Cytomegalovirus PP65 antigenemia monitoring as a guide for preemptive therapy: a cost effective strategy for prevention of cytomegalovirus disease in adult liver transplant recipients

Prevention of Cytomegalovirus Infection in Solid Organ Transplant Recipients: Guidelines by the Korean Society of Infectious Diseases and the Korean Society for Transplantation

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients. The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold. Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cell-mediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Epidemiology and risk factors for cytomegalovirus infection in glomerular diseases treated with immunosuppressive therapy

AIM

Cytomegalovirus (CMV) infections are associated with morbidity and mortality. We aimed to describe the epidemiology, risk factors and outcomes of CMV infection among patients with glomerulonephritis (GN) who received potent immunosuppressants (IS).

METHODS

Single-centre retrospective study of adults with biopsy-proven GN prescribed methylprednisolone (MP), cyclophosphamide (CYC) or rituximab (RTX). Primary endpoint was CMV infection defined by significant CMV antigenaemia (>10 positive cells in 10⁶ cells) or viraemia (>2000 copies/mL). Death was related to CMV if CMV infection occurred within the same hospitalization as death.

RESULTS

Ninety-four patients were studied. CYC was prescribed in 65% and MP in 71% of the cohort. Only two patients received RTX and 15 patients received plasma exchanges (PEX). Median follow up was 31.9 (IQR: 13.7, 53.6) months. CMV infection occurred in 13 patients (13.8%) at 1.3 (0.6, 3.0) months from biopsy. Patients with CMV infection had higher serum creatinine [404 (272, 619) vs. 159 (93, 317) μmol/L, P < 0.001] and greater proteinuria [UPCR 7.5, (4.8, 11.8) vs. 4.2 (2.3, 8.4) g/g, P = 0.02] than those who did not have CMV infection. Also, more patients received CYC (92% vs. 60%, P = 0.03), RTX (15% vs. 0, P = 0.02) and PEX (38% vs. 12%, P = 0.01) than those who did not have CMV infection. Two patients had CMV-related deaths.

CONCLUSION

Cytomegalovirus infection is common in GN patients receiving potent IS. Surveillance and possibly anti-viral prophylaxis should be considered for high-risk patients.

Reactivated cytomegalovirus proctitis in an immunocompetent patient presenting as nosocomial diarrhea: a case report and literature review

BACKGROUND

Reactivated cytomegalovirus (CMV) infection has been known to cause significant morbidity and mortality in immunocompromised patients. However, CMV disease rarely develops in immunocompetent patients, and reported cases often present with a mild, self-limiting course, without severe life-threatening sequelae. While the colon is the most common gastrointestinal site affected by CMV disease in immunocompetent patients, rectal involvement is rarely reported. CMV proctitis can present in two distinct forms, primary and reactivated. However, reactivated CMV proctitis is rarely reported as a causative etiology of nosocomial diarrhea, except in transplant patients. Herein we present a case of reactivated CMV proctitis in an immunocompetent patient, presenting as nosocomial diarrhea. Previously reported cases of reactivated CMV proctitis in immunocompetent patients are also reviewed.

CASE PRESENTATION

A 79-year-old female was admitted because of metabolic encephalopathy caused by dehydration and hypernatremia. The patient's consciousness level returned rapidly after fluid supplementation. However, she subsequently presented with abdominal pain and diarrhea on day 8 of admission. Abdominal contrast-enhanced computed tomography on day 10 of admission demonstrated inflammation around the rectum, suggesting proctitis. Colonoscopy on day 16 of admission showed a giant ulcer at the rectum. Pathology of rectal biopsy confirmed CMV infection. The patient recovered without sequelae after 38 days of valganciclovir treatment. Follow-up colonoscopy revealed a healed ulcer over the rectum. Ten cases in the literature, plus our case, with reactivated CMV proctitis in immunocompetent patients were reviewed. We found that most patients were elderly (mean, 72 years) with a high prevalence of diabetes mellitus (54.5%). Cardinal manifestations are often non-specific (diarrhea, hematochezia, tenesmus), and eight (72.7%) developed CMV proctitis following a preceding acute, life-threatening disease, rather than as an initial presentation on admission. These manifestations frequently develop during hospitalization, and are thus often regarded as nosocomial diarrhea.

CONCLUSIONS

Clinicians should be aware of the possibility of nosocomial onset of reactivated CMV proctitis in patients hospitalized due to a preceding critical illness, although the benefits of antiviral therapy remain unclear.

Cytomegalovirus Treatment

In treating cytomegalovirus (CMV) infection, it is crucial to decide whether one is treating pre-emptively or if one is treating established disease. Disease may be further divided into viral syndrome and tissue-invasive disease. Generally, mild disease in immunosuppressed patients may be treated with oral valganciclovir. Treatment may also be started with valganciclovir for CMV retinitis in AIDS patients. In other tissue-invasive syndromes, starting with intravenous ganciclovir or foscarnet at full doses (adjusted for renal function) is preferred. Treatment at full doses should be continued until symptom resolution and until blood antigenemia (or DNAemia) is cleared. Patients receiving treatment must be closely monitored for side effects to the drugs, as well as for response. Drug-resistant CMV is a therapeutic challenge; combination therapy with both ganciclovir and foscarnet may be tried. In extreme cases, resorting to unconventional agents like leflunomide or maribavir may be necessary. Immune reconstitution, through reduction in immunosuppression, or the introduction of anti-retroviral therapy, should be attempted. CMX001 is a novel agent active against double-stranded viruses; thus far, resistance to CMX001 does not confer resistance to ganciclovir or foscarnet. Hence, prophylaxis or pre-emptive treatment with CMX001 may allow the use of ganciclovir or foscarnet for treatment.

Clinical utility of viral load in management of cytomegalovirus infection after solid organ transplantation

The negative impact of cytomegalovirus (CMV) infection on transplant outcomes warrants efforts toward improving its prevention, diagnosis, and treatment. During the last 2 decades, significant breakthroughs in diagnostic virology have facilitated remarkable improvements in CMV disease management. During this period, CMV nucleic acid amplification testing (NAT) evolved to become one of the most commonly performed tests in clinical virology laboratories. NAT provides a means for rapid and sensitive diagnosis of CMV infection in transplant recipients. Viral quantification also introduced several principles of CMV disease management. Specifically, viral load has been utilized (i) for prognostication of CMV disease, (ii) to guide preemptive therapy, (iii) to assess the efficacy of antiviral treatment, (iv) to guide the duration of treatment, and (v) to indicate the risk of clinical relapse or antiviral drug resistance. However, there remain important limitations that require further optimization, including the interassay variability in viral load reporting, which has limited the generation of standardized viral load thresholds for various clinical indications. The recent introduction of an international reference standard should advance the major goal of uniform viral load reporting and interpretation. However, it has also become apparent that other aspects of NAT should be standardized, including sample selection, nucleic acid extraction, amplification, detection, and calibration, among others. This review article synthesizes the vast amount of information on CMV NAT and provides a timely review of the clinical utility of viral load testing in the management of CMV in solid organ transplant recipients. Current limitations are highlighted, and avenues for further research are suggested to optimize the clinical application of NAT in the management of CMV after transplantation.

