Evaluation of diagnostic methods for the detection of cytomegalovirus in recipients of allogeneic stem cell transplants

Rubella virus-associated uveitis at a tertiary care hospital in Germany between 2013 and 2019

Uveitis is a process of intraocular inflammation that may involve different sections of the uveal tract. Apart from systemic or localized immune-mediated diseases, infections are key players in the etiology of uveitis and entail different treatment strategies. Rubella virus (RuV) is a recognized causative agent for the development of Fuchs uveitis, representing a major cause of virus-associated intraocular inflammation. A cohort of 159 patients diagnosed with different forms of uveitis between 2013 and 2019 was subjected to diagnostic antibody testing of the aqueous or vitreous humor. The diagnostic panel included RuV, cytomegalovirus, herpes simplex virus, varicella-zoster virus, and toxoplasmosis. Within this cohort, 38 RuV-associated uveitis (RAU) patients were identified based on a pathologic Goldman-Witmer coefficient indicative of an underlying RuV infection. With a mean age of 45.9 years, the RAU patients were younger than the non-RAU patients (56.3, p < 0.001). The evaluation of clinical parameters revealed a predominance of anterior uveitis and late sequalae such as cataract and glaucoma among the RAU patients. In 15 of the patients a history of prior RuV infections could be confirmed. The study underlines the importance of long-term surveillance of RuV associated diseases that originate from infections before the introduction of RuV vaccination programs.

A New Gold Rush: A Review of Current and Developing Diagnostic Tools for Urinary Tract Infections

Urinary tract infections (UTIs) are one of the most common infections in the United States and consequently are responsible for significant healthcare expenditure. The standard urine culture is the current gold standard for diagnosing urinary tract infections, however there are limitations of the test that directly contribute to increased healthcare costs. As a result, new and innovative techniques have been developed to address the inefficiencies of the current standard-it remains to be seen whether these tests should be performed adjunctly to, or perhaps even replace the urine culture. This review aims to analyze the advantages and disadvantages of the newer and emerging diagnostic techniques such as PCR, expanded quantitative urine culture (EQUC), and next generation sequencing (NGS).

Sex-Differential Impact of Human Cytomegalovirus Infection on In Vitro Reactivity to Toll-Like Receptor 2, 4 and 7/8 Stimulation in Gambian Infants

Human cytomegalovirus (HCMV) infection rates approach 100% by the first year of life in low-income countries. It is not known if this drives changes to innate immunity in early life and thereby altered immune reactivity to infections and vaccines. Given the panoply of sex differences in immunity, it is feasible that any immunological effects of HCMV would differ in males and females. We analysed ex vivo innate cytokine responses to a panel of toll-like receptor (TLR) ligands in 108 nine-month-old Gambian males and females participating in a vaccine trial. We found evidence that HCMV suppressed reactivity to TLR2 and TLR7/8 stimulation in females but not males. This is likely to contribute to sex differences in responses to infections and vaccines in early life and has implications for the development of TLR ligands as vaccine adjuvants. Development of an effective HCMV vaccine would be able to circumvent some of these potentially negative effects of HCMV infection in childhood.

Limited Impact of Human Cytomegalovirus Infection in African Infants on Vaccine-Specific Responses Following Diphtheria-Tetanus-Pertussis and Measles Vaccination

Human cytomegalovirus (HCMV) infection has a profound effect on the human immune system, causing massive clonal expansion of CD8, and to a lesser extend CD4 T cells. The few human trials that have explored the effect of HCMV infection on responses to vaccination are conflicting, with some studies suggesting no effect whilst others suggest decreased or increased immune responses. Recent studies indicate substantial differences in overall immune system reactivity to vaccines based on age and sex, particularly cellular immunity. 225 nine-month old Gambian infants were immunized with diphtheria-tetanus-whole cell pertussis and/or measles vaccines. HCMV infection status was determined by the presence of CMV DNA by PCR of urine samples prior to vaccination. The effect of HCMV infection on either protective antibody immunity or vaccine-specific and overall cellular immune responses 4 weeks post-vaccination was determined, further stratified by sex. Tetanus toxoid-specific antibody responses were significantly lower in HCMV+ infants compared to their HCMV- counterparts, while pertussis, diphtheria and measles antibody responses were generally comparable between the groups. Responses to general T cell stimulation with anti-CD3/anti-CD28 as well as antigen-specific cytokine responses to purified protein derivative (PPD) were broadly suppressed in infants infected with HCMV but, perhaps surprisingly, there was only a minimal impact on antigen-specific cellular responses to vaccine antigens. There was evidence for subtle sex differences in the effects of HCMV infection, in keeping with the emerging evidence suggesting sex differences in homeostatic immunity and in responses to vaccines. This study reassuringly suggests that the high rates of HCMV infection in low income settings have little clinically significant impact on antibody and cellular responses to early life vaccines, while confirming the importance of sex stratification in such studies.

Multiplex PCR Based Urinary Tract Infection (UTI) Analysis Compared to Traditional Urine Culture in Identifying Significant Pathogens in Symptomatic Patients

OBJECTIVE

To evaluate whether multiplex PCR-based molecular testing is noninferior to urine culture for detection of bacterial infections in symptomatic patients.

