Histopathology of fatal adenovirus infection of the respiratory tract in young children

Viral loads in nasopharyngeal aspirates and tracheal aspirates among children hospitalized with invasive ventilation for human adenovirus pneumonia

Purpose

To evaluate viral loads in children with human adenovirus (HAdV) pneumonia at different stages of disease and compare the viral load between upper and lower respiratory tract samples.

Methods

We prospectively enrolled children who required invasive ventilation for HAdV pneumonia. Nasopharyngeal aspirate (NPA) and tracheal aspirate (TA) samples were collected throughout the entire period of invasive ventilation. Viral detection and quantification were performed using quantitative real-time polymerase chain reaction.

Results

Ninety-four children were enrolled. The median age of the children was 12.0 months (IQR: 11.0–24.0), and > ninety percent of patients were aged between 6 and 59 months. Seven hundred and nine paired NPA-TA samples were collected. The median viral loads of the NPA and TA samples were 7.31 log10 and 7.50 log10 copies/mL, respectively. Viral loads generally decreased steadily over time. The median viral load after 1, 2, 3, and > 3 weeks of the disease course was 8.65, 7.70, 6.69, and 5.09 log10 copies/mL, respectively, in NPA samples and 8.67, 7.79, 7.08, and 5.53 log10 copies/mL, respectively, in TA samples. Viral load showed a significant negative correlation with time since symptom onset in both NPA samples (Spearman r =  − 0.607, P = 0.000) and TA samples (Spearman r =  − 0.544, P = 0.000). The predicted duration of HAdV shedding was 60.17 days in the NPA group and 65.81 days in the TA group. Viral loads in NPA and TA from the same subjects correlated well with each other (R² = 0.694). HAdV loads in NPA and TA were most comparable during the early phase of infection (95% limits of agreement, − 1.36 to 1.30 log10 copies/mL, R² = 0.746). Variation increased during the late phase of infection (i.e., in follow-up samples), with viral loads remaining significantly higher in TA than NPA.

Conclusions

In children with HAdV pneumonia, viral loads in both NPA and TA steadily decreased during the course of the disease, and the predicted duration of viral shedding was more than 2 months. The HAdV DNA load of NPA is highly correlated with that of TA, especially in the initial phase of infection.

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.

The novel antiviral properties of brassicasterol against human adenovirus

Aim: To investigate whether brassicasterol has inhibitory effects against adenovirus (AdV). Materials & methods: The antiviral effects of brassicasterol against AdV 3 and 7 were tested in human airway epithelial cells. Brassicasterol cytotoxicity was assessed by WST-1 assay. AdV DNA was quantified by qPCR. Results: Brassicasterol inhibited AdV 3 and 7 infection of airway epithelial cells in a dose-dependent manner. Similarly, brassicasterol also inhibited AdV 3 and 7 production in infected cells. No apparent cytotoxicity of brassicasterol was detected. Further study showed that brassicasterol inhibited AdV DNA replication, but had no impact on viral entry of cells and viral genome import to nucleus. Conclusion: Brassicasterol exerts anti-AdV effects probably through the inhibition of viral DNA replication.

Adenovirus 7 Induces Interlukin-6 Expression in Human Airway Epithelial Cells via p38/NF-κB Signaling Pathway

Human Adenovirus (AdV) infection is very common and usually has a significant impact on children. AdV-induced inflammation is believed to be one of the main causes of severe symptoms. However, an inflammatory response profile in the airway in AdV-infected children is still lacking, and the mechanism underlying AdV-induced inflammation in the airway is also poorly understood. In the current study, we determined the expression of a panel of inflammation cytokines in the airway samples from AdV 7 infected children and further investigated the molecular mechanism underlying AdV 7-induced cytokine expression. Our results showed that eight out of 13 tested inflammatory cytokines were significantly increased in nasal washes of AdV 7-infected children comparing to healthy control, with IL-6 showing the highest enhancement. AdV 7 infection of bronchial epithelial cell line and primary airway epithelial cells confirmed that AdV 7 increased IL-6 mRNA and protein expression in an infection dose-dependent manner. Promoter analysis revealed that AdV 7 infection transactivated IL-6 promoter and a NF-κB binding site in IL-6 promoter was involved in the transactivation. Further analysis showed that upon AdV 7 infection, NF-κB p65 was phosphorylated and translocated into nucleus and bound onto IL-6 promoter. Signaling pathway analysis revealed that p38/NF-κB pathway was involved in AdV 7 infection induced IL-6 elevation. Taken together, our study shows that AdV 7 infection triggers the expression of a range of inflammatory cytokines including IL-6 in the airway of infected children, and AdV 7 enhances IL-6 expression by transactivating IL-6 promoter via p38/NF-κB signaling pathway. Findings of our current study have provided more information toward a better understanding of AdV-induced airway inflammation, which might also benefit the development of intervention strategies.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

The Repertoire of Adenovirus in Human Disease: The Innocuous to the Deadly

Adenoviridae is a family of double-stranded DNA viruses that are a significant cause of upper respiratory tract infections in children and adults. Less commonly, the adenovirus family can cause a variety of gastrointestinal, ophthalmologic, genitourinary, and neurologic diseases. Most adenovirus infections are self-limited in the immunocompetent host and are treated with supportive measures. Fatal infections can occur in immunocompromised patients and less frequently in the healthy. Adenoviral vectors are being studied for novel biomedical applications including gene therapy and immunization. In this review we will focus on the spectrum of adenoviral infections in humans.

Acute Lung Injury

A wide variety of insults can produce acute lung damage, inclusive of those that injure the lungs directly. The clinical syndrome of acute onset respiratory distress, dyspnea, and bilateral infiltrates is referred to as acute respiratory distress syndrome. The histologic counterpart of acute respiratory distress syndrome is diffuse alveolar damage, classically characterized by hyaline membranes. Other histologic features of acute lung injury include intraalveolar fibrin, organization, interstitial edema, and reactive pneumocytes. Diffuse alveolar damage and other histologic features of acute lung injury are nonspecific as to etiology, and once identified require the pathologist to search the biopsy for further features that may help identify a specific etiology. This chapter reviews the temporal sequence of acute lung injury and explores the large variety of specific etiologic causes with emphasis on helpful histologic features to identify.