Quantitation of cytomegalovirus DNA load in dried blood spots correlates well with plasma viral load

An assay to accurately quantitate cytomegalovirus (CMV) load in finger-stick-collected dried blood spots (DBS) could potentially be useful for field studies or for analyzing patient self-collected specimens. We therefore assessed CMV DNA load in paired venipuncture-collected plasma samples and finger-stick DBS, using a previously validated quantitative PCR assay. Assay variability, sensitivity, and changes in viral load during antiviral therapy in finger-stick DBS were compared to the reference plasma quantitative PCR assay, using 106 prospectively collected pairs of finger-stick DBS and plasma samples from 35 solid-organ transplant (SOT) patients. The DBS assay showed good agreement with the reference plasma viral load assay on the log10 scale (Pearson correlation coefficient, 0.92; P < 0.001). The 95% limit of detection of the DBS assay was estimated at 2,700 plasma copies/ml (675 plasma IU/ml). In 94% (76/81) of paired DBS and plasma samples above the limit of detection, the difference in CMV load was <1 log10. CMV viral load changes during antiviral treatment were comparable in plasma and DBS. We conclude that finger-stick DBS provides a convenient sample type for quantitation of CMV load that correlates well with plasma levels. Future studies to optimize and evaluate this methodology for patient self-collected samples are warranted.

Quantification of cytomegalovirus glycoprotein Bn DNA in hematopoietic stem cell transplant recipients by real-time PCR

Based on sequence variation in the N-terminus of the UL55 gene, which encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into four gBn genotypes. We assessed the distribution of CMV gBn genotypes and the correlation between CMV gBn DNA (detected by real-time PCR) and CMV-positive pp65 cells (identified by immunohistochemical staining) in a cohort of hematopoietic stem cell transplant patients. The distribution of gB genotypes was as follows: gBn1, 60% of patients; gBn2, 13.3%; mixed gBn1 and gBn3 infection, 26.7%; and gBn4 and other mixed infections, 0%. CMV gBn1 was the most common genotype. The detected level of CMV gB DNA correlated well with the number of CMV-positive pp65 cells detected by immunostaining (r = 0.585).

Quantification of cytomegalovirus DNA by a fully automated real-time PCR for early diagnosis and monitoring of active viral infection in solid organ transplant recipients

BACKGROUND

Quantification of cytomegalovirus (CMV) DNA by real-time PCR is currently considered an alternative diagnostic approach for the evaluation of active infection in transplant patients. The pp65 antigenemia assay has been used as reference test for monitoring active CMV infection and guiding preemptive therapy in transplant recipients. However, this assay suffers from some limitations: need for immediate processing of the samples, labour-intensive process, lack of standardization and subjective result interpretation.

OBJECTIVES

The aim of this study was to evaluate the performance of a new commercially available real-time PCR assay coupled with a fully automated DNA extraction system (COBAS Ampliprep/COBAS Taqman CMV Test, Roche Diagnostics) for the detection of CMV-DNA in plasma comparing it with pp65 antigenemia assay for monitoring active CMV infection in solid organ transplant recipients (SOTRs).

STUDY DESIGN

A total of 266 consecutive samples from 45 SOTRs were monitored with pp65 antigenemia and in parallel with CMV-DNA quantitation by real-time PCR assay.

RESULTS

Fifty-eight samples resulted PCR-positive, 163 negative and for 45 samples the CMV-DNA values obtained were below the lower limit of quantification (<150 copies/ml); pp65 antigen was detected in 47 samples and resulted negative in 219 specimens. Concordance between the two evaluations was 76.7%; also a good correlation was observed (r=0.718). Considering the existing treatment criteria based on pp65 antigenemia evaluation corresponding to pp65 levels≥20 positive cells/200,000, preemptive therapy was administered to four asymptomatically infected patients. The corresponding cut-off value of CMV-DNA load calculated for discrimination between self-clearing infections and those requiring therapy was 2500 copies/ml (or 2275 IU/ml).

CONCLUSION

The fully automated real-time PCR from Roche provided specific and sensitive results and represented a rapid and simple assay for the evaluation and monitoring of CMV infection in SOTRs. Further studies are required to validate the threshold level for the initiation of preemptive therapy.

Recent advances in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected adults

INTRODUCTION

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in HIV-infected adults. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, recent advances in the diagnostic tools have been changing the situation.

AREAS COVERED

Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Nested or conventional polymerase chain reaction (PCR) has a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash, but often produces false positives. Although quantitative real-time PCR is promising for discriminating colonization from PCP, the targeted DNA sequences and the cut-off values remain to be standardized. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for evaluation of immunocompromised patients with suspected PCP and normal chest radiography.

EXPERT OPINION

Although these new tools have been making the diagnosis of PCP less invasive and more accurate, any one of them can not make a definitive diagnosis by itself. The diagnostic criteria based on the combination of the testing ought to be established.

Overview of the diagnosis of cytomegalovirus infection

Cytomegalovirus (CMV) is recognized as the most common congenital viral infection in humans and an important cause of morbidity and mortality in immunocompromised hosts. This recognition of the clinical importance of invasive CMV disease in the setting of immunodeficiency and in children with congenital CMV infection has led to the development of new diagnostic procedures for the rapid identification of CMV. Diagnosis of acute maternal CMV infection by the presence of immunoglobulin (Ig)M and low-avidity IgG requires confirmation of fetal infection, which is typically performed using polymerase chain reaction (PCR) assays for CMV on amniotic fluid. Viral culture of the urine and saliva obtained within the first two weeks of life continues to be the gold standard for diagnosis of congenitally-infected infants. PCR assays of dried blood spots from newborns have been shown to lack sufficient sensitivity for the identification of most neonates with congenital CMV infection for universal screening purposes. However, saliva PCR assays are currently being assessed as a useful screening method for congenital CMV infection. In the immunocompromised host, newer rapid diagnostic assays, such as phosphoprotein 65 antigenemia and CMV real-time PCR of blood or plasma have allowed for preemptive treatment, reducing morbidity and mortality. However, lack of standardized real-time PCR protocols hinders the comparison of data from different centers and the development of uniform guidelines for the management of invasive CMV infections in immunocompromised individuals.

The role of the cytomegalovirus antigenemia assay in the detection and prevention of cytomegalovirus syndrome and disease in solid organ transplant recipients: A review of the British Columbia experience

BACKGROUND

The pp65 cytomegalovirus (CMV) antigenemia assay has been used as a means of guiding the pre-emptive therapy of CMV disease in solid organ transplant (SOT) recipients. Recently, concerns have been raised regarding the utility of the test to accurately and precisely detect viral activity early enough to reduce the morbidity and mortality associated with CMV OBJECTIVE: To determine the performance characteristics of the method of antigenemia testing of SOT recipients used at Vancouver General Hospital, Vancouver, British Columbia.

METHODS

All SOT recipients between January 1, 1999, and June 30, 2000, were retrospectively reviewed for six months following transplantation. Physical examination results, laboratory parameters, antigenemia results and treatment information were reviewed.

RESULTS

A total of 134 kidney, liver, lung and kidney-pancreas transplant recipients were included in the analysis. The overall performance characteristics of the antigenemia assay in predicting CMV disease included a sensitivity of 64%, a specificity of 81%, a positive predictive value of 76% and a negative predictive value of 71%. A mean of 18 days passed between the onset of signs and symptoms of CMV disease/syndrome and the first recorded positive antigenemia result, and only 26% of patients had a positive test result before the onset of symptoms. It was found that an antigenemia test breakpoint of at least one positive cell for defining a positive test provided the most sensitive and specific prediction, with increased odds of developing CMV disease.

