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  • 1
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 3044-3044
    Abstract: Abstract 3044 Human herpesviruses may cause severe complications after Hematopoietic Stem Cell Transplantation (HSCT) as interstitial pneumonia, encephalitis and post-transplantation lymphoproliferative disease (PTLD). Monitoring these viruses and providing precise, rapid and early diagnosis of related clinical diseases constitute an essential measure to improve outcomes. A prospective survey on the incidence and clinical features of herpesvirus infections after HSCT has not yet been performed in Brazilian patients. Additionally, the impact of most of these infections on the HSCT outcome is still unclear. We sought to develop a test based on real-time polymerase chain reaction (qPCR) to screen and quantify all known human herpesviruses (CMV, EBV, HSV1, HSV2, VZV, HHV6, HHV7 and HHV8) in plasma samples from patients submitted to HSCT. DNA purification from plasma samples has been performed with the QIAamp DNA Blood Mini Kit (manually) or with the QIAamp DNA Blood Mini QIAcube Kit and the QIAcube robot (Qiagen). At least two sets of primers previously described have been tested for each virus for the approach using SYBR Green in order to select for the sets with best efficiency and sensitivity. The sets of primers and TaqMan® probes for the hydrolysis approach have also been previously described. Lambda phage and a commercial internal positive control (IPC, Life Technologies) have been tested as internal controls. The viruses probes were labeled with FAM, while the IPC probe was labeled with VIC. All qPCR reactions have been performed in a 7900HT (Life Technologies). Infected cell cultures and plasma specimens with a known viral load/amplicon copy number have been used as controls. By august 2012, 824 whole blood and plasma were collected from 91 patients. Initially, we tested a screening approach based on three sets of triplex qPCR reactions (including the internal control) using SYBR Green and melting analysis. Although the test showed good linearity across 6 to 7 orders of magnitude in the log scale for most of the targets, the discrimination was poor for low-copy samples (≤ 103 copies of the target/ reaction) or complex samples (positive for more than one virus). We then chose to optimize a strategy based on the use of hydrolysis probes, the gold standard in molecular pathology. Except for EBV, which has been amplified and detected in a duplex reaction along with the IPC, the other amplicons have been screened and quantified in singleplex reactions. All targets presented efficiencies between 90–100% and linearity ranging from at least 25 to 108 copies per reaction. For most of the viruses the lower limit of detection (LOD) is around 5 copies of target per reaction, representing 250 copies/mL of plasma; HHV6 and VZV detection, with sensitivity around 25 copies per reaction, is under further optimization. No cross-reaction or false positive results were detected and within-run and between-run precision estimates are equal or higher than 95%. A semi-automated workflow, using the QIAcube robot for DNA extraction and the QIAgility for reaction setup is under validation. Accuracy will be assigned by testing commercial controls (Acrometrix® plasma panels and controls). Based on the precision of the test, we predict that it will be possible to use this new test to screen batches of 10 samples in 96-well plates or 46 samples in 384-well plates in singlicates for the eight known herpesviruses with high sensitivity and specificity. Only selected samples will then be submitted to fine quantification in a second round of qPCR reactions including the appropriate standard curve(s). This strategy allows for a fast and comprehensive detection and of the known hepersviruses in post-HSCT patients, while integrating the main advantages of the hydrolysis probe, which are high sensitivity and specificity. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 122, No. 21 ( 2013-11-15), p. s4649-s4649
    Abstract: Human herpesviruses may cause severe complications after allogeneic hematopoietic stem cell transplantation (HSCT) such as interstitial pneumonia, encephalitis, delayed engraftment and post-transplant lymphoproliferative disease. A prospective survey on the incidence of primary infection or reactivation and clinical features of the eight human herpesviruses after HSCT has not yet been performed in Brazilian patients. Additionally, the impact of most of these infections on the transplant outcome is still unclear. Methods Between August 2010 and December 2012, peripheral blood samples from 99 allogeneic HSCT recipients were collected weekly after transplant until day +100, totalizing 824 samples. Median age was 15 years (range: 2-72), 60% were male, and acute leukemias were the most frequent diagnosis (54%). Stem cell sources were bone marrow in 62%, umbilical cord blood in 22% and mobilized peripheral blood in 16%. Fifty–one percent of donors were related. In a semi-automated workflow, the DNA was extracted from plasma in the QIAcube robot. A test based on quantitative real-time PCR (Taqman®) was optimized to screen and quantify all known human herpesviruses (CMV, EBV, HSV1, HSV2, VZV, HHV6, HHV7 and HHV8). The PCR reactions were set up using QIAgility robot for high-precision pipetting, and have been performed in a 7900HT (Life Technologies). Infected cell cultures and plasma specimens with a known viral load/amplicon copy number have been used as controls. The limit of detection of the qPCR was 5 copies per reaction, representing 250 copies/mL of plasma for all of the viruses. Results The incidences of primary infection or reactivation of herpesviruses were as follows: CMV=41%, HHV6=11%, HHV8=5.5%, EBV=3%, HSV1=3%, VZV=3%, HHV7=2%, and HSV2=1%. CMV reactivation was significantly more frequent in adults (72% vs. 27% for children, p 〈 0.0001), and in those or receiving fludarabine (60% vs. 29%, p=0.03) and TBI (68% vs. 32%, p=0.01) in the conditioning regimen, but in a multivariate analysis, only age greater than 18 years remained significant (HR 3.4, 95%CI 1.7-6.7). HHV6 reactivation was significantly more frequent after umbilical cord blood transplant than after transplant from other sources (41% vs. 6%, respectively, p 〈 0.0001) and in those receiving TBI in the conditioning regimen (19% vs. 3%, p=0.01) and in those receiving mycophenolate mofetil as GVHD prophylaxis (22% vs. 2%, p=0.004). In a multivariate analysis, only the use of cord blood remained significantly associated with the risk of HHV6 reactivation (HR 5.7, 95%CI 1.2-26.2). CMV reactivation was associated with a higher risk of acute graft-versus-host disease (GVHD), with a cumulative incidence at 100 days of 37% vs. 17% (p=0.02), but had no impact on the other outcomes. HHV6 reactivation had no significant impact on outcomes. HHV8 reactivation was associated with an increased risk of chronic GVHD (83% vs. 49%, p=0.001). Conclusion HHV6 primary infection or reactivation is more frequent after umbilical cord blood transplantation. CMV and HHV6 primary infection or reactivation are frequent after HSCT, but had no significantly impact on the transplant outcomes, possibly due to monitoring and preemptive measures. Monitoring these viruses constitute an essential measure to improve outcomes. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2013
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
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