High Frequency of Detection by PCR of Viral Nucleic Acid in The Blood of Infants Presenting with Clinical Myocarditis

Lymphocytic Myocarditis in Children with Parvovirus B19 Infection: Pathological and Molecular Insights

BACKGROUND

This study aims to evaluate the role of parvovirus B19 (B19V) in the pathogenesis of myocarditis in a paediatric population, including post-mortem samples from two children.

METHODS

From 2004 to 2023, endomyocardial biopsies (EMBs) from children under 16 years of age were analyzed using histology, immunohistochemistry, and molecular pathology. A total of 306 children with acute and 1060 children with chronic lymphocytic myocarditis were identified.

RESULTS

B19V infection was more frequent in acute myocarditis than in chronic myocarditis (43% vs. 14%), with higher viral loads in acute cases regardless of age. The most prominent cardiac CD3+ T cell infiltration was noted in children < 2 years, correlating with high cardiac B19V loads. In two male infants who died from B19V infection, B19V DNA was localized in the endothelial cells of multiple organs using in situ hybridization. Virus replication was found in the endothelial cells of small cardiac arterioles and venules but not in capillaries. B19V DNA/mRNA was also detected in immune cells, especially in the spleen and lymph nodes, revealing virus replication in B lymphocytes.

CONCLUSIONS

B19V can induce severe lymphocytic myocarditis, especially in young children. The simultaneous histopathological and molecular assessment of EMBs is important for early diagnosis of viral myocarditis, preventing severe disease, and ensuring appropriate therapy.

Seroepidemiology of Human Parvovirus B19 Infection among the Population of Vojvodina, Serbia, over a 16-Year Period (2008-2023)

This study aimed to estimate the serological status and dynamic changes in the prevalence of Parvovirus B19 (PVB19) antibodies within the general population residing in the northern part of the Republic of Serbia (Province of Vojvodina) during a 16-year period. Serum samples were analyzed for Human PVB19-specific IgM and IgG antibodies using enzyme-linked immunosorbent assay (ELISA). Throughout the study period, the overall seroprevalence was 49.51%. Approximately 10% of patients exhibited a serologic profile positive for PVB19 IgM antibodies. Notably, seroprevalence varied significantly, ranging from 9.12% in the pediatric cohort (ages 1-4 years) to 65.50% in the adult demographic (40-59 years old). Seroprevalence was higher (51.88%) among women compared to men (42.50%). Immunologically naive pregnant women in the age groups 26-36 and 36-45 years had 45% (OR = 0.55, 95% CI: 0.31-1.00) and 52% (OR = 0.48; 95% CI: 0.24-0.94) lower odds of having negative IgM and IgG compared to those in age group 16-25 years old. Improved knowledge of the epidemiology of PVB19 may assist clinicians in the differential diagnosis of PVB19 clinical manifestations. The PVB19 detection is particularly important for monitoring individuals in risk groups such as women of reproductive age, medical staff, patients with hematological disorders, and those with immunodeficiency.

Multisystem Involvement Induced by Human Parvovirus B19 Infection in a Non-immunosuppressed Adult: A Case Report

Background

Human parvovirus B19 (B19V) infection is usually symptomless and occurs in the childhood. While in immunocompromised adults, B19V infection also presents various clinical symptoms due to the host's immune status. The classic symptoms include erythema, anemia, arthropathy, and edema, but neurological involvement is rare.

Case Presentation

In this report, we present a case of B19V infection caused multiple organ dysfunction in a non-immunosuppressed adult. Metagenomic next-generation sequencing (mNGS) was used and successfully detected the pathogen in multiple types of samples, including blood, cerebrospinal fluid (CSF), and bronchoalveolar lavage fluid (BALF). The diagnosis was subsequently confirmed by polymerase chain reaction (PCR). He was treated with intravenous gamma globulin, resulting in a significant resolution of symptoms after 1 month.

Conclusion

Multisystem involvement induced by B19V infection was found in this case report. mNGS performed great advantages in rapidly and accurately diagnosing B19V infection in multiple types of samples, which helps the timely adjustment of treatment and improves the prognosis.

