Comparison of different immunostaining techniques and monoclonal antibodies to the lower matrix phosphoprotein (pp65) for optimal quantitation of human cytomegalovirus antigenemia

Advances and Challenges in Cytomegalovirus Detection Methods for Liver Transplant Donors

Cytomegalovirus (CMV) infection is a highly prevalent opportunistic infection among liver transplant recipients. When the liver donor is infected with CMV, there is a risk of transmission to the recipient, leading to CMV infection. To improve the postoperative outcome of liver transplantation, it is crucial to shift the focus of CMV detection to the donor and achieve early diagnosis, as well as implement effective preventative and therapeutic measures. However, the commonly used CMV detection methods in the past had limitations that prevented their early and accurate diagnosis in liver transplant donors. This review focuses on the latest advancements in CMV detection methods that can potentially be applied to liver transplant donors. The objective is to compare and evaluate their clinical utility, thereby providing guidance and support for rapid and accurate diagnosis of CMV infection in the clinic. The clustered regularly interspaced short palindromic repeats-associated proteins (CRISPR-Cas) system-based assay emerges as a promising method for detecting the virus, offering great prospects for early and expedient CMV infection diagnosis in clinical settings.

Detection of Viral RNA Splicing in Diagnostic Virology

This chapter is the first one to introduce the detection of viral RNA splicing as a new tool for clinical diagnosis of virus infections. These include various infections caused by influenza viruses, human immunodeficiency viruses (HIV), human T-cell leukemia viruses (HTLV), Torque teno viruses (TTV), parvoviruses, adenoviruses, hepatitis B virus, polyomaviruses, herpesviruses, and papillomaviruses. Detection of viral RNA splicing for active viral gene expression in a clinical sample is a nucleic acid-based detection. The interpretation of the detected viral RNA splicing results is straightforward without concern for carry-over DNA contamination, because the spliced RNA is smaller than its corresponding DNA template.

Although many methods can be used, a simple method to detect viral RNA splicing is reverse transcription-polymerase chain reaction (RT-PCR). In principle, the detection of spliced RNA transcripts by RT-PCR depends on amplicon selection and primer design. The most common approach is the amplification over the intron regions by a set of primers in flanking exons. A larger product than the predicted size of smaller, spliced RNA is in general an unspliced RNA or contaminating viral genomic DNA. A spliced mRNA always gives a smaller RT-PCR product than its unspliced RNA due to removal of intron sequences by RNA splicing. The contaminating viral DNA can be determined by a minus RT amplification (PCR). Alternatively, specific amplification of a spliced RNA can be obtained by using an exon-exon junction primer because the sequence at exon-exon junction is not present in the unspliced RNA nor in viral genomic DNA.

Prevention of Late-Onset Cytomegalovirus Infection and Disease in Donor-Positive/Recipient-Negative Kidney Transplant Recipients Using Low-Dose Valganciclovir

BACKGROUND

The main challenge with cytomegalovirus (CMV) prophylaxis in IgG donor-positive/recipient-negative (D+/R-) kidney transplant recipients is late-onset CMV disease. We evaluated a novel protocol for the prevention of late-onset CMV infection and disease in D+/R- organ recipients.

METHODS

Our prospective, observational, cohort study included 100 adult kidney transplant recipients. Prophylaxis with low-dose valganciclovir (450 mg/d, 3 times a week for 6 months) was administered to D+/R- recipients. Risk factors for CMV infection and disease were identified. Renal function and the outcomes of CMV infection and disease were compared between D+/R- (n = 15) and recipient-positive (R+; n = 81) organ recipients.

RESULTS

D+/R- recipients showed significant independent risk factors with high hazard ratios for CMV infection (2.04) and disease (10.3). The proportion of CMV infection in D+/R- and R+ recipients was 80% and 46% (P = .023), and that of CMV disease was 33% and 6.2% (P = .008), repectively. D+/R- recipients developed CMV infection and disease within 6 months after transplantation. However, both CMV infection- and disease-free survival rates beyond 1 year post-transplantation defined as late-onset were stable in D+/R- recipients. Moreover, serum creatinine levels at 1 year post-transplantation were comparable between D+/R- and R+ recipients (1.45 ± 0.71 vs 1.16 ± 0.35 mg/dL, P = .26).

CONCLUSION

Our novel protocol prevented late-onset CMV infection and disease beyond 1 year post-transplantation in D+/R- recipients.

Steroid Withdrawal Using Everolimus in ABO-Incompatible Kidney Transplant Recipients With Post-Transplant Diabetes Mellitus

BACKGROUND

The effectiveness of everolimus (EVR) for ABO-incompatible (ABOi) kidney transplantation is unknown. We evaluated outcomes of conversion from steroid to EVR in ABOi kidney transplant recipients.

METHODS

We performed a retrospective observational cohort study of 33 de novo consecutive adult ABOi living donor kidney transplant recipients. Desensitization was performed using 0 to 4 sessions of plasmapheresis and 1 to 2 doses of 100 mg rituximab according to the anti-A/B antibody titer. ABOi recipients were administered a combination of tacrolimus, mycophenolate mofetil, and methylprednisolone. Diabetic patients were converted from methylprednisolone to EVR at 1 to 15 months post-transplantation to prevent diabetes progression. Graft outcomes, hemoglobin A1c (HbA1c) levels, and cytomegalovirus infection rates were compared between the EVR (n = 11) and steroid (n = 22) groups.

RESULTS

Mean postoperative duration was 814 and 727 days in the EVR and steroid groups, respectively (P = .65). Between the 2 groups, graft survival rate (100% vs 95.5%, P > .99), acute rejection rate (9.1% vs 18.2%, P = .64), and serum creatinine levels (1.46 mg/dL vs 1.68 mg/dL, P = .66) were comparable. Although HbA1c levels were elevated in the steroid group (5.47%, 5.87%; P = .003), no significant deterioration was observed in the EVR group without additional insulin administration (6.10%, 6.47%; P = .21). Cytomegalovirus infection rate was significantly lower in the EVR group than in the steroid group (18.2% vs 63.6%, P = .026).

CONCLUSION

Conversion from steroid to EVR in ABOi kidney transplant recipients maintained excellent graft outcomes and avoided diabetes progression and cytomegalovirus infection.

The pentameric complex of human Cytomegalovirus: cell tropism, virus dissemination, immune response and vaccine development

Between the 1980s and 1990s, three assays were developed for diagnosis of human cytomegalovirus (HCMV) infections: leuko (L)-antigenemia, l-viremia and l-DNAemia, detecting viral protein pp65, infectious virus and viral DNA, respectively, in circulating leukocytes Repeated initial attempts to reproduce the three assays in vitro using laboratory-adapted strains and infected cell cultures were consistently unsuccessful. Results were totally reversed when wild-type HCMV strains were used to infect either fibroblasts or endothelial cells. Careful analysis and sequencing of plaque-purified viruses from recent clinical isolates drew attention to the ULb' region of the HCMV genome. Using bacterial artificial chromosome technology, it was shown by both gain-of-function and loss-of-function experiments that UL131-128 genes are indispensable for virus growth in endothelial cells and virus transfer to leukocytes. In addition, a number of clinical isolates passaged in human fibroblasts had lost both properties (leuko-tropism and endothelial cell-tropism) when displaying a mutation in the UL131-128 locus (referred to as UL128L). In the following years, it was shown that pUL128L was complexed with gH and gL to form the pentameric complex (PC), which is required to infect endothelial, epithelial and myeloid cells. The immune response to PC was studied extensively, particularly its humoral component, showing that the great majority of the neutralizing antibody response is directed to PC. Although anti-HCMV antibodies may act with other mechanisms than mere neutralizing activity, these findings definitely favour their protective activity, thus paving the way to the development of a potentially protective HCMV vaccine.