Human Bocavirus 1 Is a Novel Helper for Adeno-associated Virus Replication

Human bocavirus 1 (HBoV1) is an autonomous parvovirus that infects well-differentiated primary human airway epithelia (HAE) in vitro In human embryonic kidney HEK293 cells, the transfection of a duplex HBoV1 genome initiates viral DNA replication and produces progeny virions that are infectious in HAE. HBoV1 takes advantage of signaling pathways in the DNA damage response for efficient genome amplification in both well-differentiated (nondividing) HAE and dividing HEK293 cells. On the other hand, adeno-associated virus 2 (AAV2) is a helper-dependent dependoparvovirus, and productive AAV2 replication requires coinfection with a helper virus (e.g., adenovirus or herpesvirus) or treatment with genotoxic agents. Here, we report that HBoV1 is a novel helper virus for AAV2 replication. Coinfection by HBoV1 and AAV2 rescued AAV2 replication in HAE cells. The helper function of HBoV1 for AAV2 is not limited to HAE cells but also includes HEK293 and HeLa cells. Importantly, the helper function of HBoV1 for AAV2 relies on neither HBoV1 replication nor the DNA damage response. Following transfection of HEK293 cells, the minimal requirements for the replication of the AAV2 duplex DNA genome and the production of progeny virions included the HBoV1 NP1 and NS4 proteins and a newly identified viral long noncoding RNA (BocaSR). However, following infection of HEK293 and HeLa cells with AAV2 virions, HBoV1 NS2 (but not NS4), NP1, and BocaSR were required for AAV2 DNA replication and progeny virion formation. These new methods for packaging the AAV2 genome may be useful for generating recombinant AAV-packaging cell lines and the directed evolution of AAV capsids.IMPORTANCE We first report that an autonomous parvovirus, HBoV1, helps the replication of a dependoparvovirus, AAV2, in differentiated human airway epithelia. We identified the minimal sets of HBoV1 genes required to facilitate the replication of the AAV2 duplex genome and for AAV2 infection. Notably, together with the expression of the NP1 and BocaSR genes, HBoV1 NS2 is required for the productive infection of HEK293 and HeLa cells by AAV2, whereas NS4 is sufficient for viral DNA replication of an AAV2 duplex genome. The identification of HBoV1 as a helper virus for AAV2 replication has implications for the improvement of recombinant AAV production in HEK293 cells and cell types that do not express the adenovirus E1 gene as well as for the rescue of wild-type AAV genomes from tissues during directed evolution in the absence of wild-type adenovirus. A further understanding of the mechanism underlying HBoV1 helper-dependent AAV2 replication may also provide insights into its functions in HBoV1 replication.

Surgical Pathologic Diagnosis

Surgical pathology results can play a crucial role in the management of immunocompromised patients. Here we highlight factors that differ between immunocompromised and immunocompetent hosts, such as variation in inflammatory response. Conditions that are covered include drug reactions, disease within solid organ allografts, immune reconstitution inflammatory syndrome, specific immunodeficiency syndromes, neoplasms related to viral infections, and viral, bacterial, fungal, and parasitic infections. Special techniques including immunohistochemistry, in situ hybridization and molecular detection of pathogen nucleic acid from formalin-fixed, paraffin-embedded tissue are discussed.

Infection

Community-Acquired Pneumonia (CAP) is the first leading cause of death due to infection worldwide.Many gram-positive, gram-negative bacteria, funguses and viruses can cause the infectious pulmonary disease, and the severity of pneumonia depends on the balance between the microorganism charge, the body immunity defenses and the quality of the underlying pulmonary tissue. The microorganisms may reach the lower respiratory tract from inhaled air or from infected oropharyngeal secretions. The same organism may produce several different patterns that depend on the balance between the microorganism charge and the body immunity defenses.CAP is classified into three main groups: lobar pneumonia, bronchopneumonia and interstitial pneumonia.Lobar pneumonia is characterized by the filling of alveolar spaces by edema full of white and inflammatory cells. Necrotizing pneumonia consists of a fulminant process associated with focal areas of necrosis that results in abscesses. Bronchopneumonia or lobular pneumonia, is characterized by a peribronchiolar inflammation with thickening of peripheral bronchial wall, the diffusion of inflammation to the centrilobular alveolar spaces and development of nodules.The interstitial pneumonia represents with the destruction and esfoliation of the respiratory ciliated and mucous cells. The interstitial septa, the bronchial and bronchiolar walls become thickened for the inflammation process and lymphocytes interstitial infiltrates.Chest radiography represents an important initial examination in all patients suspected of having pulmonary infection and for monitoring response to therapy.Its role is to identify the pulmonary opacities, their internal characteristics and distribution, pleural effusion and presence of other complications as abscesses and pneumothorax.High spatial CT resolution allows accurate assessment of air space inflammation.The CT findings include nodules, interlobular septal thickening, intralobular reticular opacities, ground-glass opacities, tree-in-bud pattern, lobar-segmental consolidation, lobular consolidation, abscesses, pneumatocele, pleural effusion, pericardial effusion, mediastinal and hilar lymphoadenopaties, airway dilatation and emphysema.

Effect of radiological extent and severity of bronchiectasis on pulmonary function

Background

The aim of this study was to ascertain the effect of the extent and severity of bronchiectasis as determined with high-resolution computed tomography (HRCT) on lung function in patients with pure bronchiectasis, bronchiectasis and asthma, and bronchiectasis and chronic obstructive pulmonary disease (COPD).

Methods

One hundred nineteen patients (71 with pure bronchiectasis, 25 asthmatic patients with bronchiectasis, and 23 COPD patients with bronchiectasis) underwent HRCT and pulmonary function tests. Computed tomography features were scored by the consensus of 2 radiologists.

