Myocarditis associated with parvovirus B19 infection in two siblings with merosin-deficient congenital muscular dystrophy

Recombinant Virus-like Particles of Human Parvovirus B19 with the Internal Location of VP1 Unique Region Produced by Hansenula polymorpha

Human parvovirus B19 (HPV B19) is pathogenic to human, which can cause fifth disease, transient aplastic crisis, arthritis, myocarditis, autoimmune disorders, hydrops fetalis, and so on. Currently, no approved vaccines or antiviral drugs are available against HPV B19, and thus the development of effective vaccines is needed. The capsid of HPV B19 is composed of two types of proteins, i.e., the major capsid protein VP2 and the minor protein VP1. Previous experimental studies have shown that the dominant immune responses against HPV B19 are elicited by VP1, especially the unique region on the N-terminus of VP1. It has been found that VP2 alone or VP2 and VP1 together can assemble into virus-like particle (VLP). The VLP structure formed by VP2 has been resolved, however, the location of VP1 in the capsid, especially the location of VP1 unique region with strong immunogenicity, is still not clear. In the present work, using the Hansenula polymorpha expression system developed by our laboratory, two kinds of recombinant HPV B19 VLPs were expressed, i.e., the VLP co-assembled by VP1 and VP2 (VP1/VP2 VLP) and the VLP whose VP1 content was improved (VP1h/VP2 VLP). The expression, purity, and morphology of these two VLPs were characterized, and then their immunogenic properties were investigated and compared with those of the VLP containing VP2 alone (VP2 VLP) previously developed by our group. Furthermore, the location of the VP1 unique region in the VLPs was determined by using the immunogold electron microscopy (IGEM). Our experimental results show that the VP1h/VP2 VLP elicits a stronger neutralization against the HPV B19 than VP2 and VP1/VP2 VLPs, which implies that the increase of VP1 content significantly improves the level of neutralizing antibodies. In addition, the IGEM observations suggest that the unique region of VP1 may be located inside the recombinant VLP. The VLPs recombinantly expressed by our Hansenula polymorpha system may serve as a promising candidate immunogen for HPV B19 vaccine development.

Parvovirus B19-Associated Myocarditis: A Literature Review of Pediatric Cases

Parvovirus B19 (B19V) infection may lead to myocarditis, a life-threatening condition in pediatric patients. In this review, we aim to present published pediatric cases of B19V-associated myocarditis in order to understand the deep complex connections and draw useful conclusions. We performed a comprehensive search of MEDLINE, Science Direct, and Google Scholar electronic databases. A total of 32 cases were included in our study. The most common presenting symptom was tachycardia in 22/32 patients (68.7%), followed by tachypnoea (21/32, 65.6%), fever, and rash (12/32, 37.5% for both of them). Cardiac arrest, loss of consciousness, and systemic infection were associated with the worst prognosis, with statistically significant differences (p-value 0.001, 0.02, 0.001. respectively). A percentage as high as 90.4% of patients with left ventricular (LV) dysfunction and reduced ejection fraction (EF) were discharged. Twelve patients required ventilatory support, five required extracorporeal membrane oxygenation (ECMO), and three underwent heart surgery. Treatment with immunosuppressive agents and immunoglobulin was found to be beneficial for patients (p-value 0.006 and 0.004, respectively). In conclusion, B19V myocarditis has high mortality rates in children. There is no specific antiviral treatment for B19V infection and therapeutic strategies for myocarditis aim to delay the worsening of heart failure and to preserve the LV function. Inotropic drugs, diuresis, ventilatory support, Intravenous immunoglobulin (IVIG), and immunosuppressive therapy seem to help the recovery of the myocardium in children with LV dilation, dysfunction, and reduced EF. Children with cardiac arrest, arrhythmias, and loss of consciousness have the worst prognosis.

Fatal parvovirus B19 infections: a report of two autopsy cases

Parvovirus B19 (PVB19) commonly infects children and is usually asymptomatic. Lethal outcomes of PVB19 infection are unusual; nevertheless, the two cases reported here are rare examples of PVB19-induced hemophagocytic syndrome and myocarditis in infants and children. The two cases show the indisputable usefulness of immunohistochemistry and in situ hybridization in the detection of PVB19. In the death investigations, histopathological examinations provided stronger evidence than did serology or molecular biology. The cases also highlight the importance of forensic autopsy in vaccine-related death. As vaccine-related deaths are what people fear and may cause declines in vaccination rates, it is important to clarify deaths temporally or causally associated with vaccine administration.