Strategies to control human cytomegalovirus infection in adult hematopoietic stem cell transplant recipients

Human cytomegalovirus (HCMV) represents the major viral complication after hematopoietic stem cell transplantation. HCMV infection may be controlled by the reconstituting immune system and remain subclinical or can lead to severe systemic and/or organ disease (mainly pneumonia and gastroenteritis) when immune reconstitution is delayed or impaired. In order to prevent the occurrence of HCMV disease, a prompt diagnosis of HCMV infection is mandatory. The adoption of pre-emptive therapy strategies guided by virological monitoring dramatically reduced the occurrence of HCMV disease. However, late-onset end-organ disease may occur in some patients with apparent immune reconstitution. In the near future, introduction of immunological monitoring and immunotherapies could markedly improve management of HCMV infection.

Cytomegalovirus Reactivation in Adult Recipients of Autologous Stem Cell Transplantation: a Single Center Experience

INTRODUCTION

Cytomegalovirus (CMV) reactivation and infection are well-recognized complications after allogeneic stem cell transplantation (SCT). Only a few studies have addressed CMV reactivation after autologous SCT (ASCT).

METHODS

We retrospectively reviewed medical records of 210 adult patients who underwent ASCT for lymphoma or multiple myeloma (MM) at a single center from January 1(st), 2007 until December 31(st), 2012. All patients were monitored weekly with CMV antigenemia test till day 42 after transplantation, and for 2 months after last positive test in those who had any positive CMV antigenemia test before day 42.

RESULTS

Thirty-seven (17.6%) patients had CMV reactivation; 23 patients had lymphoma while 14 had MM as the underlying disease. There was no difference in the rate of CMV reactivation between lymphoma and MM patients (20% versus 14.7%, P = 0.32). The majority of the patients were treated with ganciclovir/valganciclovir, all patients had their reactivation resolved with therapy, and none developed symptomatic CMV infection. None of the patients who died within 100 days of transplantation had CMV reactivation. Log-rank test showed that CMV reactivation had no effect on the overall survival of patients (P values, 0.29).

CONCLUSION

In our cohort, CMV reactivation rate after ASCT was 17.6%. There was no difference in reactivation rates between lymphoma and MM patients. With the use of preemptive therapy, symptomatic CMV infection was not documented in any patient in our cohort. CMV reactivation had no impact on patients' survival post ASCT.

Long-Term Follow-up of a Cohort of HIV-Infected Patients Who Discontinued Maintenance Therapy for Cytomegalovirus Retinitis

PURPOSE

To determine the long-term safety of discontinuation of maintenance therapy for cytomegalovirus retinitis (CMVR) and to identify predictors for relapse.

METHOD

This was a prospective cohort study. Patients with treated CMVR who responded to HAART were followed by ophthalmologic assessment, markers for CMV replication (blood and urine cultures, CMV antigenemia, CMV DNA by PCR), and in vitro lymphoproliferative responses to CMV and other antigens after discontinuation of CMVR maintenance therapy.

RESULTS

23 patients were followed a median of 34 (range, 5-61) months. Median CD4 count was 321/mm3 at enrollment and 395/mm3 at last follow-up. HIV RNA was <50 copies/mL in 78% of patients at enrollment and 65% at last follow-up. One CMVR reactivation occurred at 12 months at a CD4 count of 395/mm3 (21%) and HIV RNA <50 copies/mL. Urine cultures were a poor predictive marker for reactivation. Other CMV replication markers had good negative predictive value. 96% of patients had a good lymphoproliferative response to CMV antigen in vitro.

CONCLUSION

Maintenance therapy for CMVR can safely be discontinued in patients who have responded to HAART. Combining our results with the published literature, the risk of reactivation is estimated at 0.016 per person year of follow-up. Markers to predict relapse and the need for re-initiation of maintenance therapy are not yet identified.

A randomized trial of hyperimmune globulin to prevent congenital cytomegalovirus

BACKGROUND

Congenital infection with human cytomegalovirus (CMV) is a major cause of morbidity and mortality. In an uncontrolled study published in 2005, administration of CMV-specific hyperimmune globulin to pregnant women with primary CMV infection significantly reduced the rate of intrauterine transmission, from 40% to 16%.

METHODS

We evaluated the efficacy of hyperimmune globulin in a phase 2, randomized, placebo-controlled, double-blind study. A total of 124 pregnant women with primary CMV infection at 5 to 26 weeks of gestation were randomly assigned within 6 weeks after the presumed onset of infection to receive hyperimmune globulin or placebo every 4 weeks until 36 weeks of gestation or until detection of CMV in amniotic fluid. The primary end point was congenital infection diagnosed at birth or by means of amniocentesis.

RESULTS

A total of 123 women could be evaluated in the efficacy analysis (1 woman in the placebo group withdrew). The rate of congenital infection was 30% (18 fetuses or infants of 61 women) in the hyperimmune globulin group and 44% (27 fetuses or infants of 62 women) in the placebo group (a difference of 14 percentage points; 95% confidence interval, -3 to 31; P=0.13). There was no significant difference between the two groups or, within each group, between the women who transmitted the virus and those who did not, with respect to levels of virus-specific antibodies, T-cell-mediated immune response, or viral DNA in the blood. The clinical outcome of congenital infection at birth was similar in the two groups. The number of obstetrical adverse events was higher in the hyperimmune globulin group than in the placebo group (13% vs. 2%).

CONCLUSIONS

In this study involving 123 women who could be evaluated, treatment with hyperimmune globulin did not significantly modify the course of primary CMV infection during pregnancy. (Funded by Agenzia Italiana del Farmaco; CHIP ClinicalTrials.gov number, NCT00881517; EudraCT no. 2008-006560-11.).

Laboratory diagnosis of viral infection

Since the last Handbook of Clinical Neurology volume on this topic, viral diagnosis has made tremendous strides, moving from the margin to the mainstream of clinical care. For many years, conventional virus isolation was the mainstay of viral diagnosis since it was sensitive and “open-minded.” However, growth in conventional cell culture entails an inherent delay that limits its clinical impact. Although rapid culture and viral antigen methods detect fewer pathogens and are less sensitive than conventional culture, both require less expertise and have greatly reduced time to result. Polymerase chain reaction has ushered in a new era in virology, especially in the diagnosis of neurologic diseases. Molecular amplification methods are rapid, highly sensitive, can be automated, quantitative, and detect viruses not amenable to routine culture. User-friendly, walk-away tests with results in an hour, as well as multiplex tests that can detect 20 viruses in a single reaction, are now a reality. As the variety of test methods and commercial products proliferate, the challenges for clinicians and laboratories are selecting which tests to utilize in which clinical scenarios, and understanding how to interpret the results. The advantages and limitations of each method are discussed in this chapter, with special attention to neurologic disease.

