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

Persistence of a Skewed Repertoire of NK Cells in People with HIV-1 on Long-Term Antiretroviral Therapy

HIV-1 infection greatly alters the NK cell phenotypic and functional repertoire. This is highlighted by the expansion of a rare population of FcRγ- NK cells exhibiting characteristics of traditional immunologic memory in people with HIV (PWH). Although current antiretroviral therapy (ART) effectively controls HIV-1 viremia and disease progression, its impact on HIV-1-associated NK cell abnormalities remains unclear. To address this, we performed a longitudinal analysis detailing conventional and memory-like NK cell characteristics in n = 60 PWH during the first 4 y of ART. Throughout this regimen, a skewed repertoire of cytokine unresponsive FcRγ- memory-like NK cells persisted and accompanied an overall increase in NK surface expression of CD57 and KLRG1, suggestive of progression toward immune senescence. These traits were linked to elevated serum inflammatory biomarkers and increasing Ab titers to human CMV, with human CMV viremia detected in approximately one-third of PWH at years 1-4 of ART. Interestingly, 40% of PWH displayed atypical NK cell subsets, representing intermediate stages of NK-poiesis based on single-cell multiomic trajectory analysis. Our findings indicate that NK cell irregularities persist in PWH despite long-term ART, underscoring the need to better understand the causative mechanisms that prevent full restoration of immune health in PWH.

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.

Newer developments in viral hepatitis: Looking beyond hepatotropic viruses

Viral hepatitis in the entirety of its clinical spectrum is vast and most discussion are often restricted to hepatotropic viral infections, including hepatitis virus (A to E). With the advent of more advanced diagnostic techniques, it has now become possible to diagnose patients with non-hepatotropic viral infection in patients with hepatitis. Majority of these viruses belong to the Herpes family, with characteristic feature of latency. With the increase in the rate of liver transplantation globally, especially for the indication of acute hepatitis, it becomes even more relevant to identify non hepatotropic viral infection as the primary hepatic insult. Immunosuppression post-transplant is an established cause of reactivation of a number of viral infections that could then indirectly cause hepatic injury. Antiviral agents may be utilized for treatment of most of these infections, although data supporting their role is derived primarily from case reports. There are no current guidelines to manage patients suspected to have viral hepatitis secondary to non-hepatotropic viral infection, a gap that needs to be addressed. In this review article, the authors analyze the common non hepatotropic viral infections contributing to viral hepatitis, with emphasis on recent advances on diagnosis, management and role of liver transplantation.

Cytomegalovirus Hepatitis in Immunocompetent and Immunocompromised Hosts

Human cytomegalovirus (HCMV) infection is common and affects between 40-100% of the worldwide population. However, the majority of cases are asymptomatic and when severe disease occurs, it is usually restricted to immunocompromised patients. Liver involvement by HCMV differs significantly, accordingly to the immune status of the host. In immunocompromised patients, particularly liver transplant patients, it often causes clinically significant hepatitis. On the other hand, in immunocompetent patients, HCMV hepatitis requiring hospitalization is extremely rare. This review aims to appraise studies regarding the pathophysiology of HCMV hepatitis, including mechanisms of latency and reactivation and its contribution to disease development, clinical presentation, diagnostic modalities and treatment, with a focus on comparing different aspects between immunocompromised and immunocompetent hosts.

Polymerase chain reaction for detection of mucosal cytomegalovirus infection in patients with acute ulcerative colitis

Background

Cytomegalovirus (CMV) infection is associated with acute exacerbations of ulcerative colitis (UC) but its clinical relevance remains uncertain. The primary aim of this study was to assess the prevalence of CMV infection in UC patients using viral polymerase chain reaction (PCR) analysis of mucosal biopsy samples. Secondary aims were to establish whether the disease was due to a primary infection or reactivation and to note associated risk factors and clinical outcomes.

Methods

Since 2011, a policy of biopsy for CMV infection was adopted for severe UC patients in a large tertiary center. A retrospective review was undertaken to identify patients with mucosal biopsies for exacerbations of UC from October 2011 through January 2014.

Results

Sixty biopsies for CMV PCR were obtained from 52 patients, 15 of whom were positive. In these patients, 9/9 tested were seropositive for anti-CMV IgG, while none were seropositive for anti-CMV IgM. Steroid refractory disease was a significant predictor of CMV positivity; however, there was no difference between the CMV-positive and -negative groups in rates of immunosuppression, or clinical and endoscopic severity. Six patients in the CMV-positive group received infliximab; all received concurrent antiviral therapy and did not require surgery.

