Predictive value of cytomegalovirus DNA detection by polymerase chain reaction in blood and bronchoalveolar lavage in lung transplant patients

Human cytomegalovirus: a survey of end-organ diseases and diagnostic challenges in solid organ transplant recipients

PURPOSE OF REVIEW

Human cytomegalovirus (CMV) infection is one of the most important infectious complications in solid organ transplant (SOT) recipients, leading to significant morbidity and mortality. Therefore, early detection and prompt treatment are imperative to improve transplant outcomes. This article highlights the clinical characteristics of the most common CMV end-organ diseases in SOT recipients and their diagnostic modalities and challenges.

RECENT FINDINGS

CMV can cause a variety of end-organ diseases in SOT recipients. Although CMV nucleic acid amplification by polymerase chain reaction (PCR) is frequently employed to detect CMV reactivation or infection, its predictive value for various CMV end-organ diseases remains uncertain. Given the limitation of PCR or other noninvasive tests, confirmation of CMV end-organ disease may require tissue biopsy, which may not be feasible or available, or may cause untoward complications.

SUMMARY

The utility of PCR to diagnose CMV end-organ disease is limited. As CMV can infect any organ system(s), clinicians caring for SOT recipients need to maintain vigilance for any signs and symptoms of end-organ disease to allow early recognition and prompt treatment. Invasive procedures might be needed to confirm the diagnosis and minimize the empirical use of antiviral therapy that may have substantial drug toxicities.

Mangifera indica L. Leaves as a Potential Food Source of Phenolic Compounds with Biological Activity

It is well recognized that functional foods rich in antioxidants and antiinflammation agents including polyphenols, probiotics/prebiotics, and bioactive compounds have been found to have positive effects on the aging process. In particular, fruits play an important role in regular diet, promoting good health and longevity. In this study, we investigated on biological properties of extract obtained from Mangifera indica L. leaves in preclinical in vitro models. Specifically, the profile and content of bioactive compounds, the antimicrobial potential toward food spoilage and pathogenic bacterial species, and the eventually protective effect in inflammation were examined. Our findings revealed that MLE was rich in polyphenols, showing a content exclusively in the subclass of benzophenone/xanthone metabolites, and these phytochemical compounds demonstrated the highest antioxidant capacity and greatest in vitro antibacterial activity toward different bacterial species such as Bacillus cereus, B. subtilis, Pseudomonas fluorescens, Staphylococcus aureus, and St. haemolyticus. Furthermore, our data showed an in vitro anti-inflammatory, antioxidant, and antifibrotic activity.

International Society for Heart and Lung Transplantation consensus statement for the standardization of bronchoalveolar lavage in lung transplantation

Bronchoalveolar lavage (BAL) is a key clinical and research tool in lung transplantation (LTx). However, BAL collection and processing are not standardized across LTx centers. This International Society for Heart and Lung Transplantation-supported consensus document on BAL standardization aims to clarify definitions and propose common approaches to improve clinical and research practice standards. The following 9 areas are covered: (1) bronchoscopy procedure and BAL collection, (2) sample handling, (3) sample processing for microbiology, (4) cytology, (5) research, (6) microbiome, (7) sample inventory/tracking, (8) donor bronchoscopy, and (9) pediatric considerations. This consensus document aims to harmonize clinical and research practices for BAL collection and processing in LTx. The overarching goal is to enhance standardization and multicenter collaboration within the international LTx community and enable improvement and development of new BAL-based diagnostics.

Cytomegalovirus Viral Load in Bronchoalveolar Lavage to Diagnose Lung Transplant Associated CMV Pneumonia

BACKGROUND

The diagnostic yield for cytomegalovirus (CMV) polymerase chain reaction (PCR) viral load in bronchoalveolar lavage (BAL) or in plasma to diagnose CMV pneumonia in lung transplant recipients remains uncertain and was investigated in a large cohort of consecutive lung transplant recipients.

METHODS

Bronchoscopies within the first year of lung transplantation with CMV detectable in BAL by PCR (ie, viral load, ≥273 IU/mL) were included (66 recipients; 145 bronchoscopies); at each bronchoscopy episode, 2 independent experts reviewed clinical and laboratory information to determine whether the patient at that time fulfilled the criteria for CMV pneumonia per current international recommendations. Corresponding plasma CMV PCR viral load determined at time of the bronchoscopy (n = 126) was also studied. Optimal CMV PCR viral load cutoff for CMV pneumonia diagnosis was determined using receiver operating characteristics.

RESULTS

CMV was detected in BAL with CMV PCR in 145 episodes, and 34 (23%) of these episodes fulfilled the criteria for CMV pneumonia. The area under the curve-receiver operating characteristics for CMV in BAL was 90% at the optimum cutoff (4545 IU/mL) with a corresponding sensitivity of 91% and specificity of 77% (in plasma the corresponding values were 274 IU/mL, 63% and 76%, respectively).