Fetal human cytomegalovirus transmission correlates with delayed maternal antibodies to gH/gL/pUL128-130-131 complex during primary infection

Primary human cytomegalovirus (HCMV) infections during pregnancy are associated with a high risk of virus transmission to the fetus. To identify correlates of intrauterine HCMV transmission, serial serum samples from HCMV transmitter and non-transmitter pregnant women with primary HCMV infection were analyzed for the presence of neutralizing antibodies against different glycoproteins and glycoprotein complexes, which are known to mediate entry into distinct types of host cells. Neutralizing activity was detected in the sera early after primary infection; absorption with a soluble pentameric complex formed by gH/gL/pUL128-131, but not with gH/gL dimer or with gB, abolished the capacity of sera to neutralize infection of epithelial cells. Importantly, an early, high antibody response to pentamer antigenic sites was associated with a significantly reduced risk of HCMV transmission to the fetus. This association is consistent with the high in vitro inhibition of HCMV infection of epithelial/endothelial cells as well as cell-to-cell spreading and virus transfer to leukocytes by anti-pentamer antibodies. Taken together, these findings indicate that the HCMV pentamer complex is a major target of the antibody-mediated maternal immunity.

Monitoring of human cytomegalovirus and virus-specific T-cell response in young patients receiving allogeneic hematopoietic stem cell transplantation

In allogeneic hematopoietic stem-cell transplantation (HSCT) recipients, outcome of human cytomegalovirus (HCMV) infection results from balance between viral load/replication and pathogen-specific T-cell response. Using a cut-off of 30,000 HCMV DNA copies/ml blood for pre-emptive therapy and cut-offs of 1 and 3 virus-specific CD4⁺ and CD8⁺ T cells/µl blood for T-cell protection, we conducted in 131 young patients a prospective 3-year study aimed at verifying whether achievement of such immunological cut-offs protects from HCMV disease. In the first three months after transplantation, 55/89 (62%) HCMV-seropositive patients had infection and 36/55 (65%) were treated pre-emptively, whereas only 7/42 (17%) HCMV-seronegative patients developed infection and 3/7 (43%) were treated. After 12 months, 76 HCMV-seropositive and 9 HCMV-seronegative patients (cumulative incidence: 90% and 21%, respectively) displayed protective HCMV-specific immunity. Eighty of these 85 (95%) patients showed spontaneous control of HCMV infection without additional treatment. Five patients after reaching protective T-cell levels needed pre-emptive therapy, because they developed graft-versus-host disease (GvHD). HSCT recipients reconstituting protective levels of HCMV-specific T-cells in the absence of GvHD are no longer at risk for HCMV disease, at least within 3 years after transplantation. The decision to treat HCMV infection in young HSCT recipients may be taken by combining virological and immunological findings.

Valganciclovir as pre-emptive therapy for cytomegalovirus infection in allogeneic haematopoietic stem cell transplant recipients

BACKGROUND

In haematopoietic stem cell transplant (HSCT) recipients, cytomegalovirus (CMV) infection contributes significantly to morbidity and mortality in both the early and late post-transplant period. Ganciclovir (GCV) is the treatment of choice for CMV, but requires intravenous administration, a fact that complicates its long-term use. Oral valganciclovir (VGCV) and intravenous GCV were recently shown to have similar efficacy for pre-emptive CMV treatment in solid organ transplant recipients, but relatively limited data are available in HSCT recipients. The objectives of this study were to compare the efficacy of VGCV versus intravenous GCV or foscarnet (FOS) for pre-emptive therapy of active CMV infection in allogeneic HSCT and to determine the incidence of adverse effects and relapses.

METHODS

This was a 2-year prospective, comparative cohort study in which 237 episodes of pre-emptive therapy for active CMV infection were collected in 166 allogeneic HSCT recipients out of 717 included in the Spanish Network for Research on Infection in Transplantation (RESITRA/REIPI) database. Intravenous GCV was the first-line treatment in 112 episodes, intravenous FOS in 38 episodes, and oral VGCV in 87 episodes.

RESULTS

VGCV was used as pre-emptive therapy for active CMV infection in 87 episodes. Excluding episodes considered as relapse, VGCV was as successful (91.4% [74/81]) as GCV (83.7% [87/14]) or FOS (75.8% [25/33]). In the VGCV arm, 7 (8.6%) cases were considered treatment failures: 4 (4.9%) because of adverse events, 1 (1.2%) due to persistent viral activity and 2 (2.5%) based on clinical decision. There were also 6 (7.4%) cases of recurrent infection. No statistically significant differences were found when compared to GCV or FOS.

CONCLUSIONS

In allogeneic HSCT recipients, VGCV seemed effective and safe in the pre-emptive therapy of active CMV infection.

Endothelial cells and CMV dissemination

Evaluation of: Sacher T, Andrassy J, Kalnins A et al. Shedding light on the elusive role of endothelial cells in cytomegalovirus dissemination. PLoS Pathog. 7(11), E1002366 (2011). Using the murine CMV animal model and the well-established model of Cre-lox-P-mediated green-fluorescence tagging of endothelial cell (EC)-derived mouse CMV to quantify the role of infected ECs in transplantation-associated CMV dissemination (in mice expressing Cre recombinase under the control of either the Tie2 or the Tek promoter selectively expressed in vascular EC-Tie-Cre and Tek-Cre mice), it was shown that EC-derived virus contributed to 50% of the total viral load during primary infection, and there was no preference for dissemination of EC-derived viruses over viruses produced by other cell types. In addition, during secondary viremia, there was only a negligible contribution of EC-derived virus to dissemination to other organs. These results are novel in the methodology employed and are somewhat interesting. However, the data are limited to the mouse model with a short-term follow-up, and the immunodeficient host has not yet been studied. In humans, these conclusions must be taken with caution. First, in primary infection occurring through natural routes, epithelial cells are infected first, then ECs, unless primary infection occurs through blood transfusion, in which case endothelial vascular cells may become infected first. In both cases, the virus transport occurs through the intervention of leukocytes, namely monocytes and polymorphonuclear leukocytes. As monocytes differentiate to macrophages, they become highly susceptible to human CMV replication inside organ tissues, while polymorphonuclear leukocytes are active in virus capturing from infected endothelial vascular cells and transporting to distant sites.

Nuclear lamins are differentially expressed in retinal neurons of the adult rat retina

Lamins are type V intermediate filament proteins that support nuclear membranes. They are divided into A-type lamins, which include lamin A and C, and B-type lamins, which include lamin B1 and B2. In the rat brain, lamin A and C are expressed in relatively equal amounts, while the expressions of lamin B1 and B2 vary depending on the cell type. Lamins play important roles in normal morphogenesis and function. In the nervous system, their abnormal expression causes several neurodegenerative diseases such as peripheral neuropathy, leukodystrophy and lissencephaly. The retina belongs to the central nervous system (CNS) and has widely been used as a source of CNS neurons. We investigated the expression patterns of lamin subtypes in the adult rat retina by immunohistochemistry and found that the staining patterns differed when compared with the brain. All retinal neurons expressed lamin B1 and B2 in relatively equal amounts. In addition, horizontal cells and a subpopulation of retinal ganglion cells expressed lamin A and C, while photoreceptor cells expressed neither lamin A nor C, and all other retinal neurons expressed lamin C only. This differential expression pattern of lamins in retinal neurons suggests that they may be involved in cellular differentiation and expression of cell-specific genes in individual retinal neurons.

