective

In this study, a commercial CMV viral load assay was compared with an in-house viral load assay.

Materials and Methods

A total of 176 whole-blood samples were tested for CMV DNAemia using both assays.

Results

Our evaluation showed a difference of 1 log₁₀copies/ml between the two assay systems in determining CMV viral loads in the clinical samples.

Conclusion

The in-house viral load assay had a better correlation with clinical findings compared to the commercial assay. Quality assessment of these assays was done by the United Kingdom National External Quality Assessment Scheme (UKNEQAS), an external proficiency testing programme, and by the National Institute for Biological Standard and Control (NIBSC) standard. For UKNEQAS and NIBSC standards, the bias between the assays was 0.73 log₁₀and 0.85 log₁₀, respectively. This difference is well within the acceptable range already reported in the literature.

Immunological Prediction of Cytomegalovirus (CMV) Replication Risk in Solid Organ Transplantation Recipients: Approaches for Regulating the Targeted Anti-CMV Prevention Strategies

The current cytomegalovirus (CMV) prevention strategies in solid organ transplantation (SOT) recipients have contributed towards overcoming the detrimental effects caused by CMV lytic infection, and improving the long-term success rate of graft survival. Although the quantification of CMV in peripheral blood is the standard method, and an excellent end-point for diagnosing CMV replication and modulating the anti-CMV prevention strategies in SOT recipients, a novel biomarker mimicking the CMV control mechanism is required. CMV-specific immune monitoring can be employed as a basic tool predicting CMV infection or disease after SOT, since uncontrolled CMV replication mostly originates from the impairment of immune responses against CMV under immunosuppressive conditions in SOT recipients. Several studies conducted during the past few decades have indicated the possibility of measuring the CMV-specific cell-mediated immune response in clinical situations. Among several analytical assays, the most advancing standardized tool is the QuantiFERON®-CMV assay. The T-Track® CMV kit that uses the standardized enzyme-linked immunospot assay is also widely employed. In addition to these assays, immunophenotyping and intracellular cytokine analysis using flow cytometry (with fluorescence-labeled monoclonal antibodies or peptide-major histocompatibility complex multimers) needs to be adequately standardized and validated for potential clinical applications.

Peripheral blood leukocytes and serum nested polymerase chain reaction are complementary methods for monitoring active cytomegalovirus infection in transplant patients

BACKGROUND

Human cytomegalovirus is an important cause of morbidity and mortality in immunocompromised patients. Qualitative polymerase chain reaction (PCR) has proven to be a sensitive and effective technique in defining active cytomegalovirus infection, in addition to having low cost and being a useful test for situations in which there is no need for quantification. Real-time PCR has the advantage of quantification; however, the high cost of this methodology makes it impractical for routine use.

OBJECTIVE

To apply a nested PCR assay to serum (sPCR) and to evaluate its efficiency to diagnose active cytomegalovirus infection compared with PCR of peripheral blood leukocytes (L-PCR).

METHODS

Samples of 37 patients were prospectively evaluated. An internal control was created and applied to sPCR to exclude false-negative results.

RESULTS

In total, 21 patients (57%) developed active cytomegalovirus infection. After analyzing the two methods for the diagnosis of active infection, higher sensitivity and negative predictive value of the L-PCR versus sPCR (100% versus 62%), and higher specificity and positive predictive value of sPCR versus L-PCR (81% versus 50% and 72%, respectively) were observed. Discordant results were observed in 11 patients who were L-PCR-positive but sPCR-negative for active cytomegalovirus infection, five of whom developed clinical symptoms of cytomegalovirus. Clinical symptoms were observed in 14 patients, 12 of whom were diagnosed with active infection by nested L-PCR (P=0.007) and seven by nested sPCR (P=0.02). Higher specificity and a positive predictive value for sPCR were observed.

CONCLUSION

Nested L-PCR and sPCR were considered to be complementary methods for the diagnosis and management of symptomatic cytomegalovirus infection.

Cost-effective immunosuppressive options for solid organ transplantation: a guide to lower cost for the renal transplant recipient in the USA

Of the numerous risks associated with immunotherapy for the prevention of rejection, cost is perhaps the most universal. In the USA and some other countries, the costs of immunosuppression make transplantation unavailable for some medically viable transplant candidates, and for others who receive a transplant, the long-term costs are economically crippling. Minimization and tapering of immunosuppression, use of generics, manipulation of metabolism, infection surveillance instead of prophylaxis, and advantageous routes of administration are some strategies that can be employed to reduce immunotherapy expense. Using these strategies, we describe an immunosuppression regimen for kidney transplantation that might be only a third of the cost of current 'standard' regimens in the USA. Such a regimen might allow some patients who might not otherwise qualify economically to safely receive a kidney transplant. The purpose of creating an alternative, lower-cost immunotherapy regimen is to give patients a choice. Responsible stewardship of scarce donor organs is the primary, and clearly appropriate, limiting factor.

Gastrointestinal cytomegalovirus disease in the immunocompromised patient

Cytomegalovirus (CMV) has emerged as a significant opportunistic pathogen in the era of immunosuppression. CMV was a common cause of gastrointestinal disease in AIDS patients, but the introduction of highly active antiretroviral therapy has led to a dramatic decline in AIDS-related disease. Among patients with solid organ transplants, CMV has become an increasingly important cause of gastrointestinal disease as more routine use of early CMV prophylaxis has increased delayed-onset disease, which is often tissue invasive at presentation. The role of CMV in inflammatory bowel disease is controversial; treatment may be indicated in selected cases of steroid-refractory disease with evidence of CMV. Diagnosis of gastrointestinal CMV disease generally requires endoscopic biopsy with histologic confirmation. CMV culture of biopsy material may be falsely positive because of contamination from latently infected cells. The standard induction treatment of gastrointestinal CMV disease uses intravenous ganciclovir, though the use of oral valganciclovir is increasing, especially for long-term maintenance or suppression therapy.

