Adenovirus myocarditis: retrospective diagnosis by gene amplification from formalin-fixed, paraffin-embedded tissues

Human adenovirus infections in pediatric population - an update on clinico-pathologic correlation

Human adenoviruses can cause infections at any age but most commonly in pediatric population, especially in young children and infants. By the time of 10 years old, most children have had at least one episode of adenovirus infection. Adenoviruses can cause many symptoms similar to common cold, including rhinorrhea, fever, cough, and sore throat. Lower respiratory infections such as bronchitis, bronchiolitis, and pneumonia can be severe and even fatal. Other diseases such as conjunctivitis, gastroenteritis, cystitis, myocarditis, cardiomyopathy, and meningoencephalitis can also be associated with adenovirus infections. A variety of recent advancement of structural and molecular biology methods have revamped the taxonomy of adenoviruses and furthered our understanding of the diversity of related clinical diseases. Because of the wide spectrum and complexity of diseases associated with human adenovirus infections, the scope of this review is limited to basic virology and epidemiology of adenoviruses with a main focus on the clinico–pathologic correlation. Clinical manifestations and pathology of any infectious disease are always related; therefore, it is logical to review clinico–pathologic correlation within the specific disease entity caused by adenoviruses to better understand this common viral infection in pediatric population.

Comprehensive polymerase chain reaction assay for detection of pathogenic DNA in lymphoproliferative disorders of the ocular adnexa

Infectious agents have been identified as a major cause of specific types of human cancers worldwide. Several microorganisms have been identified as potential aggravators of ocular adnexal neoplasms; however, given the rarity of these neoplasms, large epidemiological studies are difficult to coordinate. This study aimed to conduct an exhaustive search for pathogenic DNA in lymphoproliferative disorders (LPD) of the ocular adnexa in a total of 70 patients who were diagnosed with LPD of the ocular adnexa between 2008 and 2013. Specimens were screened for bacterial, viral, fungal, and parasitic DNA by multiplex polymerase chain reaction (PCR) and quantitative real-time PCR. Among cases of conjunctival mucosa-associated lymphoid tissue lymphoma, human herpes virus (HHV)-6, HHV-7, chlamydia, Epstein-Barr virus (EBV) and bacterial 16S ribosomal DNA were detected. In cases of IgG4-related ocular disease, similar pathogens were detected but in a larger number of patients. Our PCR assays detected DNAs of various infectious agents in tumor specimens, especially HHV6, HHV7, and EBV, with different positive rates in various types of LPD. Chronic inflammatory stimulation or activation of oncogenes from these infectious agents might be involved in the pathogenesis of LPD of the ocular adnexa.

Ljungan virus: a commentary on its association with fetal and infant morbidity and mortality in animals and humans

Epidemiologic and experimental data support the notion that Ljungan virus (LV), endemic in some rodent populations in Sweden, Denmark, and the United States, can cause morbidity and mortality in animals and humans. LV infection can cause type I diabetes mellitus, myocarditis, and encephalitis in bank voles and experimental mice, and lemmings. Mouse dams infected with LV experience high rates of stillbirth that may persist across generations, and their fetuses may develop cranial, brain, and limb malformations. In humans, epidemiologic and serologic data suggest that LV infection correlates with intrauterine fetal death, malformations, placental inflammation, myocarditis, encephalitis, and Guillain-Barré syndrome. The proposed role of LV infection in SIDS is unconvincing. Further research is necessary to clarify the role of LV infection in animal and human disease.