Lymphotropic herpesvirus DNA detection in patients with active CMV infection - a possible role in the course of CMV infection after hematopoietic stem cell transplantation

BACKGROUND

The natural history of cytomegalovirus (CMV) infection and disease in transplant recipients prompts researchers to look for other factors contributing to this infection. The ubiquity of lymphotropic herpesviruses (EBV, HHV-6, and HHV-7) and the possibility of their activation during immunosuppression may suggest their participation in progression of CMV infection in patients after hematopoietic stem cell transplantation (HSCT).

MATERIAL/METHODS

The presence of CMV, EBV, HHV-6 and HHV-7 was confirmed through detection of viral DNA isolated from leukocytes. Allo-HSCT recipients (n=55) were examined repeatedly within the average period of 14±7.3 months post-transplant.

RESULTS

CMV DNA was detected in 24% of samples, while EBV, HHV-6 and HHV-7 were detected in 20%, 15% and 14% of samples, respectively. Based on the presence of CMV infection at particular time-points (months) after transplantation, the recipients were divided into 3 groups: Group I (N=15) with persistent infection, Group II (N=20) with transient infection, and Group III (N=20) without CMV infection. In Group I, the mean CMV load was significantly higher than in Group II, and the clinical condition of Group I patients was poorer. All these patients manifested clinical symptoms, and all had episodes of GvHD. All Group I patients developed multiple infections; EBV in 80%, HHV-6 in 47% and HHV-7 in 87% of patients. In the remaining groups, with the exception of HHV-6 in group II, the frequency of infected patients was lower. In addition, CMV presence was often preceded by another herpesvirus.

CONCLUSIONS

The results suggest that other herpesviruses, mainly HHV-7, could predispose CMV to cause chronic infection.

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.

Role of prenatal diagnosis and counseling in the management of 735 pregnancies complicated by primary human cytomegalovirus infection: a 20-year experience

BACKGROUND

The burden of congenital human cytomegalovirus (HCMV) infection is well recognized. However, screening for maternal infection remains controversial in view of diagnostic challenges, counseling difficulties, and absence of medical treatment.

OBJECTIVE

To assess the role of prenatal diagnosis and counseling in the management of pregnancy complicated by primary HCMV infection.

STUDY DESIGN

Retrospective study aimed at investigating diagnostic features, options, and pregnancy outcome in 735 women with primary HCMV infection over a period of 20 years (1990-2009).

RESULTS

Overall, 25.6% women were found to be seronegative before the actual pregnancy. However, none were informed about HCMV infection and potential prevention strategies. Diagnosis of primary HCMV infection was achieved by seroconversion in 44.4% cases and by different combinations of virus-specific IgM, low IgG avidity, and DNAemia in 43.9% cases. Non-specific symptoms and/or haematological/biochemical alterations were recalled by 73.5% women. The onset of infection could be established, and counseling adjusted accordingly in >90% cases. The overall rate of vertical transmission was 37.1%, ranging from 5.6% for preconceptional infections to 64.1% for third trimester infections. Amniocentesis was chosen by 43.1% women, whereas pregnancy termination was requested by 15.6%.

CONCLUSIONS

Reference virology centers and ad hoc trained and experienced physicians are required for accurate diagnosis of primary infection in pregnancy and ensuing counseling. Prenatal diagnosis has a central role in the management of pregnancies complicated by primary HCMV infection. HCMV-seronegative women should receive adequate information.

Prognostic markers of symptomatic congenital human cytomegalovirus infection in fetal blood

OBJECTIVE

To identify fetal cord blood prognostic markers of symptomatic congenital human cytomegalovirus infection (HCMV).

DESIGN

Retrospective observational study.

SETTING

Fetal medicine unit in Milan and Medical virology unit in Pavia, Italy.

POPULATION

HCMV-infected and -uninfected fetuses of mothers with primary HCMV infection during the period 1995-2009.

METHODS

Overall, 94 blood samples from as many fetuses of 93 pregnant women experiencing primary HCMV infection were examined for multiple immunological, haematological and biochemical markers as well as virological markers. Congenital HCMV infection was diagnosed by detection of virus in amniotic fluid, and symptomatic/asymptomatic infections were determined by ultrasound scans, nuclear magnetic resonance imaging, histopathology or clinical examination at birth. Blood sample markers were retrospectively compared in symptomatic and asymptomatic fetuses with congenital infection.

MAIN OUTCOME MEASURES

A statistical analysis was performed to determine the value of each parameter in predicting outcome.

RESULTS

Univariate analysis showed that most nonviral and viral markers were significantly different in symptomatic (n = 16) compared with asymptomatic (n = 31) fetuses. Receiver operator characteristics analysis indicated that, with reference to an established cutoff for each marker, the best nonviral factors for differentiation of symptomatic from asymptomatic congenital infection were β(2) -microglobulin and platelet count, and the best virological markers were immunoglobulin M antibody and DNAaemia. β(2) -Microglobulin alone or the combination of these four markers reached the optimal diagnostic efficacy.

CONCLUSIONS

The determination of multiple markers in fetal blood, following virus detection in amniotic fluid samples, is predictive of perinatal outcome in fetuses with HCMV infection.

Human cytomegalovirus tropism for endothelial/epithelial cells: scientific background and clinical implications

Human cytomegalovirus (HCMV) has been routinely isolated from and propagated in vitro in human embryonic lung fibroblast (HELF) cell cultures, while in vivo it is known to infect predominantly endothelial and epithelial cells. In recent years, genetic determinants of the HCMV tropism for endothelial/epithelial cells were identified in the UL131A/UL130/UL128 locus of HCMV genome of wild-type strains. UL131A-UL128 gene products form a complex with glycoprotein H (gH) and L (gL) resulting in a gH/gL/UL131A-UL128 complex that is required for HCMV entry into endothelial/epithelial cells. In contrast, virus entry into fibroblasts has its genetic determinants in the complex gH/gL/gO (or gH/gL). During primary HCMV infection, the neutralising antibody response measured in endothelial cells (EC) is potent, occurs very early and is directed mostly against combinations of two or three gene products of the UL131A-128 locus. On the contrary, neutralising antibodies measured in fibroblasts appear late, are relatively weak in potency and are directed against gH and gB. The T-cell immune response to UL131A-UL128 gene products remains to be investigated. Recently, a role has been proposed for neutralising antibody in conferring prevention/protection against HCMV infection/disease in pregnant women with primary HCMV infection. However, the level of cooperation between humoral immunity and the well-established T-cell protection remains to be defined.

A randomized controlled trial of plasma real-time PCR and antigenemia assay for monitoring CMV infection after unrelated BMT

Preemptive therapy is the standard strategy for preventing CMV disease after allogeneic hematopoietic SCT. In this study, unrelated BMT recipients were randomly assigned to a plasma real-time PCR group or an antigenemia group to compare the value of these monitoring tools for CMV reactivation. Ganciclovir (GCV) was started at 5 mg/kg/day when PCR reached 300 copies per ml or when antigenemia reached three positive cells per two slides. A total of 88 patients were randomized into the antigenemia group (n=45) or the PCR group (n=43). A significantly higher number of patients reached the threshold in the antigenemia group than in the PCR group (73.3 vs 44.2%, P=0.0089). However, only three patients (one in the antigenemia group and two in the PCR group) developed early CMV disease. These patients exclusively had colitis and were successfully treated with GCV or foscarnet. The median number of antigenemia-positive cells at the start of GCV was 47 in the PCR group. These findings suggest that antigenemia assay with the current cutoff was too sensitive and led to unnecessary use of GCV. However, the appropriateness of the threshold may be different by the methodology used, and therefore, it is difficult to generalize.