Results

There were no statistically significant differences among the 3 patient groups regarding the extent of bronchiectasis, bronchial dilatation degree, bronchial wall thickening, decreased attenuation in the lung parenchyma, or presence of mucus in the large and small airways. In the pure bronchiectasis group, a negative correlation was found between forced vital capacity (FVC) % of predicted, forced expiratory volume in 1 sec (FEV₁) % of predicted, the FEV₁/FVC ratio and the extent of bronchiectasis, bronchial wall thickening, bronchial wall dilatation, and decreased attenuation. At multivariate analysis the main morphologic changes associated with impairment of FVC and FEV₁ were the extent of bronchiectasis and a decreased attenuation in the lung parenchyma. The decrease in the FEV₁/FVC ratio was associated with bronchial wall dilatation. No correlation was found between morphologic changes and indices of pulmonary function in the asthma and COPD patients.

Conclusions

Morphologic changes associated with bronchiectasis do not influence lung function in patients with asthma and COPD directly, although they do play a role in impairing pulmonary function in patients with bronchiectasis alone.

Acute lower respiratory tract infections by adenovirus in children: histopathologic findings in 18 fatal cases

Adenoviruses (Ads) are the 2nd-most common cause of acute lower respiratory tract infections of viral etiology in immunocompetent children who require hospitalization in Argentina. A new pathogenic genomic variant, Ad7h, has been identified and was associated with severe sequelae and a high mortality rate. A retrospective observational study was conducted in hospitalized children with acute lower respiratory tract infections between March 1988 and May 2005. Nasopharyngeal or tracheal aspirates, bacteriological analysis on blood samples and pleural fluids, and histopathologic studies on autopsies were performed. A total of 415 children were included in the study. Sixty-two patients died in the acute stage of illness (1-8 weeks), and postmortem examination was performed on 18 of them. Mean age was 8.25 months. The male to female ratio was 1.3∶1. The Ad was genome typed in 9% of all children, of whom 29 corresponded to the Ad7h variant. This genome type was diagnosed in 7 of the autopsies performed. Necrotizing bronchitis and bronchiolitis with abundant typical adenoviral inclusion nuclear cells and diffuse alveolar damage were the most important findings. Superimposed bacterial infection occurred in 11 cases, and cytomegalovirus was found in 1. In our population, Ad respiratory infection was found to have a severe course with sequelae or death. No differences were observed between lesions caused by other previously described genome types and those found in cases in which Ad7h was identified.

Implications of the innate immune response to adenovirus and adenoviral vectors

Adenovirus (AdV) is a common cause of respiratory illness in both children and adults. Respiratory symptoms can range from those of the common cold to severe pneumonia. Infection can also cause significant disease in the immunocompromised and among immunocompetent subjects in close quarters. Fortunately, infection with AdV in the normal host is generally mild. This is one reason why its initial use as a gene-therapy vector appeared to be so promising. Unfortunately, both innate and adaptive responses to the virus have limited the development of AdV vectors as a tool of gene therapy by increasing toxicity and limiting duration of transgene expression. This article will focus on the innate immune response to infection with wild-type AdV and exposure to AdV gene-therapy vectors. As much of the known information relates to the pulmonary inflammatory response, this organ system will be emphasized. This article will also discuss how that understanding has led to the creation of new vectors for use in gene therapy.

The role of viruses in the etiology and pathogenesis of common cold

Numerous viruses are able to cause respiratory tract infections. With the availability of new molecular techniques, the number of pathogens detected in specimens from the human respiratory tract has increased. Some of these viral infections have the potential to lead to severe systemic disease. Other viruses are limited to playing a role in the pathogenesis of the common cold syndrome. This chapter focuses on the viral pathogens that are linked to common cold. It is not the intention to comprehensively review all the viruses that are able to cause respiratory tract infections—this would go beyond the scope of this book. The list of viruses that are briefly reviewed here includes rhinoviruses, respiratory syncytial virus, parainfluenza virus, adenovirus, metapneumovirus and coronavirus. Bocavirus is discussed as one example of a newly identified pathogen with a less established role in the etiology and pathogenesis of common cold. Influenza virus does not cause what is defined as common cold. However, influenza viruses are associated with respiratory disease and the clinical picture of mild influenza and common cold frequently overlaps. Therefore, influenza virus has been included in this chapter. It is important to note that a number of viruses are frequently co-detected with other viruses in humans with respiratory diseases. Therefore, the viral etiology and the role of viruses in the pathogenesis of common cold is complex, and numberous questions remain to be answered.

Novel human adenovirus causing nosocomial epidemic keratoconjunctivitis

In 2000, we encountered cases of nosocomial infections with epidemic keratoconjunctivitis (EKC) at a university hospital in Kobe, in the western part of Japan. Two human adenovirus (HAdV) strains, Kobe-H and Kobe-S, were isolated from patients with nosocomial EKC infection. They were untypeable by existing neutralizing antisera; however, the isolate was neutralized with homologous antisera. We then encountered several cases of EKC due to nosocomial infections in eye clinics in different parts of Japan. A total of 80 HAdVs were isolated from patients with EKC at eight different hospitals. The partial hexon gene sequences of the isolates were determined and compared to those of the prototype strains of 51 serotypes. All isolates had identical partial hexon nucleotide sequences. Phylogenetic analysis classified these isolates into species of HAdV-D. The isolates showed 93.9 to 96.7% nucleotide identity with HAdV-D prototype strains, while all 32 HAdV-D prototype strains ranged from 93.2 to 99.2% identity. The sequences of the loop 2 and fiber knob regions from the representative strain, Kobe-H, were dissimilar in all prototype strains of 51 serotypes. We believe that this virus is a novel serotype of HAdV that causes EKC.