Cytomegalovirus infection with perineal pain after living donor liver transplantation: report of four cases

We report on 4 adult cases of presumptive cytomegalovirus (CMV) disease with perineal pain after living donor liver transplantation. Patients presented with severe perineal pain without any other symptoms related to CMV infection, except pyrexia. All patients had an episode of acute cellular rejection (ACR) before the onset of perineal pain, and 1 patient needed OKT3 therapy. The severe perineal pain was not well controlled with medication, and 1 patient needed epidural anesthesia. In the first 3 patients, pp65 CMV antigenemia (pp65CMV-Ag) test results were positive and intravenous administration of ganciclovir (GCV) therapy was initiated. In the last patient, GCV therapy was preemptively administered before a positive pp65CMV-Ag test result was confirmed. After administration of GCV, the pain gradually disappeared and all patients had negative pp65CMV-Ag test results. In conclusion, unusual perineal pain can be a symptom related to CMV infection. CMV infection needs to be kept in mind when a liver transplant recipient has severe perineal pain, especially after receiving treatment for ACR.

Detection and monitoring of cytomegalovirus infection in renal transplant patients by quantitative real-time PCR

OBJECTIVES

To establish a sensitive and specific real-time PCR for quantitation of cytomegalovirus (CMV) DNA in clinical specimens.

SUBJECTS AND METHODS

In a prospective study, CMV DNA was quantified in blood samples of 255 kidney recipients with and without CMV-related symptoms between the years 2000 and 2005 in Kuwait. In a selected group of patients, the effect of anti-CMV chemotherapy was monitored by quantitative real-time PCR (qRT-PCR).

RESULTS

The established qRT-PCR assay had a sensitivity to detect 30 CMV DNA copies. CMV DNA was detected in 54/255 (24%) patients; of these, 17 (31.5%) were asymptomatic, and 37 patients (68.5%) had symptomatic CMV infection. Sequential blood specimens were collected from all CMV-positive patients and tested by CMV pp65 antigenemia and qRT-PCR assays. There was a moderate positive correlation between the two assays (Pearson's correlation = 0.52). The median CMV viral load measured by qRT-PCR was higher in symptomatic (6.5 x 10(4) copies/ml) than in asymptomatic (185copies/ml) patients (p = 0.001). The estimated cut-off value of CMV DNA for CMV symptoms/disease was > or =800 copies/ml of blood. Testing of sequential samples from patients treated with symptomatic CMV infection showed that the viral load was significantly reduced after 3 weeks of anti-CMV chemotherapy (p = 0.001).

CONCLUSION

The reported qRT-PCR is a sensitive method for quantitation of CMV DNA in the blood of kidney recipients and can be useful in monitoring the efficacy of anti-CMV therapy.

Comparative analysis of a double primer PCR assay with plasma, leukocytes and antigenemia for diagnosis of active human cytomegalovirus infection in bone marrow transplant patients

The aim of the study was to determine the prognostic value of a double primer PCR assay to detect human cytomegalovirus (HCMV) infection or disease in bone marrow transplant (BMT) recipients. A total of 209 blood samples including peripheral blood mononuclear cells (PBMN), polymorphonuclear (PMN) leukocytes and plasma from 26 BMT recipients were tested by PCR assay. To discriminate between latent and active HCMV infection, 177 blood samples were also tested by a quantitative antigenemia assay. HCMV serology status of donors and recipients was determined before transplantation by an enzyme immunosorbent assay method. Using the double primer PCR assay, the number of positive samples increased by an average of 11.6%. Symptomatic active HCMV infection was diagnosed in 14 (53.8%) out of 26 BMT patients. There was a good association between double primer PCR assay of PMN leukocytes and antigenemia assays for detection of active HCMV infection in all patients. Detection of HCMV DNA in PMN leukocytes of BMT patients by double primer PCR assay can be an alternative method for antigenemia assay. However, quantitative PCR methods will be necessary for monitoring antiviral treatment.

Lethal cytomegalovirus ischemic colitis presenting with fever of unknown origin

We report a fatal case of cytomegalovirus (CMV) ischemic colitis in a renal transplant recipient. The disease was manifested with fever of unknown origin for 27 days followed by progressive right lower abdominal pain. The clinical condition deteriorated rapidly with development of disseminated intravascular coagulopathy and internal bleeding despite right hemicolectomy and antiviral therapy. The patient died 11 days after the onset of abdominal pain. We conclude that the possibility of CMV ischemic colitis should be suspected if a patient presents with fever and abdominal pain in the early months after transplantation, and that early viral detection by CMV polymerase chain reaction can be lifesaving.

Quantitative pp65 antigenemia in the diagnosis of cytomegalovirus disease: prospective assessment in a cohort of solid organ transplant recipients

OBJECTIVES

To assess the accuracy of quantitative pp65 antigenemia (pp65Ag) in the diagnosis of CMV disease, in a cohort of solid-organ transplant recipients.

METHODS

Prospective observational study during the first 6 months following transplantation, with determination of pp65Ag at weeks 2, 4, 6, 8, 10, 11, 12, 14 and 16. Sensitivity (S), specificity (E), positive and negative predictive values (PPV, NPV), and the optimal cut-off point for diagnosing CMV disease, were determined.

RESULTS

The cohort consisted of 35 liver, 26 renal and 12 heart graft recipients. Thirteen (17.2%) were seronegative and received a seropositive graft. Of 583 blood samples, pp65Ag was positive in 109 (18.7%) from 37 patients (51%). Twenty-two patients developed CMV disease (0.3 episodes/patient); gastrointestinal disease was the most frequent (15 episodes), followed by viral syndrome (3 episodes). Patients with positive pp65Ag had a relative risk for CMV disease of 6.19 [IC95%=1.99-19.04], (P=.0001). Diagnostic values of pp65Ag were: S=86%, E=65%, PPV=51%, NPV=92%. The cut-off of > or =10 infected cells/10(5), at weeks 2, 4, 6 and 8 obtained the best PPV (0, 67, 91 and 54%), and NPV (47, 52, 67 and 50%).

CONCLUSIONS

In the studied population, the presence of positive pp65Ag was associated with a high risk of developing CMV disease, and the most useful cut-off point for the diagnosis was > or =10 infected cells/10(5).