Myocardial inflammation, cellular death, and viral detection in sudden infant death caused by SIDS, suffocation, or myocarditis

The significance of minor myocardial inflammatory infiltrates and viral detection in SIDS is controversial. We retrospectively compared the demographic profiles, myocardial inflammation, cardiomyocyte necrosis, and myocardial virus detection in infants who died of SIDS in a safe sleep environment, accidental suffocation, or myocarditis. Formalin-fixed, paraffin-embedded myocardial sections were semiquantitatively assessed for CD3 lymphocytes and CD68 macrophages using immunohistochemistry and for cardiomyocyte cell death in H&E-stained sections. Enteroviruses and adenoviruses were searched for using PCR technology. The means of lymphocytes, macrophages, and necrotic cardiomyocytes were not statistically different in SIDS and suffocation cases. Enterovirus, not otherwise specified, was detected in one suffocation case and was the only virus detected in the three groups. Very mild myocardial lymphocyte and macrophage infiltration and scattered necrotic cardiomyocytes in SIDS are not pathologic, but may occur after the developing heart is exposed to environmental pathogens, including viruses.

Inflammatory cardiomyopathy: there is a specific matrix destruction in the course of the disease

Cardiomyopathies are responsible for a high proportion of cases of congestive heart failure and sudden death, as well as for the need for transplantation. Understanding of the causes of these disorders has been sought in earnest over the past decade. We hypothesized that DCM is a disease of the cytoskeleton/sarcolemma, which affects the sarcomere. Evaluation of the sarcolemma in DCM and other forms of systolic heart failure demonstrates membrane disruption; and, secondarily, the extracellular matrix architecture is also affected. Disruption of the links from the sarcolemma to ECM at the dystrophin C-terminus and those to the sarcomere and nucleus via N-terminal dystrophin interactions could lead to a "domino effect" disruption of systolic function and development of arrhythmias. We also have suggested that dystrophin mutations play a role in idiopathic DCM in males. The T-cap/MLP/alpha-actinin/titin complex appears to stabilize Z-disc function via mechanical stretch sensing. Loss of elasticity results in the primary defect in the endogenous cardiac muscle stretch sensor machinery. The over-stretching of individual myocytes leads to activation of cell death pathways, at a time when stretch-regulated survival cues are diminished due to defective stretch sensing, leading to progression of heart failure. Genetic DCM and the acquired disorder viral myocarditis have the same clinical features including heart failure, arrhythmias, and conduction block, and also similar mechanisms of disease based on the proteins targeted. In dilated cardiomyopathy, the process of progressive ventricular dilation and changes of the shape of the ventricle to a more spherical shape, associated with changes in ventricular function and/or hypertrophy, occurs without known initiating disturbance. In those cases in which resolution of cardiac dysfunction does not occur, chronic DCM results. It has been unclear what the underlying etiology of this long-term sequela could be, but viral persistence and autoimmunity have been widely speculated.

Role of virus-induced myocardial affections in sudden infant death syndrome: a prospective postmortem study

The cause of sudden infant death syndrome (SIDS) is an unresolved problem of high relevance. Previous studies indicate a role of infections. In our prospective study, we investigated the frequency of virus-induced myocardial affections in SIDS. Postmortem samples from SIDS victims and control subjects were investigated prospectively. Pediatric cases of unnatural death served as controls. Samples were studied for enteroviruses, adenoviruses, parvovirus B19, and Epstein-Barr virus applying PCR. Immunohistochemical investigations for inflammatory cells, the necrosis marker C5b-9((m)) complement complex, and the enteroviral capsid protein VP1 were performed. Overall, 62 SIDS victims were studied. As controls, 11 infants were enrolled. Enteroviruses were detected in 14 (22.5%), adenoviruses in 2 (3.2%), Epstein-Barr viruses in 3 (4.8%), and parvovirus B19 in 7 (11.2%) cases of SIDS. Control group samples were completely virus negative. Compared with controls, immunohistochemical investigations partially revealed a significant increase in the number of T lymphocytes in SIDS myocardial samples (p < 0.05). Furthermore, cases with elevated numbers of leukocytes and macrophages, microfocal C5b-9((m))(+) necroses, and enteroviral VP1 capsid protein within the myocardium were detected. Applying a comprehensive combination of molecular and immunohistochemical techniques, our results demonstrate a clearly higher prevalence of viral myocardial affections in SIDS. Our results emphasize the importance of PCR-based diagnosis of viral myocardial affections. We suggest preliminary criteria for cellular immunohistochemical diagnosis of viral myocardial affections derived from our findings. For future investigations in SIDS, we suggest a comprehensive approach that includes PCR and immunohistochemistry. Our results offer novel strategies for diagnosis of pediatric myocardial viral affections.