Comparison of quantitative cytomegalovirus real-time PCR in whole blood and pp65 antigenemia assay: clinical utility of CMV real-time PCR in hematopoietic stem cell transplant recipients

Successful preemptive therapy for cytomegalovirus (CMV) infection in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infection. Although the pp65 antigenemia assay has been widely used for this purpose, real-time quantification of CMV DNA has recently been recognized as an alternative diagnostic approach. However, the guidelines for antiviral therapy based on real-time quantitative polymerase chain reaction (RQ-PCR) have yet to be established. From November 2004 to March 2005, a total of 555 whole blood samples from 131 hematopoietic stem cell transplant (HSCT) recipients were prospectively collected. RQ-PCR was conducted using an Artus CMV LC PCR kit (QIAGEN). Both qualitative and quantitative correlations were drawn between the two methods. Exposure to the antiviral agent influenced the results of the two assays. Additionally, the discrepancy was observed at low levels of antigenemia and CMV DNA load. Via ROC curve analysis, the tentative cutoff value for preemptive therapy was determined to be approximately 2x10(4) copies/mL (sensitivity, 80.0%; specificity, 50.0%) in the high risk patients, and approximately 3x10(4) copies/mL (sensitivity, 90.0%; specificity, 70.0%) in the patients at low risk for CMV disease. Further study to validate the optimal cutoff value for the initiation of preemptive therapy is currently underway.

Preemptive therapy for systemic and pulmonary human cytomegalovirus infection in lung transplant recipients

The incidence and treatment of both systemic and pulmonary human cytomegalovirus (HCMV) infection as well as HCMV-specific T-cell immune responses were investigated in 57 consecutive lung transplant recipients (LTR) by using as cutoffs for preemptive therapy: 300 000 DNA copies/mL whole blood for systemic infections and 100 000 DNA copies/mL bronchoalveolar lavage fluid for lung infections. Results showed that out of 29/57 LTR (50.9%) needing preemptive antiviral therapy, 15 (51.7%) reached the blood cutoff, 8 (27.6%) the pulmonary cutoff and 6 (20.7%) both the blood and the lung cutoff (3 simultaneously and 3 subsequently). Recovery of HCMV-specific T-cell immune responses was achieved much earlier for CD8+ than CD4+ T cells. However, protection from HCMV reactivation was conferred by the presence of both arms of the T-cell response. In two LTR reaching the pulmonary cutoff and not preemptively treated, a full HCMV-specific CD4+ and CD8+ T-cell response was associated with resolution of lung infection. Antirejection steroid therapy suppressed T-cell immune responses, thus facilitating HCMV reactivation. In conclusion, in LTR, monitoring HCMV infection in both blood and lungs, may improve preemptive therapy efficacy. In addition, monitoring the HCMV-specific T-cell immune response appears useful for predicting control of HCMV infection in the posttransplant period.

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.

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.

Human cytomegalovirus serum neutralizing antibodies block virus infection of endothelial/epithelial cells, but not fibroblasts, early during primary infection

A panel of human sera exhibited a >or=128-fold higher neutralizing potency against a human cytomegalovirus (HCMV) clinical isolate propagated and tested in endothelial (or epithelial) cells than against the same virus infecting human fibroblasts. In a group of 18 primary infections, the reverse geometric mean titre was in the range of 10-15 in human fibroblasts within the first 3 months after the onset of infection, whereas the endothelial cell infection-neutralizing activity was already present within the first 10 days, reaching median levels of 122, 320 and 545 at respectively 30, 60 and 90 days after onset, then declining slowly. This difference was also confirmed in the majority of reactivated and remote HCMV infections, as well as in a hyperimmune globulin preparation. The antibody response to HCMV pUL131A, pUL130 and pUL128 locus products, which are required for endothelial/epithelial cell infection, provided a potential molecular basis for such a differential neutralizing activity. In addition, monoclonal/monospecific antibodies raised against the pUL131A, pUL130 and pUL128 proteins were found to display an inhibitory activity on HCMV plaque formation and HCMV leukocyte transfer from HCMV-infected cells. Hence, conventional determination of the neutralizing activity of human sera in fibroblasts is misleading. Antibodies to pUL131A, pUL130 and pUL128 appear to display a major HCMV-neutralizing and dissemination-inhibiting activity.

Comparison of a new Light Diagnostics and the CMV Brite to an in-house developed human cytomegalovirus antigenemia assay

BACKGROUND

Antigenemia, i.e. detection and quantification of human cytomegalovirus (HCMV) peripheral blood pp65-positive leukocytes, is still one of the two major assays available for diagnosis and monitoring of HCMV infections.

OBJECTIVES

To evaluate the performance of a new commercial assay under development (Light Diagnostics).

STUDY DESIGN

To compare the performance of the new assay with a commercial assay (CMV Brite) already available on 300 blood samples from immunocompromised patients using as a reference the original in-house developed assay.

RESULTS

Although 30 blood samples gave discrepant results among the 3 antigenemia assays, the Light Diagnostics detected an overall number of antigenemia-positive blood samples (sensitivity 84%) identical to that detected by CMV Brite (sensitivity 88%) and in-house assay (91/300, 30.3%). Problems of non-specific cytoplasmic staining were encountered with the CMV Brite assay in 219/300 (73%) blood samples.

CONCLUSIONS

The Light Diagnostics assay provides results comparable to those of the reference assay both in terms of specificity and sensitivity (number of pp65-positive leukocytes).

Valganciclovir as treatment for cytomegalovirus disease in solid organ transplant recipients

BACKGROUND

Cytomegalovirus (CMV) infection causes morbidity in solid organ transplant (SOT) recipients, either by direct injury or in association with chronic allograft rejection or other opportunistic infections. Ganciclovir is the treatment of choice, but this agent requires intravenous administration, which affects its feasibility for long-term use. Valganciclovir, which has an oral bioavailability of 60%, has proven to be useful for prophylaxis of CMV infection in high-risk SOT recipients and for treating retinitis in persons with acquired immunodeficiency syndrome.

OBJECTIVE

To compare the efficacy of valganciclovir (alone or as sequential therapy after a regimen of intravenous ganciclovir) with intravenous ganciclovir alone for preemptive therapy or treatment of CMV disease (viral syndrome or focal disease) in SOT recipients and to determine the incidence of adverse effects and relapses.

METHODS

In this 2-year prospective, comparative cohort study, 376 episodes of preemptive therapy or treatment of CMV disease were recorded among 334 of 3467 SOT recipients included in the Spanish Network for Research on Infection in Transplantation (RESITRA) database. Intravenous ganciclovir was the first-line treatment in 170 episodes; valganciclovir followed by intravenous ganciclovir was administered in 82 episodes, and valganciclovir alone was administered in 112 episodes.

RESULTS

Valganciclovir was used as preemptive therapy or treatment for CMV disease in 84 and 28 episodes, respectively. Duration of treatment was longer in valganciclovir recipients than in ganciclovir recipients for both preemptive therapy (21 vs. 15 days; P < .001) or viral syndrome treatment (21 vs. 18 days; P < .01). In the valganciclovir arm, 94 (83.9%) of 112 episodes were treated successfully, with no statistical difference in the success rates versus the ganciclovir arm (85.8%) or ganciclovir-valganciclovir arm (95.1%). Eighteen episodes (16.1%) treated with valganciclovir were considered to have resulted in treatment failure (because of persistent antigenemia in 4 [3.6%], on the basis of clinical decision in 7 [6.2%], and because of recurrent disease in 7 [6.2%]). There were no incidents in which valganciclovir treatment was withdrawn because of toxicity.