Viral Infections of the Lung

The lungs are among the most vulnerable to microbial assault of all organs in the body. From a contemporary vantage, lower respiratory tract infections are the greatest cause of infection-related mortality in the United States, and rank seventh among all causes of deaths in the United States.2,3 From a global and historic perspective, the scope and scale of lower respiratory tract infection is greater than any other infectious syndrome, and viral pneumonias have proven to be some of the most lethal and dramatic of human diseases. The 1918–1919 influenza pandemic, perhaps the most devastating infectious disease pandemic in recorded history, resulted in an estimated 40 million deaths worldwide, including 700,000 deaths in the U.S.4 The global outbreak of severe acute respiratory syndrome (SARS) during 2003, although considerably smaller in scale, resulted in 8098 cases and 774 deaths5 and is a dramatic contemporary example of the ability of viral pneumonias to rapidly disseminate and cause severe disease in human populations.

Adenovirus infections and lung disease

Adenovirus, particularly its E1A protein, has been investigated in the pathogenesis of chronic obstructive pulmonary disease (COPD). High levels of E1A DNA were found in the lungs of COPD patients, where its expression increased with disease severity. In lung epithelial cells, E1A increased intercellular adhesion molecule-1 and interleukin-8 expression, as well as nuclear factor-kappaB activation, in response to inflammatory stimuli. In addition to regulating the mediators that promote emphysema, E1A upregulates transforming growth factor-beta1 expression in bronchiolar epithelial cells and transforms lung epithelial cells to express mesenchymal markers. These results support its additional role in the airway remodeling process reported in COPD.

Quantitative detection and rapid identification of human adenoviruses

We have established a method of quantitative detection and rapid identification of human adenoviruses (hAdVs). Using LightCycler PCR with a primer set, we were able to amplify 554 bp of the hexon gene from each of 51 prototype strains of hAdVs. The sensitivity of LightCycler PCR was 10 copies of hAdV DNA/reaction. When LightCycler PCR was performed using a set of primers, hAdV was positive for 74.4% (99 of 133) of conjunctivitis patients and for 27.3% (81 of 297) of respiratory infection patients. We also attempted to measure hAdV in the potentially contaminated eye drops used by patients, detecting 5.4 x 10(2) to 1.6 x 10(6) copies/ml of hAdV. We determined the 350-bp nucleotide sequence of the amplified hexon gene and compared it with the sequences of the 51 prototype strains. Phylogenetic analysis based on 350 bp of the hexon gene identified 99 positive conjunctival swabs as 24 cases of AdV type 3 (AdV-3), 14 cases of AdV-4, 1 case of AdV-8, 19 cases of AdV-19a, and 41 cases of AdV-37. The 81 sequences from pharyngeal or nasal mucus swabs were identified as 29 cases of AdV-2, 18 cases of AdV-1, 18 cases of AdV-5, 12 cases of AdV-4, 2 cases of AdV-37, 1 case of AdV-3, and 1 case of AdV-6. LightCycler PCR followed by phylogenetic analysis provides an effective tool for the rapid identification of hAdVs and for studying molecular epidemiology.

Adenovirus pneumonia in adults: radiographic and high-resolution CT findings in five patients

OBJECTIVE

The purpose of this study was to describe the radiographic and high-resolution CT (HRCT) findings of adenovirus pneumonia in five patients.

CONCLUSION

Adenovirus pneumonia in adults appears as bilateral patchy parenchymal opacities on chest radiographs and as bilateral ground-glass opacities with a random distribution with or without consolidation on HRCT images. These findings, however, are not specific for adenovirus pneumonia.

Acute respiratory infection with mouse adenovirus type 1

Studies of the pathogenesis of adenovirus respiratory disease are limited by the strict species-specificity of the adenoviruses. Following intranasal inoculation of adult C57BL/6 mice with mouse adenovirus type 1 (MAV-1), we detected MAV-1 early region 3 (E3) and hexon gene expression in the lungs at 7 days post-infection (dpi). We detected MAV-1 E3 protein in the respiratory epithelium at 7 dpi. We did not detect viral mRNA or protein at 14 dpi, but MAV-1 DNA was detected by PCR at 21 dpi. Chemokine transcript levels increased between 7 and 14 dpi in the lungs of infected mice. MAV-1 infection induced a patchy cellular infiltrate in lungs at 7 and 14 dpi. This is the first report demonstrating the presence of MAV-1 in the respiratory epithelium of infected mice and describing chemokine responses in the lung induced by MAV-1 respiratory infection. MAV-1 infection of mice has the potential to serve as a model for inflammatory changes seen in human adenovirus respiratory disease.

Imaging in immunocompetent children who have pneumonia

This article discusses the common clinical scenarios regarding otherwise healthy children who develop suspected pneumonia in which imaging becomes an issue. The following topics are covered concerning the roles of imaging in the management of pneumonia: evaluation for possible pneumonia, determination of a specific etiologic agent, exclusion of other pathology, evaluation of the child with failure of pneumonia to clear, and evaluation of complications related to pneumonia.

The spectrum of pathological changes in severe acute respiratory syndrome (SARS)

Aims:  To analyse the lung pathology of severe acute respiratory syndrome (SARS) and correlate the findings with the time sequence of the disease.

Methods and results:  Ten patients with a clinical diagnosis of SARS, and virological confirmation of SARS coronavirus infection were identified. Histology in most cases showed diffuse alveolar damage, from early to late phases, and the changes corresponded to the time sequence. Other variable features include multinucleated giant cells, pneumocytes with cytomegaly and variable amounts of inflammatory cells and foamy macrophages. One case showed superimposed bronchopneumonia. No viral inclusions were found. Coronavirus particles were identified in pneumocytes by electron microscopy.

Conclusions:  The predominant pathological process of SARS is diffuse alveolar damage and, in patients who die from the disease, there is evidence of organization and fibrosis. There are apparently no histological features specific for this disease, and the aetiological diagnosis depends on virological and ultrastructural studies.