CONCLUSIONS

CMV PCR viral load in BAL had a high performance to diagnose CMV pneumonia in lung transplant recipients; plasma CMV viral load did not reliably aid as a diagnostic tool.

Cytomegalovirus

Cytomegalovirus (CMV), the largest of the herpesviruses, causes a wide range of clinical syndromes, from asymptomatic infection to severe disease in immunocompromised hosts. Laboratory methods for diagnosis include molecular testing, antigenemia, culture, serology, and histopathology. Treatment of CMV infection and disease is indicated in selected immunocompromised hosts, and preventive approaches are indicated in high-risk groups. This chapter reviews the epidemiology, clinical aspects, and the laboratory diagnosis and management of CMV in immunocompromised hosts.

Molecular and Culture-Based Bronchoalveolar Lavage Fluid Testing for the Diagnosis of Cytomegalovirus Pneumonitis

Background.  Cytomegalovirus (CMV) is a major cause of morbidity and mortality in immunocompromised patients, with CMV pneumonitis among the most severe manifestations of infection. Although bronchoalveolar lavage (BAL) samples are frequently tested for CMV, the clinical utility of such testing remains uncertain. Methods.  Retrospective analysis of adult patients undergoing BAL testing via CMV polymerase chain reaction (PCR), shell vial culture, and conventional viral culture between August 2008 and May 2011 was performed. Cytomegalovirus diagnostic methods were compared with a comprehensive definition of CMV pneumonitis that takes into account signs and symptoms, underlying host immunodeficiency, radiographic findings, and laboratory results. Results.  Seven hundred five patients underwent 1077 bronchoscopy episodes with 1090 BAL specimens sent for CMV testing. Cytomegalovirus-positive patients were more likely to be hematopoietic cell transplant recipients (26% vs 8%, P < .0001) and less likely to have an underlying condition not typically associated with lung disease (3% vs 20%, P < .0001). Histopathology was performed in only 17.3% of CMV-positive bronchoscopy episodes. When CMV diagnostic methods were evaluated against the comprehensive definition, the sensitivity and specificity of PCR, shell vial culture, and conventional culture were 91.3% and 94.6%, 54.4% and 97.4%, and 28.3% and 96.5%, respectively. Compared with culture, PCR provided significantly higher sensitivity and negative predictive value (P ≤ .001), without significantly lower positive predictive value. Cytomegalovirus quantitation did not improve test performance, resulting in a receiver operating characteristic curve with an area under the curve of 0.53. Conclusions.  Cytomegalovirus PCR combined with a comprehensive clinical definition provides a pragmatic approach for the diagnosis of CMV pneumonitis.

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.

The clinical utility of whole blood versus plasma cytomegalovirus viral load assays for monitoring therapeutic response

BACKGROUND

In patients with cytomegalovirus (CMV) disease, regular monitoring of viral loads and treatment until negative are recommended. However, with more sensitive polymerase chain reaction (PCR) assays and cellular peripheral sample types, detection of low-level viremia is achievable. We compared a whole blood real-time PCR with a plasma PCR assay for monitoring therapeutic response.

METHODS

Patients enrolled in a trial to treat CMV disease for 21 days had regular viral load monitoring. The results of a plasma-based PCR assay were compared with a real-time PCR assay of whole blood and assessed for their ability to predict recurrence.

RESULTS

In 219 evaluable patients, viral loads in plasma versus whole blood demonstrated good correlation but significant difference in absolute value and clearance kinetics. Virus was still detectable by day 21 in 154 of 219 (70.3%) patients with the whole blood versus 105 of 219 (52.1%; P<0.001) patients with the plasma assay. The positive predictive value of persistent plasma viremia at day 21 for virologic recurrence was 41.9% vs. 36.3% for the whole blood assay. In the subset of patients with a negative plasma but positive whole blood at day 21 (n = 49), the incidence of virologic recurrence was similar to that of all patients with a negative plasma assay (23.1% vs. 23.6%).

CONCLUSIONS

When treating CMV disease, enhanced detection of residual viremia using a whole blood real-time PCR does not seem to offer significant clinical advantages nor allows for better prediction of recurrence of CMV viremia or disease. The treat-to-negative paradigm may not hold true when such assays are used.

Clinical utility of CMV early and late transcript detection with NASBA in bronchoalveolar lavages

BACKGROUND

Cytomegalovirus (CMV) infection can cause severe disease in immunocompromised individuals, with CMV pneumonia, most commonly seen in lung or bone marrow transplant recipients, carrying a particularly high fatality rate. Early and accurate diagnosis of CMV pneumonia is therefore critical.