CONCLUSIONS

Based on performance characteristics, the Vancouver General Hospital's current method of antigenemia testing to guide pre-emptive ganciclovir therapy in SOT patients is not optimal for the early detection of disease. Further study is needed on new molecular testing methods to determine if our ability to predict CMV disease can be improved.

A short-term preemptive treatment for cytomegalovirus infection in seropositive patients after liver transplantation

BACKGROUND/PURPOSE

Cytomegalovirus (CMV) infection remains a challenge following liver transplantation. Preemptive treatment is an effective strategy for CMV infection. However, how long preemptive treatment should be applied is not defined.

METHODS

Clinical records of preemptive treatment for CMV infection in patients who underwent liver transplantation were collected. CMV antigenemia (pp65) was monitored weekly during hospital stay and subsequently on follow up whenever indicated clinically. Antiviral treatment was administered based on positive antigenemia (>1 positive cell per 500,000 leukocytes) and discontinued when antigenemia became negative.

RESULTS

CMV infection was diagnosed in 58 (43.9%) of 132 liver transplantation patients. All 58 patients were seropositive for CMV before transplantation. CMV infection was first diagnosed at a median time of 20 days (interquartile range [IQR] 15.3-26) after transplantation. Twelve (20.7%) patients developed repeated infections. Only one of 58 patients (1.7%) was suspected to have invasive disease. The median (IQR) duration of antiviral treatment was 7 (7-12) days. Of these patients with CMV infection, 14 (24.1%) patients developed acute rejection peri-anti-CMV treatment and 36 (62.1%) developed other infectious complications.

CONCLUSION

Preemptive treatment is an effective way to halt the progression of asymptomatic CMV infection. A brief course of antiviral treatment is enough for seropositive patients with CMV infection after liver transplantation.

The effect of cytomegalovirus antigenemia titer on the efficacy of preemptive therapy for the prevention of cytomegalovirus disease after kidney transplantation

There is some controversy regarding the exact cytomegalovirus (CMV) antigenemia titer that should be used as a guideline for preemptive anti-CMV therapy. We performed 634 consecutive kidney transplantations between January 2000 and June 2007. Preemptive therapy employed intravenous gancyclovir treatment when the CMV antigenemia titer was >or=50/4x10(5) leukocytes after kidney transplantation. The 634 recipients were allocated into 2 groups according to the peak CMV antegenemia: group A, CMV antigenemia titer<50/4x10(5) (n=550); and group B, >or=50/40x10(5) (n=84). Among the 634 recipients, 264 were positive for CMV antigenemia, and 61 developed symptomatic CMV infections. The incidence of symptomatic CMV infections in group B was significantly higher than in group A. Two cases in both groups developed tissue-proven CMV disease: group A CMV colitis and CMV nephritis, and group B, 2 cases of CMV colitis. Graft and patient survival rates in groups A and B at 5 years posttransplantation were not different. The authors concluded that a CMV antigenemia titer of >or=50/4x10(5) leukocytes can be considered an appropriate guideline for preemptive anti-CMV therapy.

Successful lung transplantation in an HIV- and HBV-positive patient with cystic fibrosis

Prior to the advent of highly active antiretroviral therapy (HAART), HIV-infected patients were usually not considered as transplant candidates because of the poor prognosis of their underlying disease and concerns regarding the potential detrimental effects of immunosuppression on viral load and immune status. However, with the significant HAART-associated improvements in morbidity and mortality, good short-term outcomes after liver and kidney transplantation for patients with HIV infection have been reported. Nevertheless, HIV infection is currently considered a contraindication to lung transplantation in most transplant centers worldwide. The results of a double lung transplant performed in an HIV and HBV co-infected patient with cystic fibrosis (CF) and end-stage respiratory failure (ESRF) are presented after a 2-year follow-up. Approval of and recommendations for the management of this patient were obtained from the Italian National Center for Transplantation as an extension of the ongoing Italian protocol for liver and kidney transplantation in HIV-infected individuals. The operation was successful and the patient recovered rapidly after surgery. A cautious infectious and immunosuppressive management allowed so far the avoidance of major infectious complications and rejection. To the best of our knowledge, this is the first report of lung transplantation in an HIV and HBV co-infected patient.

Methodology for monitoring cytomegalovirus infection after renal transplantation

BACKGROUND

The aim of this study was to evaluate the diagnostic value of different detection methods for cytomegalovirus (CMV) infection after renal transplantation and also to establish a system to monitor therapy for CMV infection.

METHODS

We retrospectively studied 1516 renal transplant recipients from June 1994 to December 2006. All patients were screened for CMV-DNA. A total of 1402 patients had received CMV-IgG/IgM detection since June 1996 and 660 had received CMV antigen detection since June 2000.

RESULTS

A total of 664 (43.8%) recipients developed CMV infection. The sensitivity, specificity and Youden index of the three methods, respectively, were 18.84%, 100% and 0.1884 for ELISA, 91.86%, 82.98% and 0.7484 for PCR, and 88.06%, 96.95% and 0.8501 for the CMV-pp65 antigenemia test. The sensitivity and specificity of the two combined detection methods (CMV-DNA and CMV-pp65) for post-operation CMV infection were 93.49% and 99.06%; the two detection methods had significant dependability (p<0.05) in diagnosis of CMV infection and in evaluation of therapeutic effect of antiviral drugs.

CONCLUSIONS

Only ELISA can be used as a screening index in order to distinguish whether the donors or recipients are infected with CMV or not. CMV-pp65 antigenemia can help guide clinical therapy for CMV infection. CMV-pp65 and CMV-PCR combined together provide a more effective method to monitor CMV infection and predict its outcome.

Diagnostic value of HCMV pp65 antigen detection by FCA for symptomatic and asymptomatic infection: compared to quantification of HCMV DNA and detection of IgM antibody in infants

Human cytomegalovirus (HCMV) can cause symptomatic or asymptomatic infection in infants. One hundred and twenty-six infants were assessed clinically for disease in infantile period. Eighty of them were classified as symptomatic infection on the basis of physical, instrumental, and laboratory findings, 5 were demonstrated by following up to have later developed HCMV disease, and the other 41 infants were classified as asymptomatic infection. HCMV DNA was positive in all urine samples of the symptomatic infants detected by quantitative polymerase chain reaction. HCMV-IgM antibody detected by chemiluminescent immunoassay (CLIA) was positive in 62 of the 85 symptomatic infants, but was negative in all of the samples of asymptomatic infants. HCMV pp65 antigen detected by flow cytometry assay (FCA) was positive in 77 of the 85 symptomatic infants and in none of the asymptomatic infants. The coincidence to symptom of HCMV pp65 antigen detection was higher than those of HCMV DNA and HCMV-IgM antibody detection. The sensitivity, specificity, positive prognostic value and the negative prognostic value of HCMV pp65 antigen detection for diagnosis of HCMV infection was 90.6, 100, 100 and 83.7%, respectively. We concluded that detection of pp65 antigen by FCA is more sensitive for diagnosis of HCMV infection than detection of HCMV-IgM antibody and is better than HCMV DNA quantification for distinguishing the symptomatic and asymptomatic HCMV infection in infants.