PCR-based diagnosis of enterovirus and parvovirus B19 in paraffin-embedded heart tissue of children with suspected sudden infant death syndrome

The diagnosis of viral myocarditis remains difficult and generally depends on clinical and histologic criteria. Viral cultures and serology are often unrewarding with low yields. The purpose of this study was to analyze the usefulness of PCR in the rapid diagnosis of myocarditis in children. PCR was used to analyze 120 myocardial tissue samples from 60 cases of sudden infant death syndrome (SIDS) and 56 myocardial tissue samples from 36 cases with well-known causes of sudden death (11 children younger than 1 year and 25 children 1-10 years old). The myocardial tissue samples were evaluated for the presence of enteroviruses and parvovirus B19 using PCR primers designed to consensus and unique sequences of these viral genomes. Enteroviruses could be detected in 14 cases of SIDS, whereas the detection of enteroviral nucleic acid within the control group was negative. Seven cases with myocardial infection caused by parvovirus B19 were found in the SIDS group. The detection of parvoviruses in the control group of the 11 children younger than 1 year was negative, whereas 3 positive cases of parvoviruses could be detected in the control group of children from 1 to 10 years old. In the myocardial sample of one SIDS case, both enteroviruses and parvovirus B19 could be detected. Our results emphasize the importance of modern molecular biologic methods in cases of sudden infant death even when conventional histologic examination revealed no serious findings in heart muscle tissue.

Detection of viruses in myocardial tissues by polymerase chain reaction. evidence of adenovirus as a common cause of myocarditis in children and adults

OBJECTIVES

The purpose of this study was to analyze cardiac tissue and blood for viral genomes using polymerase chain reaction (PCR) to define the common viral etiologies of myocarditis by age group.

BACKGROUND

Enteroviruses are considered the most common cause of myocarditis at all ages. Diagnosis relies on viral cultures, serology, and cardiac histology, which lack sensitivity, as well as PCR. However, in many cases enteroviruses are not detected.

METHODS

Cardiac samples were obtained for PCR analysis from patients with myocarditis (n = 624) and dilated cardiomyopathy (DCM) (n = 149). Patients were analyzed by age group, including neonates (n = 116), infants (n = 191), toddlers (n = 87), children (n = 110), adolescents (n = 92), and adults (n = 177). After nucleic acids had been extracted from an endomyocardial biopsy, an explant, or autopsy samples, PCR and reverse transcription PCR were performed to detect the genomic sequences of enterovirus, adenovirus, cytomegalovirus (CMV), herpes simplex virus (HSV), Epstein-Barr virus (EBV), parvovirus, respiratory syncytial virus (RSV), and influenza A virus.

RESULTS

Viral genome was amplified (adenovirus = 142, enterovirus = 85, CMV = 18, parvovirus = 6, influenza A = 5, HSV = 5, EBV = 3, RSV = 1) from 239 (38%) of the 624 samples from myocarditis patients, including 26 patient samples in which dual infection was found. Virus was detected in 30 (20%) of 149 DCM patient samples; only adenovirus (n = 18) and enterovirus (n = 12) were detected.

CONCLUSIONS

Polymerase chain reaction identified adenovirus as the most common virus in the myocardium of children and adults with myocarditis and DCM. Although enteroviruses are also found in these patients, they appear to be a less common cause of myocarditis than adenovirus.

Coxsackie B3 myocarditis in 4 cases of suspected sudden infant death syndrome: diagnosis by immunohistochemical and molecular-pathologic investigations

Immunohistochemical and molecular-pathologic techniques have improved the diagnosis of myocarditis as compared with conventional histologic staining methods done according to the Dallas criteria. Most investigations were carried out on adults, and only a few authors investigating childhood deaths applied these modern methods, used for diagnosing myocarditis. We report on four children under one year of age, who suddenly died without prodromal symptoms. Their deaths were attributed to SIDS (sudden infant death syndrome). Immunohistochemical (LCA, CD68, CD45R0, MHC-class-II-molecules, VP1-capsid-protein of enteroviruses) and molecular-pathologic (RT-PCR) investigations, however, suggested that death was caused by a coxsackie-B3-myocarditis. In the future, these methods should be used for investigating cases with suspicion of SIDS.