METHODS

Retrospective record review of 582 consecutive elderly patients presenting with symptoms of lower urinary tract infection (UTI) was conducted. All patients had traditional urine cultures and PCR molecular testing run in parallel.

RESULTS

A total of 582 patients (mean age 77; range 60-95) with symptoms of lower UTI had both urine cultures and diagnostic PCR between March and July 2018. PCR detected uropathogens in 326 patients (56%, 326/582), while urine culture detected pathogens in 217 patients (37%, 217/582). PCR and culture agreed in 74% of cases (431/582): both were positive in 34% of cases (196/582) and both were negative in 40% of cases (235/582). However, PCR and culture disagreed in 26% of cases (151/582): PCR was positive while culture was negative in 22% of cases (130/582), and culture was positive while PCR was negative in 4% of cases (21/582). Polymicrobial infections were reported in 175 patients (30%, 175/582), with PCR reporting 166 and culture reporting 39. Further, polymicrobial infections were identified in 67 patients (12%, 67/582) in which culture results were negative. Agreement between PCR and urine culture for positive cultures was 90%, exceeding the noninferiority threshold of 85% (95% conflict of interest 85.7%-93.6%).

CONCLUSION

Multiplex PCR is noninferior to urine culture for detection and identification of bacteria. Further investigation may show that the accuracy and speed of PCR to diagnose UTI can significantly improve patient outcomes.

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.

Cytomegalovirus viral load kinetics in patients with HIV/AIDS admitted to a medical intensive care unit: a case for pre-emptive therapy

Background

Cytomegalovirus (CMV) infection is associated with severe diseases in immunosuppressed patients; however, there is a lack of data for pre-emptive therapy in patients with HIV/AIDS.

Method

This was a retrospective study, which enrolled patients diagnosed with HIV/AIDS (CD4<200 cells/μl), who had detectable CMV viral load (VL) during their stay in an adult medical intensive care unit between 2009–2012.

Results

After screening 82 patients’ records, 41 patients met the enrolment criteria. Their median age was 37 (interquartile range [IQR]: 31–46), and median CD4 count was 29 cells/μl (IQR: 5–55). Sixteen patients (39%) had serial measurements of CMV VL before treatment with ganciclovir. Patients whose baseline CMV VL values were between 1,000–3,000 copies/ml had significantly higher values (median of 14,650 copies/ml) on follow-up testing done 4–12 days later. Those with undetectable VLs at baseline testing had detectable VLs (median of 1,590 copies/ml) mostly within 20 days of follow-up testing. Patients who had VLs >1,000 copies/ml at baseline testing had significantly higher mortality compared to those who had <1,000 copies/ml {hazard ratio of 3.46, p = 0.003 [95% confidence interval (CI): 1.55–7.71]}. Analysis of the highest CMV VL per patient showed that patients who had VLs of >5,100 copies/ml and did not receive ganciclovir had 100% mortality compared to 58% mortality in those who received ganciclovir at VLs of >5,100 copies/ml, 50% mortality in those who were not treated and had low VLs of <5,100 copies/ml, and 44% mortality in those who had ganciclovir treatment at VLs of <5,100 copies/ml (p = 0.084, 0.046, 0.037, respectively).

Conclusion

This study showed a significantly increased mortality in patients with HIV/AIDS who had high CMV VLs, and suggests that a threshold value of 1,000 copies/ml may be appropriate for pre-emptive treatment in this group.

High prevalence of HCMV and viral load in tumor tissues and peripheral blood of glioblastoma multiforme patients

Glioblastoma multiforme is the most prevalent and malignant tumor of the central nervous system. In the last few years, accumulating evidence has suggested an association between human cytomegalovirus (HCMV) infection and glioblastoma multiforme. In this study, tumor tissues and peripheral blood of patients with glioblastoma multiforme were examined for the presence of HCMV DNA. Twenty-two fresh surgical brain specimens and 20 peripheral blood samples were analyzed by real-time PCR (qPCR) and hemi-nested PCR (nPCR) for the presence of pp65 and (glycoprotein B) gB viral genomic regions, respectively. HCMV DNA was detected in the majority of the tumor samples analyzed (95% by qPCR and 91% by nPCR). About half of the patients with tumors positive for HCMV also had detectable viral DNA in their peripheral blood (47% by qPCR and 61% by nPCR). Genome copy numbers were determined and in the majority of the tumor samples cellular DNA outnumbers viral DNA (average of 1 infected cell in 33 cells). The gB genotypes were determined in HCMV-positive samples and gB2 was the most prevalent genotype in the tumor and blood samples. The results show a high prevalence of HCMV in glioblastoma multiforme samples reinforcing a possible association between HCMV infection and tumor development.