Management of human cytomegalovirus infection in transplant recipients by the pre-emptive therapy approach

Human cytomegalovirus (HCMV) infections are still a major infectious complication in the post-transplant period of both solid organ transplant recipients (SOTRs) and hematopoietic stem cell transplant recipients (HSCTRs). For many years, the major diagnostic assay has been antigenemia, allowing semi-quantification of HCMV load in blood from transplanted patients with disseminated HCMV infection. More recently, the real-time PCR assay has replaced antigenemia for HCMV DNAemia quantification. Prevention of HCMV disease is based on either prophylaxis or pre-emptive therapy with antiviral drugs. The latter approach has been in use in our department for the last 15 years. A cut-off of 300,000 DNA copies/ml whole blood in SOTRs with either primary or reactivated infection, and a cut-off of 10,000 DNA copies/ml blood in HSCTRs proved to be safe and effective in prospective randomized, controlled trials. With this approach, HCMV disease is consistently prevented, except for a limited number of cases of organ localization in the absence of virus in blood. In these cases, HCMV infection/disease must be diagnosed by local biopsy samples.

Pediatric liver transplantation

In previous decades, pediatric liver transplantation has become a state-of-the-art operation with excellent success and limited mortality. Graft and patient survival have continued to improve as a result of improvements in medical, surgical and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. The utilization of split-liver grafts and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, have had a significant impact on graft and patient survival. Future developments of pediatric liver transplantation will deal with long-term follow-up, with prevention of immunosuppression-related complications and promotion of as normal growth as possible. This review describes the state-of-the-art in pediatric liver transplantation.

Prophylaxis followed by preemptive therapy versus preemptive therapy for prevention of human cytomegalovirus disease in pediatric patients undergoing liver transplantation

Twenty-one pediatric liver transplant recipients were enrolled in a study comparing prophylaxis followed by preemptive therapy (10 patients) versus preemptive therapy alone (11 patients) for prevention of human cytomegalovirus (HCMV) disease. In the prophylaxis arm, patients were treated with ganciclovir for 30 days, then preemptive therapy was initiated with virologic monitoring for pp65 antigenemia. In the preemptive therapy arm, patients were treated on reaching 100,000 DNA copies/mL whole blood. An interim analysis showed that, although numbers of both infected and treated patients were comparable in the two arms, the median number of total days of antiviral therapy per patient (30 vs. 18, P<0.01) was significantly higher in the prophylaxis arm. No case of HCMV disease occurred in either arm. Therefore, the trial was interrupted and prophylaxis replaced with preemptive therapy alone. In parallel, the development of T-cell-mediated immune response was found to be comparable in both arms.

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

BACKGROUND

Cytomegalovirus (CMV) infection in immunocompromised patients can lead to viremia associated with morbidity and mortality. Monitoring of viral loads in blood is critical for initiating and monitoring antiviral treatment.

OBJECTIVES

Validate quantitative real-time PCR assay targeting the US17 and UL54 regions of the CMV genome for automated DNA and extraction and amplification.

STUDY DESIGN

3422 blood specimens from organ transplant recipients, including longitudinal specimens from 12 organ transplant recipients, were tested by CMV PCR and pp65 antigenemia.

RESULTS

CMV PCR for both US17 and UL54, was more sensitive and detected CMV DNA earlier and for longer than the CMV pp65 antigenemia test. Using antigenemia results as a reference standard, an optimal cutoff of 500 normalized copies was calculated for both US17 and UL54 PCR targets based on high sensitivity, specificity, and positive and negative predictive values. CMV DNA levels tracked well with clinical symptoms, response to treatment, and antigenemia.

CONCLUSIONS

Detection of persistent increases in CMV DNA levels above 500 normalized copies by this real-time PCR assay is indicative of symptomatic CMV disease in organ transplant recipients. Quantitative real-time PCR for CMV DNA can be used in lieu of antigenemia for monitoring CMV infection and determining when to initiate preemptive treatment.

Intensivtherapie nach Organtransplantation

Nach langen Diskussionen bietet das Transplantationsgesetz, das seit 01.12.1997 in Kraft ist, Rechtssicherheit. Das Gesetz dient dem Schutz des Spenders und des Empfängers, und es bietet Rechtssicherheit für alle in der Transplantationsmedizin Tätigen. Das Gesetz legt die Rechte und Verpflichtungen der Beteiligten und die Wege der Organspende und -vermittlung fest. Das Gesetz unterscheidet zwischen der Organentnahme bei Lebenden und bei Verstorbenen und legt die Rahmenbedingungen fest. Die Umsetzung der Todesbestimmung soll nach den Erkenntnissen der medizinischen Wissenschaft erfolgen und ist in den Richtlinien der Bundesärztekammer (3. Fortschreibung 1997) festgelegt worden.

Relationship between pp65 antigenemia levels and real-time quantitative DNA PCR for Human Cytomegalovirus (HCMV) management in immunocompromised patients

Background

Quantitative real-time PCR assays, which are more rapid and practical than pp65 antigenemia determination, are progressively becoming the preferred method for monitoring Human Cytomegalovirus (HCMV) reactivation. However, the relationship between HCMV DNA and antigenemia levels is still under investigation. The aim of this study was to analyse the relationship between HCMV DNA and pp65 antigenemia levels in order to identify clinically useful threshold values for the management of patients.

Methods

475 consecutive samples from 156 immunosuppressed patients were tested for HCMV by pp65 antigenemia and Real-time PCR assay.

Results

136 out of 475 consecutive samples derived from 48 patients showed evidence of HCMV infection. HCMV DNA was detected in 106 samples, pp65 antigen in 3, and both markers in 27. pp65 antigen detection was associated with higher HCMV DNA levels. The cut-off HCMV DNA level that best predicted pp65 antigenemia in this series of samples was 11,500 copies/ml, but different threshold levels could be observed for specific groups of patients. HCMV disease was observed in 5 out of 48 patients with active HCMV infection. The presence of clinical symptoms was associated with positive pp65 and with higher antigenemia levels. Higher HCMV DNA load at the onset of viral replication was correlated to the development of clinical symptoms.

Conclusion

Both pp65 antigenemia and HCMV DNA load can be useful for the prospective monitoring of immunocompromised subjects. Specific cut-off levels capable of triggering preemptive antiviral treatment should be determined in accordance to the type of test used and the characteristics of patients and prospectively validated.

Real-time PCR assay compared with antigenemia assay for detecting cytomegalovirus infection in kidney transplant recipients

Human cytomegalovirus (CMV) infection is a major cause of morbidity and mortality among kidney transplant recipients. The CMVpp65 antigenemia assay has been used for preemptive therapy. Real-time polymerase chain reaction (PCR) technology for CMV DNA quantification in blood has demonstrated a good correlation with the currently employed CMV antigenemia assay. In this study, 90 renal transplant recipients were prospectively enrolled from July 2004 and May 2005. Monitoring of CMV infection was routinely performed with CMV antigenemia and real-time PCR assays. Real-time plasma PCR and CMV antigenemia assays were assessed on 797 samples. CMV antigenemia correlated with a positive CMV PCR (chi(2) = 78.05; P < .0001). Not only the positive rate but also the number of positive cells correlated with the number of PCR DNA copies (F = 26.07, r(2) = .25, P < .0001). To define an optimal cutoff value of CMV DNA load to initiate treatment in kidney transplant patients, we considered a CMV antigenemia titer of >50 positive cells per 400,000 leukocytes as the gold standard in our previous study. The optimal cutoff value for the quantitative real-time PCR assay was predicted to be 86 copies/microL. Thus, we observed that CMV real-time PCR assay would not completely replace antigenemia assay in kidney transplant recipients, but can be used complementarily to screen antigenemia and monitor preemptive therapy.