Parvovirus B19 myocarditis in children: a diagnostic and therapeutic approach

Parvovirus B19 is one of the most frequent causes of pediatric myocarditis, associating high mortality rates or need for cardiac transplantation. The aim of this study is to describe the clinical course of Parvovirus B19 myocarditis in children with emphasis on the role of endomyocardial biopsy and cardiac magnetic resonance, and the use of an innovative therapeutic strategy. Eleven patients and 12 episodes of polymerase chain reaction (PCR)-confirmed Parvovirus B19 myocarditis were prospectively collected for 14 years. Diagnosis was confirmed either histopathologically or by magnetic resonance. A life-threatening clinical presentation is described, similar to previous series, but with 83.3% overall survival without transplantation. We also present a case of recurrent myocarditis, which is extraordinarily rare. Electrocardiographic patterns presented chiefly peaked p waves, low QRS voltages, and negative T waves on inferior or lateral leads. Endomyocardial biopsy is the gold standard diagnostic test; alternatively magnetic resonance could be a useful diagnostic tool. A good concordance between myocardial and blood PCRs was observed. Seven patients received treatment with corticosteroids and beta interferon and all underwent a significant cardiac function improvement.

CONCLUSION

A severe clinical presentation is reported, similar to previous reports but with better outcomes. Endomyocardial biopsy is the gold standard diagnostic test; alternatively magnetic resonance may be used. Both blood and myocardium PCR can be used in children to establish the microbiological etiology. Steroids with IFNß could be a useful therapeutic option, although further multicenter studies are needed to confirm these results.

WHAT IS KNOWN

• Parvovirus B19 is one of the most frequent causes of myocarditis in children. It is associated with a fulminant clinical presentation. • Endomyocardial biopsy is the gold standard diagnostic test but it is an invasive procedure.

WHAT IS NEW

• Myocarditis may recur in pediatrics, even it is extraordinarily rare. • IFNβ with steroids may be a useful therapeutic option to improve the outcomes.

Fatal human herpes virus 6B myocarditis: Postmortem diagnosis of HHV-6B based on CD134+ T-cell tropism

Human herpes virus 6 (HHV-6) is one of the most important pathogens of viral myocarditis, and is often responsible for sudden death in young adults. A 59-year-old immunocompetent man died of serious lymphocytic myocarditis, and his peripheral blood sample showed HHV-6 DNAemia. Recently, HHV-6 cell entry and reactivation have been suggested to be regulated by the expression of specific CD receptors on T lymphocytes. Here, we report a case of HHV-6 myocarditis diagnosed using an experimental method focused on this unique cell tropism. The interaction between HHV-6 and CD expression was assessed using an immunofluorescence assay. Colocalization between HHV-6B and CD134 was detected in lymphocytes infiltrating the myocardium, which was highly suggestive of an active HHV-6B infection and could be a useful criterion for postmortem diagnosis of HHV-6B myocarditis in the acute phase.

Could the unfortunate outcome of pediatric acute myocarditis be predicted? Factors contributing to a poor outcome in myocarditis

OBJECTIVE

Myocarditis has spontaneous resolution in 50% of patients. Our study aimed to define risk factors for developing dilated cardiomyopathy (DCM) and death in pediatric patients with acute myocarditis (AM).

METHODS

The retrospective cohort study included all patients with treated AM. The Mother and Child Health Institute from January 2011 to March 2019.

RESULTS

In the study, 62 patients were included, 40 boys and 22 girls (11.15±5.86 years) with AM. Twelve out of sixty-two children had acute fulminant myocarditis. Four patients died in the acute phase of AM, and 11 developed DCM. Follow up was 27.14±36.52 months. Patients with poor outcome (DCM development) were under the age of seven (odds ratio [OR] 10.1; p=0.003), more likely to be girls (OR 4.6; p=0.03), and had fulminant myocarditis (OR 27.0; <0.001). An ejection fraction (EF) <55% and fractional shortening (FS) <30% increased risk of DCM 13- and 5-fold, respectively, but patients with EF between 40 and 55% remain at highest risk of developing DCM. There was a 12-fold increased risk for DCM in patients with left ventricular end-diastolic diameter Z score >2+. The receiver operator curve showed that the lactate dehydrogenase (LDH) cut-off value for developing DCM was 1780 mmol/l (sensitivity 80%, specificity 100%).

CONCLUSION

Acute fulminant myocarditis was an independent risk factor for DCM. Children with EF between 40 and 50% at admission were at highest risk of developing DCM. Lactate dehydrogenase value could be a significant prognostic value for the outcome of pediatric myocarditis.

Could the unfortunate outcome of pediatric acute myocarditis be predicted? Factors contributing to a poor outcome in myocarditis

OBJECTIVE

Myocarditis has spontaneous resolution in 50% of patients. Our study aimed to define risk factors for developing dilated cardiomyopathy (DCM) and death in pediatric patients with acute myocarditis (AM).