CONCLUSION

Valganciclovir is safe and useful for preemptive therapy and treatment of CMV disease.

Validation of a DNAemia cutoff for preemptive therapy of cytomegalovirus infection in adult hematopoietic stem cell transplant recipients

A randomized trial comparing a DNAemia cutoff of 10 000 copies per ml whole blood and first pp65 antigenemia positivity for initiation of preemptive therapy of human cytomegalovirus (HCMV) infection in adult hematopoietic stem cell transplant recipients was completed. DNAemia was chosen for cutoff definition since it is more automatable and standardizable than antigenemia, and more closely reflects the actual viral replication. The primary end point of the study was to compare the number of patients treated in the two arms. A total of 83 patients (42 in the DNAemia, and 41 in the antigenemia arm) were enrolled in the study. The incidence of HCMV infection, as detected by the relevant randomization assay (76% in the DNAemia versus 85% in the antigenemia arm), was comparable in the two arms, whereas the number of patients treated was significantly lower in the DNAemia arm (63 versus 80%, P=0.02). A single patient in the DNAemia arm suffered from biopsy-proven HCMV gastric disease diagnosed in the absence of detectable virus in blood. The incidence of graft-versus-host disease, and transplantation-related mortality did not differ between the two arms. In conclusion, our study shows that the use of a cutoff significantly reduces the number of patients requiring antiviral treatment, thus sparing unnecessary drug administration.

Monitoring human cytomegalovirus infection in transplant recipients

Human cytomegalovirus (HCMV) infection remains one of the most challenging infectious complications in both solid organ transplant (SOT) and hemopoietic stem cell transplant (HSCT) recipients. In the last two decades advances have been made in the diagnosis and monitoring of HCMV infection in SOT and HSCT recipients following introduction of quantitative assays such as rapid virus isolation in blood (viremia), quantitation of pp65 in peripheral blood leukocytes (antigenemia), and quantitation of viral genome in blood (DNAemia). The availability of these rapid diagnostic assays has allowed treatment administration during the presymptomatic phase of HCMV infection (preemptive treatment) and greatly reduced HCMV-related morbidity and mortality, particularly among HSCT recipients. Definition of clinically validated thresholds for initiating preemptive treatment in SOT and HSCT recipients is a major goal in the transplantation setting. With respect to universal prophylaxis of HCMV infection in transplant recipients, the preemptive treatment approach shows advantages in (i) treating a lower number of patients for shorter periods of time and (ii) avoiding the reported emergence of HCMV disease after interruption of anti-HCMV prophylaxis. To understand the mechanism behind long-term control of HCMV infection in transplant recipients, the HCMV-specific T-cell response must be evaluated.

Nuclear localization of valosin-containing protein in normal muscle and muscle affected by inclusion-body myositis

Inclusion-body myopathy with Paget's disease and frontotemporal dementia (IBMPFD) is a disease of muscle, bone, and brain that results from mutations in the gene encoding valosin-containing protein (VCP). The mechanism of disease resulting from VCP mutations is unknown. Previous studies of VCP localization in normal human muscle samples have found a capillary and perinuclear distribution, but not a nuclear localization. Here we demonstrate that VCP is present in both myonuclei and endothelial cell nuclei in normal human muscle tissue. The immunodetection of VCP varies with acetone or paraformaldehyde fixation. Within the nucleus, VCP associates with the nucleolar protein fibrillarin and Werner syndrome protein (Wrnp) in normal and IBMPFD muscle. In patients with inclusion-body myositis (IBM), normal nuclear localization is present and some rimmed vacuoles are lined with VCP. These findings suggest that impairment in the nuclear function of VCP might contribute to the muscle pathology occurring in IBMPFD.

Use of a DNAemia cut-off for monitoring human cytomegalovirus infection reduces the number of preemptively treated children and young adults receiving hematopoietic stem-cell transplantation compared with qualitative pp65 antigenemia

We performed a randomized trial comparing the use of quantitative DNAemia versus positive antigenemia for starting preemptive antihuman cytomegalovirus (HCMV) therapy in hematopoietic stem-cell transplantation (HSCT) recipients. In the DNAemia arm, antiviral therapy was initiated on reaching a DNAemia cut-off of 10 000 DNA copies/mL of whole blood, whereas in the antigenemia arm, therapy was started in the presence of a positive antigenemia. The aim of the study was to compare the number of patients treated in the 2 arms. On the whole, 178 patients (89 in each arm), receiving unmanipulated HSCT from either a relative or an unrelated donor, completed the study. Although the incidence of HCMV infection was comparable in DNAemia and antigenemia arms (34% vs 42%, respectively, P = .259), the number of patients treated was significantly lower in the DNAemia arm (18% vs 31%, P = .026). No patient developed HCMV disease. The use of a DNAemia cut-off avoids unnecessary antiviral treatment.

Inconsistent responses of cytomegalovirus-specific T cells to pp65 and IE-1 versus infected dendritic cells in organ transplant recipients

CD4(+) and CD8(+) T cells specific for human cytomegalovirus (HCMV) and two immunodominant HCMV antigens (pp65 and IE-1) were monitored in 20 solid organ transplant recipients undergoing primary (n = 4) or reactivated (n = 16) HCMV infection during the first year after transplantation by using as a stimulator either HCMV-infected autologous dendritic cells (DCs) or pp65- or IE-1 peptide mixtures. Turnaround times for test performance were 7 days for infected DCs and 24 h for peptides. Using infected DCs, HCMV-specific T-cell restoration occurred in all patients for CD8(+) and in 18/20 (90%) for CD4(+) T-cell subpopulations, resulting in virus clearance from blood. Using peptide mixtures, T-cell responses were less frequently detected. In detail, 14 (70%) patients showed pp65-specific CD8(+) T cells and 10 (50%) patients IE-1-specific CD8(+) T cells, whereas pp65-specific CD4(+) T cells were detected in 14 (70%) patients, and IE-1-specific CD4(+) T cells in three (15%) patients only. Protection from HCMV infection was associated with the presence of a HCMV-specific T-cell response directed against multiple viral proteins, but not against pp65 or IE-1 only. In conclusion, the use of pp65 and IE-1 peptide mixtures for rapid monitoring of HCMV-specific T-cell responses in solid organ transplant recipients underestimates the actual T-cell immune response against HCMV.

Evaluation of Cytomegalovirus DNAaemia versus pp65-Antigenaemia Cutoff for Guiding Preemptive therapy in Transplant Recipients: A Randomized Study

Methods

A bicentre, randomized, prospective open-label study aimed at defining a DNAaemia versus antigenaemia cutoff for guiding preemptive therapy of human cytomegalovirus (HCMV) infections in solid organ transplant recipients (SOTR) was completed. Overall, 99 patients were enrolled in the DNAaemia arm and 101 patients in the antigenaemia arm. Patients were randomized to be monitored for HCMV infection in the blood by either assay. Antiviral treatment was started in both seropositive and seronegative patients when levels greater than 300,000 DNA copies/ml blood or 100 pp65-positive leukocytes in the relevant arm were reached.