Update in infectious diseases in liver transplant recipients

The prevention and management of bacterial, fungal, and viral infections are important components in the care of the liver transplant recipient. Although much progress has been made, challenges still remain. This article provides updates on the management of bilomas and peritonitis, the prevention and management of invasive Candida and Aspergillus infections, the prevention and management of cytomegalovirus disease, and the current status of liver transplantation in HIV-infected patients.

Comparison of pp65 antigenemia, quantitative PCR and DNA hybrid capture for detection of cytomegalovirus in transplant recipients and AIDS patients

The cytomegalovirus (CMV) antigenemia assay has been used frequently for rapid diagnosis of CMV infection, and antigenemia threshold values are recommended for triggering preemptive therapy. Hybrid capture of CMV's DNA and quantitative polymerase chain reaction (qPCR) are increasingly being adopted for early detection of CMV. The performance of the antigenemia assay, qPCR in plasma and hybrid capture in leukocytes were compared in 110 immunocompromised patients (38 bone-marrow transplants, 50 renal transplants and 22 AIDS patients). The most sensitive test was hybrid capture for transplants, while antigenemia and the qPCR showed similar performance for patients with AIDS. QPCR and hybrid capture thresholds requiring antiviral therapy were calculated using a receiver-operating-characteristic curve for antigenemia values corresponding to 2 positive cells for bone-marrow transplants and to 10 positive cells for renal transplants and AIDS patients. These threshold values varied with the group of patients considered, with corresponding sensitivities higher than 86% and specificities higher than 76% for hybrid capture, and sensitivities higher than 61% and specificities higher than 75% for qPCR in plasma. Hybrid capture in leukocytes can substitute for antigenemia in the case of transplants, and qPCR in plasma can substitute for it in the case of AIDS patients.

Survival of liver transplant patients coinfected with HIV and HCV is adversely impacted by recurrent hepatitis C

Although liver transplantation (LTx) in HIV-positive patients receiving highly active antiretroviral therapy (HAART) has been successful, some have reported poorer outcomes in patients coinfected with hepatitis C virus (HCV). Here we discuss the impact of recurrent HCV on 27 HIV-positive patients who underwent LTx. HIV infection was well controlled post-transplantation. Survival in HIV-positive/HCV-positive patients was shorter compared to a cohort of HIV-negative/HCV-positive patients matched in age, model for end-stage liver disease (MELD) score, and time of transplant, with cumulative 1-, 3- and 5-year patient survival of 66.7%, 55.6% and 33.3% versus 75.7%, 71.6% and 71.6%, respectively, although not significantly (p = 0.07), and there was a higher likelihood of developing cirrhosis or dying from an HCV-related complication in coinfected subjects (RR = 2.6, 95% CI, 1.06-6.35; p = 0.03). Risk factors for poor survival included African-American race (p = 0.02), MELD score > 20 (p = 0.05), HAART intolerance postLTx (p = 0.01), and postLTx HCV RNA > 30000000 IU/mL (p = 0.00). Recurrent HCV in 18 patients was associated with eight deaths, including three from fibrosing cholestatic hepatitis. Among surviving coinfected recipients, five are alive at least 3 years after LTx, and of 15 patients treated with interferon-alpha/ribavirin, six (40%) are HCV RNA negative, including four with sustained virological response. Hepatitis C is a major cause of graft loss and patient mortality in coinfected patients undergoing LTx.

Valganciclovir preemptive therapy for the prevention of cytomegalovirus disease in high-risk seropositive solid-organ transplant recipients

BACKGROUND

The role of valganciclovir in the prevention of cytomegalovirus (CMV) disease in high-risk seropositive transplant patients is not known.

METHODS

We prospectively followed 301 seropositive solid organ transplant recipients to assess the efficacy and safety of valganciclovir (VGCV) in the prevention of CMV disease in high-risk patients. Asymptomatic patients with an antigenemia test >or=25 positive cells/2x10(5) polymorphonuclear cells received valganciclovir 900 mg twice a day as preemptive therapy until resolution of antigenemia (minimum 14 days). Additionally, patients treated with antilymphocytic drugs for more than 6 days received prophylaxis with VGCV 900 mg once a day during 90 days. Mean follow-up was 14 months (range 6-20 months).

RESULTS

Thirty-eight patients received VGCV; 24 as preemptive therapy and 14 due to the use of antilymphocytic drugs. No patient developed CMV disease during the follow-up. Viral load (antigenemia) decreased a mean of 78% from baseline after 7 days of VGCV therapy (P=0.024) and 98% at day 14 (P=0.029). Two patients showed a relapse of the antigenemia test >or=25 positive cells and were successfully treated with a repeated course of VGCV. Leukopenia (<2500/mm3) developed in 3/24 (12.5%) recipients in the preemptive therapy group and required to discontinuing the drug in one of them.

CONCLUSIONS

VGCV is safe and highly efficacious in the prevention of CMV disease in high-risk seropositive organ transplant recipients.

Evaluation of three polymerase chain reaction tests targeting morphological transforming region II, UL-83 gene and glycoprotein O gene for the detection of human cytomegalovirus genome in clinical specimens of immunocompromised patients in Chennai, India

Background

Human Cytomegalovirus (HCMV) continues to be an important cause of morbidity and occasional mortality in immunocompromised patients. Polymerase chain reaction (PCR) is the most sensitive and commonly used method for the assessment of HCMV infection in the immunocompromised patients at risk from severe associated clinical manifestations. However, there is little consistency in the qualitative PCR used for different regions of HCMV genome. Therefore, the performance of three Qualitative PCR tests to detect HCMV genome in clinical specimens from immunocompromised patients was evaluated. With pp65 antigenemia assay as the "gold standard", nested PCR for morphological transforming region II (mtr II) and glycoprotein O (gO) gene and uniplex PCR for UL 83 gene were applied on 92 consecutive clinical specimens obtained from 74 immunocompromised patients with clinically suspected HCMV disease. Virus isolation was attempted on 12 clinical specimens from six pp65 antigenemia positive patients. Based on the pp 65 antigenemia results as "gold standard", the sensitivity, specificity, positive predictive value and negative predictive value for each PCR was calculated.

Results

The PCR targeting mtr II region showed a higher sensitivity (100%) and negative predictive value (100%) than the other two PCRs in detecting HCMV DNA from clinical specimens obtained from different immunocompromised patient population of Chennai region, India.

Conclusion

The results suggests that the optimal method of detection of HCMV DNA could be achieved by PCR using primer sequences targeting mtr II region of genome of HCMV in Chennai region, India.