Adenovirus type 7 induces interleukin-8 in a lung slice model and requires activation of Erk

Adenovirus (Ad), particularly Ad type 7 (Ad7), causes severe lung infection and pneumonia. Initially, Ad causes neutrophilic inflammation of the distal airways and alveoli. Interleukin-8 (IL-8) is the major lung neutrophil chemotaxin, and we have shown that Ad7 induces IL-8 release from the A549 alveolar epithelial cell line. We sought to determine whether ex vivo human and bovine lung tissue containing primary pneumocytes could be used as a more accurate and relevant model to study Ad acute inflammation. We found that cultured lung tissue preserved normal lung architecture for more than 10 days. IL-8 was generated upon exposure of the lung organ culture to Ad7. IL-8 production required activation of the Ras/Erk pathway, since a pharmacological inhibitor blocked the appearance of IL-8 in the medium. Both human and bovine lung explants supported replication of Ad7, and immunohistochemistry experiments demonstrated the presence of the Ad hexon antigen within alveolar epithelial cells. These findings show that our novel human lung organ culture accurately reproduces the in vivo infectious disease process. Thus, this organ culture model represents a valuable tool for studying the acute innate immune response to respiratory infections.

Paediatric bronchiectasis in the twenty-first century: experience of a tertiary children's hospital in New Zealand

OBJECTIVE

Despite its decline in developed countries, bronchiectasis appeared to be a common diagnosis in Auckland, New Zealand children. The aims of this study were: to document the number of children in Auckland with bronchiectasis, their severity, clinical characteristics and possible aetiologies; to assess whether there was a relationship between ethnicity and poverty; and to estimate a crude bronchiectasis prevalence rate for New Zealand.

METHODS

A retrospective review of the case histories of all children attending a tertiary children's hospital in Auckland with bronchiectasis diagnosed by high-resolution chest computed tomography (CT) scan, during the period 1998-2000 was undertaken. Data collected included patient demographics, number of hospitalizations pre- and post-diagnosis, lung function tests, radiology and investigations. The New Zealand deprivation 1996 index was applied to the data to obtain a measure of socio-economic status.

RESULTS

Bronchiectasis was found to be common, with an estimated prevalence of approximately one in 6000 in the Auckland paediatric population. It was disproportionately more common in the Pacific Island and Maori children. In Pacific Island children, bronchiectasis not caused by cystic fibrosis was nearly twice as common in the general population than cystic fibrosis. Socio-economic deprivation and low immunization rates may be significant contributing factors. The bronchiectasis seen was extensive. Ninety-three percent had bilateral disease and 64% had involvement of four or more lobes on chest CT scan. A wide range of comorbidities and underlying aetiologies were evident.

CONCLUSIONS

Paediatric bronchiectasis in Auckland, New Zealand, is common but underresourced. Only the most severe cases are being recognized, providing a significant challenge for paediatric health professionals.

Viral pneumonias in adults: radiologic and pathologic findings

Numerous viruses, including influenza virus, measles virus, Hantavirus, adenovirus, herpesviruses, varicella-zoster virus, cytomegalovirus, and Epstein-Barr virus, can cause lower respiratory tract infection in adults. Viral pneumonia in adults can be classified into two clinical groups: so-called atypical pneumonia in otherwise healthy hosts and viral pneumonia in immunocompromised hosts. Influenza virus types A and B cause most cases of viral pneumonia in immunocompetent adults. Immunocompromised hosts are susceptible to pneumonias caused by cytomegalovirus, herpesviruses, measles virus, and adenovirus. The radiographic findings, which consist mainly of patchy or diffuse ground-glass opacity with or without consolidation and reticular areas of increased opacity, are variable and overlapping. Computed tomographic findings, which are also overlapping, consist of poorly defined centrilobular nodules, ground-glass attenuation with a lobular distribution, segmental consolidation, or diffuse ground-glass attenuation with thickened interlobular septa. The radiologic findings reflect the variable extents of the histopathologic features: diffuse alveolar damage (intraalveolar edema, fibrin, and variable cellular infiltrates with a hyaline membrane), intraalveolar hemorrhage, and interstitial (intrapulmonary or airway) inflammatory cell infiltration. Clinical information such as patient age, immune status, community outbreaks, symptom onset and duration, and presence of a rash remain important aids in diagnosis of viral causes.

Latent adenovirus infection in COPD

We have concentrated on the adenovirus as the source of the heightened inflammatory response of the lungs of patients with COPD. We have concentrated in particular on the responses to agents such as lipopolysaccharides and environmental particulates that contaminate the air we breathe, and we have accumulated evidence that the E1A gene of this virus could be the key player in this process. As other intracellular pathogens such as Chlamydia pneumoniae have recently been implicated in the pathogenesis of COPD, our studies on the adenovirus E1A could serve as the model for investigating the interaction between host and extrinsic factors in the chronic progression of this debilitating lung disease.

Internalization of adenovirus by alveolar macrophages initiates early proinflammatory signaling during acute respiratory tract infection