Efficiency and risk factors for CMV transmission in seronegative hematopoietic stem cell recipients

Cytomegalovirus (CMV) transmission via stem cells or marrow in CMV donor seropositive/recipient seronegative (D+/R-) hematopoietic cell transplantation (HCT) is surprisingly inefficient, and factors associated with transmission in these high-risk HCT recipients are unknown. In a retrospective cohort of D+/R- HCT recipients, cumulative incidence curve estimates were used to determine posttransplantation rates of CMV and multivariable Cox proportional models to assess risk factors associated with transmission. A total of 447 patients from 1995 to 2007 were eligible for enrollment. Overall, 85 of 447 (19.0%) acquired CMV at a median of 49 days (IQR 41-60) posttransplantation. CMV disease before day 100 occurred in 6 of 447 (1.3%) patients and in 7 of 447 (1.6%) after day 100. The donor graft, specifically the total nucleated cell count (adjusted hazard ratio [HR] 2.7; 95% confidence interval [CI], 1.4-4.7, P = .0002), was the only factor associated with CMV transmission in multivariable analyses. Notably, the source stem cells (marrow versus peripheral blood stem cell [PBSC]), screening method, and graft-versus-host disease (GVHD) were not associated with transmission. Thus, a highly cellular graft was the only identifiable risk factor associated with CMV transmission, suggesting that viral genomic content of the donor graft determines transmission efficiency in D+/R- HCT recipients.

Virological and immunological correlates of mother-to-child transmission of cytomegalovirus in The Gambia

BACKGROUND

Cytomegalovirus (CMV) is the most common congenital infection and can follow primary and recurrent maternal infection. We studied correlates of vertical transmission of CMV in The Gambia, where most children acquire CMV during the first year of life.

METHODS

A cohort of 281 mothers and infants was recruited at birth. Infants were prospectively followed up for CMV infection during the first year of life. Excretion of CMV and antiviral immune response were studied at birth in mothers of children infected in utero, early during infancy, or late during infancy or not infected at 1 year of age.

RESULTS

Congenital infection was diagnosed in 3.9% of newborns, and 85% of children were infected by 1 year. Excretion of CMV in colostrum or in the genital tract was more common in mothers of congenitally (100%) or early infected children (48%) than in mothers of late-infected (20%) or uninfected children (27%). Higher rates of viral excretion were associated with significantly higher levels of serum anti-CMV immunoglobulin G and higher frequencies of CMV-specific CD4+ T cells.

CONCLUSION

In the context of recurrent maternal infection, transmission of CMV in utero and during early postnatal life is associated with excretion of the virus in colostrum and the genital tract.

Cytomegalovirus infection induces T-cell differentiation without impairing antigen-specific responses in Gambian infants

Cytomegalovirus (CMV) infection induces profound differentiation of T cells, and is associated with impaired responses to other immune challenges. We therefore considered whether CMV infection and the consequent T-cell differentiation in Gambian infants was associated with impaired specific responses to measles vaccination or polyclonal responses to the superantigen staphylococcal enterotoxin B (SEB). While the concentration of undifferentiated (CD27(+) CD28(+) CCR7(+)) T-cells in peripheral blood was unaffected by CMV, there was a large increase in differentiated (CD28(-) CD57(+)) CD8 T-cells and a smaller increase in differentiated CD4 cells. One week post-vaccination, the CD4 cell interferon-gamma (IFN-gamma) response to measles was lower among CMV-infected infants, but there were no other differences between the cytokine responses, or between the cytokine or proliferative responses 4 months post-vaccination. However, the CD8 T cells of CMV-infected infants proliferated more in response to SEB and the antibody response to measles correlated with the IFN-gamma response to CMV, indicating that CMV infection actually enhances some immune responses in infancy.

Sensitive detection of human cytomegalovirus in tumors and peripheral blood of patients diagnosed with glioblastoma

Human cytomegalovirus (HCMV) has been described to be associated with several human malignancies, though the frequency of detection remains controversial. It is unclear whether HCMV plays an active role in malignant tumor progression or becomes reactivated under pathologic conditions that result in chronic inflammation or immunosuppression. In this study, we report on the investigation of detecting HCMV in the tumors and peripheral blood of patients with newly diagnosed glioblastoma multiforme (GBM). Using immunohistochemistry, in situ hybridization, and polymerase chain reaction amplification of viral DNA, the detection of HCMV was investigated in tumor and blood specimens from patients with GBM as well as in the peripheral blood of normal volunteers and patients undergoing craniotomy for diagnoses other than GBM. We found that a high percentage (>90%) of GBM tumors, not surrounding normal brain, are associated with HCMV nucleic acids and proteins. Furthermore, a significant proportion of patients (80%) with newly diagnosed GBM have detectable HCMV DNA in their peripheral blood, while sero-positive normal donors and other surgical patients did not exhibit detectable virus, suggesting either a systemic reactivation of HCMV within patients with GBM or shedding of viral DNA from infected tumor cells into the periphery. These results confirm the association of HCMV with malignant gliomas and demonstrate that subclinical HCMV viremia (presence of viral DNA in blood without clinical symptoms of infection) is a previously unrecognized disease spectrum in patients with GBM.

Cytomegalovirus infection in severe ulcerative colitis patients undergoing continuous intravenous cyclosporine treatment in Japan

AIM: To investigate active cytomegalovirus (CMV) infection following the cyclosporine A (CyA) treatment of steroid-refractory ulcerative colitis (UC).

METHODS: Twenty-three patients with severe UC not responding to steroid therapy (male 14, and female 9) enrolled at Nagoya University Hospital from 1999 to 2005. They received continuous intravenous infusion of CyA (average 4 mg/kg per day) for 1 mo. Serum and colonic biopsy samples were collected before CyA treatment and 4 d, 10 d, 20 d, and 30 d after treatment. Patients were evaluated for CMV by using serology (IgM antibody by ELISA), quantitative real-time PCR for CMV DNA, and histopathological assessment of hematoxylin and eosin (HE)-stained colonic biopsies. CMV infection was indicated by positive results in any test.