Influenza A Virus Infection Damages Zebrafish Skeletal Muscle and Exacerbates Disease in Zebrafish Modeling Duchenne Muscular Dystrophy

INTRODUCTION

Both genetic and infectious diseases can result in skeletal muscle degeneration, inflammation, pain, and/or weakness. Duchenne muscular dystrophy (DMD) is the most common congenital muscle disease. DMD causes progressive muscle wasting due to mutations in Dystrophin. Influenza A and B viruses are frequently associated with muscle complications, especially in children. Infections activate an immune response and immunosuppressant drugs reduce DMD symptoms. These data suggest that the immune system may contribute to muscle pathology. However, roles of the immune response in DMD and Influenza muscle complications are not well understood. Zebrafish with dmd mutations are a well-characterized model in which to study the molecular and cellular mechanisms of DMD pathology. We recently showed that zebrafish can be infected by human Influenza A virus (IAV). Thus, the zebrafish is a powerful system with which to ask questions about the etiology and mechanisms of muscle damage due to genetic and/or infectious diseases.

METHODS

We infected zebrafish with IAV and assayed muscle tissue structure, sarcolemma integrity, cell-extracellular matrix (ECM) attachment, and molecular and cellular markers of inflammation in response to IAV infection alone or in the context of DMD.

RESULTS

We find that IAV-infected zebrafish display mild muscle degeneration with sarcolemma damage and compromised ECM adhesion. An innate immune response is elicited in muscle in IAV-infected zebrafish: NFkB signaling is activated, pro-inflammatory cytokine expression is upregulated, and neutrophils localize to sites of muscle damage. IAV-infected dmd mutants display more severe muscle damage than would be expected from an additive effect of dmd mutation and IAV infection, suggesting that muscle damage caused by Dystrophin-deficiency and IAV infection is synergistic.

DISCUSSION

These data demonstrate the importance of preventing IAV infections in individuals with genetic muscle diseases. Elucidating the mechanisms of immune-mediated muscle damage will not only apply to DMD and IAV, but also to other conditions where the immune system, inflammation, and muscle tissue are known to be affected, such as autoimmune diseases, cancer, and aging.

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.

Rhabdomyolysis associated with human parvovirus B19 infection in a patient with Fukuyama-type congenital muscular dystrophy

Patients with Fukuyama-type congenital muscular dystrophy sometimes experience transient exacerbations of muscle weakness. We took care of a 9-year-old boy with Fukuyama-type congenital muscular dystrophy who presented with acute respiratory failure and decreased exercise ability with marked elevation of serum creatine kinase indicating rhabdomyolysis. At that time, his younger sister suffered from erythema infectiosum. Although he had no particular symptoms, he was tested and proven to have acute human parvovirus B19 infection based on detection of anti-B19 IgM and parvovirus B19 DNA in his serum. His acute rhabdomyolysis was possibly triggered by human parvovirus B19 infection.

Parvovirus b19 associated hepatitis

Parvovirus B19 infection can present with myriads of clinical diseases and syndromes; liver manifestations and hepatitis are examples of them. Parvovirus B19 hepatitis associated aplastic anemia and its coinfection with other hepatotropic viruses are relatively underrecognized, and there is sufficient evidence in the literature suggesting that B19 infections can cause a spectrum of liver diseases from elevation of transaminases to acute hepatitis to fulminant liver failure and even chronic hepatitis. It can also cause fatal macrophage activation syndrome and fibrosing cholestatic hepatitis. Parvovirus B19 is an erythrovirus that can only be replicate in pronormoblasts and hepatocytes, and other cells which have globosides and glycosphingolipids in their membrane can also be affected by direct virus injury due to nonstructural protein 1 persistence and indirectly by immune mediated injury. The virus infection is suspected in bone marrow aspiration in cases with sudden drop of hemoglobin and onset of transient aplastic anemia in immunosuppressed or immunocompetent patients and is confirmed either by IgM and IgG positive serology, PCR analysis, and in situ hybridization in biopsy specimens or by application of both. There is no specific treatment for parvovirus B19 related liver diseases, but triple therapy regimen may be effective consisting of immunoglobulin, dehydrohydrocortisone, and cyclosporine.