Molecular diagnosis of myocarditis and dilated cardiomyopathy in children: clinicopathologic features and prognostic implications

Myocarditis is the most common cause of heart failure in children. We investigated viral etiology of myocarditis/dilated cardiomyopathy (DCM) in children and correlated molecular findings with pathologic and clinical data. Polymerase chain reaction (PCR) or reverse transcription (RT)-PCR were used to analyze 59 endomyocardial biopsies from 48 consecutive young (<18 yrs) patients (pts) with clinical and histologic diagnosis of myocarditis and DCM, employing primers designed to amplify specific sequences of various DNA and RNA viruses. Nucleic acids were successfully extracted in 41 pts and viral genomes were found in 20 (49%): 12 out of 26 pts (46%) with myocarditis, 6 out of 13 (46%) pts with DCM, and both patients with endocardial fibroelastosis. Enteroviruses were more common in DCM (72%), whereas adenoviruses and enteroviruses shared the same rate (36%) in myocarditis. The mumps virus genome was detected in the two pts with endocardial fibroelastosis. More diffuse inflammatory infiltrates and myocyte damage as well as more impaired left ventricular end diastolic volume and shortening fraction were noted in viral positive cases. PCR positive pts had a worse outcome, resulting in transplantation or death. Three out of 8 pts with viral myocarditis who underwent cardiac transplantation had recurrent PCR-proven graft viral infection. Viral myocarditis/DCM appeared to be a more severe disease than nonviral forms. Enteroviruses were more common in DCM, whereas adenoviruses were as frequent as enteroviruses in myocarditis. Persistence of viral infection was associated with disease deterioration. Viral myocarditis relapsed after transplantation.

Active versus borderline myocarditis: clinicopathological correlates and prognostic implications

OBJECTIVE

To compare active (AM) with borderline (BM) myocarditis to verify whether the pathological distinction between the two forms may help to identify patients with different clinical and haemodynamic characteristics and to aid prognosis.

MATERIALS

Myocarditis was diagnosed in 56 patients on endomyocardial biopsy (EMB) within one year from clinical onset of the disease between 1991 and 1998. Fourteen patients were excluded because of a lack of adequate and complete information. EMBs and clinical records of the 42 remaining patients were reviewed. Immunohistochemistry on bioptic samples was regularly performed. Polymerase chain reaction (PCR) for a panel of viruses was performed in 23 patients (55%). Clinicopathological correlations were calculated.

RESULTS

The histological diagnosis was AM in 26 patients (62%) and BM in 16 (38%). Significant differences were found in the following parameters: presence of left bundle branch block on ECG (AM 2 (8%) v BM 5 (31%), p = 0.05); left ventricular volume on echocardiogram (mean (SD) AM 90 (42) ml/m(2) v BM 128 (50) ml/m(2), p = 0.002); mass to volume ratio (AM 1.0 (0) v BM 0.8 (0.1), p = 0.03); time interval between clinical onset of the disease and EMB (AM 40 (55) v BM 90 (93) days, p = 0.04); and degree of inflammatory infiltrates, scored on a scale of 0 to 3 (AM 1.65 (0.8) v BM 0.85 (0.3), p = 0.004). In 6 of 15 patients (40%) with AM and in 2 of 8 (25%) with BM, a viral genome was detected by PCR (NS). At follow up, no differences in death or heart transplantation were detected between the two forms (AM 4 patients (15%) v BM 2 patients (12.5%)). Three of eight PCR positive patients (37.5%) and 1 of 15 virus negative patients (7%) died or underwent heart transplantation.