OBJECTIVES

Current diagnostic tests for CMV pneumonia in bronchoalveolar lavage (BAL) specimens are either insensitive or poor prognostic indicators of disease. We therefore examined nucleic acid sequence-based amplification (NASBA) assays for CMV transcripts in BAL for the prediction of CMV pneumonia and associated diseases.

STUDY DESIGN

A total of 220 BAL specimens from lung transplant recipients and other patients with suspected viral pneumonia were studied. Ninety-nine samples had previously tested positive for CMV by shell vial (SV) culture, while the other 121 had tested negative. All specimens were assayed for CMV pp67 and immediate early (IE) transcripts by NASBA. Results were correlated with evidence of concurrent or subsequent CMV pneumonia, rejection, and infection with other microbes.

RESULTS

From a total of 220 BAL specimens, 27 tested positive for pp67 mRNA, 25 tested positive for IE mRNA, and 17 tested positive for both. Only 10 specimens tested positive for CMV by either or both NASBA assays while testing negative by SV assay. However, 74 specimens were SV positive but negative in both NASBA assays. Detection of CMV by any of the three methods was associated with an increased prevalence of pneumonia (i.e., pulmonary interstitial inflammation with radiographic or clinical evidence of lung injury), but not with pulmonary CMV pathology. Detection of CMV by SV was associated with moderate to severe graft rejection. There was no evidence of increased bacterial or fungal pulmonary infections associated with a positive CMV result by any of the three assays.

CONCLUSIONS

Detection of either CMV pp67 or IE mRNA transcripts by NASBA in BAL specimens can occasionally identify CMV infections that are negative by conventional shell vial culture, but does not have sufficient sensitivity or positive predictive value to be employed routinely for pre emptive management of pulmonary CMV disease in transplant recipients.

ASSOCIATION OF CYTOMEGALOVIRUS DNA CONCENTRATION IN EPITHELIAL LINING FLUID AND SYMPTOMATIC CYTOMEGALOVIRUS INFECTION IN LUNG TRANSPLANT RECIPIENTS

BACKGROUND

The authors have investigated the effectiveness of virus detection from bronchoalveolar lavage (BAL) samples for the identification of symptomatic cytomegalovirus (CMV) infection in lung transplant recipients.

METHODS

Thus, 275 BAL samples taken from 105 lung transplant recipients during follow-up were analyzed by quantitative polymerase chain reaction (PCR) and virus isolation.

RESULTS

Quantitative PCR detected virus in all 24 BAL samples taken at onset of symptomatic disease, and virus culture in only 7 samples (29.2%). Twenty-three of 251 BAL samples (9.2%) were positive by PCR, although they were obtained in an asymptomatic phase. Quantitation of CMV DNA from BAL allowed no discrimination between symptomatic and asymptomatic infection in individual cases. However, when the urea dilution method was used to recalculate the CMV DNA concentration for the epithelial lining fluid (ELF) diluted in the BAL, a CMV DNA level of more than 10 copies/mL ELF was clearly associated with symptomatic disease.

CONCLUSION

The CMV DNA level in ELF may be a marker for symptomatic CMV infection.

Increased human cytomegalovirus (HCMV) DNA load in peripheral blood leukocytes after lung transplantation correlates with HCMV pneumonitis

BACKGROUND

Human cytomegalovirus (HCMV) reactivation and disease remain relatively common in lung transplant recipients (LTR) despite the use of ganciclovir prophylaxis protocols for all HCMV at-risk patients. The specific aims of this study were to (1) describe the HCMV DNA viral load in the peripheral blood leukocytes (PBL) of a cohort of LTR during the first 6 months after lung transplantation; (2) prospectively determine whether HCMV DNA viral load predicts episodes of HCMV pneumonitis in LTR; and (3) study the effect of ganciclovir on HCMV viral load.

METHODS

Competitive polymerase chain reaction using an internal standard and fluorometric detection were used to quantitate HCMV DNA in the PBL of a cohort of 26 LTR monthly for the first 6 months after transplantation (145 samples). All patients were treated with standard triple immunosuppression, and ganciclovir prophylaxis was given to all at-risk LTR (donor or recipient HCMV seropositive) for at least 8 weeks after transplantation.

RESULTS

Thirteen episodes of histopathologically proven HCMV pneumonitis in nine subjects occurred during follow-up with a wide intra- and intersubject variation in the HCMV DNA PBL levels. HCMV detection had a sensitivity of 92% and specificity of 76% for HCMV pneumonitis (negative likelihood ratio, 9.5), whereas greater than 10-fold increases in HCMV DNA load had a specificity of 93% and sensitivity of 67% (positive likelihood ratio, 11). HCMV DNA detection had an adjusted odds ratio for HCMV pneumonitis of 107 (95% confidence interval, 14-821; P<0.005). In those with detectable HCMV DNA in PBL (n=44), HCMV DNA levels were 4.4 (95% confidence interval, 1.2-16.8) times higher in those with HCMV pneumonitis than in those without HCMV pneumonitis. Although ganciclovir treatment was very effective in treating HCMV pneumonitis and suppressing HCMV DNA levels, thrice weekly ganciclovir prophylaxis only partially controlled HCMV DNA levels and did not eliminate HCMV pneumonitis risk as three patients developed HCMV pneumonitis while on this regimen.