Cardiac findings in congenital muscular dystrophies

Cardiac involvement (CI) in congenital muscular dystrophies (CMDs) has been only rarely investigated so far. By means of a systematic literature search we reviewed the literature about CI in CMD and found that CI is apparently absent in Ullrich CMD or CMD with integrin deficiency and only mild in Bethlem CMD. CI in merosin deficiency includes dilated cardiomyopathy and systolic dysfunction. CI in dystroglycanopathies seems most prevalent among all CMDs and includes dilated cardiomyopathy, systolic dysfunction, and myocardial fibrosis in Fukuyama CMD. Among the nonspecified dystroglycanopathies, CI manifests as dilated cardiomyopathy, hypertrophic cardiomyopathy (CMP) or systolic dysfunction. With CMD type 1C, as well as with limb-girdle muscular dystrophy 2I, up to half of the patients develop dilated cardiomyopathy. In rigid-spine syndrome, predominantly the right heart is affected secondary to thoracic deformity. In patients who carry LMNA mutations, CI may manifest as dilated cardiomyopathy, hypertrophic cardiomyopathy, or fatal ventricular arrhythmias. Overall, CI in patients with CMD varies considerably between the different CMD types from absent or mild CI to severe cardiac disease, particularly in merosin deficiency, dystroglycanopathies, and laminopathies. Patients with CMD with CI require regular cardiologic surveillance so that severe, treatable cardiac disease is not overlooked.

Molecular diagnosis of the viral component in cardiomyopathies: pathophysiological, clinical and therapeutic implications

BACKGROUND

Myocarditis is defined as the inflammation of myocardium associated with cardiac dysfunction. Despite this clear-cut definition, diagnosis and etiologic treatment continue to create considerable debate. Viral infections are frequent causes of myocarditis and there is evidence that persistent viral infection is associated with poor prognosis in different subtypes of cardiomyopathy.

OBJECTIVE

To review methods for diagnosis of viral myocarditis and present the use of polymerase chain reaction (PCR)-based protocols for evaluating viral infection in myocarditis/cardiomyopathies.

METHODS

A review of published literature.

RESULTS/CONCLUSION

There is increasing evidence that PCR-based protocols can provide reliable molecular evidence for the presence of viral infection in myocardium. Thus application of molecular techniques will allow collection and analysis of more information on the epidemiology of viral cardiomyopathies, patient risk stratification and appropriate medical treatment.

Parvovirus B19 infection associated with dilated cardiomyopathy in patients with previous anthracycline exposure

We describe two children with previous anthracycline exposure for cancer who presented with acute decompensated left ventricular dysfunction. Both patients had evidence of dilated cardiomyopathy and required mechanical ventilation and inotropic support. Parvovirus B19 was detected by polymerase chain reaction of the blood. After several weeks of ventilation and inotropic support, both patients were weaned from ventilation and managed with oral carvedilol, ACE inhibition, and diuretics. Acute left ventricular decompensation in patients following anthracycline exposure may not be solely attributed to drug exposure, and viral etiologies should be considered.

Clinical aspects of parvovirus B19 infection

Parvovirus B19 is a significant human pathogen that causes a wide spectrum of clinical complications ranging from mild, self-limiting erythema infectiosum in immunocompetent children to lethal cytopenias in immunocompromised patients and intrauterine foetal death in primary infected pregnant women. The infection may also be persistent and can mimic or trigger autoimmune inflammatory disorders. Another important clinical aspect to consider is the risk of infection through B19-contaminated blood products. Recent advances in diagnosis and pathogenesis, new insights in the cellular immune response and newly discovered genotypes of human parvoviruses form a platform for the development of modern therapeutic and prophylactic alternatives.

Active, fulminant, lethal myocarditis associated with parvovirus B19 infection in an infant

We report a case of fulminant myocarditis in an 11-month-old female infant who had no other clinical signs of parvovirus infection. The patient presented with severe respiratory distress and died in sudden cardiac arrest 3 h after admission. The clinical presentation was similar to that of an asthmatic attack. Autopsy revealed signs of acute lymphocytic myocarditis. Parvovirus DNA was demonstrated by polymerase chain reaction (PCR) analysis of tissue sections obtained from the heart, lungs, liver, kidneys, and spleen. Transmission electron microscopy of myocardial tissue showed crystalline arrays with the appearance of parvovirus. The results of immunohistochemical analysis for the detection of parvovirus antigens were negative, and no viral inclusions were demonstrable. We suggest that the current diagnostic procedure underestimates the prevalence of parvovirus-associated myocarditis. PCR analysis should be used as a complement in suspected cases, to enhance the rate of detection of the infection and to reach a correct diagnosis.