RESULTS: No patients had active CMV infection before CyA treatment. Eighteen of 23 UC patients treated with CyA were infected with active CMV (IgM antibody in 16/23 patients, 69.6%; CMV DNA in 18/23 patients, 78.2%; and inclusion bodies in 4/23 patients, 17.3%). There was no difference in the active CMV-infection rate between males and females. Active CMV infection was observed after approximately 8 d of CyA treatment, leading to an exacerbation of colitis. Fifteen of these 18 patients with active CMV infection (83.3%) required surgical treatment because of severe deteriorating colitis. Treatment with ganciclovir rendered surgery avoidable in three patients.

CONCLUSION: Our results suggest that active CMV infection in severe UC patients treated with CyA is associated with poor outcome. Further, ganciclovir is useful for treatment of CMV-associated UC after immuno-suppressive therapy.

Cytomegalovirus and burns: current perceptions, awareness, diagnosis, and management strategies in the United States and Germany

Trauma and immunosuppressed patients are at risk for cytomegalovirus (CMV) disease. Attributing pathogenicity in burn patients remains difficult and controversial because data are sparse. In this work, we surveyed U.S. and German burn centers and evaluated them for awareness, perceptions, diagnosis, and treatment of CMV in patients with burn injury. A total of 58% German (G) and 21% U.S. centers responded. CMV infection incidence was 1:280 G and 1:870 U.S. A total of 41% G and 78% U.S. burn centers considered CMV to be of minor importance and 41% G and 13% U.S. centers considered CMV to be of significant importance. A total of 70% G and 97% U.S. centers performed no admission screening. When testing, 70% G and 19% U.S. centers used serology; 52% G and 25% U.S. centers used body fluid viral isolation; and 43% G and 6% U.S. centers used leukocyte CMV-DNA analysis. A total of 72% G and 48% U.S. centers distinguished infection from disease. Human CMV disease was diagnosed by CMV-DNA (82% G, 19% U.S.), direct virus isolation (43% G, 13% U.S.), or RNA detection (26% G, 0% U.S.). A total of 43% G and 19% U.S. would treat the established disease. Establishing consistent guidelines for screening, diagnosis, and treatment seems prudent in caring for the immunocompromised burn patient.

Evaluation of the COBAS Amplicor HCMV Monitor for early detection and monitoring of human cytomegalovirus infection after allogeneic stem cell transplantation

Early diagnosis of human cytomegalovirus (HCMV) infection and the introduction of preemptive antiviral therapy have reduced HCMV-related mortality after allogeneic stem cell transplantation. A critical goal remains stratifying risk profiles and minimizing potential harm owing to antiviral overtreatment. We compared the commercially available standardized COBAS Amplicor CMV Monitor (CACM) to an in-house PCR assay, for the monitoring of HCMV infection. Seventy-two patients were surveyed by an in-house PCR of whole blood, quantitative viral load assessment by CACM and virus culture assays in a prospective and a retrospective study. A high concordance between CACM and PCR was documented. The viral load at onset correlated with the peak viral load (Spearman rank correlation R=0.634, P=0.0004). In patients developing HCMV disease, both viral loads were in trend higher (P=0.823, respectively P=0.053), and the viremic episodes longer (P=0.015), as compared to asymptomatically HCMV-infected patients. The serological pre-transplant status was the major risk factor for the development of HCMV disease, showing highest risk for seropositive patients receiving a seronegative graft, whereas donor type (related or unrelated) and graft type (bone marrow or peripheral blood mobilized stem cells) did not have an influence. HCMV infection proved to be a risk factor for the development of non-viral opportunistic infections (P=0.002).

Evaluation of pulmonary infiltrates in patients after stem cell transplantation

Hematopoietic stem cell transplantation is potentially curative therapy that has become the standard of care for many hematologic malignancies. Pulmonary complications occur in about 50% of stem cell transplant recipients and no other organ dysfunction has a higher mortality. Unfortunately the diagnosis of these infiltrates is hampered by the poor yield from routine studies and this patient population is rarely able to tolerate more risky procedures that will obtain tissue for microscopy and culture. A bronchoalveolar lavage (BAL) is usually insufficient to make a diagnosis of invasive fungal, significant bacterial, or pathogenic viral infections in patients that will still benefit from a change in therapy. In this review we discuss the infectious etiologies of pulmonary infiltrates post hematopoietic stem cell transplant, the non-infectious causes of infiltrates such as diffuse alveolar hemorrhage, engraftment syndrome, and idiopathic pneumonia syndrome, and the yield of newer diagnostic procedures ranging from peripheral blood galactomannan to cytomegalovirus antigenemia, and report on new technologies that promise more accurate and timely diagnoses of these infiltrates.

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.