Prospective study of relationship between cytomegalovirus pneumonia and viral load in renal transplant recipients

The present study prospectively examined the relationship between cytomegalovirus interstitial pneumonia (CMV-IP) and viral load among 56 renal transplant recipients. We sought to identify the cutoff of viral load to predict CMV-IP. Blood samples were obtained weekly within the first 2 months and every second week during 2 to 6 months after kidney transplantations. A commercial real-time polymerase chain reaction (PCR)-method was applied to quantify CMV-DNA in plasma or in leukocytes. Among 54 renal transplant recipients who were analyzed for CMV-DNA in the blood (96.4%), 8 experienced CMV-IP (14.3%) and 2 died (3.6%). After kidney transplantation, CMV-DNA loads were near 0 in plasma before the week 4 and before the week 3 in leukocytes among both groups. From week 5 (week 4, in leukocytes), plasma CMV-DNA loads in the CMV-IP group increased, the peak value reached at week 8 in plasma and the week 9 in leukocytes. Whereas, the CMV-DNA loads both in plasma and in leukocytes in the non-CMV-IP group fluctuated at lower levels, those in plasma were significantly different between the 2 groups at the weeks 5, 7, and 9. For CMV-DNA in leukocytes, there were significant differences between 2 groups from week 6 to week 11. The present study demonstrated that dynamic determination of CMV-DNA may predict the occurrence of CMV-IP. Viral loads over 10(4) copies/mL plasma continuing for 3 weeks may serve as a cutoff to predict CMV-IP.

Strategies for the prevention of cytomegalovirus infection and disease in pediatric liver transplantation recipients

Cytomegalovirus (CMV) is the most common opportunistic infection following solid organ transplantation. Prevention and management of CMV infection has assumed a higher priority as transplantation has become a frequent treatment for many congenital and acquired disorders, as more potent immunosuppressive agents have become available, new molecular and virologic assays to detect CMV have made their way from research to clinical laboratories and new antiviral medications and biologics have been developed. Management strategies are diverse; however, there are little or no data from large controlled pediatric trials demonstrating the superiority of any particular approach. This review outlines the current strategies employed to prevent CMV infection and disease and summarizes the strengths and limitations of each regimen to guide clinicians in the selection of the optimal preventative approach.

Clinical utility of cytomegalovirus viral load testing for predicting CMV disease in D+/R- solid organ transplant recipients

Despite prophylaxis, cytomegalovirus (CMV) disease is common in donor seropositive (D+)/recipient seronegative (R-) transplant patients after cessation of prophylaxis. Early detection of CMV may allow for pre-emptive therapy to prevent active disease. The clinical utility of quantitative plasma viral load measurements for predicting CMV disease was determined in 364 D+/R- organ transplant patients receiving prophylaxis (100 d of valganciclovir or oral ganciclovir). Measurements were performed every 2 weeks until day 100 and at months 4, 4.5, 5, 6, 8 and 12 post-transplant. CMV disease occurred in 64 (17.6%) patients by 12 months. Using a positive cut-off value of >400 copies/mL, sensitivity was 38%, specificity 60%, positive predictive value 17%, and negative predictive value 82% for prediction of CMV disease. Therefore, routine monitoring would have predicted disease in only 24/64 (38%) patients. The test characteristics were not improved by changing the viral load cut-off point for defining a positive result. Similarly, single time point measures at the end of prophylaxis or month 4 had low sensitivity for disease prediction. Overall, regular CMV plasma viral load measurements were only of modest value in predicting CMV disease.

Occult herpes family viral infections are endemic in critically ill surgical patients

OBJECTIVE

Herpes family viruses have been recognized as pathogens for many years in immunosuppressed transplant or human immunodeficiency virus patients, but they have garnered little attention as potential pathogens in the nonimmunosuppressed critically ill. The objective of this study was to define the prevalence of and risk factors for development of herpes family virus infection in chronic critically ill surgical patients.

DESIGN

Prospective epidemiologic study.

SETTING

A 38-bed surgical intensive care unit in a major university hospital.

PATIENTS

Nonimmunosuppressed intensive care unit patients in intensive care unit for >/=5 days.

INTERVENTIONS

None; patients received no antiviral treatment during the study.

MEASUREMENTS AND MAIN RESULTS

Weekly cultures for cytomegalovirus (CMV) and herpes simplex virus, viral serologies, and T-cell counts were performed. The prevalence (95% confidence interval) of positive respiratory cultures for herpes simplex or CMV was 35% (22-49%); 15% (5-25%) cultured positive for CMV, 23% (11-35%) cultured positive for herpes simplex virus, and one patient's respiratory secretions culturing positive for both CMV and herpes simplex virus. The prevalence of CMV viremia was only 5.8% (1-10%). CMV+ patients had longer hospital admissions, intensive care unit admissions, and periods of ventilator dependence than CMV- patients, despite having comparable severity of illness scores. CMV+ patients also had significantly higher numbers of blood transfusions, prevalence of steroid exposure, and prevalence of hepatic dysfunction, and all were immunoglobulin G positive at the beginning of the study. In contrast, herpes simplex virus-positive patients had lengths of hospital admissions, lengths of intensive care unit admissions, and periods of ventilator dependence comparable with patients without viral infections (p >.05).

CONCLUSIONS

There is a significant prevalence (22-49%) of occult active herpes family viruses in chronic critically ill surgical patients. The clinical significance of these viral infections is unknown, although CMV+ patients have significantly higher morbidity rates than CMV- patients. Several factors suggest pathogenicity, but further study is needed to define causality.

Heightened peripheral blood lymphocyte CD69 expression is neither sensitive nor specific as a noninvasive diagnostic test for renal allograft rejection

It has been reported that acute allograft rejection is associated with heightened expression of the peripheral blood lymphocyte (PBL) early activation marker CD69 and that this may serve as a potential biomarker of rejection. This study sought to determine whether PBL CD69 expression correlates with both acute clinical and subclinical renal allograft rejection as well as clinically inapparent cytomegalovirus (CMV) infection. Flow cytometric determination of PBL CD69 expression was performed at the time of clinical and protocol biopsies (n = 131) in 45 renal transplant recipients. Nineteen patients also underwent weekly monitoring of PBL CD69 expression for the initial 15 wk after transplantation. Simultaneous screening for CMV viremia was performed with a semiquantitative PCR assay. No differences were seen in either CD4+ or CD8+ lymphocyte CD69 expression between the biopsy diagnoses. CMV viremia however, independent of rejection, was associated with greater CD69 expression on CD8+ lymphocytes (17.8 +/- 10.4% versus 9.6 +/- 4.8%; P < 0.0001) but not CD4+ lymphocytes. No individuals experienced clinical CMV disease. Weekly monitoring of PBL CD69 expression did not change coincident with the diagnosis of rejection; however, CMV viremia coincided with a substantial rise in the proportion of CD8+69+ lymphocytes in a number of individuals. Thus, PBL CD69 expression is neither sensitive nor specific for the noninvasive diagnosis of renal allograft rejection. Furthermore, clinically inapparent CMV viremia is associated with heightened expression of this activation marker on CD8+ lymphocytes. This latter finding suggests that clinically inapparent CMV viremia may be a potential confounder for biomarkers of rejection that examine peripheral blood lymphocytes.