CONCLUSIONS

BM seems to encompass inflammatory forms with a less aggressive inflammatory infiltrate evolving towards left ventricular dilatation. The term "chronic myocarditis" seems to be more appropriate. The absence of myocyte necrosis does not predict a more favourable prognosis, whereas the absence of a viral genome seems to predict it.

Inflammatory left ventricular microaneurysms as a cause of apparently idiopathic ventricular tachyarrhythmias

BACKGROUND

We sought to investigate the arrhythmogenic role, incidence, treatment, and prognosis of inflammatory left ventricular (LV) microaneurysms in patients with apparently idiopathic ventricular tachyarrhythmias. Methods and Results-- We studied 156 consecutive patients (71 men, 85 women; mean age, 44.1+/-11.8 years) with severe ventricular arrhythmias and normal 2D echo cardiac parameters by coronary and ventricular angiography, biventricular endomyocardial biopsy, and electrophysiological study. Polymerase chain reaction was used to detect genomic sequences of enterovirus, adenovirus, Epstein Barr virus, cytomegalovirus, herpes simplex viruses, influenza A and B viruses, and hepatitis C virus in frozen endomyocardial samples. Of these patients, 15 (9.6%) showed angiographic evidence of single or multiple LV microaneurysms. All 15 patients had recurrent episodes of ventricular tachycardia with right bundle-branch block morphology, and the arrhythmias originated within or close to the aneurysms in those patients (n=6) undergoing ventricular mapping. A lymphocytic myocarditis was observed in LV biopsies of all patients and in the right ventricles of 3 patients. Polymerase chain reaction analysis was performed in 12 and viral genomes were found in 5 (42%): hepatitis C virus in 2, enterovirus in 2, and influenza virus A in 1. The patients were treated with antiarrhythmics, and cardiac function was preserved for the next 47+/-39.5 months of follow-up. No major clinical event was registered, and arrhythmias were successfully treated by antiarrhythmics.

CONCLUSIONS

Inflammatory LV microaneurysms, often of viral origin, are a consistent cause of apparently idiopathic ventricular arrhythmias. Their prognosis so far has been benign, and aggressive therapeutic strategies have been unnecessary.

Polymerase chain reaction analysis for viruses in paraffin-embedded myocardium from dogs with dilated cardiomyopathy or myocarditis

OBJECTIVE

To perform polymerase chain reaction (PCR) analysis on paraffin-embedded myocardium from dogs with dilated cardiomyopathy (DCM) and dogs with myocarditis to screen for canine parvovirus, adenovirus types 1 and 2, and herpesvirus.

SAMPLE POPULATION

Myocardial specimens from 18 dogs with an antemortem diagnosis of DCM and 9 dogs with a histopathologic diagnosis of myocarditis were evaluated.

PROCEDURE

Paraffin-embedded myocardial specimens were screened for viral genome by PCR analysis. Positive-control specimens were developed from cell cultures as well as paraffin-embedded tissue specimens from dogs with clinical and histopathologic diagnoses of viral infection with canine parvovirus, adenovirus types 1 and 2, and herpesvirus. The histologic characteristics of all myocardial specimens were classified regarding extent, location, and type of inflammation and fibrosis.

RESULTS

Canine adenovirus type 1 was amplified from 1 specimen from a dog with DCM. Canine parvovirus, adenovirus type 2, and herpesvirus were not amplified from any myocardial specimens. Histologic analysis of specimens from dogs with DCM revealed variable amounts of fibrosis; myocardial inflammation was observed in 1 affected dog. Histopathologic analysis of specimens from dogs with myocarditis disclosed variable degrees of inflammation and fibrosis.

CONCLUSIONS AND CLINICAL RELEVANCE

Viral agents canine parvovirus, adenovirus types 1 and 2, and herpesvirus are not commonly associated with DCM or active myocarditis in dogs. Additional studies evaluating for nucleic acid from viruses that less commonly affect dogs or different types of infectious agents may be warranted to gain insight into the cause of DCM and myocarditis in dogs.