Cytomegalovirus infection in burns: a review

Sepsis is responsible for significant morbidity and mortality in patients suffering from severe burn injuries. Burn patients are known to be immunocompromised, and it is generally accepted that the immunosuppressed patient may experience human cytomegalovirus (HCMV) infection and disease. Review of the very limited available literature identifies a seroconversion rate of between 18 and 22% for burn patients who were seronegative for HCMV prior to suffering their burn injury. Furthermore, approximately 50% of HCMV antibody-positive patients may reactivate. Blood products and allografted skin have clinically been identified as possible sources of HCMV transmission in burn patients. Experience in the treatment of infection or disease in burn patients is very scarce and limited to immunoglobulin therapy. Animal experiments have demonstrated that murine cytomegalovirus (MCMV)-seropositive skin grafts are able to infect immunodeficient mice as well as burned mice. Murine studies have also demonstrated that infection with MCMV enhances susceptibility to secondary bacterial infection and increases mortality in these animals. Burned mice challenged with MCMV have a significantly higher level of bacterial translocation to mesenteric lymph nodes than either control thermally injured mice without MCMV inoculation or non-burned mice injected with MCMV alone. In summary, it remains controversial whether HCMV infection per se alters outcome for the majority of burn patients. Subgroups of severely burned, seronegative patients may benefit from blood products and skin from seronegative donors. Antiviral strategies are not yet evaluated for the burn patient. Further investigations utilizing modern diagnostic techniques seem necessary.

Comparison of a duplex quantitative real-time PCR assay and the COBAS Amplicor CMV Monitor test for detection of cytomegalovirus

A duplex quantitative real-time PCR (qPCR) assay was designed to detect both the polymerase gene (pol) and the glycoprotein gene (gB) of cytomegalovirus (CMV). The detection limit of the qPCR was determined to be 1 to 3 copies/reaction and the linear measure interval was 10(3) to 10(8) copies/ml. The qPCR system was compared to the COBAS Amplicor CMV Monitor test (COBAS) by an analysis of 138 plasma samples. Both systems detected CMV in 71 cases and had negative results for 33 samples. In addition, 34 samples were positive by qPCR and negative by the COBAS assay, but in no case was the COBAS result positive and the qPCR result negative. Thus, qPCR detected 48% more positive cases than the COBAS method. For samples with > or = 10(5) copies/ml by qPCR, a saturation effect was seen in the COBAS assay and quantification required dilution. Copy numbers for pol and gB by qPCR generally agreed. However, the reproducibility of qPCR assays and the need for an international standard are discussed. Discrepant copy numbers for pol and gB by qPCR were found for samples from two patients, and sequence analysis revealed that the corresponding CMV strains were mismatched at four nucleotide positions compared with the gB fragment primer sequences. In conclusion, a duplex qPCR assay in a real-time format facilitates quantitative measurements and minimizes the risk of false-negative results.

Comparison of DNA amplification, mRNA amplification, and DNA hybridization techniques for detection of cytomegalovirus in bone marrow transplant recipients

A total of 676 specimens from 63 recipients of bone marrow allografts were tested for cytomegalovirus (CMV) by the following assays: CMV pp67 NucliSens (NS), AMPLICOR CMV MONITOR (RA), and the Digene CMV DNA test (DG). In a consensus analysis, the sensitivities and specificities were 60 and 99% (NS), 96 and 98% (RA), and 90 and 76% (DG), respectively; for detection of symptomatic CMV infection, they were 60 and 97% (NS), 65 and 97% (RA), and 95 and 77% (DG), respectively. In multivariate analysis, the major risk factor for symptomatic CMV infection was an increase in the viral load in the DG assay; in univariate analyses, maximum viral loads in both DG and RA assays and a rising viral load in the RA assay were also significant. The earliest detection of CMV replication was provided by the RA assay (mean, 39 days posttransplantation), followed by the DG assay (mean, 48 days) and the NS assay (mean, 58 days).

Prevention of cytomegalovirus disease in recipients of allogeneic stem cell transplants

The main risk factors for cytomegalovirus (CMV) disease in recipients of allogeneic stem cell transplants (SCT) are recipient CMV seropositivity and acute graft-versus-host disease. Currently, two antiviral strategies, prophylactic or preemptive antiviral treatment, are used for prevention of CMV disease. Preemptive treatment is most favorable when short-term (14-day) treatment is applied. Several methods are available for monitoring of CMV reactivation. PCR-based CMV DNA detection assays are the most sensitive methods; however, the clinical benefit of this high sensitivity is unclear. Even more, there is lack of clarity whether PCR tests can better be performed with plasma, whole blood, or peripheral blood leukocyte samples. Recovery of a CMV-specific CD8(+) cytotoxic-T-lymphocyte (CTL) response is necessary for preventing CMV reactivation and disease. Reconstitution of absolute CMV-specific CTL counts to values above 10 x 10(6) to 20 x 10(6) CTLs/liter is associated with protection from CMV disease. In the near future, preemptive therapy might be withheld in patients with CMV reactivation who are shown to have adequate CMV-specific cytotoxic T-cell levels. Antiviral therapy with (val)acyclovir has been studied only as prophylactic treatment for prevention of CMV infection. High-dose oral valacyclovir is more effective than acyclovir when used in addition to preemptive treatment of CMV reactivation with ganciclovir or foscarnet. Three antiviral drugs have been tested for preemptive therapy of CMV reactivation and/or treatment of CMV disease. Although intravenous ganciclovir is considered the drug of choice, foscarnet has similar efficacy and less toxicity, especially hematologic toxicity. Cidofovir has not been tested extensively, but so far the results are disappointing. Oral valganciclovir for preemptive treatment of SCT recipients is currently being studied. In addition to antiviral therapy, adoptive immunotherapy with CMV-specific cytotoxic T cells as prophylactic or preemptive therapy is a very elegant strategy; however, generation of these cells is expensive and time-consuming, and therefore the therapy is not available at every transplantation center. Magnetic selection of CMV-specific CD8(+) T cells from peripheral blood by using HLA class I-peptide tetramers may be very promising, making this strategy more accessible.