Conclusions

PCR of mucosal biopsies detected CMV infection due to viral reactivation in almost a third of patients with deteriorating or acute severe UC. Steroid refractory disease was significantly associated with CMV positivity, but no significant relationship was demonstrated with either disease severity or immunosuppression in our cohort. Treatment with anti-tumor necrosis factor agents was administered safely in combination with antiviral drugs.

Subclinical herpesvirus shedding among HIV-1-infected men on antiretroviral therapy

OBJECTIVE

We evaluated the subclinical shedding of six different herpesviruses in antiretroviral drug-treated HIV-positive [HIV(+)] MSM, and determined how this is associated with markers of inflammation and immune activation.

METHODS

We obtained blood, semen, throat washing, urine, and stool from 15 antiretroviral-treated HIV-1-infected MSM with CD4 T-cell reconstitution, and 12 age-matched HIV-negative [HIV (-)] MSM from the Multicenter AIDS Cohort Study at four timepoints over 24 weeks to measure DNA levels of cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus 1 and 2, human herpesvirus 6 (HHV6), and HHV8. T-cell activation and plasma levels of soluble markers of inflammation and activation were also measured at the corresponding timepoints.

RESULTS

HIV(+) participants had a trend for higher total herpesvirus shedding rate. HIV(+) participants also had a significantly higher rate of shedding EBV and CMV compared with the HIV(-) group. Herpesvirus shedding was mostly seen in throat washings. In the HIV(+) group, herpesvirus shedding rate inversely correlated with plasma levels of interferon γ-induced protein 10 and soluble CD163. CMV DNA levels negatively correlated with levels of T-cell activation. There was a trend for a positive correlation between EBV shedding rate and plasma soluble CD14. HHV6 shedding rate negatively correlated with plasma levels of interleukin-6, soluble CD163, and interferon gamma-induced protein 10. Correlations were not observed among HIV(-) individuals.

CONCLUSION

Among treated HIV-infected MSM, there are higher subclinical shedding rates of some herpesviruses that occur in different body compartments and negatively correlate with levels of inflammation and immune activation.

Inflammasome expression and cytomegalovirus viremia in critically ill patients with sepsis

BACKGROUND

CMV viremia is a contributor to poor outcomes in critically ill patients with sepsis.

OBJECTIVES

To assess the expression levels of genes encoding inflammasome-related proteins in the development of CMV viremia in critically ill patients with sepsis.

STUDY DESIGN

A cohort of CMV-seropositive critically ill patients with sepsis due to bloodstream infection underwent weekly testing for CMV viremia. Blood samples to evaluate mRNA levels of genes encoding CASP1, ASC, NLRP1, NLRP3, and NLRP12 were collected at the time of enrollment. Clinical outcomes were assessed at 30days or until death/discharge from ICU.

RESULTS

CMV viremia was documented in 27.5% (8/29) of the patients, a median of 7days after the onset of bacteremia. Patients with sepsis who developed CMV viremia had higher CASP1 although this was not statistically significant (relative mean 3.6 vs 1.8, p=0.13). Development of high grade CMV viremia however, was significantly associated with CASP1; septic patients who developed high grade CMV viremia had significantly higher CASP1than all other patients (relative mean 5.5 vs 1.8, p=0.016).

CONCLUSIONS

These data document possible involvement of inflammasome in the pathogenesis of CMV. Regulating the host immune response by agents that target these genes may have implications for improving CMV-related outcomes in these patients.

Cytomegalovirus Infection in Patients with Sepsis Due to Bloodstream Infections: Lower Risk and Better Outcomes in New versus Already Hospitalised Intensive Care Unit Admissions

