Distinguishing Cytomegalovirus (CMV) Infection and Disease with CMV Nucleic Acid Assays

Human cytomegalovirus (CMV) continues to be a significant cause of morbidity and mortality among transplant recipients. Molecular assays have been developed for the detection and quantification of CMV nucleic acid. In evaluating the clinical utility of these assays, correlations with clinical outcome are essential. The Amplicor CMV Monitor and NucliSens CMV pp67 tests were compared to the CMV antigenemia assay for 45 transplant recipients and 1 patient with Wegener's granulomatosis. Twenty-three patients remained antigenemia negative throughout the monitoring period, none of whom developed CMV disease. In this patient group, both the Amplicor and NucliSens assays showed very high specificity; only 1 of the 324 specimens assayed by NucliSens and none of the 303 specimens assayed by Amplicor were positive. Twenty-three patients were antigenemia positive during the monitoring period, 12 of whom developed 13 episodes of symptomatic CMV disease. In this patient group, the NucliSens assay was positive at or before the development of symptoms in 12 of the 13 episodes of CMV disease. All eight patients with symptomatic CMV disease who were tested by the Amplicor assay were positive at or before the development of disease. For the 11 asymptomatic patients, the NucliSens assay was positive less frequently than the antigenemia or Amplicor assays. The NucliSens assay was more likely to be positive at higher antigenemia or viral load levels. Both the NucliSens and Amplicor assays appear to have clinical utility in monitoring patients for CMV disease

Detection of Influenza Virus Infection Using Two PCR Methods

Rapid, accurate, and cost-effective methods to identify the cause of respiratory tract infections are needed to maximize clinical benefit. Outpatients with acute respiratory illness were tested for influenza using a singleplex reverse transcriptase polymerase chain reaction (SRT-PCR) method. A multiplex RT-PCR (MRT-PCR) method tested for influenza and 17 other viruses and was compared with SRT-PCR using chi-square tests. Among 935 patients, 335 (36%) tested positive for influenza A and influenza B using SRT-PCR. Using MRT-PCR, 320 (34.2%) tested positive for influenza A and influenza B. This study supports MRT-PCR as a comparable method for detecting influenza among patients seeking outpatient care for acute respiratory illnesses

Diagnosis of Human Metapneumovirus Infection in Immunosuppressed Lung Transplant Recipients and Children Evaluated for Pertussis

Human metapneumovirus (hMPV) is a recently discovered paramyxovirus that is known to cause respiratory tract infections in children and immunocompromised individuals. Given the difficulties of identifying hMPV by conventional culture, molecular techniques could improve the detection of this virus in clinical specimens. In this study, we developed a real-time reverse transcription-PCR (RT-PCR) assay designed to detect the four genetic lineages of hMPV. This assay and a commercial real-time nucleic acid sequence-based amplification (NASBA) assay (bioMérieux, Durham, NC) were used to determine the prevalence of hMPV in 114 immunosuppressed asymptomatic and symptomatic lung transplant recipients and 232 pediatric patients who were being evaluated for pertussis. hMPV was detected in 4.3% of the immunosuppressed lung transplant recipients and in 9.9% of children evaluated for pertussis. Both RT-PCR and NASBA assays were efficient in detection of hMPV infection in respiratory specimens. Even though hMPV was detected in a small number of the lung transplant recipients, it was still the most prevalent etiologic agent detected in patients with respiratory symptoms. In both of these diverse patient populations, hMPV infection was the most frequent viral respiratory tract infection identified. Given our findings, infection with hMPV infection should be determined as part of the differential diagnosis of respiratory illnesses

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

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