Viral and fungal infections after liver transplantation--part II

Viral and fungal infections in liver transplant recipients are important to recognize and treat early because of their association with substantial morbidity and mortality. Some viruses, such as cytomegalovirus and human herpesvirus 6, have immunomodulatory properties and can facilitate other infections, including fungal infections. Cytomegalovirus has long been recognized as an important virus in transplantation, but in the past decade other viruses have also received attention in the medical literature because of their association with particular clinical syndromes. Although human herpesvirus 6 has been associated with fever, rash, and encephalitis, a direct cause-and-effect relationship is still lacking. Human herpesvirus 8 has been found to be the cause of Kaposi sarcoma. Molecular techniques (e.g., pp65 antigenemia and polymerase chain reaction) that have been introduced for routine diagnosis of viruses have facilitated the diagnosis of asymptomatic viral infections and the institution of preemptive therapy. Nonetheless, the diagnosis of invasive fungal infections in liver transplant recipients is often delayed and thus associated with high mortality. Despite the use of new antifungal agents in clinical practice and the reduced incidence of fungal infections because of antifungal prophylaxis regimens, mortality has not decreased. Future patient outcomes may improve with early identification of patients who have risk factors for invasive fungal infections and with the development of new molecular diagnostic techniques for early detection.

Outcome, Incidence, and Timing of Infectious Complications in Small Bowel and Multivisceral Organ Transplantation Patients

BACKGROUND

Infectious complications still represent a major cause of morbidity and mortality in patients with organ transplantation. In particular, small bowel or multivisceral transplantation is complicated to a greater extent than other grafts as a consequence of infectious complications including sepsis.

METHODS

This prospective study assessed outcome, incidence, and timing of infections in sequential patients undergoing small bowel or multivisceral transplantation (SB/MVTx) performed at a university transplant center between January 2001 and October 2003. Nineteen patients underwent transplantation during this period, 13 of whom (68%) undergoing isolated SB and 6 (32%) MV grafts with or without liver.

RESULTS

The median follow up was 524 days (interquartile range=252-730) with an overall 24.4 person/year of observation. Postoperative mortality rate was 0.1 death/person/year; all patients, except one who died intraoperatively, were alive 6 months postsurgery. There were 100 documented infections including: 59 bacterial (2.4 events/person/year), 35 viral (1.4 events/person/year) and 6 fungal (0.2 events/person/year). Patients developed at least one episode of bacterial infection in 94% of the cases, viral infection in 67%, and fungal infection in 28%.

CONCLUSIONS

This cohort describes the very common and complex nature of infectious complications in this challenging group of transplantation patients. Larger cohorts are needed to specifically address infection risk factors and longer term outcomes.

Anesthesia Considerations for Pediatric Thoracic Solid Organ Transplant

This article discusses the indications, perioperative management, postoperative complications, and patient outcome of pediatric heart transplantation and pediatric lung transplantation. Special emphasis is placed on the anesthetic considerations relevant for children who are undergoing or have received a solid thoracic organ transplant.

Quality assurance, efficiency indicators and cost-utility of the evaluation workup for liver transplantation

We report the results of a retrospective review of the outpatient pretransplantation workup for United Network for Organ Sharing (UNOS) 3 patients adopted at a liver transplantation (LT) center and illustrate the efficiency indicators used for quality evaluation and cost-analysis. A single-center, pre-LT evaluation workup was performed on an outpatient basis at a cost per patient evaluation of 2,770 Euros (). Objective measures were: the number of patients admitted to and excluded from each phase of the algorithm; the rate of patients admitted to pre-LT evaluation out of the total of referred patients (the referral efficiency rate); the rate of waitlisted patients out of those admitted to pre-LT evaluation (the evaluation efficiency rate); the rate of waitlisted patients out of those referred for LT (the process efficiency rate); and the cost per waitlisted patient, as the ratio of the cost per patient evaluation to the evaluation efficiency rate. From January 1, 1996, to October 1, 2004, 1,837 patients were referred for LT on an outpatient basis. Based on preemptive evaluation of the available clinical data, 412 patients (22.4%) were excluded from pre-LT evaluation and 1,425 (77.6%) were admitted to preliminary consultation. Among these, 603 (42.3%) were excluded from and 822 (57.7%) were admitted to pre-LT evaluation with a referral efficiency rate of 44.7% (822 of 1,837). Out of the patients evaluated for LT, 484 were waitlisted with a cost-utility and evaluation efficiency rate of 58.8% each (484 of 822). Of the 1,837 patients originally addressed for LT 484 were waitlisted, yielding a process efficiency rate of 26.3% (484 of 1,837) and a cost per waitlisted patient of 4,710.8. In conclusion, the 3 indicators allowed monitoring of the efficiency of the pre-LT evaluation algorithm. The current process efficiency rate at our center is low (26.3%), but avoiding early referrals we might increase it to 31.6%, with a 12% net saving on costs per waitlisted patient (from 4,710.8 to 4,165.4).

Role of Immunosuppressive Regimen on the Incidence and Characteristics of Cytomegalovirus Infection in Heart Transplantation: A Single-Center Experience With Preemptive Therapy

OBJECTIVE

This retrospective single-center report sought to evaluate the relation of immunosuppressive regimen with the incidence and characteristics of cytomegalovirus (CMV) infection from 1999 to 2003.

PATIENTS AND METHODS

Immunosuppression consisted of cyclosporine microemulsion (Neoral), azathioprine (AZA), and prednisolone associated with either thymoglobulin or ATG high-dosage induction from 1999 to 2000 (AZA, 64 patients [AZA-Thymo = 38 patients and AZA-ATG 26 patients]), or cyclosporine microemulsion (Neoral), mycophenolate mofetil (MMF), and prednisolone with low-dose thymoglobulin induction from 2001 onward (n = 52 patients). Ganciclovir preemptive therapy was guided by pp65 antigenemia monitoring without CMV prophylaxis.

RESULTS

The study groups were homogeneous with respect to major perioperative risk factors. Comparing the two AZA subgroups no difference emerged as to percentage of pp65 antigenemia-positive, preemptively treated patients reflecting CMV disease incidence and relapses. AZA-Thymo patient showed significantly shorter time to first positive pp65-antigenemia and higher viral load (AZA-Thymo vs AZA-ATG, P = .004 and P = .009). The two subgroups did not differ with regard to incidence of rejection, superinfection, and graft coronary disease. By shifting from AZA to MMF no difference emerged as to incidence and characteristics of CMV infections, but there was a significant reduction in acute rejection and superinfection (AZA vs MMF P = .001 and P = .008).

CONCLUSIONS

The distinct immunological properties of thymoglobulin versus ATG significantly altered the pattern of CMV expression. MMF with reduced-dose induction did not engender a higher CMV morbidity.

Analysis of a quantitative PCR assay for CMV infection in liver transplant recipients: an intent to find the optimal cut-off value

BACKGROUND

Preemptive therapy required highly predictive tests for CMV disease. CMV antigenemia assay (pp65 Ag) has been commonly used for rapid diagnosis of CMV infection. Amplification methods for early detection of CMV DNA are under analysis.

OBJECTIVES

To compare two diagnostic methods for CMV infection and disease in this population: quantitative PCR (qPCR) performed in two different samples, plasma and leukocytes (PMNs) and using a commercial diagnostic test (COBAS Amplicor Monitor Test) versus pp65 Ag.

STUDY DESIGN

Prospective study conducted in liver transplant recipients from February 2000 to February 2001.