Few studies have examined cytomegalovirus (CMV) reactivation exclusively in immunocompetent patients with sepsis due to bloodstream infections. In a cohort of CMV-seropositive critically ill otherwise non-immunosuppressed patients with sepsis due to bloodstream infection, weekly testing for CMV viraemia was performed. Outcomes were assessed at 30 days or until death/discharge from the intensive care unit (ICU). CMV viraemia developed in 20% (20/100) of the patients. Age ( P=0.044) and blood transfusions ( P=0.022) were significantly associated with CMV viraemia. There was no difference in the primary endpoint (mortality and/or multi-organ failure) between patients with and without CMV viraemia ( P=0.49). However, CMV viraemia was associated with significantly fewer ICU-free days ( P=0.023) and fewer ventilator-free days ( P=0.031). Patients hospitalised in the ICU for more than 48 hours prior to the onset of bloodstream infection were more likely to develop CMV viraemia ( P=0.006), have high-grade viraemia ( P=0.010), and fewer ICU-free days ( P=0.018) and ventilator-free days ( P=0.029) than those admitted within 48 hours of bloodstream infection. Thus, CMV reactivation was associated with fewer ICU- and ventilator-free days, however overall mortality was not affected. Patients already in the ICU at the onset of sepsis had higher risk of CMV reactivation and worse outcomes than new ICU-bound patients suggesting that a targeted approach for interventions for CMV could conceivably be directed towards those with a more protracted course of illness.

Treatment and prevention of cytomegalovirus infection in heart and lung transplantation: an update

INTRODUCTION

Heart and lung transplantation are standard therapeutic strategies to improve survival and quality of life in selected patients with end-stage heart or lung diseases. Cytomegalovirus (CMV) is one the most clinically relevant and frequent post-transplant infectious agents, which may cause direct acute syndromes, and chronic indirect graft-related injury. Despite effective antiviral drugs being available to prevent and treat CMV infection, due to the immunosuppression burden and the specific characteristics of thoracic grafts, CMV infection remains a major clinical problem in heart and lung transplant recipients.

AREAS COVERED

We performed an extensive literature search focused on studies specifically including heart or lung transplantation, when available, or kidney transplant recipients when data on thoracic transplants were not available. We discuss the pros and cons supporting the use of currently available drugs and strategies for CMV prevention and treatment, highlighting current unmet needs.

EXPERT OPINION

While (Val)Ganciclovir remains the cornerstone of anti-CMV therapy, prolonged universal prophylaxis may expose a large number of patients to an excess of drug toxicity. Additional drugs with lower toxicity may be available in the context of anti-CMV prophylaxis, and effective CMV-risk stratification, by means of novel immune monitoring assays, which may help to customize the therapeutic approach.

Cytomegalovirus infection in the bone marrow transplant patient

Cytomegalovirus (CMV) infection is an important contributor to the morbidity and mortality associated with bone marrow transplantation (BMT). Infection may lead to CMV disease involving multiple organs such as pneumonia, gastroenteritis, retinitis, central nervus system involvement and others. CMV seropositivity is an important risk factor and approximately half of BMT recipients will develop clinically significant infection most commonly in the first 100 d post-transplant. The commonly used tests to diagnose CMV infection in these patients include the pp65 antigenemia test and the CMV DNA polymerase chain reaction (PCR) assay. Because of its greater sensitivity and lesser turnaround time, the CMV PCR is nowadays the preferred test and serves as a main guide for pre-emptive therapy. Methods of CMV prevention include use of blood products from seronegative donors or leukodepleted products. Prophylaxis or pre-emptive therapy strategies for CMV prevention may be used post-transplant with the latter becoming more common. The commonly used antivirals for pre-emptive therapy and CMV disease management include intravenous gancyclovir and foscarnet. The role of intravenous immunoglobulin, although used commonly in CMV pneumonia is not clear.

Recent developments in kidney transplantation in children

PURPOSE OF REVIEW

Renal transplantation in childhood is a well established procedure with excellent short-term outcomes. However, waiting times for transplantation are still relatively long if living donation cannot be performed, and long-term outcomes after transplantation have not significantly improved during the last decade.

RECENT FINDINGS

This review describes alternative modalities to improve donation rates such as en bloc kidney transplantation from young donors, ABO-incompatible transplantation and kidney paired donation. This review also deals with long-term post-transplant morbidities, such as follows: first, medication side-effects (metabolic syndrome, cardiovascular disease) and with the benefits of steroid and calcineurin inhibitor drug minimization; second, the deleterious impact of viral infections and their management and third, chronic antibody-mediated rejection, its therapeutic and prevention possibilities.

SUMMARY

Donor shortage and long-term morbidities, after transplantation, are still relevant issues in paediatric renal transplantation medicine. Significant research and efforts have been made to advance the field and create novel approaches for improvement of transplantation rates and post-transplant graft or patient survival. These modalities are to be established in the routine setting.