Mature CD8(+) T lymphocyte response to viral infection during fetal life

Immunization of newborns against viral infections may be hampered by ineffective CD8(+) T cell responses. To characterize the function of CD8(+) T lymphocytes in early life, we studied newborns with congenital human cytomegalovirus (HCMV) infection. We demonstrate that HCMV infection in utero leads to the expansion and the differentiation of mature HCMV-specific CD8(+) T cells, which have similar characteristics to those detected in adults. High frequencies of HCMV-specific CD8(+) T cells were detected by ex vivo tetramer staining as early as after 28 weeks of gestation. During the acute phase of infection, these cells had an early differentiation phenotype (CD28(-)CD27(+)CD45RO(+), perforin(low)), and they acquired a late differentiation phenotype (CD28(-)CD27(-)CD45RA(+), perforin(high)) during the course of the infection. The differentiated cells showed potent perforin-dependent cytolytic activity and produced antiviral cytokines. The finding of a mature and functional CD8(+) T cell response to HCMV suggests that the machinery required to prime such responses is in place during fetal life and could be used to immunize newborns against viral pathogens.

Mature CD8(+) T lymphocyte response to viral infection during fetal life

Immunization of newborns against viral infections may be hampered by ineffective CD8(+) T cell responses. To characterize the function of CD8(+) T lymphocytes in early life, we studied newborns with congenital human cytomegalovirus (HCMV) infection. We demonstrate that HCMV infection in utero leads to the expansion and the differentiation of mature HCMV-specific CD8(+) T cells, which have similar characteristics to those detected in adults. High frequencies of HCMV-specific CD8(+) T cells were detected by ex vivo tetramer staining as early as after 28 weeks of gestation. During the acute phase of infection, these cells had an early differentiation phenotype (CD28(-)CD27(+)CD45RO(+), perforin(low)), and they acquired a late differentiation phenotype (CD28(-)CD27(-)CD45RA(+), perforin(high)) during the course of the infection. The differentiated cells showed potent perforin-dependent cytolytic activity and produced antiviral cytokines. The finding of a mature and functional CD8(+) T cell response to HCMV suggests that the machinery required to prime such responses is in place during fetal life and could be used to immunize newborns against viral pathogens.

Development and clinical application of a fully controlled quantitative PCR assay for cell-free cytomegalovirus in human plasma

BACKGROUND

Cytomegalovirus (HCMV) disease continues to be a major problem in certain patient groups, including bone marrow transplant (BMT) recipients. The quantification of HCMV genome is clinically useful for the diagnosis of HCMV disease, for the virological surveillance of high-risk patients and for monitoring antiviral therapy.

OBJECTIVES

To develop a novel, robust, and fully controlled PCR (qPCR) for the quantification of HCMV DNA in plasma samples and to demonstrate its clinical usefulness in the BMT setting.

STUDY DESIGN

The newly developed HCMV qPCR employs cell culture-derived murine CMV as an internal control for both extraction and amplification. Following amplification using common primers, detection of both internal control and patient HCMV amplicons is by specific probes and a chemiluminescence microtitre plate system. Its performance was evaluated using the routine non-quantitative nested HCMV PCR on whole blood (NQPCR) and correlated with clinical events such as disease and antiviral therapy.

RESULTS

A high level of concordance (85.1%) was found between the novel assay and the NQPCR, with the qPCR being slightly more sensitive. The samples giving discordant results generally had levels of HCMV DNA close to the limit of detectability or had been stored for prolonged periods.

CONCLUSIONS

The use of plasma as an analyte by the newly developed assay avoids the detection of cell-associated virus. On the other hand, testing a comparatively large volume of plasma ensures that sensitivity is not compromised by not detecting cell-associated HCMV. In a small preliminary evaluation in BMT recipients, changes in HCMV 'viral load' correlated with initiation and discontinuation of antiviral therapy and were biologically plausible.

Evaluation of the NucliSens CMV pp67 assay for detection and monitoring of human cytomegalovirus infection after allogeneic stem cell transplantation

Preemptive treatment based on the sensitive detection of CMV-DNA has helped to reduce HCMV-related mortality after allogeneic stem cell transplantation (SCT). Detection of active viral replication might help to better predict HCMV disease. In this study, 33 recipients at risk for HCMV infection after allogeneic SCT were prospectively monitored 1x/week for active HCMV infection by NASBA, whole blood DNA-PCR and virus culture assays. Preemptive antiviral therapy was initiated after the second positive PCR result, while NASBA results were not considered for clinical decision-making. Overall, a high agreement between PCR and NASBA on a per sample (85.3%) and per patient (87.9%) level was demonstrated. HCMV DNA titers in the blood were found to be higher in PCR(+)/NASBA(+) compared to PCR(+)/NASBA(-) samples (P < 0.01). None of the NASBA-negative patients developed HCMV disease. Sixteen of 18 patients receiving PCR-based preemptive therapy were also found NASBA positive. There was no difference between the assays for the time to the first positive test result. However, the time to the first negative test result upon initiation of antiviral therapy was significantly shorter for the NASBA assay (P = 0.002), indicating a high positive predictive value to assess the efficacy of antiviral therapy. Three patients developed late-onset HCMV disease, all of whom were found to be PCR and NASBA positive. In conclusion, the data presented clearly demonstrate the value of patient monitoring using the NASBA assay to early diagnose active HCMV infection and to assess the efficacy of antiviral therapy in high risk patients after allogeneic SCT. A prospective comparison of PCR-based vs NASBA-based preemptive therapy is ongoing.