METHODS

The retrospective cohort study included all patients with treated AM. The Mother and Child Health Institute from January 2011 to March 2019.

RESULTS

In the study, 62 patients were included, 40 boys and 22 girls (11.15±5.86 years) with AM. Twelve out of sixty-two children had acute fulminant myocarditis. Four patients died in the acute phase of AM, and 11 developed DCM. Follow up was 27.14±36.52 months. Patients with poor outcome (DCM development) were under the age of seven (odds ratio [OR] 10.1; p=0.003), more likely to be girls (OR 4.6; p=0.03), and had fulminant myocarditis (OR 27.0; <0.001). An ejection fraction (EF) <55% and fractional shortening (FS) <30% increased risk of DCM 13- and 5-fold, respectively, but patients with EF between 40 and 55% remain at highest risk of developing DCM. There was a 12-fold increased risk for DCM in patients with left ventricular end-diastolic diameter Z score >2+. The receiver operator curve showed that the lactate dehydrogenase (LDH) cut-off value for developing DCM was 1780 mmol/l (sensitivity 80%, specificity 100%).

CONCLUSION

Acute fulminant myocarditis was an independent risk factor for DCM. Children with EF between 40 and 50% at admission were at highest risk of developing DCM. Lactate dehydrogenase value could be a significant prognostic value for the outcome of pediatric myocarditis.

An overview of the immune mechanisms of viral myocarditis

Viral myocarditis has been identified as a major cause of dilated cardiomyopathy (DCM) that can lead to heart failure. Historically, Coxsackieviruses and adenoviruses have been commonly suspected in myocarditis/DCM patients in North America and Europe. However, this notion is changing as other viruses such as Parvovirus B19 and human herpesvirus-6 are increasingly reported as causes of myocarditis in the United States, with the most recent example being the severe acute respiratory syndrome coronavirus 2, causing the Coronavirus Disease-19. The mouse model of Coxsackievirus B3 (CVB3)-induced myocarditis, which may involve mediation of autoimmunity, is routinely used in the study of immune pathogenesis of viral infections as triggers of DCM. In this review, we discuss the immune mechanisms underlying the development of viral myocarditis with an emphasis on autoimmunity in the development of post-infectious myocarditis induced with CVB3.

miR‑217 and miR‑543 downregulation mitigates inflammatory response and myocardial injury in children with viral myocarditis by regulating the SIRT1/AMPK/NF‑κB signaling pathway

The aim of the present study was to investigate the expression levels and roles of microRNA (miR)‑217 and miR‑543 in viral myocarditis, and to examine their underlying mechanisms. Coxsackievirus B3 (CVB3) was used to establish in vivo and in vitro models of viral myocarditis. The levels of miR‑217 and miR‑543 were detected using reverse transcription‑quantitative PCR. The association between miR‑217 and miR‑543 and sirtuin‑1 (SIRT1) was predicted and confirmed by TargetScan and dual‑luciferase reporter assay. Cell viability was detected using Cell Counting Kit‑8 assay, and cell apoptosis was measured by analyzing the expression levels of Bcl‑2 and Bax, and by flow cytometry. In addition, the synthesis of various pro‑inflammatory factors was determined by ELISA. In addition, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured in cardiomyocytes following transfection and CVB infection. miR‑217 and miR‑543 were found to be highly expressed in the peripheral blood of pediatric patients with viral myocarditis, in the peripheral blood and myocardial tissues of viral myocarditis mice and in CVB3‑infected cardiomyocytes. SIRT1 was found to be a target of both miR‑217 and miR‑543, and SIRT1 expression level was downregulated in viral myocarditis. Further analysis indicated that the reduced cell viability, increased cell apoptosis, enhanced synthesis of inflammatory factors, increased MDA content and decreased SOD activity associated with myocarditis were significantly reversed after inhibition of miR‑217 or miR‑543. Importantly, the present results showed that all the effects of miR‑217 and miR‑543 inhibition on cardiomyocytes were significantly suppressed following SIRT1 knockdown. Collectively, the present data indicated that miR‑217 and miR‑543 were significantly upregulated in viral myocarditis, and downregulation of miR‑217 and miR‑543 attenuated CVB3 infection‑induced cardiomyocyte injury by targeting SIRT1. miR‑217 and miR‑543 may be potential therapeutic targets for developing novel viral myocarditis treatments in the future.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Recent Advances in Replication and Infection of Human Parvovirus B19