Ganciclovir-resistant cytomegalovirus infections among lung transplant recipients are associated with poor outcomes despite treatment with foscarnet-containing regimens

Ganciclovir-resistant cytomegalovirus (CMV) infections are reported infrequently among lung transplant recipients receiving extended valganciclovir prophylaxis. We performed a single-center, retrospective review of ganciclovir-resistant CMV infections in a program that employed valganciclovir prophylaxis for ≥6 months after lung transplant. CMV infections were diagnosed in 28% (170/607) of patients. UL97 mutations were detected in 9.4% (16/170) of CMV-infected patients at a median of 8.5 months posttransplant (range, 5 to 21) and despite prophylaxis for a median of 7 months (range, 4 to 21). UL97 mutations were canonical; 25% (4/16) of strains carried concurrent UL54 mutations. Ganciclovir-resistant CMV was more likely with breakthrough infections (75% [12/16] versus 19% [30/154]; P = 0.00001) and donor positive/recipient negative (D+/R-) serostatus (75% versus 45% [69/154]; P = 0.03). The median whole-blood CMV load was 4.13 log10 copies/cm(3) (range, 2.54 to 5.53), and 93% (14/15) of patients had low-moderate immune responses (Cylex Immunoknow). Antiviral therapy was successful, failed, or eradicated viremia followed by relapse in 12% (2/16), 31% (5/16), and 56% (9/16) of patients, respectively. Eighty-seven percent (14/16) of patients were treated with foscarnet-containing regimens; toxicity developed in 78% (11/14) of these. Median viral load half-life and time to viremia eradication among foscarnet-treated patients were 2.6 and 23 days, respectively, and did not correlate with protection from relapse. Sixty-nine percent (11/16) of patients developed CMV pneumonitis, and 25% (4/16) died of it. Serum viral load was independently associated with death among foscarnet-treated patients (P = 0.04). In conclusion, ganciclovir-resistant CMV infections remained a major cause of morbidity and mortality following lung transplantation. Foscarnet-based regimens often eradicated viremia rapidly but were ineffective in the long term and limited by toxicity.

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.

Diagnostic workup for diffuse parenchymal lung disease: schematic flowchart, literature review, and pitfalls

PURPOSE

The term diffuse parenchymal lung disease (DPLD) refers to a group of disorders affecting the lung parenchyma that can be categorized into those of known and those of unknown etiology. Early diagnosis is important since some forms of DPLD are characterized by a rapid progression to respiratory failure. Notwithstanding the fact that recently guidelines have been published, some issues concerning the practical evaluation of a patient with suspected DPLD remain unclear.

METHODS

In this article we propose a practical approach to the diagnosis and differentiation of DPLD. Moreover, a critical appraisal is provided based on the current literature and frequent pitfalls are highlighted.

CONCLUSION

we propose a practical workup, but in spite of increasing evidence concerning the diagnosis of DPLD, further studies will be needed to clarify several issues for efficient investigation of newly diagnosed patients with DPLD.

Determination, validation and standardization of a CMV DNA cut-off value in plasma for preemptive treatment of CMV infection in solid organ transplant recipients at lower risk for CMV infection

BACKGROUND

Valganciclovir preemptive therapy guided by the viral load is the current strategy recommended for preventing CMV disease in CMV-seropositive Solid Organ Transplant Recipients (SOTR) at lower risk for developing CMV infection. However, universal viral load cut-off has not been established for initiating therapy.

OBJECTIVES

Our goal was to define and validate a standardized cut-off determined in plasma by real-time PCR assay for initiating preemptive therapy in this population.

STUDY DESIGN

A prospective cohort study of consecutive cases of CMV-seropositive SOTR was carried out. The cut-off value was determined in a derivation cohort and was validated in the validation cohort. Viral loads were determined using the Quant CMV LightCycler 2.0 real-time PCR System (Roche Applied Science) and results were standardized using the WHO International Standard for human CMV.

RESULTS

A viral load of 3983 IU/ml (2600 copies/ml) was established as the optimal cut-off for initiating preemptive therapy in a cohort of 141 patients with 982 tests and validated in a cohort of 252 recipients with a total of 2022 test. This cut-off had a 99.6% NPV indicating that the great majority of patients at lower risk will not develop CMV disease without specific antiviral therapy. The high sensitivity and specificity (89.9% and 88.9%, respectively) and the relatively small numbers of patients with CMV disease confirm that real-time PCR was optimal.

CONCLUSIONS

We have established a cut-off viral load for starting preemptive therapy for CMV-seropositive SOT recipients. Our results emphasized the importance of a mandatory follow-up protocol for CMV-seropositive patients receiving preemptive treatment.