RESULTS

Analyses were performed on 164 samples collected weekly during early post-transplant period from 33 patients. Agreements higher than 78% were observed between the three assays. Optimal qPCR cut-off values were calculated using ROC curves for two specific antigenemia values. For antigenemia >or=10 positive cells, the optimal cut-off value for qPCR in plasma was 1330 copies/ml, with a sensitivity (S) of 58% and a specificity (E) of 98% and the optimal cut-off value for qPCR-cells was 713 copies/5x10(6) cells (S:91.7% and E:86%). Using a threshold of antigenemia >or=20 positive cells, the optimal cut-off values were 1330 copies/ml for qPCR-plasma (S 87%; E 98%) and 4755 copies/5x10(6) cells for qPCR-cells (S 87.5%; E 98%). Prediction values for the three assays were calculated in patients with CMV disease (9 pts; 27%). Considering the assays in a qualitative way, the most sensitive was CMV PCR in cells (S: 100%, E: 54%, PPV: 40%; NPV: 100%). Using specific cut-off values for disease detection the sensitivity, specificity, PPV and NPV for antigenemia >or=10 positive cells were: 89%; 83%; 67%; 95%, respectively. For qPCR-cells >or=713 copies/5x10(6) cells: 100%; 54%; 33% and 100% and for plasma-qPCR>or=1330 copies/ml: 78%, 77%, 47%, 89% respectively.

CONCLUSIONS

Optimal cut-off for viral load performed in plasma and cells can be obtained for the breakpoint antigenemia value recommended for initiating preemptive therapy with high specificities and sensitivities. Diagnostic assays like CMV pp65 Ag and quantitative PCR for CMV have similar efficiency and could be recommended as methods of choice for diagnosis and monitoring of active CMV infection after transplantation.

Indirect Outcomes Associated with Cytomegalovirus (Opportunistic Infections, Hepatitis C Virus Sequelae, and Mortality) in Liver-Transplant Recipients with the Use of Preemptive Therapy for 13 Years

BACKGROUND

The effect of preemptive therapy on indirect sequelae associated with cytomegalovirus (CMV) in liver-transplant recipients has not been clearly delineated.

METHODS

Thirteen years of outcome with the use of preemptive therapy were assessed in a cohort of 216 consecutive liver-transplant recipients.

RESULTS

The incidence of major infections (31% vs. 44.3%), bacterial infections (31% vs. 39.2%), bacteremia (19% vs. 29.1%), or fungal infections (3.4% vs. 7.6%) did not differ significantly for patients with CMV infection who received preemptive therapy compared with those who never developed CMV infection and did not receive antiviral prophylaxis for CMV (P>0.20 for all variables). The rate of opportunistic infections also did not differ when patients were stratified by primary CMV infection, reactivation infection, or no CMV infection. Recurrent hepatitis C virus (HCV) hepatitis occurred in 55.6% of the patients with CMV treated with preemptive therapy and 49.8% of those without CMV infection (P>0.20). The probability of survival at 6 months, 12 months, 2 years, and 3 years was also comparable for the two groups.

CONCLUSIONS

Liver-transplant recipients with CMV infection, including high-risk R-/D+ patients, when followed using the preemptive therapy approach had no significant difference in meaningful outcomes such as opportunistic superinfections, HCV recurrence rates, rejection, and survival when compared with the patients in whom CMV infection never developed and who did not receive antiviral prophylaxis for CMV.

Cytomegalovirus infection in critically ill patients: associated factors and consequences

OBJECTIVE

To determine the prevalence, associated findings, and consequences of cytomegalovirus (CMV) antigenemia in critically ill patients.

DESIGN

A retrospective, case-control clinical study.

SETTING

A 12-bed university hospital medical-surgical ICU.

PATIENTS

Two hundred thirty-seven patients with fever for > 72 h, without proven evidence of bacteriologic and/or fungal origin, and whose pp65 antigenemia assays were studied. Patients with HIV infection and transplant recipients were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

CMV antigenemia was diagnosed within 20 +/- 12 days (mean +/- SD) after ICU admission in 17% patients in whom the pathology was suspected. The 40 patients in the CMV group were matched with 40 other patients in the control group. CMV infection was linked to renal failure (58% vs 33%, respectively; p = 0.02) and steroid use (55% vs 33%, respectively; p = 0.04). Patients with CMV had a significantly longer stay in the ICU (41 +/- 28 days vs 31 +/- 22 days, respectively; p = 0.04), a longer duration of mechanical ventilation (35 +/- 27 days vs 24 +/- 20 days, respectively; p = 0.03), a higher rate of nosocomial infection (75% vs 50%, respectively; p = 0.04), and a higher mortality (50% vs 28%, p = 0.02).

CONCLUSIONS

CMV antigenemia is not an uncommon diagnosis in critically ill ICU patients with unexplained prolonged fever after 10 days of hospitalization, regardless of their immune system status. Although associated with a higher morbidity and mortality, the clinical significance of CMV is unknown. Further prospective studies should evaluate the impact on ICU outcome and whether CMV is truly a pathogen or simply another indicator of immunosuppression.

Clinically-based determination of safe DNAemia cutoff levels for preemptive therapy or human cytomegalovirus infections in solid organ and hematopoietic stem cell transplant recipients

Transplantation Centers using human cytomegalovirus (HCMV) antigenemia-based preemptive therapy will need to replace in the near future the antigenemia assay with a more standardized and automatable assay, such as a molecular assay quantifying HCMV DNA in blood (DNAemia). Thus, in view of replacing antigenemia with clinically safe cutoff values, DNAemia levels corresponding to antigenemia cutoffs guiding HCMV preemptive therapy were determined retrospectively in solid organ and hematopoietic stem cell transplant recipients (HSCTR) using an "in-house" quantitative PCR (QPCR) method. Since preemptive therapy had prevented appearance of HCMV disease in all patients tested, DNA cutoffs determined retrospectively had to be considered as safe clinically as antigenemia cutoffs used prospectively. However, in solid organ transplant recipients (SOTR), initiating preemptive therapy upon an antigenemia cutoff of 100 pp65-positive leukocytes, a DNAemia cutoff of 300,000 copies/ml blood had positive and negative predictive values of >90%, indicating that a DNAemia cutoff could achieve, in terms of prevention of HCMV disease, the same clinical results as the antigenemia cutoff. In HSCTR, initiating preemptive therapy upon first antigenemia positivity, a DNAemia cutoff of 10,000 copies/ml blood had a positive predictive value of >90%, indicating that the great majority of patients treated under the antigenemia guidance would have been treated also using this DNA cutoff. On the other hand, the negative predictive value of 28.6% indicated that two out of three HSCTR had been treated under the antigenemia guidance having the same levels of viral DNA as the untreated patients. The data suggest that a quantitative cutoff could be adopted as a guiding criterion for preemptive therapy also in HSCTR. Regression analysis allowed to determine the DNAemia (corresponding to QPCR) cutoff values for two commercial assays tested both in solid organ and HSCTR. Retrospective DNAemia cutoff values will be verified for safety in prospective trials.

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.