Parvovirus B19 (B19V) is pathogenic to humans and causes bone marrow failure diseases and various other inflammatory disorders. B19V infection exhibits high tropism for human erythroid progenitor cells (EPCs) in the bone marrow and fetal liver. The exclusive restriction of B19V replication to erythroid lineage cells is partly due to the expression of receptor and co-receptor(s) on the cell surface of human EPCs and partly depends on the intracellular factors essential for virus replication. We first summarize the latest developments in the viral entry process and the host cellular factors or pathways critical for B19V replication. We discuss the role of hypoxia, erythropoietin signaling and STAT5 activation in the virus replication. The B19V infection-induced DNA damage response (DDR) and cell cycle arrest at late S-phase are two key events that promote B19V replication. Lately, the virus infection causes G2 arrest, followed by the extensive cell death of EPCs that leads to anemia. We provide the current understanding of how B19V exploits the cellular resources and manipulate pathways for efficient virus replication. B19V encodes a single precursor mRNA (pre-mRNA), which undergoes alternate splicing and alternative polyadenylation to generate at least 12 different species of mRNA transcripts. The post-transcriptional processing of B19V pre-mRNA is tightly regulated through cis-acting elements and trans-acting factors flanking the splice donor or acceptor sites. Overall, in this review, we focus on the recent advances in the molecular virology and pathogenesis of B19V infection.

MicroRNA-381 protects myocardial cell function in children and mice with viral myocarditis via targeting cyclooxygenase-2 expression

The present study aimed to determine the expression of cyclooxygenase (COX)-2 and microRNA (miRNA/miR)-381 in the blood of children with viral myocarditis (VM), and investigate the association between COX-2 and miR-381 in the occurrence and development of the disease using a mouse model. A total of 26 children with VM (15 boys and 11 girls) were included in the present study. Peripheral blood was collected from all children. The mouse model of VM was constructed by coxsackievirus B3 (CVB3) infection. Peripheral blood and myocardial tissues were collected from all mice for analysis. Reverse transcription-quantitative polymerase chain reaction was used to determine the expression of COX-2 mRNA and miR-381 in serum and myocardial tissues. ELISA was used to measure the content of COX-2 protein in serum from humans and mice, and western blotting was employed to determine the expression of COX-2 protein in myocardial tissues from mice. Contents of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) were evaluated using an automatic biochemical analyzer. A dual luciferase assay was conducted to identify interactions between COX-2 mRNA and miR-381. Children with VM had increased COX-2 levels and decreased miR-381 expression in peripheral blood, compared with those who had recovered from VM. CVB3 infection resulted in damage in the myocardium of mice, and elevated CK-MB and LDH contents. VM model mice exhibited increased COX-2 levels and decreased miR-381 expression in peripheral blood and myocardial tissues compared with normal mice. miR-381 binds to the 3'-untranslated seed regions of both human and mouse COX-2 mRNA to regulate their expression. The present study demonstrated that children with VM have decreased miR-381 expression and elevated COX-2 expression in peripheral blood. miR-381 may inhibit myocardial cell damage caused by CVB3 infection and protect myocardial cell function by targeting COX-2 expression.

Analyses of Tissue Culture Adaptation of Human Herpesvirus-6A by Whole Genome Deep Sequencing Redefines the Reference Sequence and Identifies Virus Entry Complex Changes

Tissue-culture adaptation of viruses can modulate infection. Laboratory passage and bacterial artificial chromosome (BAC)mid cloning of human cytomegalovirus, HCMV, resulted in genomic deletions and rearrangements altering genes encoding the virus entry complex, which affected cellular tropism, virulence, and vaccine development. Here, we analyse these effects on the reference genome for related betaherpesviruses, Roseolovirus, human herpesvirus 6A (HHV-6A) strain U1102. This virus is also naturally “cloned” by germline subtelomeric chromosomal-integration in approximately 1% of human populations, and accurate references are key to understanding pathological relationships between exogenous and endogenous virus. Using whole genome next-generation deep-sequencing Illumina-based methods, we compared the original isolate to tissue-culture passaged and the BACmid-cloned virus. This re-defined the reference genome showing 32 corrections and 5 polymorphisms. Furthermore, minor variant analyses of passaged and BACmid virus identified emerging populations of a further 32 single nucleotide polymorphisms (SNPs) in 10 loci, half non-synonymous indicating cell-culture selection. Analyses of the BAC-virus genome showed deletion of the BAC cassette via loxP recombination removing green fluorescent protein (GFP)-based selection. As shown for HCMV culture effects, select HHV-6A SNPs mapped to genes encoding mediators of virus cellular entry, including virus envelope glycoprotein genes gB and the gH/gL complex. Comparative models suggest stabilisation of the post-fusion conformation. These SNPs are essential to consider in vaccine-design, antimicrobial-resistance, and pathogenesis.