Cytomegalovirus infection in solid organ transplantation: economic implications

Cytomegalovirus (CMV) is a pathogen, commonly encountered in the recipients of solid organ transplantation and is an important cause of morbidity and mortality in these patients. CMV infection and disease have been shown to increase the cost of care in transplant recipients and several different strategies of prevention have been shown to be effective in clinical trials. A systematic review of published information on the economic impact of CMV in solid organ transplantation was performed; both clinical- and decision-analysis-based studies were reviewed. Clinical studies have shown that CMV infection and disease is associated with increased length of hospital stay and overall costs. Decision-analysis-based studies suggest that in general, antiviral chemoprophylaxis against CMV in transplant recipients is a cost-effective intervention compared with other established healthcare interventions such as strategies for colorectal cancer screening. Prophylaxis with oral or parenteral ganciclovir is probably the most cost-effective strategy; however, restricting prophylaxis to high-risk groups (such as donor seropositive/recipient seronegative status and the use of an antilymphocyte antibody) or chemoprophylaxis for an extended period does not improve cost effectiveness. Pre-emptive therapy is an evolving strategy for prevention of CMV disease in transplant recipients and is rapidly gaining in popularity. Well-designed trials incorporating prospective cost data and comparing pre-emptive therapy versus conventional antiviral prophylaxis are needed to establish the superiority of one strategy over the other.

Cytomegalovirus infection after liver transplantation: viral load as a guide to treating clinical infection

BACKGROUND

Quantitative commercial assays for early and accurate detection of active cytomegalovirus (CMV) infection after liver transplantation are widely available. However, meaningful interpretation of viral load measurements is hampered by the lack of definitive cutoff points that correlate with clinically significant disease.

METHODS

One hundred fifty liver allograft recipients were prospectively monitored for the presence of CMV DNA for the first 12 weeks after orthotopic liver transplantation using the Murex hybrid capture system. The first CMV DNA value after liver transplantation, a weekly rise in CMV DNA (gradient value), and the CMV DNA value on clinical detection of active infection (critical value) were analyzed as risk factors for CMV infection.

RESULTS

Forty-four (29.3%) of 150 patients had detectable CMV DNA within 12 weeks of transplantation, and 20 (13.3%) experienced symptomatic CMV infection. Multiple regression analysis demonstrated that baseline CMV DNA level above 10 pg/mL, positive weekly increase in CMV DNA level, and critical CMV DNA level above 13 pg/mL were independent risk factors for clinically significant infection. Using Cox's multiple regression model, the hazard ratio was 13.9 for baseline CMV DNA above 10 (P =0.0001; 95% confidence interval, 3.5-54) and 13 for a weekly increase in the gradient (P =0.0003; 95% confidence interval, 3.5-50). Critical CMV DNA level above 13 correlated with active infection (100% sensitivity, 98% specificity, 90% positive predictive value, 100% negative predictive value).

CONCLUSION

Baseline and gradient CMV DNA viral load levels correlate with active CMV infection in liver allograft recipients. These data indicate that CMV viral load detection by hybridization methodology is useful in predicting active CMV infection and could be used in a preemptive strategy in liver allograft recipients.

The clinical use of various blood compartments for cytomegalovirus (CMV) DNA quantitation in transplant recipients with CMV disease

BACKGROUND

The quantitation of cytomegalovirus (CMV) DNA is a cornerstone in the management of CMV disease in transplant recipients. However, a consensus as to what is the optimal blood compartment for the detection and quantitation of CMV DNA in peripheral blood is nonexistent.

METHODS

With an automated quantitative assay, we have simultaneously quantified the CMV DNA load in whole blood (WB), plasma (PL), peripheral blood leukocytes (PBL), and peripheral blood mononuclear cells (PBMC) in 319 samples from 17 transplant recipients with 19 episodes of CMV disease that were treated with 2 weeks of intravenous ganciclovir.

RESULTS

Higher levels of CMV DNA were observed in WB than PL (PL minus WB mean difference, 0.67 log; 95% confidence interval, -1.02 to -0.32; P=0.0009). This observation was most evident before treatment with intravenous ganciclovir (pretreatment geometric mean CMV DNA was 45,412 copies per ml of WB vs. 14,995 copies per ml of PL). In contrast, the CMV DNA levels between PBL and PBMC were highly comparable throughout the course of CMV disease and its treatment. Intravenous ganciclovir exerted a uniform effect on the four blood compartments with no statistically significant difference in the degree and rate of CMV DNA decline between WB and PL and between PBL and PBMC.

CONCLUSIONS

Although our study demonstrates the adequacy of all blood compartments for CMV DNA quantification, the higher sensitivity of WB and its yield of higher CMV DNA render it an optimal sample for monitoring CMV DNA load during CMV disease in immunocompromised patients.

Comparative quantitation of cytomegalovirus (CMV) DNA in solid organ transplant recipients with CMV infection by using two high-throughput automated systems

Cytomegalovirus (CMV) DNA quantitation in clinical specimens is progressively becoming a cornerstone in the diagnosis and management of CMV infection in the immunocompromised host. We evaluated two automated and reproducible PCR tests, the LightCycler (Roche Molecular Biochemicals, Indianapolis, Ind.) and the COBAS AMPLICOR CMV Monitor (Roche Diagnostics, Pleasanton, Calif.), for the detection of CMV DNA in blood samples from transplant recipients with CMV infection as determined by shell vial culture. Following a log transformation analysis, the mean CMV DNA in plasma (PL), whole blood (WB), peripheral blood leukocytes (PBL), and peripheral blood mononuclear cells (PBMC) using the LightCycler was 6.79 copies per ml, 7.23 copies per ml, 6.38 copies per 2 x 10(6) cells, and 6.27 copies per 2 x 10(6) cells, respectively. This compares to 7.86 copies per ml, 8.37 copies per ml, 7.59 copies per 2 x 10(6) cells, and 7.44 copies per 2 x 10(6) cells, respectively, using COBAS AMPLICOR CMV Monitor. While higher CMV DNA levels were observed for the various blood compartments analyzed using COBAS AMPLICOR CMV Monitor, a high degree of correlation was evident between the two automated systems (jackknife correlation r = PL 0.77 [95% confidence interval (CI); 0.64, 0.90], WB 0.77 [95% CI; 0.62, 0.92], PBL 0.77 [95% CI; 0.67, 0.88], and PBMC 0.81 [95% CI; 0.72, 0.89], all P < 0.001). Therefore, we conclude that either automated diagnostic system is accurate for CMV DNA quantitation.