Monitoring of viral load by quantitative plasma PCR during active cytomegalovirus infection of individual liver transplant patients

A quantitative PCR test, the Cobas Amplicor CMV Monitor, was used for the monitoring of viral load in the peripheral blood of 27 individual liver transplant patients and correlated with cytomegalovirus (CMV) pp65 antigenemia. Altogether, 243 specimens were analyzed. During the first 3 months, 20 patients showed PCR positivity which correlated with pp65 antigenemia. Of those, 13 patients developed symptomatic CMV infection 27 to 52 days after transplantation, with a significantly higher peak viral load in PCR and in pp65 assay compared with the seven asymptomatic infections (median 10,200 versus 2,240 copies/ml, P < 0.05, and median 100 versus 30 pp65-positive cells/50,000 leukocytes, P < 0.01). Five were primary infections of D+/R- cases (donor CMV seropositive and recipient seronegative) and demonstrated, except in one case, a high peak viral load (>10,000 copies/ml; range, 10,200 to 21,600 copies, and > or =50 positive cells, range, 50 to 800 cells). The peak viral loads of the six D+/R+ patients with symptomatic infection varied widely (range, 2,290 to 126,000 copies and 50 to 300 positive cells). Two D-/R+ patients developed symptomatic infection with a lower viral load (range, 1,120 to 6,510 copies and 25 to 100 positive cells). All symptomatic infections were successfully treated with ganciclovir. The asymptomatic infections all in D+/R+ patients with low copy numbers (<5,500 copies) were monitored until CMV disappeared. One of the seven PCR-negative patients had one sample with low antigenemia, but the subsequent specimens were all negative. The time-related correlation of the two methods was also good. In summary, quantitative PCR could equally well be used as the CMV pp65 assay for the monitoring of viral load in individual transplant patients.

Patients with HIV infection and fever: a diagnostic approach

Fever is a common sign among patients with HIV infection and frequently leads to a medical consultation. It is generally caused by infections. The type of infection depends on the stage of the disease. Opportunistic infections occur only in the presence of severe immunodeficiency. A systematic approach will identify most causes of fever. Since the incidence of opportunistic infections has dramatically decreased with the use of highly active antiretroviral treatments, other causes of fever including immune restoration disease, neoplasm and drug-fever should be considered.

Multiplex, quantitative, real-time PCR assay for cytomegalovirus and human DNA

We created a multiplex, quantitative, real-time PCR assay that amplifies cytomegalovirus (CMV) and human DNA in the same reaction tube, allowing for a viral load determination that is normalized to measured human DNA. The assay targets a conserved region of the CMV DNA polymerase gene that is not affected by known drug resistance mutations. All 36 strains of CMV detected by culture or qualitative PCR in a population of lung transplant recipients were detected. The assay detected 1 to 10 copies of CMV plasmid DNA. The analytic sensitivity was not affected by the presence of DNA from 10(6) human cells but was reduced approximately 10-fold by alkaline lysates of leukocyte preparations. CMV quantitation was linear over a range of 10(1) to 10(6) copies. The intraassay and interassay coefficients of variation were 29 and 40%. Human DNA was regularly detected in patient plasma samples, and the amount was increased by storage of blood at room temperature before plasma separation and by plasma separation techniques that allowed leukocyte contamination. Applied to whole blood, the assay provides a measurement of CMV DNA in relation to cellular content without a need for cell counting procedures. Applied to plasma, the assay can reveal artifactual increases in plasma CMV levels resulting from leukocyte contamination. Further study of the utility of this assay to monitor patient populations at risk for CMV disease is warranted.

Dose-adjusted preemptive therapy for cytomegalovirus disease based on real-time polymerase chain reaction after allogeneic hematopoietic stem cell transplantation

We have prospectively evaluated the efficacy of real-time PCR-guided preemptive therapy for CMV diseases in allogeneic hematopoietic stem cell transplant recipients with grades II-IV acute GVHD. The dose of ganciclovir was adjusted according to the viral load determined by real-time polymerase chain reaction (PCR). On detecting CMV reactivation in the plasma, ganciclovir was initiated at a dose of 5 mg/kg body weight once daily, and the dose was increased to twice daily if viral load continued to increase after initiating ganciclovir. In 39 evaluable patients, CMV reactivation assessed by real-time PCR became positive in 30 (77%). One developed CMV gastroenteritis before PCR became positive. Thus the remaining 29 patients were treated preemptively with ganciclovir. The dose of ganciclovir was increased in 12 patients (41%) of preemptively treated patients for increasing viral load. CMV diseases were diagnosed in two patients (one gastroenteritis and one retinitis), and late CMV disease was diagnosed in one patient (gastritis). The treatment was generally well-tolerated, but three patients (10%) developed neutropenia (neutrophil count less than 1.0 x 10(9)/l). In conclusion, real-time PCR-guided preemptive therapy with decreased dose of ganciclovir is feasible and does not increase the frequency of CMV diseases if the dose is adjusted according to the viral load.

