Aims Parvovirus B19 (B19V) is often assumed to be a cause of dilated cardiomyopathy (DCM), based on the quantification of B19V DNA in endomyocardial biopsies (EMB). Whether the presence of B19V DNA... Show moreAims Parvovirus B19 (B19V) is often assumed to be a cause of dilated cardiomyopathy (DCM), based on the quantification of B19V DNA in endomyocardial biopsies (EMB). Whether the presence of B19V DNA correlates with active infection is still debated. Application of the enzyme endonuclease to blood samples results in degradation of B19V DNA remnants but leaves viral particles intact, which enables differentiation between active and past infection. In this study, the susceptibility to degradation by endonuclease of B19V DNA in blood was compared between DCM patients and a control group of recent B19V infections.Methods and results Twenty blood samples from 20 adult patients with DCM, who previously tested positive for B19V DNA in EMB and/or blood, were tested with B19V PCR before and after application of endonuclease to the samples. Six blood samples tested positive for B19V DNA with a mean viral load of 2.3 x 10(4) IU/mL. In five samples, B19V DNA became undetectable after endonuclease (100% load reduction); in one sample DNA load showed a 23% log load reduction (viral load before endonuclease: 9.1 x 10(4) IU/mL; after: 6.5 x 10(3) IU/mL). Presence of cardiac inflammation did not differ between patients with B19V DNAemia (1/4) and patients without B19V DNAemia (6/14) (P value = 1.0). In all 18 control samples of proven recent B19V infections, DNA remained detectable after application of endonuclease, showing only a mean log load reduction of 2.3% (mean viral load before endonuclease: 8.1 x 10(11) IU/mL; after: 8.0 x 10(11) IU/mL). Load reduction differed significantly between the DCM group and the control group; indicating the presence of intact viral particles in the control group with proven active infection and the presence of DNA remnants in the DCM group (P value = 0.000).Conclusion During recent B19V infection, viral DNA levels in blood were unaffected by endonuclease. In contrast, B19V DNA in blood in patients with DCM became undetectable or strongly reduced after application of endonuclease. Circulating viral DNA in this subset of patients with presumed parvovirus-associated DCM does not consist of intact viral particles. Viral replicative activity cannot be assumed from demonstrating B19V DNA in cardiac tissue or in blood in DCM patients. Show less
Background: Diagnosis of congenital viral infection at birth is generally attempted by direct detection of the virus by PCR in various neonatal materials. How to reliably diagnose intrauterine... Show moreBackground: Diagnosis of congenital viral infection at birth is generally attempted by direct detection of the virus by PCR in various neonatal materials. How to reliably diagnose intrauterine infection with parvovirus B19 (B19 V) at birth is unknown.Objectives: To evaluate the performance of B19 V DNA detection in cord blood (CB) or neonatal dried blood spots (DBS) in diagnosing fetal infection. Study design: Two cohorts of children diagnosed prenatally with an intrauterine B19 V infection were included in this study. CB samples of intrauterine B19 V infections that were sent to a reference laboratory for congenital infections in Stuttgart, Germany in the period 1995-2014 were tested in triplicate for B19 V DNA by quantitative PCR. DBS from children with intrauterine B19 V infection that underwent IUT at the LUMC, Leiden, the Netherlands in the period 2009-2014 were tested for B19 V DNA by quantitative B19 V PCR in triplicate.Results: Fourteen of twenty (70 %) CB samples tested positive for B19 V DNA. The positivity rate was 40 % (4/10) in those with a prenatal diagnosis< 20 weeks gestation. When intrauterine B19 V infection was diagnosed thereafter, 100 % (10/10) samples were B19 V DNA positive. Of the thirteen available DBS, twelve (92 %) tested positive. Viral load in CB and DBS corresponded inversely with time from fetal diagnosis to birth.Conclusion: B19 V DNA can be detected in neonatal blood samples of children following intrauterine B19 V infection, although the possibility of false-negatives, even in severe infections, should be considered. B19 V viral load at birth correlates with timing of infection. Show less
Congenital Human Parvovirus B19 (B19V) infection can lead to life threatening fetal complications as hydrops, fetal demise or severe fetal anaemia and thrombocytopenia. Maternal symptoms frequently... Show moreCongenital Human Parvovirus B19 (B19V) infection can lead to life threatening fetal complications as hydrops, fetal demise or severe fetal anaemia and thrombocytopenia. Maternal symptoms frequently pass unnoticed at the time of maternal infection and there was little information on the mechanism and time course of vertical transmission of B19V during gestation. Treatment consists of intrauterine fetal red blood cell and/ or platelet transfusion (IUT). The indication for treatment with IUT is set by performing fetal ultrasound screening for fetal anaemia and signs of fetal hydrops. The fetal middle cerebral artery peak systolic flow correlates well with the severity of fetal anaemia. The first two chapters of this thesis give an overview of the existing literature concerning fetal hydrops and congenital B19V infection. In the ensuing chapters we describe the course of maternal and fetal B19V infection by the B19V viral load and maternal immune response. We did not find a correlation between the fetal or maternal B19V viral load and the severity of fetal anaemia or thrombocytopenia. Thrombocytopenia is frequently encountered in congenital B19V infection, but fetal bleeding complications are not. The use of fetal platelet transfusion is therefore a matter of debate. The long- term neurodevelopment of affected fetus can be significantly delayed at a later age despite a technically correct IUT procedure. The possibility of cerebral damage due to congenital B19V infection is discussed. Parents should be counselled of these risks before the IUT procedure and long term follow -up following congenital B19V infection is advised Show less