Assessment of cytomegalovirus infections using neopterin and a new immunoblot

Human cytomegalovirus (HCMV) infections are a major cause of morbidity and mortality in immunocompromised patients despite advances in diagnostic tests and antiviral therapies. The underlying study investigates the diagnostic value of the immune marker neopterin and a recently developed HCMV-specific western blot to detect HCMV infections and to differentiate them into either syndromes or diseases. The mean period of observation was 1428 days. Thirteen HCMV diseases and nine syndromes were diagnosed retrospectively. The first appearance of clinical signs or symptoms was always associated with a marked increase of serum and urine neopterin. The HCMV-specific IgM response followed in the mean 9 days later. Median values and the course of the neopterin levels were significantly higher during the HCMV diseases. In addition, the strength of the humoral immune response was related to the severity of the HCMV infection. Patients with HCMV diseases developed antibodies against a higher number of epitopes. The anti-HCMV IgM response persisted in more than 80% of the patients for longer than 3 years. In conclusion, combining the HCMV-specific western blot and neopterin permit detection of the immune response against HCMV, reflect the severity of the infection and might guide the anti-viral therapy.

Mycophenolate mofetil does not modify the incidence of cytomegalovirus (CMV) disease after kidney transplantation but prevents CMV-induced chronic graft dysfunction

Ganciclovir, which is used to treat cytomegalovirus (CMV) infection, has been shown in rodent models to abolish CMV-mediated chronic cellular damage and endothelial cell proliferation; when associated with mycophenolate mofetil (MMF), it has been shown to increase its anti-herpes virus activity. This study tested the hypothesis that kidney graft recipients who received antirejection prophylaxis with MMF and who were treated with ganciclovir for a declared CMV disease could be protected from chronic graft dysfunction. Investigated was the impact of ganciclovir-treated CMV diseases in consecutive first kidney recipients according to their immunosuppressive therapy. The azathioprine (Aza)-treated group (Aza group) included 319 patients. The MMF-treated group (MMF group) included 126 patients. CMV disease was clinically defined and confirmed by virological proof of CMV infection and was treated for at least 14 d with ganciclovir. Despite having the same incidence (21.6% in the Aza group versus 24.6% in the MMF group) and severity, CMV disease was significantly associated with graft loss independent of acute rejection episodes or other factors when tested in a Cox proportional model in the Aza group only (P < 10(-4)). It was shown for the first time that patients whose CMV disease is treated with ganciclovir while they are on MMF therapy are protected from the long-term deleterious consequences of CMV disease on graft survival, independent of acute rejection. It is suggested that the enhanced anti-herpes virus activity of ganciclovir by MMF could contribute to this reported effect, which may represent a significant contribution of MMF efficacy to graft survival.

Viral infections after renal transplantation

Viral infections are a leading cause of posttransplantation morbidity and mortality. A number of recent developments have altered our understanding and management of these disorders. The pathogenetic roles of several viruses, including human herpesviruses 6 and 8, have been newly established. Molecular-based diagnostic tests now make more rapid diagnosis possible. The licensing of new potent antiviral agents offers a wider choice of drugs for viral prophylaxis and treatment. The use of more potent immunosuppressive agents is responsible in part for the increasing incidence of some viral infections, but this varies among drugs, and individual viruses differ in their sensitivity to immunosuppressive agents. This review summarizes the natural history, diagnosis, prevention, and treatment of many common viral infections after renal transplantation.

Comparison between antigenemia and a quantitative-competitive polymerase chain reaction for the diagnosis of cytomegalovirus infection after heart transplantation

BACKGROUND

Antigenemia and quantitative polymerase chain reaction (PCR) are widely used for cytomegalovirus (CMV) diagnosis after heart transplantation due to their enhanced predictive values for disease detection when specific cut-off values are used. The purpose of this study was to compare, in the same patient setting, the predictive values of quantitative PCR and antigenemia for CMV disease detection, using specific cut-off values.

METHODS

Thirty heart transplant receptors were ch prospectively monitored for active CMV infection and disease detection, using quantitative PCR and anti- po genemia. Positive and negative predictive values for pr CMV disease detection were calculated using cut-off pr values for both antigenemia (5 and 10 positive cells/300,000 neutrophils) and quantitative-PCR (50,000 and 100,000 copies/10(6) leukocytes).

RESULTS

Active CMV infection was diagnosed in 93.3% of patients and CMV disease in 23.3%. The positive and negative predictive (%) values for CMV disease detection were 35/100 and 46.7/100, respectively, for quantitative PCR and antigenemia. Using 5 and 10 positive cells/300,000 neutrophils as cut-off values for antigenemia, the positive and negative predictive values (%) for disease detection were respectively 63.6/100 and 70/100. For quantitative PCR, the positive and th negative predictive values (%) for cut-off values of to 50,000 and 100,000 copies/10(6) leukocytes were 53.8/100 and 60/94.1, respectively.

CONCLUSION

In our series, antigenemia and quantitative-PCR had enhanced and similar predictive values for CMV disease detection when specific cut-off values were used. The choice between these two methods for disease detection may rely less on their efficiency and more on the experience and familiarity with them.

The influence of cytomegalovirus viraemia on the outcome of recurrent hepatitis C after liver transplantation

BACKGROUND

Several interrelated host and hepatitis C virus (HCV) associated factors have been proposed to explain the variable outcomes in HCV recurrence. Recent evidence suggests that cytomegalovirus (CMV) infection not only is co-factor in progression of HCV recurrence but may precipitate allograft rejection. We investigated whether short-term CMV viremia influences HCV recurrence, the number and grade of acute rejection episodes, and the histological course of HCV recurrence during the first year after orthotopic liver transplantation (OLT) for HCV-related cirrhosis.

