Search

Objectives: Disseminated adenovirus (AdV) infections following allogeneic stem cell transplantation (allo-SCT) are increasingly recognised, particularly in children. This study evaluated the clinical relevance of disseminated AdV infections in adult allo-SCT recipients, after different conditioning regimens., Methods: In a cohort of 107 adult allo-SCT recipients, receiving either reduced intensity conditioning (RIC, n = 48) or myeloablative conditioning (MAC, n = 59), AdV DNA levels in plasma were determined retrospectively at 1, 3 and 6 months following transplantation. Results of this screening regimen were compared with a cohort of 58 paediatric allo-SCT recipients, in whom AdV DNA load was monitored prospectively, as part of a pre-emptive treatment strategy. In positive cases, the course of AdV DNA load and clinical outcome were assessed., Results: AdV DNA levels > or =1000 copies/mL were detected in five adults (4.7%) and eight children (13.8%). Screening for AdV viraemia at 1, 3 and 6 months would have detected seven of eight paediatric patients. One adult, receiving MAC, died with disseminated AdV disease and in four (three RIC and one MAC) AdV viraemia was transient without clinical symptoms specifically attributable to AdV. Seven paediatric patients with AdV viraemia were pre-emptively treated with ribavirin or cidofovir and in three of them disseminated AdV infection was related to a fatal outcome., Conclusions: Disseminated AdV infections following allo-SCT was a rare event in the adults and cause morbidity in a minority of these patients. In four of five adult patients, spontaneous clearance of AdV viraemia occurred. Results did not differ between the conditioning regimens that were applied in the adult cohort.

Adenoviruses have been recognized as important pathogens in immunocompromised hosts. Particularly in pediatric allogeneic stem cell transplant recipients, the morbidity of the patients and mortality in those patients with disseminated infections have been found to increase over the last few years. Severe infections are predominantly but not exclusively caused by subgroup C adenoviruses. A multiplex real-time PCR assay using molecular beacons as probes was developed to enable monitoring of adenovirus DNA in those patients with simultaneous identification of subgroups. An internal control was coamplified in the multiplex PCR to check for the DNA isolation procedure as well as the presence of inhibitors in the clinical samples. The assay has been applied retrospectively in patient groups with different clinical outcomes of infection. In fatal cases, significantly higher adenovirus loads developed, exceeding even 10(11) copies/ml of serum or plasma. Patients with viral loads over 10(6) copies/ml appear to have an increased risk for fatal complications. This quantitative real-time PCR assay has been prospectively used clinically since 2002 to study the course of adenovirus infection. In addition, the assay provides objective start and end points of therapeutic interventions, including the clinically important evaluation of antiviral drugs.

Laboratory diagnosis of viral respiratory infections is generally performed by virus isolation in cell culture and immunofluorescent assays. Reverse transcriptase PCR is now recognized as a sensitive and specific alternative for detection of respiratory RNA viruses. A rapid real-time multiplex PCR assay was developed for the detection of influenza A and influenza B viruses, human respiratory syncytial virus (RSV), parainfluenza virus 1 (PIV1), PIV2, PIV3, and PIV4 in a two-tube multiplex reaction which used molecular beacons to discriminate the pathogens. A total of 358 respiratory samples taken over a 1-year period were analyzed by the multiplex assay. The incidence of respiratory viruses detected in these samples was 67 of 358 (19%) and 87 of 358 (24%) by culture and real-time PCR, respectively. Culture detected 3 influenza A virus, 2 influenza B virus, 57 RSV, 2 PIV1, and 2 PIV3 infections. All of these culture-positive samples and an additional 5 influenza A virus, 6 RSV, 2 PIV1, 1 PIV2, 1 PIV3, and 3 PIV4 infections were detected by the multiplex real-time PCR. The application of real-time PCR to clinical samples increases the sensitivity for respiratory viral diagnosis. In addition, results can be obtained within 6 h, which increases clinical relevance. Therefore, use of this real-time PCR assay would improve patient management and infection control.

Successful preemptive cytomegalovirus (CMV) therapy in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infections. The pp65 antigenemia assay has been used for this purpose with considerable success. Quantification of CMV DNA is currently regarded to be an alternative diagnostic approach. The precise relationship between these two methods has still to be defined, but is essential to compare diagnostic results. This study compared the results of both assays with a large series of transplant recipients in different categories. An internally controlled quantitative real-time CMV DNA PCR was used to test 409 plasma samples from solid organ transplant (SOT) and stem cell transplant (SCT) patients. Levels of CMV DNA in plasma correlated well with classified outcomes of the pp65 antigenemia test. Despite this correlation, the quantitative CMV PCR values in a class of antigen test results were within a wide range, and the definition of an optimal cutoff value for initiating treatment required further analysis by a receiver-operating characteristic curve analysis. This is essential for reactivating infections in particular. For the SCT patients the optimal cutoff value of CMV DNA load defining relevant viral reactivation (in this assay, 10,000 copies/ml) was slightly higher than that for the SOT patients (6,300 copies/ml). Based on a comparison with the established pp65 antigenemia assay, quantification of CMV DNA in plasma appeared to be capable of guiding the clinical management of transplant recipients. This approach may have important advantages, which include a superior reproducibility and sensitivity, allowing the inclusion of kinetic criteria in clinical guidelines.

Background The relative incidence and clinical impact of individual respiratory viruses remains unclear among children presenting to the hospital emergency department with acute respiratory tract infection (ARTI). Methods During two winter periods, respiratory virus real-time multiplex PCR results were evaluated from children (< 18 years) presenting to the emergency department of a tertiary referral hospital with ARTI that had been sampled within 48 hours of hospital presentation. In an attempt to identify virus-specific distinguishing clinical features, single virus infections were correlated with presenting signs and symptoms, clinical findings and outcomes using multivariate logistic regression. Results In total, 274 children with ARTI were evaluated and most were aged < 3 years (236/274, 86%). PCR detected respiratory viruses in 224/274 (81.8%) children and included 162 (59%) single and 62 (23%) mixed virus infections. Respiratory syncytial virus (RSV) and human rhinovirus (HRV) single virus infections were common among children aged < 3 years, but proportional differences compared to older children were only significant for RSV (95% CI 1.3-15). Clinical differentiation between viral ARTIs was not possible due to common shared presenting signs and symptoms and the high frequency of mixed viral infections. We observed virus-associated outcome differences among children aged < 3 years. Oxygen treatment was associated with RSV (OR 3.6) and inversely correlated with FLU (OR 0.05). Treatment with steroids (OR 3.4) or bronchodilators (OR 3.4) was associated with HRV. Severe respiratory complications were associated with HRV (OR 3.5) and inversely correlated with RSV (OR 0.24). Conclusions Respiratory viruses are frequently detected in young children presenting to the hospital emergency department with ARTI and require PCR diagnosis since presenting signs and symptoms are not discriminant for a type of virus. RSV and HRV bear a high burden of morbidity in the pediatric clinical setting. [ABSTRACT FROM AUTHOR]

Reports on the cases of parainfluenza 4 virus (hPIV4) infections in infants detected by a multiplex real-time polymerase chain reaction (PRC) method. Medical history of the infants; Information on PCR method; Respiratory illnesses that are caused by hPIV4.