Molecular Aspects of Myocarditis

Myocarditis is an acquired form inflammatory heart muscle disease, manifested as acute and chronic conditions. While many etiologies have been reported, the most common cause of this disease is infection, primarily viral. Typically, the specific causative agent(s) and mechanism(s) are elusive. Over the past several years, various new findings have added to our understanding of myocarditis. These include the identification of adenoviruses as important causative agents, a new receptor protein likely to play an important role in the virulence of certain agents affecting the myocardium, and the effect of viruses on the cardiac cytoskeleton. This report reviews the current understanding of myocarditis, proposes a hypothesis about the long-term sequelae, and suggests possible new therapeutic strategies.

Hepatitis C virus from the hearts of patients with myocarditis and cardiomyopathy

The myocardium may be the target of several types of viral infections. The importance of hepatitis C virus (HCV) infection has been recently noted in patients with myocarditis and in patients with dilated or hypertrophic cardiomyopathy. The present study sought to detect HCV genomes in formalin-fixed paraffin sections of autopsied hearts from patients with myocarditis and patients with dilated or hypertrophic cardiomyopathy. Paraffin sections were deparaffinized, RNA was extracted, and the positive and negative strands of HCV RNA were detected by performing reverse transcription and nested polymerase chain reaction. The polymerase chain reaction products were cloned and sequenced. beta-actin gene was used as a control for the successful amplification of a housekeeping gene. Among 106 hearts examined, beta-actin gene was amplified in 61 hearts (57.5%). Among the latter, HCV RNA was detected in 13 hearts (21.3%), and negative strands in 4 hearts (6.6%). HCV RNA was found in 4 hearts (33.3%) with myocarditis, in 3 hearts (11.5%) with dilated cardiomyopathy, and in 6 hearts (26.0%) with hypertrophic cardiomyopathy. The sequences recovered from nine patients were highly homologous to the standard strain of HCV. HCV genomes were not found in either 35 hearts from patients with myocardial infarction or 20 hearts from patients with noncardiac diseases. These HCV RNA positive samples were obtained from 1 heart in 1979, 7 hearts between 1980 and 1989, and 5 hearts since 1990, indicating that HCV RNA can be amplified from paraffin-embedded hearts preserved for many years. This method of detecting HCV genomes in formalin-fixed paraffin cardiac specimens has enabled us to widen our research into HCV infection and has been helpful in identifying the presence of HCV infection in cardiac myopathic disorders.

Detection of adenoviral genome in the myocardium of adult patients with idiopathic left ventricular dysfunction

BACKGROUND

The use of molecular biological techniques has demonstrated the importance of enteroviral infection of the myocardium in the pathogenesis of myocarditis and dilated cardiomyopathy in adults and adenovirus and enterovirus infection in children. The aim of this study was to determine the frequency of adenoviral infection of the myocardium of adults with impaired left ventricular function of unknown origin.

METHODS AND RESULTS

Nested polymerase chain reaction (nPCR) was used to determine the frequency of detection of adenoviral DNA and enteroviral RNA in myocardial tissue samples from 94 adult patients with idiopathic left ventricular dysfunction and 14 control patients. Histological and immunohistological analyses were performed to detect myocardial inflammation. Adenoviral genomic DNA was detected by nPCR in 12 of the 94 patients with left ventricular dysfunction (in each case, adenovirus type 2), whereas enteroviral RNA was detected in another 12 patients. All control samples were negative for both viruses. In all patients, active myocarditis was excluded according to the Dallas criteria. However, there was significantly decreased CD2, CD3, and CD45RO T lymphocyte counts in the adenovirus-positive group compared with the adenovirus-negative group (P<0.05), whereas no differences were associated with enterovirus infection.

CONCLUSIONS

Although enteroviruses are an important causative agent in the pathogenesis of myocarditis and dilated cardiomyopathy, this study shows that adenovirus infection is also important in the pathogenesis of left ventricular failure in adults. However, the pathogenetic basis of disease associated with adenovirus infection may be different than that after infection with other agents, particularly with respect to activation of the host immune response.