Results

HCMV infection was detected in 81/99 (81.8%) patients in the DNAaemia arm and in 87/101 (86.1%) patients in the antigenaemia arm ( P=ns). Antiviral treatment was given to 23/99 (23.0%) patients in the DNAaemia arm and 42/101 (41.0%) patients in the antigenaemia arm ( P=0.01). In the DNAaemia arm, antiviral therapy was significantly delayed and duration of the first course of treatment was significantly greater than in the antigenaemia arm. However, total duration of treatment was comparable in the two arms. No case of HCMV disease occurred in patients treated after reaching the relevant cutoff. However, four patients (three in the antigenaemia arm, and one in the DNAaemia arm) suffered from HCMV disease prior to reaching the relevant cutoff.

Conclusions

Compared with antigenaemia, a single DNAaemia cutoff: (i) significantly reduces the number of patients requiring treatment; (ii) may be safely adopted to guide preemptive therapy of both primary and reactivated HCMV infections in SOTR; and (iii) does not significantly modify the overall duration of treatment.

A prospective study comparing quantitative Cytomegalovirus (CMV) polymerase chain reaction in plasma and pp65 antigenemia assay in monitoring patients after allogeneic stem cell transplantation

Background

Low levels of Cytomegalovirus (CMV) viral load are frequently detected following allogeneic stem cell transplantation (SCT) and CMV disease may still develop in some allogeneic SCT patients who have negative pp65-antigenemia (pp65-Ag) or undetectable DNA. Pp65Ag is a sensitive method to diagnose CMV infection. Quantitative CMV-DNA PCR assay in plasma has been proposed to monitor CMV infection in SCT patients. We evaluated the clinical utility of pp65Ag and PCR assay in plasma of SCT recipients.

Methods

In a prospective longitudinal study, 38 consecutive patients at risk of CMV infection (donor and/or recipient CMV seropositive) were weekly monitored for CMV infection by both quantitative CMV-PCR in plasma (COBAS AMPLICOR CMV MONITOR) and pp65 Ag, during the first 100 days after SCT.

Results

A total of 534 blood samples were simultaneously analysed for pp65Ag and PCR. Overall, 28/38 patients (74%) had active CMV infection within 100 days from SCT. In 16 patients, CMV was first detected by pp65 Ag alone; in 5 patients by both methods and in 6 by PCR assay alone; one patient had CMV biopsy-proven intestinal disease without pp65Ag and PCR assays positivity before CMV disease. Overall, three patients developed intestinal CMV disease (7.9%): one had negative both pp65Ag and PCR assays before CMV disease, one had disease and concomitant positivity of both methods, while in the remaining patient, only pp65Ag was positive before CMV disease.

Conclusion

Plasma PCR(COBAS AMPLICOR CMV MONITOR) and pp65Ag assays were effective in detecting CMV infection, however, discordance between both methods were frequently observed. Plasma PCR and pp65Ag assays may be complementary for diagnosis and management of CMV infection.

Novel real-time monitoring system for human cytomegalovirus-infected cells in vitro that uses a green fluorescent protein-PML-expressing cell line

Promyelocytic leukemia (PML) bodies are discrete nuclear foci that are intimately associated with many DNA viruses. In human cytomegalovirus (HCMV) infection, the IE1 (for "immediate-early 1") protein has a marked effect on PML bodies via de-SUMOylation of PML protein. Here, we report a novel real-time monitoring system for HCMV-infected cells using a newly established cell line (SE/15) that stably expresses green fluorescent protein (GFP)-PML protein. In SE/15 cells, HCMV infection causes specific and efficient dispersion of GFP-PML bodies in an IE1-dependent manner, allowing the infected cells to be monitored by fluorescence microscopy without immunostaining. Since a specific change in the detergent solubility of GFP-PML occurs upon infection, the infected cells can be quantified by GFP fluorescence measurement after extraction. With this assay, the inhibitory effects of heparin and neutralizing antibodies were determined in small-scale cultures, indicating its usefulness for screening inhibitory reagents for laboratory virus strains. Furthermore, we established a sensitive imaging assay by counting the number of nuclei containing dispersed GFP-PML, which is applicable for titration of slow-growing clinical isolates. In all strains tested, the virus titers estimated by the GFP-PML imaging assay were well correlated with the plaque-forming cell numbers determined in human embryonic lung cells. Coculture of SE/15 cells and HCMV-infected fibroblasts permitted a rapid and reliable method for estimating the 50% inhibitory concentration values of drugs for clinical isolates in susceptibility testing. Taken together, these results demonstrate the development of a rapid, sensitive, quantitative, and specific detection system for HCMV-infected cells involving a simple procedure that can be used for titration of low-titer clinical isolates.

Monitoring of human cytomegalovirus-specific CD4 and CD8 T-cell immunity in patients receiving solid organ transplantation

Absolute and human cytomegalovirus (HCMV)-specific CD4+ and CD8+ T-cell counts were monitored in 38 solid organ (20 heart, 9 lung and 9 kidney) transplant recipients during the first year after transplantation by a novel assay based on T-cell stimulation with HCMV-infected autologous dendritic cells. According to the pattern of T-cell restoration occurring either within the first month after transplantation or later, patients were classified as either early (n = 21) or late responders (n = 17). HCMV-specific CD4+ and CD8+ T-cell counts were consistently lower in late compared to early responders from baseline through 6 months after transplantation. In addition, in late responders, while HCMV infection preceded immune restoration, HCMV-specific CD4+ restoration was significantly delayed with respect to CD8+ T-cell restoration. The number of HCMV-specific CD4+ and CD8+ T-cells detected prior to transplantation significantly correlated with time to T-cell immunity restoration, in that higher HCMV-specific T-cell counts predicted earlier immune restoration. Clinically, the great majority of early responders (18/21, 85.7%) underwent self-resolving HCMV infections (p = 0.004), whereas the great majority of late responders (13/17, 76.5%) were affected by HCMV infections requiring antiviral treatment (p = <0.0001). Simultaneous monitoring of HCMV infection and HCMV-specific T-cell immunity predicts T-cell-mediated control of HCMV infection.

Comparison of two commercially available pp65 antigenemia tests and COBAS Amplicor CMV Monitor for early detection and quantification of episodes of human CMV-viremia in transplant recipients

The performance of two commercially available CMV pp65 antigenemia (AG) assays (CINA kit, Argene Biosoft, CK, and CMV Brite kit, IQ Products, CBK), and a quantitative PCR test (COBAS Amplicor CMV Monitor Test, Roche Diagnostics, CACM) was evaluated with 667 blood samples from 215 transplant recipients. The diagnostic value of the three tests was defined by their ability to detect episodes of systemic CMV activity. A test score was defined, assigning 7 virtual units (VU) for any episode detected first, 5 VU for any episode detected second, and three VU for any episode detected last. Within the evaluated collective, the following overall scores could be determined for the three assays: 45 VU for the CK, 39 for CACM and 31 for the CBK assay. We conclude from our results that (1) the CK is superior to the CBK assay in detecting episodes of CMV antigenemia, and (2) quantitative serum CMV PCR with CACM is not generally superior to pp65 antigenemia testing.