Adenovirus is a common respiratory pathogen which causes a broad range of distinct clinical syndromes and has recently received attention for its potential for in vivo gene delivery. Although adenovirus respiratory tract infection (ARTI) results in dose-dependent, local inflammation, the pathogenesis of this remains unclear. We hypothesized that alveolar macrophages (AMphi) rapidly internalize adenovirus following in vivo pulmonary administration and then initiate inflammatory signaling within the lung. To evaluate the role of AMphi in the induction of lung inflammation during ARTI in vivo, we directly assessed adenovirus uptake by murine AMphi and correlated uptake with the initiation of proinflammatory gene expression. Stimulation of cytokine (tumor necrosis factor alpha [TNF-alpha], interleukin-6 [IL-6], macrophage inflammatory protein-2 [MIP-2], and MIP-1alpha) expression in the lung was evaluated at the level of mRNA (by reverse transcription-PCR [RT-PCR]) and protein (by enzyme-linked immunosorbent assay) and by identification of cells expressing TNF-alpha and IL-6 mRNA in lung tissues (by in situ hybridization) and isolated lung lavage cells (by RT-PCR). Adenovirus, labeled with the fluorescent dye (Cy3), was rapidly and widely distributed on epithelial surfaces of airways and alveoli and was very rapidly ( approximately 1 min) localized within AMphi. At 30 min after infection AMphi but not airway epithelial or vascular endothelial cells expressed mRNA for TNF-alpha and IL-6, thus identifying AMphi as the cell source of initial cytokine signaling. IL-6, TNF-alpha, MIP-2, and MIP-1alpha levels progressively increased in bronchoalveolar lavage fluid after pulmonary adenovirus infection, and all were significantly elevated at 6 h (P < 0.05). To begin to define the molecular mechanism(s) by which adenovirus initiates the inflammatory signaling in macrophages, TNF-alpha expression from adenovirus-infected RAW264.7 macrophages was evaluated in vitro. TNF-alpha expression was readily detected in adenovirus-infected RAW cell supernatant with kinetics similar to AMphi during in vivo infection. Blockage of virus uptake at specific cellular sites, including internalization (by wortmannin), endosome acidification and/or lysis (by chloroquine) or by Ca(2+) chelation (by BAPTA) completely blocked TNF-alpha expression. In conclusion, results showed that during ARTI, (i) AMphi rapidly internalized adenovirus, (ii) expression of inflammatory mediators was initiated within AMphi and not airway epithelial or other cells, and (iii) the initiation of inflammatory signaling was linked to virion uptake by macrophages occurring at a point after vesicle acidification. These results have implications for our understanding of the role of the AMphi in the initiation of inflammation following adenovirus infection and adenovirus-mediated gene transfer to the lung.

Bronchiectasis: a neglected cause of respiratory morbidity and mortality

Bronchiectasis is a progressive condition characterized by irreversible destruction and dilation of airways generally associated with chronic bacterial infections. Although in Western countries, the morbidity and mortality from bronchiectasis is considered to have declined markedly in the modern era, the condition continues to cause significant morbidity and mortality in the south-west Pacific and probably also in South-East Asia. There is a high prevalence in indigenous populations in the region and factors such as poverty, substandard housing, malnutrition, barriers to medical care and inadequate education are all likely to have a major impact on prevalence and outcome of bronchiectasis. Although bronchiectasis has been viewed as a disease of medium and large airways, there is now increasing evidence of the importance of small airways disease in bronchiectasis and that it may play an integral role in pathogenesis. Chronic inflammation of the bronchial wall by mononuclear cells is common to all types of bronchiectasis. A vicious cycle of bacteria (mediated lung toxicity and bacteria) provoked, host-mediated inflammatory lung damage has been described. If progressive lung damage with its attendant morbidity and mortality is to be prevented, this vicious cycle needs to be broken. The two distinct therapeutic goals in bronchiectasis are to reduce morbidity and to prevent progression of underlying disease. It may be possible to modulate the host response directly and thus reduce tissue damage, but the precise role of immuno-modulatory therapy in bronchiectasis is still unclear. The management of this hitherto neglected disease, which reaches almost epidemic proportions in some ethnic groups and is an ongoing source of considerable morbidity and mortality, requires a comprehensive, multidisciplinary approach, which can be modelled on the successful management of chronic asthma in New Zealand.

Viruses and other miscellaneous organisms

Pulmonary infections caused by several types of viruses and other miscellaneous organisms may cause disease in HIV infection. Evidence suggests that pulmonary conditions may result from infections of the lung by HIV itself. Other viruses, most commonly cytomegalovirus, may be primary perpetrators of pneumonitis or may contribute to diseases caused by coexisting infections. Although diagnosis and assessment of the clinical significance of these infections may be difficult, their recognition is of practical importance because potentially effective therapeutic agents are available for several of them. Miscellaneous infections such as pulmonary toxoplasmosis and pertussis are other uncommon but potentially treatable complications of HIV disease.

Adenovirus-mediated gene transfer to ciliated airway epithelia requires prolonged incubation time

The efficiency of adenovirus-mediated gene transfer to airway epithelia will be an important factor in determining whether recombinant adenoviruses can be developed as vectors for transferring cystic fibrosis transmembrane conductance regulator (CFTR) cDNA to patients with cystic fibrosis. Current understanding of the biology of CF lung disease suggests that vectors should express transgene in mature, ciliated airway epithelia. We evaluated the efficiency of adenovirus-mediated gene transfer to primary cultures of normal and CF human airway epithelia. Our studies showed that the airway cells developed from an undifferentiated epithelium with markers characteristic of basal cells and a surface covered by short microvilli 3 days after seeding to a mature epithelium whose apical surface was covered with cilia by 10 to 14 days. The ability of adenovirus vectors to express a reporter gene and to correct defective cyclic AMP-stimulated Cl- transport in CF epithelia was correlated inversely with the state of differentiation. However, the inefficiency of adenovirus-mediated gene transfer could be partially corrected when the contact time between vector and epithelium was prolonged. After prolonged contact, we observed complete correction of the CF Cl- transport defect in differentiated CF airway epithelia in culture and of the Cl- transport defect in the nasal epithelia of mice homozygous for the deltaF508 mutation. The fact that gene transfer to airway epithelia required prolonged incubation with vector contrasts with the rapid infection observed in cell models such as 293 and HeLa cells, which are commonly used to study adenovirus infection. Gene transfer observed after prolonged incubation may result from mechanisms different from those that mediate infection of 293 cells. These observations suggest that interventions that either increase the contact time or alter the epithelium or the vector may be required to facilitate gene transfer to ciliated respiratory epithelia.