Use of whole genome deep sequencing to define emerging minority variants in virus envelope genes in herpesvirus treated with novel antimicrobial K21

New antivirals are required to prevent rising antimicrobial resistance from replication inhibitors. The aim of this study was to analyse the range of emerging mutations in herpesvirus by whole genome deep sequencing. We tested human herpesvirus 6 treatment with novel antiviral K21, where evidence indicated distinct effects on virus envelope proteins. We treated BACmid cloned virus in order to analyse mechanisms and candidate targets for resistance. Illumina based next generation sequencing technology enabled analyses of mutations in 85 genes to depths of 10,000 per base detecting low prevalent minority variants (<1%). After four passages in tissue culture the untreated virus accumulated mutations in infected cells giving an emerging mixed population (45-73%) of non-synonymous SNPs in six genes including two envelope glycoproteins. Strikingly, treatment with K21 did not accumulate the passage mutations; instead a high frequency mutation was selected in envelope protein gQ2, part of the gH/gL complex essential for herpesvirus infection. This introduced a stop codon encoding a truncation mutation previously observed in increased virion production. There was reduced detection of the glycoprotein complex in infected cells. This supports a novel pathway for K21 targeting virion envelopes distinct from replication inhibition.

Clinical, laboratory and instrumental criteria for myocarditis, established in comparison with myocardial biopsy: A non-invasive diagnostic algorithm

Aim. To determine the diagnostic value of different clinical, laboratory, and instrumental signs in the diagnosis of myocarditis in patients with the picture of idiopathic arrhythmias, dilated cardiomyopathy (DCM) and in a comparison group when comparing with myocardial morphological examination. Subjects and methods. A study group included 100 patients (35 women; mean age, 44.7±12.5 years) with idiopathic arrhythmias (n=20) and DCM as a syndrome (n=100). All underwent myocardial morphological examination: endomyocardial biopsy (EMB) (n=71), intraoperative biopsy (n=13), study of the explanted heart (n=6), and autopsy (n=11). A comparison group consisted of 50 patients (25 women; mean age, 53.7±11.7 years) with non-inflammatory diseases of the heart (left ventricular end-diastolic dimension 50%) who underwent open-heart surgery (n=47), EMB (n=2), or autopsy (n=1). The investigators also performed polymerase chain reaction for cardiotropic viral DNA in the blood and myocardium, anticardiac antibody (ACA) identification, myocardial scintigraphy (n=26), coronary angiography (n=47), magnetic resonance imaging (MRI) (n=25), and multislice computed tomography of the heart (n=45). The diagnostic value of the extended spectrum of clinical, laboratory, and instrumental markers for myocarditis was estimated. Results. Active/borderline myocarditis was diagnosed in 76% of the patients in the study group (75.5% in the arrhythmia subgroup and 76.3% in the DCM one) and in 24.3% of those in the comparison group (p

Human herpesvirus 6-induced inflammatory cardiomyopathy in immunocompetent children

Over the last decade, human herpesvirus 6 (HHV-6) has been implicated in the etiology of pediatric myocarditis and subsequent dilated cardiomyopathy (DCM). This review provides an overview of recent literature investigating the pathophysiological relevance of HHV-6 in inflammatory cardiomyopathy. We examined 11 cases of previously published pediatric myocarditis and/or DCM associated with HHV-6 and also our experience of detection of virus particles in vascular endothelium of HHV-6 positive endomyocardial biopsy tissue by electron microscopy. The exact role of the presence of HHV-6 and its load remains controversial as the virus is also found in the heart of healthy controls. Therefore, the question remains open whether and how cardiac HHV-6 may be of pathogenetic importance. Quantitative polymerase chain reaction or mRNA testing allows differentiation between low-level latent virus found in asymptomatic myocardium and active HHV-6 infection. Although only a small number of pediatric cases have been reported in literature, HHV-6 should be considered as a causative agent of inflammatory cardiomyopathy, especially in children under three who might be experiencing a primary infection. Future studies are needed to establish a threshold for determining active infection in biopsy samples and the role of coinfections other cardiotropic viruses.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.