rologie i - European Congress of Virology

5 th European Congress of VirologyObjectives: a study of the impact of viral co infections, in vitro and in vivoduring the follow up of 36 umbilical cord blood stem cell recipients inBordeaux (2011 2012).1) Experimental study: to analyse the impact of AdV HCMV co infectionin vitro on the replication of each virus (infections, co infections andsuper infections of MRC5 cells, with laboratory strains HCMV AD169and AdV5) and cell gene expression (interferon beta mRNAs).2) Clinical study: to describe the natural history of viral co infections incord blood recipients, with HCMV, EBV, HHV6, BKV and AdV monitoringand analyse the clinical outcome according to the existence of singleviral infections or co infections.Results: HCMV AdV co infection enhanced HCMV replication in MRC5cells; this tendency observed during in vitro simultaneous co infection reacheda difference of 2 log10 for HCMV viral load in culture supernatantswhen AdV superinfection was applied 48 hours after HCMV infection(quantitative real time PCR assays for HCMV UL83 and AdV Hexon genesin culture supernatants). Confocal microscopic examination of infectedcells demonstrated simultaneous co infection in certain cells (immune fluorescencein infected cells with antibodies directed against HCMV pp65,HCMV IE1 and pan AdV, Argène Biomérieux, France). Interferon betamRNAs relative quantification indicated a two to three fold increase in coinfected cultures compared to single infections. Clinically, only 4 patientsout of 36 presented no viral opportunistic infection. Single infections werediagnosed in 7 patients (19%), dual infections in 9 (25%) and in 16 patients(44%) three viruses or more were detected during the first term followingtransplantation. The analysis of patient’s outcome, taking into accountmajor clinical endpoints (viral disease, Graft versus Host Disease anddeath) and virological data (viral loads and kinetics) is presently beingperformed.Conclusions: Viral co habitation in cord blood recipients is frequent andcould have a clinical impact. Viral co infection experiments confirm thepossible existence of co activation mechanisms in dually infected cells.REF 551Comparison of two assays for CMV viral load expressed in InternationalUnits in plasma and whole bloodPaolo RAVANINI, Tiziana DI FATTA, Maura BANDI, Anna MariaNICOSIA, Maria Grazia CROBUAOU Maggiore della Carità, Novara, ITALYRecently an international standard for CMV has been established by WHO.This improvement can lead to a better comparison among the results obtainedwith different diagnostic assays and biological materials (plasma andwhole blood).In this study, the results of two CMV viral load assays were compared toverify the concordance of the results expressed in International Units (IU),the sensitivity of the assays and the different biological materials, and to seta possible conversion factor between results from plasma and whole blood.Two Real Time PCR assays were used (RealTime CMV, Abbott; AlertCMV Q PCR, Nanogen). All results were expressed in IU/ml. Plasma andwhole blood samples, collected at the same time for both materials from47 kidney transplant recipients, were tested with both assays. The resultssuggest that both plasma and whole blood can be effectively used with bothassays for the monitoring of CMV viral loads in transplant recipients. Bothassays show good sensitivity in plasma (92.3 and 94.9% respectively),while in whole blood the Abbott assay shows better sensitivity (84.6 vs71.8%). In both cases, the sensitivity in plasma appears higher than inwhole blood. The concordance of the results in IU/ml is good between thetwo assays (100% of the results under 0.5 Log variation for both materials).The mean viral load difference between whole blood and plasma resultsis 1.63 fold. This conversion factor should be taken into account in theassessment of different threshold values for preemptive therapy when theviral load is determined in plasma or whole blood.REF 550Low level DNAemia of Parvovirus B19 (genotypes 1–3) in Adult TransplantRecipients is not Associated with AnaemiaSusanne MODROW, Annelie PLENTZ, Michael WÜRDINGER,Matthias KUDLICHUniversity of Regensburg, Institute for Medical Microbiology, Regensburg,GERMANYAfter acute parvovirus B19 (B19 V) infection of immunocompetentindividuals, viral genomes persist lifelong in various tissues. In immunocompromisedpatients, acute B19 V infection may be associated withsevere anaemia. It is unclear whether reactivation of latent B19 V genomesmay contribute to persistent viraemia and anaemia in transplant recipients.We retrospectively analyzed the impact of B19 V infection in 371 adulttransplant recipients (kidney, liver, heart, bone marrow). The patients’ pretransplantation serostatus was determined. 1431 serum or plasma samplesobtained in monthly intervals during six months following transplantationwere analyzed for the presence of B19 V DNA by qPCR which allowsdiscrimination between B19 V genotypes 1 3.Overall, 82% of the patients were seropositive indicating past B19 V infection.B19 V DNA was detected in of 4.0% of all patients and classified asgenotype 1 in 12, genotype 2 in one and genotype 3 in two patients, theDNA load ranging from