METHODS

A cohort of 39 patients transplanted for cirrhosis HCV-related was analyzed. Patients were evaluated twice weekly for CMV infection by a blood polymerase chain reaction (PCR) assay. Triple therapy with cyclosporine or tacrolimus, azathioprine and prednisolone was the initial immunosuppressive regimen. Preemptive treatment with ganciclovir was started when two consecutive PCRs for CMV were positive. Liver biopsies were performed on day 7 after OLT or when indicated. A 3-day IV 1 g methilprednisolone was given to patients with moderate or severe rejection. Ishak's score was used to grade inflammation and to stage fibrosis.

RESULTS

Neither CMV viremia nor CMV disease after OLT for HCV-related cirrhosis adversely influenced the incidence and grade of acute rejection episodes nor the histological outcome of post transplant HCV recurrence, during the first year after liver transplantation.

CONCLUSION

CMV viremia as detected by PCR does not affect the progression of HCV recurrence in liver grafts.

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.

Early increase of peripheral B cell levels in kidney transplant recipients with CMV infection or reactivation

BACKGROUND

Cytomegalovirus (CMV) infection or reactivation is a frequent complication of renal transplantation. Diagnosis of these conditions relies on the detection of circulating antigen, or of specific IgM and/or IgG, which develop over several weeks. Evocative clinical features may be detected earlier, but lack specificity. Rapid and early changes in the partition of lymphocyte subsets could be an additional indication of pending CMV infection.

METHODS

A systematic follow-up of peripheral B lymphocytes identified immunophenotypically by the determination of surface immunoglobulins (sIg), performed in 97 kidney transplant recipients, allowed to identify transient increases apparently predictive of CMV primo-infection or reactivation over the next 3 months. To better define the nature of these B cells, an extended investigation was performed for 14 prospective patients. In addition to surface Ig, membrane CD19, HLA-DR, and CD80 expression were explored. The cytoplasmic presence of mu, kappa, and lambda chains was also examined. B cell function was investigated using the ELISPOT technique, which allows an enumeration of the populations of IgG, IgA, and IgM secreting B cells.

RESULTS

Retrospective analysis of the clinical outcome of the cohort of 97 patients evidenced that early transient increases in B cell levels were significantly (P<0.0001) associated with CMV infection. The same trend was noted in the smaller series of patients who benefited from a more extensive investigation of B cells, 10 of whom presented clinical or biological signs of CMV infection. Mature B cells, expressing surface Ig, CD19, DR, and CD80 are those presenting transient increases. No significant variation of preB (cmu+/kappalambda-) or activated (spot-forming) cells was evidenced in these patients.

CONCLUSION

Individual examination of each patient's immune reconstitution profile allows to detect transient peaks of mature B cell during the initial immunosuppressive therapy, that appear to be predictive of oncoming CMV infection or reactivation.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

Monitoring human cytomegalovirus viral load in peripheral blood leukocytes of renal transplant recipients by a simple limiting dilution-PCR assay

To assess the clinical relevance of a semi-quantitative measurement of human cytomegalovirus (HCMV) DNA in renal transplant recipients within the typical clinical context of a developing country where virtually 100% of both receptors and donors are seropositive for this virus, we have undertaken HCMV DNA quantification using a simple, semi-quantitative, limiting dilution polymerase chain reaction (PCR). We evaluated this assay prospectively in 52 renal transplant patients from whom a total of 495 serial blood samples were collected. The samples scored HCMV positive by qualitative PCR had the levels of HCMV DNA determined by end-point dilution-PCR. All patients were HCMV DNA positive during the monitoring period and a diagnosis of symptomatic infection was made for 4 of 52 patients. In symptomatic patients the geometric mean of the highest level of HCMV DNAemia was 152,000 copies per 10(6) leukocytes, while for the asymptomatic group this value was 12,050. Symptomatic patients showed high, protracted HCMV DNA levels, whereas asymptomatic patients demonstrated intermittent low or moderate levels. Using a cut-off value of 100,000 copies per 10(6) leukocytes, the limiting dilution assay had sensitivity of 100%, specificity of 92%, a positive predictive value of 43% and a negative predictive value of 100% for HCMV disease. In this patient group, there was universal HCMV infection but relatively infrequent symptomatic HCMV disease. The two patient groups were readily distinguished by monitoring with the limiting dilution assay, an extremely simple technology immediately applicable in any clinical laboratory with PCR capability.

Clinical utility of quantitative cytomegalovirus viral load determination for predicting cytomegalovirus disease in liver transplant recipients

BACKGROUND

The early detection of cytomegalovirus (CMV) after liver transplantation may form the basis of a preemptive strategy for prevention of active CMV disease.

METHODS

We prospectively analyzed the clinical use of weekly quantitative polymerase chain reaction-(PCR) based plasma viral load determinations and the antigenemia assay for predicting the development of active CMV disease in 97 consecutive liver transplant recipients.

RESULTS

CMV disease occurred in 21/97 patients. Using a positive cut-off of >400 copies/ml plasma, PCR had a sensitivity of 100%, specificity 47.4%, positive predictive value 34.4% and negative predictive value 100% for prediction of CMV disease. Respective values for a positive antigenemia (>0 positive cells/slide) were 95.2, 55.3, 37.0, and 97.7%. Different cut-off points for a positive test were analyzed using receiver-operating characteristic (ROC) curves. The optimal cut-off for viral load was in the range of 2000-5000 copies/ml (sensitivity 85.7%, specificity 86.8%, PPV 64.3%, NPV 95.7% for >5000 copies/ml). The optimal cut-off for antigenemia was in the range of four to six positive cells/slide. Mean peak viral load in symptomatic patients was 73,715 copies per/ml versus 3615 copies/ml in patients with asymptomatic CMV reactivation (P<0.001). In a multivariate logistic regression analysis of risk factors for CMV disease (CMV serostatus, acute rejection, and induction immunosuppression), peak viral load and peak antigenemia emerged as the only significant independent predictors of CMV disease (for PCR, odds ratio=1.40/1000 copy/ml increase in viral load, P=0.0001; for antigenemia odds ratio=1.17/1 positive cell/slide).