CONCLUSIONS

HCMV DNA detection, absolute levels, and relative change from baseline in the PBL of LTR correlate with HCMV pneumonitis episodes and may be a useful intermediate outcome measure of the efficacy of ganciclovir prophylaxis and treatment strategies.

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.

Quantification of cytomegalovirus DNA in BAL fluid: a longitudinal study in lung transplant recipients

STUDY OBJECTIVES

Cytomegalovirus (CMV) infection is common in patients receiving solid organ transplants, and it is associated with increased morbidity as well as risk for development of chronic rejection. A rapid and sensitive diagnostic method would improve the therapeutic management of CMV infection, including the monitoring of treatment effects. We investigated whether longitudinal determinations of CMV DNA quantities in BAL fluid could be useful for this purpose.

DESIGN

CMV DNA levels in 340 BAL samples from 35 consecutive lung transplant recipients were studied during a median of 18 months. Seventeen (49%) of the patients developed CMV disease with pneumonitis. Twenty-seven CMV disease episodes were diagnosed.

RESULTS

Patients with CMV disease had a significantly higher mean level of CMV copies per milliliter BAL fluid (1,120 +/- 4,379) compared with those without (180 +/- 1,177, p < 0.01). Viral load as well as acute rejection requiring treatment (>/= A2) were independent risk factors associated with CMV disease. Differences between the groups concerning HLA-DR matching, basic immunosuppressive therapy, and CMV serologic status D/R -/+ vs D/R +/+ were not significant. A diagnostic definition of normality based on the mean level of all episodes without CMV disease +2 SD would discriminate only 9 of the 27 CMV episodes.

CONCLUSIONS

Although the viral load is increased during episodes of clinical CMV disease in lung transplant recipients, the quantitative PCR assessment of CMV DNA in BAL fluid is not discriminative enough to be useful as a diagnostic tool for CMV disease.

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.

Respiratory infections in immunocompromised patients

HIV disease has been dramatically reduced in the developed world by the introduction of highly active antiretroviral therapy, with implications that prophylactic therapy against opportunistic infections may be stopped; however, tuberculosis is an escalating problem in the HIV-infected and HIV-noninfected populations worldwide. Compliance with effective treatment regimens, especially through directly observed therapy, remains the cornerstone of tuberculosis control strategies. Although tuberculosis prophylaxis is of benefit for tuberculin skin reactors with HIV in the developed world, several reservations are voiced about this approach in resource-poor settings. Recent advances in technology, particularly in antigen-specific systems, have revolutionized the understanding of HIV immunology and helped to elucidate the mechanisms of pathogenesis in diseases such as cytomegalovirus. In bone marrow transplantation and solid-organ transplantation patients, quantitative polymerase chain reaction (PCR) to predict cytomegalovirus disease is an important advance, and patients who undergo bone marrow transplantation, CT scanning has proven useful in the diagnosis of pulmonary aspergillosis.

Cytomegalovirus and human herpesvirus 6 both cause viral disease after renal transplantation

BACKGROUND

Systemic viral disease after renal transplantation, especially after treatment with OKT3 or antithymocyte globulin, has usually been attributed to cytomegalovirus (CMV) infection. Identification of human herpesvirus 6 (HHV6) has raised the possibility that infection or reactivation of this virus may also occur in the same setting.

METHODS

We thus examined the incidence of CMV and HHV6 infection in a prospective blinded consecutive series of 30 renal and renal/pancreas transplant patients, 22 of whom received OKT3, antithymocyte globulin, or both.

RESULTS

Clinical diagnosis of a viral syndrome was made in 15 patients. Three patients with only HHV6 DNA in urine or serum had fever and abnormal liver function but not neutropenia. All five CMV-seronegative patients who received positive kidneys developed moderate to severe disease with fever and neutropenia but also had HHV6 DNA in urine or serum. Seven CMV-seropositive patients developed disease, mostly after OKT3/antithymocyte globulin, but six shed both CMV and HHV6 in urine or serum. The simultaneous detection of both HHV6 and CMV DNA in either urine or serum was the strongest predictor of disease (and also the severity of disease), with an odds ratio of 99.0 (95% confidence intervals 5.4-1814, P<0.002).

CONCLUSION

Most systemic viral disease after renal transplantation may be due to either coinfection or reactivation of CMV and HHV6 together. A wider understanding of risk factors for severe viral disease in this setting may come from testing for both viruses in all donors and patients in both clinical practice and clinical trials.