Impact of human metapneumovirus and human cytomegalovirus versus other respiratory viruses on the lower respiratory tract infections of lung transplant recipients

Viral respiratory tract infections in lung transplant recipients may be severe. During three consecutive winter‐spring seasons, 49 symptomatic lung transplant recipients with suspected respiratory viral infection, and 26 asymptomatic patients were investigated for presence of respiratory viruses either in 56 nasopharyngeal aspirate or 72 bronchoalveolar lavage samples taken at different times after transplantation. On the whole, 1 asymptomatic (3.4%) and 28 symptomatic (57.1%) patients were positive for human metapneumovirus (hMPV, 4 patients), influenza virus A (3 patients), and B (2 patients), respiratory syncytial virus (2 patients), human coronavirus (2 patients), human parainfluenza virus (2 patients), rhinovirus (5 patients), while 4 patients were coinfected by 2 respiratory viruses, and 5 were infected sequentially by 2 or more respiratory viruses. In bronchoalveolar lavage samples, hMPV predominated by far over the other viruses, being responsible for 60% of positive specimens, whereas other viruses were present in nasopharyngeal aspirates at a comparable rate. RT‐PCR (detecting 43 positive samples/128 examined) was largely superior to monoclonal antibodies (detecting 17 positive samples only). In addition, HCMV was detected in association with a respiratory virus in 4/18 HCMV‐positive patients, and was found at a high concentration (>10⁵ DNA copies/ml) in 3/16 (18.7%) patients with HCMV‐positive bronchoalveolar lavage samples and pneumonia. Coinfections and sequential infections by HCMV and respiratory viruses were significantly more frequent in patients with acute rejection and steroid treatment. In conclusion: (i) about 50% of respiratory tract infections of lung transplant recipients were associated with one or more respiratory viruses; (ii) hMPV largely predominates in bronchoalveolar lavage of symptomatic lung transplant recipients, thus suggesting a causative role in lower respiratory tract infections; (iii) RT‐PCR appears to be the method of choice for detection of respiratory viruses in lung transplant recipients, (iv) a high HCMV load in bronchoalveolar lavage is a risk factor for viral pneumonia, suggesting some measure of intervention for the control of viral infection. J. Med. Virol. 78:408–416, 2006. © 2006 Wiley‐Liss, Inc.

Prospective simultaneous quantification of human cytomegalovirus-specific CD4+ and CD8+ T-cell reconstitution in young recipients of allogeneic hematopoietic stem cell transplants

We investigated immune reconstitution against human cytomegalovirus (HCMV) in 57 hematopoietic stem cell transplant (HSCT) recipients, aged 1 to 24 years, through a novel method combining T-cell stimulation by HCMV-infected autologous dendritic cells with simultaneous cytometric quantification of HCMV-specific, IFNgamma-producing CD4(+) and CD8(+) T cells. Lymphoproliferative response (LPR) to HCMV antigens was also determined. Patients were stratified into 2 groups according to HCMV serostatus, comprising 39 HCMV-seropositive (R(+)) and 18 HCMV-seronegative (R(-)) patients who received a transplant from a sero-positive donor. Recovery of both HCMV-specific CD4(+) and CD8(+) T-cell immunity occurred in all 39 R(+) patients within 6 months and in 6 (33%) of 18 R(-) patients within 12 months. In R(+) patients, the median numbers of HCMV-specific CD8(+) and CD4(+)T cells were significantly higher than those of healthy controls, starting from days +60 and +180, respectively. In (R-) patients, the median numbers of HCMV-specific T cells were consistently lower than in R(+) patients. LPR was delayed compared with reconstitution of IFNgamma-producing T cells. Patients with delayed specific immune reconstitution experienced recurrent episodes of HCMV infection. HCMV seropositivity of young HSCT recipients is the major factor responsible for HCMV-specific immune reconstitution, irrespective of donor serostatus, and measurement of HCMV-specific T cells appears useful for correct management of HCMV infection.

Comparison of quantitative competitive polymerase chain reaction–enzyme-linked immunosorbent assay with LightCycler-based polymerase chain reaction for measuring cytomegalovirus DNA in patients after hematopoietic stem cell transplantation

Development of highly sensitive quantitative assays for cytomegalovirus (CMV) DNA detection is crucial for identification of immunodeficient patients at high risk of CMV disease. We designed 2 internally controlled competitive quantitative assays, enzyme-linked immunosorbent assay (ELISA)-based and real-time polymerase chain reaction (PCR) tests, using amplification of the same segment of the CMV genome. The aim of this study was to compare sensitivity, specificity, and laboratory performance characteristics of these assays. In both assays, a 159-bp segment of UL83 gene was amplified. External and internal controls were constructed by cloning the amplification product and heterogenous DNA segment flanked by target sequences for CMV-derived primers into bacterial plasmids, respectively. Real-time PCR was performed on LightCycler (Roche Diagnostics, Mannheim, Germany), and amplicons were detected using fluorescence resonance energy transfer probes. Alternatively, PCR products were labeled by digoxigenin, hybridized to immobilized probes, and detected by ELISA. The assays were tested on genomic DNA isolated from laboratory strains of CMV, QCMD control panel, and CMV DNA-positive peripheral blood DNA samples from hematopoietic stem cell transplant recipients, previously characterized by pp65 antigenemia and qualitative nested PCR. Real-time and ELISA-based PCR assays showed a linear course of 1-10(8) and 10-10(5) copies of CMV DNA per reaction, respectively. When compared with ELISA-based PCR, real-time PCR showed superiority in inter- and intra-assay reproducibility. Both assays were highly specific in detecting CMV DNA. No difference in amplification efficiency of internal or external standards and wild-type CMV DNA was found. The assays exhibited 83% concordance in CMV DNA detection from clinical samples, all discrepant samples having low CMV DNA copy numbers. There was a good correlation between viral DNA loads measured by the 2 assays. Statistically significant correlation was observed between the numbers of CMV DNA copies and pp65-positive leukocytes in the samples tested. Both variants of competitive PCR are adequately sensitive to be used for CMV DNA quantitation in clinical samples. LightCycler PCR, having superior performance characteristics and being less time-consuming, seems to be more suitable for routine diagnosis.

Cytomegalovirus infection after autologous stem cell transplantation: incidence and outcome in a group of patients undergoing a surveillance program

This study was performed to evaluate the incidence, risk factors, and outcome of cytomegalovirus (CMV) infection in autologous stem cell transplantation (ASCT), with the aim of performing preemptive therapy in patients with antigenemia. Starting from 2001, 171 consecutive ASCTs were performed in 136 patients; 102 of these patients were seropositive for CMV at the onset of hematological disease. In all these patients, a CMV pp65 antigenemia assay was determined weekly, starting from the day when the absolute neutrophil count went above 500/microL, and until day 60 after ASCT; subsequently, antigenemia was determined only when a CMV infection was suspected. Among the 136 transplanted patients, 40 (29.4%) presented a positive antigenemia; all of them were seropositive for CMV before ASCT; and no cases of primary infection were seen. The incidence of CMV infection in the seropositive population was 40/102 (39.3%); 6 patients (5 with multiple myeloma and 1 with non-Hodgkin's lymphoma) who received 2 ASCTs developed CMV infections after both transplantations, so that positive antigenemia developed after 46/171 (26.9%) transplantations. First positive antigenemia presented a median of 32 days (range 7-57) after stem cell reinfusion. The median antigenemia level at the first appearance was 2/200,000 (range 1-1000). No significant prognostic factors could be shown. Enteritis was present in 5 patients; 2 of them also had fever, and 1 of them also had thrombocytopenia. In 5 patients fever without any other clinical signs or symptoms was present; 30 patients were asymptomatic. Fourteen patients were treated with anti-CMV drugs. CMV reactivation was successfully treated in all patients, and no patient died from CMV disease.