CONCLUSIONS

Plasma viral load by quantitative PCR is useful for predicting CMV disease and could be used in a preemptive strategy.

Clinical utility of a quantitative polymerase chain reaction for diagnosis of cytomegalovirus disease in solid organ transplant patients

BACKGROUND

Accurate and rapid diagnosis of human cytomegalovirus (HCMV) disease in solid organ transplant patients remains a challenge. We evaluated the clinical utility of a quantitative polymerase chain reaction (QPCR) method to diagnose transplant patients with HCMV disease.

METHODS

A total of 429 plasma samples from 121 solid organ transplant patients were prospectively collected and evaluated for HCMV using a QPCR assay. To enhance the sensitivity of the QPCR assay, plasma samples were centrifuged in a manner designed to concentrate the virions before nucleic acid extraction. Quantitation was achieved by co-amplifying an internal quantitative standard (IS) that contained the same primer sequences as for HCMV. Polymerase chain reaction products were detected by hybridization to 96-well microtiter plates coated with either a HCMV- or an IS-specific probe.

RESULTS

A total of 103 patients had all samples negative by QPCR. None of the 103 patients developed HCMV disease during the study. In contrast, 18 patients showed at least 1 sample positive by the QPCR assay, but only 8 of these developed HCMV disease. The mean viral load value for patients without HCMV disease was 93 viral copies (vc) per ml of plasma (range: 35-325 vc/ml plasma) and for the 8 patients with HCMV disease was 67,686 vc/ml plasma (range: 167-1,325,000 vc/ml plasma) (P<0.001). Using a cut-off value of 100 vc/ml plasma and clinical diagnosis of HCMV disease, the QPCR assay showed a sensitivity of 100% and specificity of 99.1%.

CONCLUSION

HCMV viral load may be useful in the diagnosis of HCMV disease in solid organ transplant patients.

Intestinal transplantation in children: preliminary experience in Paris

From November 1994 to November 1998, 20 children (2.5 to 14 years) received a jejunoileal graft alone (SBTx; n = 10) or in combination with the liver (SBLTx; n = 10 and/or the right colon (5 SBTx). Indications were intractable diarrhea of infancy (n = 8), short bowel syndrome (n = 6), extensive Hirschsprung disease (n = 4), and chronic intestinal pseudoobstruction (n = 2). Immunosuppression included tacrolimus, methylprednisolone, and azathioprine. Current follow-up ranges from 6 to 54 months. Five patients died (3 SBTx) within the first 2 months. Acute liver rejection occurred in 5 patients during the first 2 months. Sixteen episodes of intestinal rejection during the first 3 months in 11 patients (8 in 4 SBTx) were successfully treated in all but 3 by increasing tacrolimus dose and/or a 3-day methyprednisolone bolus or required antilymphoglobulins in 3 cases. Surgical complications occurred 8 times after SBLTx and 3 after SBTx. Infectious complications were more frequent in SBLTx recipients. Reversible Epstein-Barr virus-related posttransplant lymphoproliferative disease occurred in 3 recipients. Five presented cytomegalovirus infection. The SB graft was removed in 5 recipients (3 chronic rejection). All patients were started with oral and/or enteral feeding from the 7th postoperative day by using either normal food or protein hydrolysate diet. Currently, 10 of 11 children (8 SBLTx) achieved digestive autonomy after 5 to 30 weeks. All recipients gained weight; however, growth velocity remained reduced during the first 6 months because of the steroid therapy. Overall graft and patient survival is higher after SBLTx. Intestinal transplantation is indicated for patients with permanent intestinal failure. However, because parenteral nutrition is generally well tolerated, even for long periods, each indication for transplantation must be weighed carefully in terms of risk and quality of life.

Detection of cytomegalovirus infections by PCR in renal transplant patients

Cytomegalovirus (CMV) is the single most important infectious agent affecting recipients of organ transplants. To evaluate the incidence and the clinical importance of CMV infection in renal transplants in Brazil, 37 patients submitted to renal allograft transplants were tested periodically for the presence of cytomegalovirus DNA in urine using the polymerase chain reaction (PCR), and for the presence of IgM and IgG antibodies against CMV by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF). The PCR-amplified products were detected by gel electrophoresis and confirmed by dot-blot hybridization with oligonucleotide probes. Thirty-two of the 37 patients (86.4%) were positive by at least one of the three methods. In six patients, PCR was the only test which detected the probable CMV infection. Ten patients had a positive result by PCR before transplantation. In general, the diagnosis was achieved earlier by PCR than by serologic tests. Active infection occurred more frequently during the first four months after transplantation. Sixteen of the 32 patients (50%) with active CMV infection presented clinical symptoms consistent with CMV infection. Five patients without evidence of active CMV infection by the three tests had only minor clinical manifestations during follow-up. Our results indicate that PCR is a highly sensitive procedure for the early detection of CMV infection and that CMV infection in renal transplant patients is a frequent problem in Brazil.

Prevalence of cytomegalovirus in the gastrointestinal tract of renal transplant recipients with persistent abdominal pain

Abdominal pain occurs frequently in renal transplant recipients receiving mycophenolate mofetil (MMF) therapy. The cause of this abdominal pain has not been fully elucidated, but may involve local irritation, as well as inhibition of rapidly dividing cells of the gastrointestinal (GI) tract. This milieu of inflammation and added immunosuppression is conducive to activation of cytomegalovirus (CMV). We therefore sought to find the prevalence of active CMV in patients presenting with abdominal pain on maintenance MMF therapy. All patients receiving a renal transplant at our center from March 1, 1997, to September 1, 1997, were studied. Any patient presenting with midepigastric pain for greater than 3 days underwent esophagogastroduodenoscopy (EGD) with biopsy. CMV was diagnosed by the presence of inclusion bodies and immunohistochemical studies. Ten patients presented with persistent midepigastric pain; nine of these patients had evidence of GI CMV. Patients who were CMV negative and received an allograft from CMV-positive donors and those with leukopenia were at significantly increased risk for the development of abdominal pain. In our study population, the majority of patients on maintenance MMF therapy who presented with persistent midepigastric pain had evidence of active CMV infection in the upper gastrointestinal tract.