Development and evaluation of an internally controlled semiautomated PCR assay for quantification of cell-free cytomegalovirus

Quantification of circulating human cytomegalovirus (HCMV) is useful in clinical contexts such as virological surveillance of bone marrow transplant recipients and monitoring of antiviral therapy. This report describes an internally controlled, quantitative, semiautomated, HCMV genome assay that was developed primarily to measure HCMV DNA in the plasma of severely leucopaenic patients. It exhibits greater sensitivity, wider dynamic range and higher sample throughput than a number of previously described commercial and "in-house" assays. Viral DNA extraction from EDTA plasma samples was automated using a BioRobot 9604 (Qiagen). HCMV strain AD169 was used to prepare a calibration curve and murine cytomegalovirus (MCMV) strain Smith was added as internal control to all calibration standards and test samples. Amplification was performed using a set of primers based on the HCMV UL50 region, capable of amplifying both human and murine CMV. The yield of biotinylated polymerase chain reaction (PCR) products was estimated using HCMV-specific and MCMV-specific enzyme-labelled probes and automated chemiluminescence detection. Log-transformed HCMV-to-MCMV signal ratios were calculated and used for quantification of test samples against simultaneously extracted MCMV-spiked calibration standards. Evaluation of the assay sensitivity by Probit analysis demonstrated a 95% probability of detection at 100 HCMV genomes per ml of plasma; the dynamic range was shown to be > or = 4 log(10). A total of 315 samples from 61 bone marrow transplant patients were analysed by both the quantitative PCR (qPCR) and by a previously validated nested nonquantitative PCR (NQPCR). A high level of concordance (90%) was observed between the two assays, although the qPCR assay exhibited slightly greater sensitivity.

Performance characteristics of an automated PCR assay for the quantification of cytomegalovirus DNA in plasma

The COBAS Amplicor CMV Monitor test (Roche Diagnostics), an automated polymerase chain reaction (PCR) assay for the quantification of cytomegalovirus (CMV) DNA in plasma samples, was evaluated in a routine diagnostic laboratory. Using cell culture-derived CMV and CMV-negative human plasma, the linear detection range of the assay as well as its intra-and inter-assay variabilities were assessed. The study design allowed distinguishing variations in results related to amplification and detection from those caused by differences in the efficiency of DNA extraction. The assay was able to identify the majority of samples correctly as positive with CMV DNA concentrations above the limit of detection. However, the reported values were often twofold or more different from the (theoretical) input, which could be explained partly by inefficient DNA extraction. The following values were computed for the coefficients of determination R(2): inter-assay variability excluding DNA extraction, R(2)=0.982; including DNA extraction, R(2)=0.977; intra-assay variability excluding DNA extraction, R(2)=0.992; including DNA extraction, R(2)=0.992. On balance, the test has acceptable within-run and between-run reproducibility. It therefore allows the comparison of results obtained at different time-points as well as in different laboratories, e.g. in multi-centre studies.

Qualitative plasma PCR assay (AMPLICOR CMV test) versus pp65 antigenemia assay for monitoring cytomegalovirus viremia and guiding preemptive ganciclovir therapy in allogeneic stem cell transplantation

The performances of a commercially available qualitative plasma PCR assay (AMPLICOR CMV test; Roche Diagnostics) and the pp65 antigenemia assay (AG) were evaluated for the monitoring of cytomegalovirus (CMV) viremia in 43 allogeneic stem cell transplant recipients. In addition, the suitabilities of both assays for triggering the initiation of preemptive ganciclovir therapy were assessed. A total of 37 CMV viremic episodes were detected in 28 patients. Positivity of plasma PCR testing in one or more consecutive specimens was the only marker of CMV viremia in 18 of the 37 episodes (PCR positive and AG negative, n = 50 specimens). Five episodes were diagnosed on the basis of a single positive AG result (AG positive and PCR negative, n = 5 specimens); both assays were eventually positive (PCR positive and AG positive, n = 27 specimens) for 14 viremic episodes; for these episodes, conversion of the PCR assay result to a positive result occurred an average of 1 week before conversion of the AG result. Overall, the concordance between the two methods was 90%, and the sensitivities of the plasma PCR assay and AG for the detection of CMV viremic episodes were 86.5 and 51.3%, respectively. Two patients who tested positive by both assays simultaneously progressed to CMV end-stage organ disease, despite the initiation of preemptive ganciclovir therapy. Conversion of the AG result to a negative result upon administration of preemptive ganciclovir therapy occurred a median of 7.5 days earlier than conversion of the plasma PCR assay result. Nineteen of the 28 patients with CMV viremia received AG-guided preemptive ganciclovir therapy; had the positivity of the plasma PCR assay triggered the initiation of preemptive therapy, 9 additional patients would have been unnecessarily treated since none of them developed CMV end-stage organ disease. Although the AMPLICOR CMV assay is more sensitive than AG, the latter appears to be more suitable both for guiding the initiation of preemptive therapy and for monitoring a patient's response to antiviral therapy.