Acute and chronic human adenovirus pneumonia: cellular and extracellular matrix components

We present a comparative histopathological study of both acute and chronic human adenovirus pneumonia, with reference to the cellular and extracellular matrix components. Seventeen lungs from autopsied patients whose ages ranged from 2 to 60 months were studied. Adenovirus types 1, 2, 3, 5, and 7 were isolated from 15 patients with acute lung disease, and types 2 and 7 were isolated from the other two patients with chronic pulmonary illness. The results indicated the occurrence of two basic patterns of adenovirus interstitial pneumonia (1) classic pattern (acute), characterized by necrosis and degeneration and many type II pneumocytes with intranuclear inclusion bodies, which were positive for adenovirus DNA by in situ hybridization, and (2) proliferative or proliferative-productive pattern (chronic), which presented with diffuse pulmonary fibrosis and the interstitial proliferation of fibroblast-like cells, compatible with myofibroblasts (positive for vimentin and alpha smooth muscle actin), and increase in collagen types I and III, elastic fibers, and proteoglycans. Alveolar collapse appears to be an important pathogenetic mechanism in the development of this pattern.

Expression of early and late adenoviral proteins in fatal adenovirus bronchopneumonia

The localization and distribution of three adenoviral proteins, hexon, E1A, and 55-kDa E1B, in 16 cases of fatal adenovirus bronchopneumonia in infants and children, are described. The proteins were immunohistochemically demonstrated in paraffin sections using monoclonal antibodies followed by the avidin-biotin-peroxidase method. The hexon antigen was present in inclusion-bearing bronchial, bronchiolar, and alveolar cells, mainly in the so-called rosette cells, as well as in necrotic debris in necrotizing areas. E1A antigen was also recognized in cells with nuclear inclusions where the reaction decorated the inclusion, nuclear chromatin, and cytoplasm but distributed mainly in alveolar cells and to a lesser extent in bronchial and bronchiolar cells. The 55-kDa E1B protein was extensively present in "activated," reactive-appearing, nuclei of bronchial, bronchiolar, and alveolar epithelial cells and in the cytoplasm of rare cells having nuclear inclusions. These activated nuclei did not stain for the other two antigens. "Smudge" cells reacted poorly or not at all with any of the antibodies. The reactivity found produced a sort of complementary pattern between the hexon-positive, inclusion-containing cells and the 55-kDa E1B-positive, inclusion-noncontaining cells. The relationships of present findings and virologic data are discussed.

Adenovirus pulmonary infections identified by PCR and in situ hybridisation in bone marrow transplant recipients

AIMS

To investigate adenovirus pulmonary infections in bone marrow transplant (BMT) recipients.

METHODS

Formalin fixed, paraffin wax embedded lung tissue was examined from 13 necropsy cases after BMT using PCR and in situ hybridisation to detect adenovirus DNA. The E1A region of the adenoviral genome was targeted for PCR. In situ hybridisation was performed only in the PCR positive cases.

RESULTS

Of the 13 lung specimens analysed, nine cases were negative for adenoviral nucleic acid. Four (30%) PCR and two (15%) in situ hybridisation positive cases were found. In some of the patients there were clinical and pathological indications that some diseases might be associated with adenovirus infection--haemorrhagic cystitis (three cases); necrotising pneumonia (one case). In necrotising pneumonia in which no pathogenic agents had been shown by conventional histological study, the in situ hybridisation technique showed positive staining for adenovirus. In a patient who died of renal failure caused by adenovirus nephritis, both PCR and in situ hybridisation were positive in the lung as well as in the kidney, although no histological change was found. Two PCR positive cases lacked positive sites for adenovirus by in situ hybridisation.

CONCLUSIONS

The combination of PCR and in situ hybridisation could be useful for diagnosing adenovirus infection of the lung in BMT recipients. These results provide a basis for exploring further the clinical use of PCR and in situ hybridisation to diagnose adenovirus infection.

Acute responses of non-human primates to airway delivery of an adenovirus vector containing the human cystic fibrosis transmembrane conductance regulator cDNA

Recombinant human adenovirus (Ad) vectors are leading candidates for human gene therapy for cystic fibrosis (CF) based on demonstration of efficient transfer of exogenous genes to rodent respiratory epithelium in vivo and human respiratory cells in vitro. The safety of Ad-mediated gene transfer to the respiratory epithelium and acute (up to 21 days) clinical responses to airway delivery of a replication-deficient recombinant, E1-, E3- Ad type 5-based vector containing the human cystic fibrosis transmembrane conductance regulator cDNA (AdCFTR) were evaluated in rhesus monkeys. Airway delivery of an Ad vector with the lacZ marker gene demonstrated beta-galactosidase expression in epithelial cells. Animals administered intratracheal AdCFTR demonstrated human CFTR cDNA expression in airway epithelial cells. Animals administered AdCFTR intranasal, and 24 hr later, intrabronchial [2 x 10(7) to 5 x 10(10) plaque-forming units (pfu), n = 12], in a fashion similar to a proposed human protocol, or only intrabronchial (10(11) pfu, n = 3), had no significant changes in clinical parameters compared to vehicle controls (n = 6). Microscopic analysis of the lung by necropsy or bronchoalveolar lavage demonstrated a dose-dependent increase in inflammatory cells, primarily lymphocytes, in the area where AdCFTR was delivered, which persisted for at least 2 months in some animals. Serum anti-Ad type 5 neutralizing antibody titers did not rise and shed Ad was not detected. The presence of AdCFTR DNA, analyzed by the polymerase chain reaction (PCR), was not detected in organs outside the lung. These data demonstrate that AdCFTR is well tolerated in non-human primates, although there is dose-dependent inflammation in the lung not clinically apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines in adenoviral disease in children: association of interleukin-6, interleukin-8, and tumor necrosis factor alpha levels with clinical outcome