Correlation and clinical utility of pp65 antigenemia and quantitative polymerase chain reaction assays for detection of cytomegalovirus in pediatric renal transplant patients

qPCR and pp65 antigenemia assays are used to monitor CMV infection in renal transplant recipients, but correlation of assays in a pediatric population has not been evaluated. Paired CMV real-time qPCR and pp65 antigenemia tests from 882 blood samples collected from 115 pediatric renal transplant recipients were analyzed in this retrospective cohort study for the strength of association and clinical correlates. The assays correlated well in detecting infection (κ = 0.61). Higher qPCR values were demonstrated with increasing levels of antigenemia (p < 0.01). Discordant test results were associated with antiviral treatment (OR 4.33, p < 0.01) and low-level viremia, with odds of concordance increasing at higher qPCR values (OR 3.67, p < 0.01), and no discordance occurring above 8500 genomic equivalents/mL. Among discordant samples, neither test preceded the other in detecting initial infection or in returning to negative while on treatment. Only two cases of disease occurred during the two-yr study period. With strong agreement in the detection of CMV infection, either qPCR or pp65 antigenemia assays can be used effectively for monitoring pediatric renal transplant patients for both detection and resolution of infection.

Herpes simplex virus type 2 (HSV-2) as a coronary atherosclerosis risk factor in HIV-infected men: multicenter AIDS cohort study

We assessed associations of herpes simplex virus types 1 and 2 (HSV-1 and -2), cytomegalovirus (CMV), and human herpesvirus 8 (HHV-8) infection with subclinical coronary atherosclerosis in 291 HIV-infected men in the Multicenter AIDS Cohort Study. Coronary artery calcium (CAC) was measured by non-contrast coronary CT imaging. Markers for herpesviruses infection were measured in frozen specimens collected 10-12 years prior to case identification. Multivariable logistic regression models and ordinal logistic regression models were performed. HSV-2 seropositivity was associated with coronary atherosclerosis (adjusted odds ratio [AOR]=4.12, 95% confidence interval [CI]=1.58-10.85) after adjustment for age, race/ethnicity, cardiovascular risk factors, and HIV infection related factors. Infection with a greater number of herpesviruses was associated with elevated CAC levels (AOR=1.58, 95% CI=1.06-2.36). Our findings suggest HSV-2 may be a risk factor for subclinical coronary atherosclerosis in HIV-infected men. Infection with multiple herpesviruses may contribute to the increased burden of atherosclerosis.

Monitoring and managing viral infections in pediatric renal transplant recipients

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. The pediatric cohort is at high risk of developing virus-related complications due to immunological naiveté and the increased alloreactivity risk that requires maintaining a heavily immunosuppressive environment. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses may affect clinical outcome. Recent technological advances and novel antiviral therapy have allowed implementation of viral and immunological monitoring protocols and adoption of prophylactic or preemptive treatment approaches in high-risk groups. These strategies have led to improved viral infection management in the immunocompromised host, with significant impact on outcome. We review the major viral infections seen following kidney transplantation and discuss strategies for preventing and managing these pathogens.

Comparison of a UL111a real-time PCR and pp65 antigenemia for the detection of cytomegalovirus

Surveillance of cytomegalovirus (CMV) replication in transplant patients is crucial for the success of transplantation. To compare a CMV pp65 antigenemia (pp65Ag) and a quantitative real-time PCR targeting the CMV-UL111a (UL111aPCR), all whole blood samples taken between July 2008 and October 2009 were identified which had been analyzed prospectively by both assays in parallel. Discordant results were re-analyzed using a published CMV duplex PCR targeting regions UL55 and UL123exon4. Of 720 samples from 81 transplant patients, CMV replication was detected in 244 specimens (34%) by the UL111aPCR (median, 1,019 geq/ml), compared to 113 (16%) detected by the pp65Ag (median, 2/250,000 leukocytes). Concordant UL111aPCR/pp65Ag results were obtained in 561 (78%) samples, being positive in 99 (14%), and negative in 462 (64%). As a rule of thumb, 1 pp65Ag-positive cell per 250,000 leukocytes corresponded to 1,000 geq/ml CMV DNA of whole blood. Discordant results were found in 159 samples (22%), being UL111aPCR-positive/pp65Ag-negative in 145 (91%; median, 650 geq/ml), or UL111aPCR-negative/pp65Ag-positive in 14 (9%; median, 1/250,000 cells). Using the duplex PCR targeting the CMV UL55 and the UL123-exon4 genes, 131 of 139 (94%) discordant UL111aPCR-positives (median UL111aPCR, 639 geq/ml; median UL55PCR, 715 geq/ml; median UL123PCR, 1,103 geq/ml) were confirmed. Of 14 discordant pp65Ag-positives, duplex PCR was also negative in 8, and of low copy number in 6. Thus, CMV UL111aPCR provides more sensitive quantitation of CMV replication than pp65Ag, however, discordant results can occur at very low viral loads.