Enteroviral genome in native hearts may influence outcome of patients who undergo cardiac transplantation

The Enterovirus may be the most common agent responsible for viral myocarditis and cardiomyopathy. Very little of the literature is available concerning the follow-up of patients who underwent transplantation with enteroviral positivity in native hearts. In the present study, 45 explanted hearts from patients who underwent orthotopic heart transplant at University of Padova were studied by reverse transcriptase (RT)-polymerase chain reaction (PCR): 27 patients had dilated cardiomyopathy (DC), 12 had ischemic cardiopathy (IC), 2 had valvular disease (VD), 2 had arrhythmogenic right ventricular cardiomyopathy (ARVC), 1 had giant cell myocarditis (GCM), and 1 had lymphocytic myocarditis (LM). Two sets of PCR primers from the highly conserved region of Enterovirus and Rhinovirus were used. Samples of both ventricles and septum were analyzed in every patients. The RT-PCR and nucleotide sequencing of amplicons were also performed on all post-transplantation follow-up biopsies in patients with Enterovirus positivity in the native heart. The viral genome was detectable in only 1 of 27 patients with DC (3%) and in 1 patient with LM. Nucleotide sequence analysis of the amplified product showed differences in nucleotide sequence of PCR samples compared with the sequence of the coxsackievirus B3 used in the current study. The patient with Enterovirus-positive DC showed a higher index of severe rejection (>3A) in the first 6 months, compared with the other patients tested. The patient with Enterovirus-positive LM died of disease recurrence 2 months after transplantation. The present study reveals a scarce presence of Enterovirus in the myocardium of patients with chronic myocardial disease. Because Enterovirus infection was predictive of a poor prognosis in these two patients, molecular studies are useful in excluding viral involvement in native hearts of transplanted patients.

Detection of intrauterine viral infection using the polymerase chain reaction

Intrauterine viral infection commonly presents as nonimmune hydrops fetalis or intrauterine growth restriction. Cytomegalovirus (CMV) and parvovirus are commonly recognized causes of fetal infection using serology and cultures. We used the polymerase chain reaction (PCR) to evaluate the frequency of fetal viral infection and the associated clinical course and outcome. Specimens (amniotic fluid, fetal blood, pleural fluid, tissue) from 303 abnormal pregnancies at risk for viral infection and 154 controls were analyzed using primers for CMV, herpes simplex virus, parvovirus B19, adenovirus, enterovirus, Epstein-Barr virus, and respiratory syncytial virus. Viral genome was detected in 144/371 samples (39%) or 124/303 patients (41%), with adenovirus (n = 74 patients; 24%), CMV (n = 30 patients; 10%), and enterovirus (n = 22 patients; 7%) most common. Only 4/154 (2.6%), unaffected control patients' samples were PCR positive. We conclude that diagnosis of fetal viral infection by PCR is common in abnormal pregnancies. Adenovirus and enterovirus may cause fetal infection that have been previously unrecognized.

The elusive search for fetal infection. Changing the gold standards

Two percent to four percent of all newborns have a major structural malformation of which only a small percentage can be explained by either aneuploidy or a single-gene disorder. No other mammal has a similar reproductive problem. It is the suggestion that previously unrecognized viral infection accounts for a large percentage of these abnormalities by interfering with appropriate embryonic cell migration, reducing hyperplasia, or damaging the precursor structure by means of an inflammatory mechanism.

Minor inflammatory lesions and sudden infant death: cause, coincidence, or epiphenomena?

Minor inflammatory changes are often found in tissues of infants who die suddenly. Recently it has been proposed that these infiltrates signal significant underlying infectious disease and are responsible for death. Currently there is no unanimity about the percentage of cases in which inflammatory infiltrates occur and no international consensus in regard to the minimal criteria required for their diagnosis or their significance. We recommend that the presence of minor inflammatory infiltrates should not detract from the diagnosis of sudden infant death syndrome (SIDS) until further study has determined otherwise.