A PCR based DNA hybridisation capture system for the detection of human cytomegalovirus. A comparative study with other identification methods

A simple, sensitive and specific colourimetric hybridisation method for the detection of HCMV DNA in clinical specimens is described. This method combines a PCR assay with a sensitive sandwich hybridisation assay. It relies on the use of a specific capture probe linked covalently to polystyrene microplates and a specific polybiotinylated detection probe. Amplified DNA fragments, sandwiched between these two probes, are detected by an enzymatic colour reaction. This PCR-based colourimetric hybridisation method was compared with other known HCMV detection methods. Clinical specimens (n = 145, corresponding to 106 patients) were tested by both a nested PCR assay and this colourimetric hybridisation method; and by either the culture method or the pp65 antigenaemia test depending on the type of sample used. The results showed that the PCR-based hybridisation method has a specificity similar to tissue culture, known as the conventional gold standard method, and could be used for the examination of the clinical specimens.

Utility of cytomegalovirus viral load in renal transplant patients in Argentina

BACKGROUND

Cytomegalovirus (CMV) is the most prevalent viral disease in solid organ transplantation. Detection of CMV DNA in peripheral blood mononuclear cells (PBMC) by polymerase chain reaction (PCR) frequently occurs in renal allograft recipients, yielding false positive results in seropositive patients free of CMV disease. We evaluated the clinical utility of a quantitative PCR-enzyme-linked immunosorbent assay (ELISA) for identifying patients with CMV disease.

METHODS

Three hundred and fifty samples from 65 consecutive renal transplant recipients were studied. DNA was extracted from PBMC weekly up to the day of discharge and after any further admission. Samples were tested by a qualitative PCR method, and all positive samples were further studied by a quantitative PCR-ELISA method. The quantitative PCR-ELISA method used an internal standard (IS) that contained the primer sequences used in the qualitative CMV PCR. Detection and quantification was performed in 96-well plates coated with IS or CMV specific probes.

RESULTS

Forty-one of 65 patients (63.1%) showed positive results by the qualitative PCR, but only 8 of these patients were diagnosed with CMV disease. Positive samples were re-analyzed by the quantitative assay. The 8 patients with CMV disease had a mean CMV viral load of 1,438+/-687 viral copies (VC)/10(6) PBMC, and the 33 without CMV disease had a mean value of 219.6+/-117.2 VC/10(6) PBMC (P<0.01). None of the 33 patients without CMV disease had viral loads higher than 500 VC/10(6) PBMC. Using 500 VC/10(6) PBMC as a cut-off value for CMV disease, the quantitative PCR showed a sensitivity and specificity of 100% compare to clinical diagnosis.

CONCLUSION

CMV viral load may be useful in the diagnosis of CMV disease in renal transplant patients.

Prevention of infections in solid organ transplant recipients

Solid organ transplantation has become an important therapeutic option for multiple chronic diseases. With the advent of newer and potent immunosuppressive regimens, graft survival has improved, but at the expense of an increased risk for the development of infections secondary to bacterial, fungal, viral and parasitic pathogens. Prevention of such infectious complications with effective, well tolerated, and cost-effective anti-microbials would be ideal to improve the outcome of transplanted patients. However, the emergence of multi-drug resistant pathogens, medication toxicity and drug-drug interactions need to be carefully evaluated. This review summarizes the most relevant data pertaining to our current understanding of infection prevention for solid organ transplant recipients. Specific recommendations are given for the prevention of each group of microorganisms and types of solid organ transplant.

Cytotoxic lymphocyte gene expression in peripheral blood leukocytes correlates with rejecting renal allografts

BACKGROUND

We have shown previously that heightened expression of the cytotoxic lymphocyte (CL) effector genes perforin (P), granzyme B (GB), and Fas ligand (FasL), is closely correlated with acute allograft rejection, particularly when two or more target genes are up-regulated.

METHODS

We used quantitative reverse transcription-polymerase chain reaction to analyze CL gene expression from peripheral blood leukocytes (PBLs) and renal allograft biopsies in 31 paired samples of PBLs and renal tissue from 25 renal allograft recipients. Our aims were (1) to determine whether the expression of CL gene expression in PBLs correlates with expression of these genes in renal allograft biopsy tissue and (2) to determine whether CL gene expression in PBLs correlates with the histological diagnosis.

RESULTS

Coordinate gene expression in PBLs and acutely rejecting allografts was found in 9/11 (82%) for P, 07/11 (64%) for GB, and 10/11 (91%) for FasL. Coordinate absence was found in 15/20 (75%) for P, 17/20 (85%) for GB, and 16/20 (80%) for FasL in nonrejecting allografts. Furthermore, up-regulation of any two genes in PBLs correlated with pathological diagnosis of rejection with excellent positive (100%) and negative (95%) predictive values.

CONCLUSION

Coordinate CL gene expression in PBLs and the allograft is usually detected. CL gene expression in PBLs is closely associated with a pathologic diagnosis of rejection. CL gene expression in PBLs may serve as a noninvasive method of monitoring for renal allograft rejection.

Rapid cytomegalovirus pp65 antigenemia assay by direct erythrocyte lysis and immunofluorescence staining

A rapid cytomegalovirus (CMV) pp65 antigenemia assay with direct erythrocyte lysis (DL) with 0.8% NH4Cl, followed by indirect immunofluorescence staining (IF), was evaluated with 82 blood samples from renal transplant recipients, and the results were compared to those of the conventional antigenemia assay with dextran sedimentation and two-cycle alkaline phosphatase, anti-alkaline phosphatase staining (DS-APAAP). The DL-IF modification gave a higher leukocyte yield compared to DS-APAAP (75.4 versus 54.9%; P < 0.05), with similar leukocyte viability rates of >95%. The DL-IF methodology involved fewer technical steps, and the assay time was shortened from 5 h to less than 3 h. Nineteen of the 82 samples concordantly tested positive for pp65 antigenemia by both assays, and the readings showed a good correlation (r = 0.996; P < 0.01). No discordant results were observed. We conclude that the CMV pp65 antigenemia assay by this novel DL-IF modification is technically simpler, cheaper, and less time-consuming but yields results comparable to those of the conventional DS-APAAP assay. The shortened assay time and increased capacity to handle more samples confer distinct advantages in the rapid diagnosis and prompt treatment of CMV disease in immunosuppressed patients.