Clinical evaluation of multiplex real-time PCR panels for rapid detection of respiratory viral infections

Respiratory viral infections are one of the leading causes of morbidity and mortality, particularly in children, the elderly and immunocompromised persons. Rapid identification of viral etiology is critical in ruling out non‐viral infections, initiating antiviral treatment and limiting the spread of the infection. Multiplex assays of more than one viral gene target in a single tube have the advantage of rapid screening of a large number of potential viral pathogens in a short time. A multiplex real‐time PCR assay was used in this study for detection of respiratory RNA and DNA viral infections in 728 specimens received from 585 adult and pediatric patients comprised of symptomatic and asymptomatic organ transplant recipients and non‐recipients for diagnosis of respiratory illnesses and for routine clinical monitoring. Multiplex PCR was more sensitive than the multiplex immunofluoresence culture assay (R‐mix) and also detected additional respiratory viruses that were not covered by the R‐mix panel. The number of respiratory viruses detected in symptomatic patients was significantly higher than asymptomatic patients in both adult and pediatric patients. Herpesviral infections were the predominant cause of lower respiratory tract infection in the organ transplant recipients, whereas respiratory syncytial virus was the most common pathogen in non‐transplant patients particularly children. Multiplex real‐time PCR for detection of respiratory viruses has the potential for rapid identification of viral pathogens. In this era of emerging viral infections, addition of newer viral targets to the multiplex PCR panels will be beneficial in determining both patient management and public health epidemiology. J. Med. Virol. 84:162–169, 2011. © 2011 Wiley Periodicals, Inc.

Comparison of the performance of polymerase chain reaction and pp65 antigenemia for the detection of human cytomegalovirus in immunosuppressed patients

INTRODUCTION

Human cytomegalovirus (HCMV) is often reactive in latently infected immunosuppressed patients. Accordingly, HCMV remains one of the most common infections following solid organ and hemopoietic stem cell transplantations, resulting in significant morbidity, graft loss and occasional mortality. The early diagnosis of HCMV disease is important in immunosuppressed patients, since in these individuals, preemptive treatment is useful. The objective of this study was to compare the performance of the in-house qualitative polymerase chain reaction (PCR) and pp65 antigenemia to HCMV infection in immunosuppressed patients in the Hospital de Clínicas of Porto Alegre (HCPA).

METHODS

A total of 216 blood samples collected between August 2006 and January 2007 were investigated.

RESULTS

Among the samples analyzed, 81 (37.5%) were HCMV-positive by PCR, while 48 (22.2%) were positive for antigenemia. Considering antigenemia as the gold standard, sensitivity, specificity, positive predictive values and negative predictive values for PCR were 87.5%, 76.8%, 51.8% and 95.5% respectively.

CONCLUSIONS

These results demonstrated that qualitative PCR has high sensitivity and negative predictive value (NPV). Consequently PCR is especially indicated for the initial diagnosis of HCMV infection. In the case of preemptive treatment strategy, identification of patients at high-risk for HCMV disease is fundamental and PCR can be useful tool.

Cytomegalovirus quantification: where to next in optimising patient management?

BACKGROUND

Over the years quantification of cytomegalovirus (HCMV) load in blood has become a mainstay of clinical management helping direct deployment of antiviral therapy, assess response to therapy and highlight cases of drug resistance.

AIMS

The review focuses on a brief historical perspective of HCMV quantification and the ways in which viral load is being used to improve patient management.

METHODS

A review of the published literature and also personal experience at the Royal Free Hospital.

RESULTS

Quantification of HCMV is essential for efficient patient management. The ability to use real time quantitative PCR to drive pre-emptive therapy has improved patient management after transplantation although the threshold viral loads for deployment differ between laboratories. The field would benefit from access to a universal standard for quantification.

CONCLUSIONS

We see that HCMV quantification will continue to be central to delivering individualised patient management and facilitating multicentre trials of new antiviral agents and vaccines in a variety of clinical settings.