Prospective evaluation of the clinical utility of different methods for the detection of human cytomegalovirus disease after liver transplantation

Standardized human cytomegalovirus (HCMV) assays were prospectively evaluated to predict HCMV disease. In 135 consecutive adult liver transplantations, pp65-antigenemia, quantitative HCMV-DNA and qualitative pp67-messenger-RNA were determined weekly. No ganciclovir prophylaxis or preemptive treatment was used. One hundred and ten (81.5%) patients showed no HCMV-infection, 25 patients were positive in at least one of the HCMV-tests (18.5%). Four suffered from HCMV viral syndrome (3.0%) and another four from tissue invasive disease. In total, pp65-antigenemia was detected in 18, HCMV-DNA in 22 and pp67-mRNA in 18 patients. The sensitivity and negative predictive value (NPV) for HCMV-disease was 100% for all tests. The PPV for symptomatic HCMV-infection was 47% for pp67 mRNA. In contrast, the PPV of pp65-antigenemia (using a threshold of > 2/200 000 cells) and quantitative PCR (using a cutoff of > 5000 copies/mL) were 80% and 89%, respectively. A cost analysis revealed symptom-triggered or preemptive treatment was less expensive than general ganciclovir prophylaxis, if the incidence of CMV disease was low (<30%). Quantitative human cytomegalovirus (HCMV)-DNA and pp65-antigen assays have a comparable sensitivity and can therefore predict the onset of HCMV symptoms at an early stage. Compared with general prophylaxis, symptom-triggered or preemptive treatment based on one of these assays might reduce the costs and also the danger of ganciclovir resistance.

Aciclovir or ganciclovir universal prophylaxis of cytomegalovirus infection in liver transplantation: an economic analysis

BACKGROUND

Cytomegalovirus (CMV) following orthotopic liver transplantation can result in significant morbidity and mortality. Prophylaxis with oral aciclovir (ACV) or ganciclovir (GCV) for all transplant recipients (universal prophylaxis) may be beneficial, but which agent is more cost-effective is unknown.

METHODS

A single centre, retrospective study of all patients who had OLT at the Western Australian Liver Transplantation Service was performed. Patients received ACV from 1992 to 1998, and GCV from 1999 to 2001. A comparative cost-effectiveness analysis for the two groups was performed based on the mean total cost of the number of cases of CMV infection and disease as the clinical end-point.

RESULTS

The ACV group comprised of 55 patients and there were 24 in the GCV group. The incidence of CMV disease was 7% and 4% for the ACV and GCV groups, respectively (P > 0.05). For CMV infection it was 16% and 8%, respectively (P > 0.05). GCV prevented more cases of CMV infection and disease than ACV but at an incremental cost of dollars A20,000 (dollars US10,172) per case prevented. Overall, ACV was more cost-effective than GCV by dollars A2200 (dollars US1119) per person. The cost benefit of ACV was derived principally through a reduced pharmaceutical cost. Both agents were well tolerated without development of antiviral resistance.

CONCLUSIONS

Universal prophylaxis of CMV infection-following liver transplantation with aciclovir is more cost-effective than with ganciclovir.

Validation of clinical application of cytomegalovirus plasma DNA load measurement and definition of treatment criteria by analysis of correlation to antigen detection

Successful preemptive cytomegalovirus (CMV) therapy in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infections. The pp65 antigenemia assay has been used for this purpose with considerable success. Quantification of CMV DNA is currently regarded to be an alternative diagnostic approach. The precise relationship between these two methods has still to be defined, but is essential to compare diagnostic results. This study compared the results of both assays with a large series of transplant recipients in different categories. An internally controlled quantitative real-time CMV DNA PCR was used to test 409 plasma samples from solid organ transplant (SOT) and stem cell transplant (SCT) patients. Levels of CMV DNA in plasma correlated well with classified outcomes of the pp65 antigenemia test. Despite this correlation, the quantitative CMV PCR values in a class of antigen test results were within a wide range, and the definition of an optimal cutoff value for initiating treatment required further analysis by a receiver-operating characteristic curve analysis. This is essential for reactivating infections in particular. For the SCT patients the optimal cutoff value of CMV DNA load defining relevant viral reactivation (in this assay, 10,000 copies/ml) was slightly higher than that for the SOT patients (6,300 copies/ml). Based on a comparison with the established pp65 antigenemia assay, quantification of CMV DNA in plasma appeared to be capable of guiding the clinical management of transplant recipients. This approach may have important advantages, which include a superior reproducibility and sensitivity, allowing the inclusion of kinetic criteria in clinical guidelines.

Sequential cytomegalovirus antigenemia monitoring in kidney transplant patients treated with antilymphocyte antibodies

BACKGROUND

Antilymphocyte antibodies (ALA) use is related to disseminated cytomegalovirus (CMV) disease after kidney transplantation. Strict surveillance of CMV infection, preemptive antiviral treatment or concomitant ganciclovir and ALA use are proposed as an attempt to prevent related clinical complications. Our objective was to describe the pattern of CMV infection, based on sequential antigenemia detection, after ALA treatment.

PATIENTS AND METHODS

Thirty renal transplant patients were prospectively screened for CMV infection after ALA treatment. CMV antigenemia (pp65 antigen detection) was monitored twice a week in the first month and weekly until 60 days after the beginning of ALA therapy. Any positive value of antigenemia was considered CMV infection.

RESULTS

Twenty-eight (93.3%) patients were CMV positive (IgG) before transplantation. The mean duration of ALA treatment was 12.1+/-2.4 days. Positive antigenemia was detected in 24 (80%) patients, a mean of 52.5+/-15 days after transplant and 44.7+/-14 days after the beginning of ALA treatment. The median antigenemia count was 7 positive cells/300,000 neutrophils (range: 1-227). Antigenemia preceded clinical symptoms by 5.8 days (0-28 days). Eighteen (75%) of 24 positive patients received ganciclovir treatment: 8 patients (26.7%) for viral syndrome, 2 patients (33.3%) for invasive disease, and 8 patients (26.7%) as part of preemptive therapy, asymptomatic with high antigenemia values. Six pp65-positive patients with low counts were followed up until a negative result and remained asymptomatic without any specific treatment.

CONCLUSION

CMV infection was frequent after ALA treatment in this group and generally occurred late after completion of treatment. Antigenemia was a reliable tool to guide preemptive treatment in these patients, and such strategy is an alternative option compared to the prophylactic use of ganciclovir with ALA treatment.

Efficacy and limitations of preemptive therapy against cytomegalovirus infections in heart transplant patients

OBJECTIVES

Cytomegalovirus (CMV) disease often represents a serious complication that promotes opportunistic infections in heart transplant recipients. In this study we evaluated the impact of preemptive gancylovir therapy, guided by pp65 antigenemia on the morbidity associated with viral reactivation.

PATIENTS AND METHODS

We have performed a CMV infection surveillance program since March 1999, with antigenemia pp65 determinations weekly for the first 2 months biweekly in the third months, and monthly to the sixth month. Patients with pp65 antigenemia value >/= 10 positive cells per 2 x 10(5) polymorphonuclear cells (PMN) were treated with intravenous gancyclovir followed by 1 month of oral gancyclovir.

RESULTS

Among the 107 patients who underwent the virological monitoring, 80 were pp65 antigenemia-positive with preemptive therapy administered in 48 cases. Five patients displayed symptomatic CMV disease (4.7% vs 18% rate in the period of 1988 to 1998 before the introduction of virologic monitoring; P <.01). We observed only one case of gancyclovir-resistant pneumonia which was successfully treated with foscarnet. CMV recurrence in 10 patients required a second cycle of gancyclovir treatment. Our experience included 13 opportunistic infections (12.7%) with 11 antigenemia-positive.

CONCLUSIONS

Preemptive therapy drastically reduces the incidence of CMV disease and the associated morbidity. Compared to universal prophylaxis, this approach may avoid unnecessary pharmacologic treatment in more than 50% of transplant recipients. Indeed, preemptive therapy does not fully prevent CMV disease, because it may manifest at the first antigenemia determination, and furthermore may select gancyclovir-resistant strains.