An optimized sensitive method for quantitation of DNA/RNA viruses in heparinized and cryopreserved plasma

Sodium heparin, an anticoagulant used widely for blood collection, has been known to inhibit DNA polymerase activity in polymerase chain reaction (PCR) assays. However, all cryopreserved plasma samples collected in the 1980s and early 1990s at the Multicenter AIDS Cohort Study were from heparin-treated blood, which poses a problem in quantifying the target nucleic acids contained in those samples by PCR assay. In this study, a nucleic acid extraction procedure was optimized to remove the heparin from extracted nucleic acids. Using this optimized method, similar human immunodeficiency virus 1 (HIV-1) and cytomegalovirus (CMV) loads of these viruses that were added to normal donor blood from ethylenediaminetetraacetic acid (EDTA), acid citrate dextrose (ACD) or sodium heparin tubes were detected by reverse transcriptase (RT) real-time PCR and real-time PCR. Comparable HIV-1 and CMV loads were also detected in the blood of persons with active HIV-1 and CMV infections collected in EDTA-, ACD- or sodium heparin-treated tubes by RT real-time and real-time PCR. The findings showed that the optimized nucleic acid extraction procedure efficiently removes the heparin inhibition effect on the performance of real-time PCR. This method could be used to extract nucleic acids from archived, heparinized plasma for PCR based quantitation of target molecules.

Preemptive therapy for cytomegalovirus based on real-time measurement of viral load in liver transplant recipients

BACKGROUND

Real-time PCR has emerged as the preferred diagnostic assay for CMV. However, its utility as a preemptive therapy tool for CMV disease and related outcomes in liver transplant recipients has not been fully defined.

METHODS

Patients comprised 117 consecutive liver transplant recipients who underwent CMV surveillance monitoring using real-time PCR. Preemptive therapy with valganciclovir was employed upon detection of viremia. Baseline viral load was considered high based on log values (median).

RESULTS

CMV viremia developed in 54% (63/117) of the patients, including 77% of R-/D+, 63% of R+/D+, 43% of R+/D-, and 10% of R-/D- patients. Overall, 23% (15/63) of the patients had recurrent viremia; R- serostatus (p=0.065) but not initial viral load correlated with recurrent viremia (p=0.80). At 12 months post-transplant, CMV disease occurred in 0.85% (1/117) of the patients (R+/D+recipient). None (0/30) of the R-/D+patients had CMV disease. Patients with CMV viremia treated preemptively did not differ significantly from those who never developed CMV viremia with regards to bacterial or fungal infections, rejection, graft loss, mortality rate, and probability of survival at 12 months (p>0.05 for all variables). The above outcomes also did not differ for patients with high (>1.9 logs) vs. low viral load (<1.9 logs) (p>0.05 for all outcomes).

CONCLUSIONS

Preemptive therapy guided by real-time PCR based monitoring led to outcomes in all patients or in those with high viral loads that were comparable to outcomes in patients who never developed viremia or had low viral loads, respectively. Late-onset CMV disease at 12 months was observed in <1% of all patients.

CMV pneumonia in HIV-infected ventilated infants

BACKGROUND

The contributing role of cytomegalovirus (CMV) in infants treated for Pneumocystis jiroveci pneumonia (PJP) is unknown. High dose steroids used in the treatment of PJP may further immunocompromise these infants contributing to the development of CMV pneumonia.

AIM

The aim of this study was to determine the role of CMV pneumonia in infants being ventilated for suspected PJP.

METHODS

In this prospective study HIV infected infants being treated with trimethoprim-sulfamethoxazole (TMP/SMX) and ventilated for suspected PJP were included if they had not responded to treatment. Open lung biopsy was performed if there was no improvement in ventilatory requirements.

RESULTS

Twenty-five HIV positive infants with a mean age of 3.3 months were included. Lung biopsy was performed in 17 (68%) and post-mortem lung tissue was obtained in 8 (32%). After evaluation of the histology, immunohistochemistry, and viral cultures from lung tissue, the most likely causes of pneumonia were: CMV and PJP dual infection 36% (n = 9), CMV pneumonia 36% (n = 9), and PJP 24% (n = 6). The pp65 test for CMV antigen was falsely negative in 24%. The mean blood CD4 count was 287/microl. There was an association between the CD4 lymphocyte status and the final diagnosis, with the CMV and PJP group (CD4 110/microl) having the lowest CD4 status (P = 0.0128). Pediatric Intensive Care Unit (PICU) mortality was 72% (n = 18) and in hospital mortality 88%.

CONCLUSION

Of the ventilated infants failing to respond to treatment, 72% had histologically confirmed CMV pneumonia, probably accounting for the high mortality in this cohort. The incidence of CMV disease in HIV infected infants being ventilated for severe pneumonia warrants that ganciclovir is used empirically until CMV disease is excluded. The role of lung biopsy in these circumstances needs to be researched.

Comparison of QIAGEN automated nucleic acid extraction methods for CMV quantitative PCR testing

We examined the effect of nucleic acid extraction methods on the analytic characteristics of a quantitative polymerase chain reaction (PCR) assay for cytomegalovirus (CMV). Human serum samples were extracted with 2 automated instruments (BioRobot EZ1 and QIAsymphony SP, QIAGEN, Valencia, CA) and CMV PCR results compared with those of pp65 antigenemia testing. Both extraction methods yielded results that were comparably linear and precise, whereas the QIAsymphony SP had a slightly lower limit of detection (1.92 log(10) copies/mL vs 2.26 log(10) copies/mL). In both cases, PCR was more sensitive than CMV antigen detection, detecting CMV viremia in 12% (EZ1) and 21% (QIAsymphony) of antigen-negative specimens. This study demonstrates the feasibility of using 2 different extraction techniques to yield results within 0.5 log(10) copies/mL of the mean value, a level that would allow for clinical comparison between different laboratory assays.

[Evaluation of cytomegalovirus quantification in blood by the R-gene real-time PCR test]

AIM OF THE STUDY

Diagnosing the presence of cytomegalovirus (CMV) in the blood of immunodepressed patients is often done by quantitative polymerase chain reaction (Q-PCR) even though the reference method remains the antigenemia pp65 (Ag-pp65) test.

OBJECTIVES

To define the predictive value of the Q-PCR in the diagnosis of CMV disease and assess treatment efficacy using the CMV R-gene test. To compare the Q-PCR results and feasibility with those of the Ag-pp65 test.

PATIENTS AND METHODS

The Q-PCR was performed in 34 whole blood samples (frozen at -80 degrees C until use) from five patients diagnosed with CMV disease, defined as the presence of clinical signs and Ag-pp65 in the nuclei of more than two cells. After extraction, viral DNA was quantified in each sample using the Q-PCR CMV R-gene kit according to the manufacturer's instructions. Immediately after blood was drawn, the Ag-pp65 test had been performed in 32 samples using CINAkit (Argene).

RESULTS

The 16 samples positive by the Ag-pp65 test were also positive by PCR; six samples negative by the Ag-pp65 test were positive by PCR; and the remaining 10 samples were negative by both techniques. During treatment, the two markers' kinetics were similar.

CONCLUSION

The CMV R-gene test has a predictive value as good as that of the Ag-pp65 test but is fast and easier to use. A prospective study with a greater number of patients is needed to define the prediction threshold for CMV disease.

Treatment-dependent loss of polyfunctional CD8+ T-cell responses in HIV-infected kidney transplant recipients is associated with herpesvirus reactivation

Antiretroviral-therapy has dramatically changed the course of HIV infection and HIV-infected (HIV(+)) individuals are becoming more frequently eligible for solid-organ transplantation. However, only scarce data are available on how immunosuppressive (IS) strategies relate to transplantation outcome and immune function. We determined the impact of transplantation and immune-depleting treatment on CD4+ T-cell counts, HIV-, EBV-, and Cytomegalovirus (CMV)-viral loads and virus-specific T-cell immunity in a 1-year prospective cohort of 27 HIV(+) kidney transplant recipients. While the results show an increasing breadth and magnitude of the herpesvirus-specific cytotoxic T-cell (CTL) response over-time, they also revealed a significant depletion of polyfunctional virus-specific CTL in individuals receiving thymoglobulin as a lymphocyte-depleting treatment. The disappearance of polyfunctional CTL was accompanied by virologic EBV-reactivation events, directly linking the absence of specific polyfunctional CTL to viral reactivation. The data provide first insights into the immune-reserve in HIV+ infected transplant recipients and highlight new immunological effects of thymoglobulin treatment. Long-term studies will be needed to assess the clinical risk associated with thymoglobulin treatment, in particular with regards to EBV-associated lymphoproliferative diseases.