To explore the pathogenic mechanisms involved in adenovirus infection, we evaluated total levels of immunoglobulins, antiadenovirus antibodies, adenovirus-specific circulating immune complexes, and cytokines in serum samples obtained from 38 hospitalized children with adenovirus infection. According to their clinical findings and outcome, the infections were classified as follows: (1) moderate (group I, n = 10), (2) severe (group II, n = 12), and (3) fatal (group III, n = 16). About 60% of the children had elevated IgM levels. IgG-containing adenovirus-specific circulating immune complexes were initially detected in 7 of 16 group III patients, 4 of whom had low serum levels of the third component of complement. A decrease in initial antiadenovirus IgG antibodies was observed in 3 of 10 patients in group III. Serum interleukin-6 was not detected in group I (none of 10), but was present in group II (7 of 12, p = 0.016) and group III (13 of 16, p < 0.001). Interleukin-8 was detected in all groups; values in fatal cases were significantly higher than in surviving children. Tumor necrosis factor alpha was not observed in group I (none of 10) and was uncommon in group II (2 of 12) but was frequently detected in group III (9 of 15, p = 0.01). Interleukin-1 and interleukin-4 were rarely detected in serum samples. Increased concentrations of interleukin-6, interleukin-8, and tumor necrosis factor alpha were associated with hypoperfusion, febrile peaks, tonic-clonic seizures, and septic shock. In 5 of 10 patients in groups II and III, autoantibodies specific for smooth muscle were found. Our findings indicate that high serum values for interleukin-6, interleukin-8, and tumor necrosis factor alpha are associated with severity of adenovirus infection.

Nosocomial adenovirus infection in a paediatric respiratory unit

We report a nosocomial outbreak due to adenovirus in a paediatric respiratory unit serving a poor socio-economic community. Of 207 children admitted during an eight-month period, 24% were neonates; the median age of the remainder was 10 months. Thirty-two cases were found to be infected with adenovirus and of these 67% died. Nine were already infected with adenovirus when admitted. Twenty-three acquired the infection after admission, giving an incidence of nosocomial acquisition of 12% with a 91% mortality rate. All but one of the adenovirus infected children were being ventilated and had an endotracheal tube in place. Nosocomial spread was likely to have been from the hands of attendants, especially those manipulating suction catheters and endotracheal tube or ventilator connections. Risk factors for acquiring nosocomial infection were young age: all but two were < 1 year of age, and a relatively prolonged ward stay necessitated by the nature of the primary condition (pneumonia, bronchiolitis, laryngotracheo bronchitis, tetanus). The measures that were taken to control spread of the virus are described. Despite these, primary cases of adenovirus infection re-introduced the virus regularly over the study period. The genome analysis showed adenovirus types to be 7c2 and 7c.

Adenovirus type 7h respiratory infections: a report of 29 cases of acute lower respiratory disease

Twenty-nine cases of pediatric acute lower respiratory disease associated with adenovirus genome type 7h were evaluated retrospectively. They constituted 2.4% of 1233 cases of acute respiratory infections treated in five hospitals in Buenos Aires, between September 1984 and September 1988. Pneumonia and bronchiolitis were the principal diagnoses. The mean age of patients was 8.8 months and 82.7% of the children were less than one year of age. None of the patients had previously been exposed to measles or was immunocompromised. A mixed infection, viral or bacterial, was demonstrated in 8 of the 29 patients. Sixteen children developed a severe pulmonary disease which required intensive care. Ten with a clinical diagnosis of multifocal pneumonia and necrotizing bronchiolitis died. Extrapulmonary manifestations were observed in the most severe cases. Observations suggest a possible high pathogenicity of adenovirus type 7h and emphasize the need for adequate control and case management programs.

Pathogenesis of adenovirus type 5 pneumonia in cotton rats (Sigmodon hispidus)

Cotton rats (Sigmodon hispidus) were inoculated intranasally with 10(2.0) to 10(10.0) PFU of human adenovirus type 5. The virus replicated to a high titer in pulmonary tissues, with the peak titer being proportional to the input dose. The 50% lethal dose was 10(9.4) PFU. Histopathologic changes were proportional to the infecting inoculum and included the infiltration of interstitial and intra-alveolar areas, moderate damage to bronchiolar epithelium, and cellular infiltration of peribronchiolar and perivascular regions. These changes could be divided into two phases: an early phase (affecting alveoli, bronchiolar epithelium, and peribronchiolar regions) with an infiltrate consisting primarily of monocytes-macrophages and neutrophils, with occasional lymphocytes, and a later phase (affecting peribronchiolar and perivascular regions) with an infiltrate consisting almost exclusively of lymphocytes. In both phases, the predominant process was the response of the host to infection, rather than direct viral damage to infected cells. An infecting inoculum of 10(8.0) PFU or larger caused severe damage to type II alveolar cells, which were swollen, showed a loss of lamellar bodies, and were surrounded by polymorphonuclear leukocytes and macrophages. No evidence of complete viral replication was found in type II alveolar cells.

Participation of immune complexes in adenovirus infection

To determine the participation of immune complexes during adenovirus infection, we evaluated serum and necropsy specimens of patients with confirmed adenovirus infection of the lower respiratory tract. In lung and kidney from seven dead patients, immunofluorescence revealed the presence of hexon, immunoglobulins and complement. These patients had clinical manifestations of kidney dysfunction. In dead patients (3/3 in whom serum was available) neither anti-adenovirus antibodies nor adenovirus-specific immune complexes could be found in the final stage of the infection. However, two of these patients had anti-adenovirus antibodies and immune complexes in samples obtained early in the infection. Most patients (16/19) who survived the infection had circulating anti-adenovirus antibodies. Half also had immune complexes specific for adenovirus in some moment of the illness. This suggests that immune complexes arise during respiratory infection by adenovirus, probably contributing to its clinical picture.

Latent adenoviral infection in the pathogenesis of chronic airways obstruction

Childhood infection of the respiratory tract has been proposed as an independent risk factor in the pathogenesis of the chronic obstructive pulmonary disease (COPD) that develops in cigarette smokers. The present study examines adult lung tissue for latent adenoviral DNA because many of its 41 serotypes cause childhood respiratory disease and the virus is known to persist in other tissues in a latent form. Lung tissue resected for solitary nodules from 20 patients with airways obstruction and 20 patients without airways obstruction, matched for age, sex, and smoking history, were compared to determine whether adenoviral DNA is more commonly found in patients with COPD. The polymerase chain reaction (PCR) was used to examine two widely separated segments of the adenoviral genome. In situ hybridization (ISH) was performed using a probe covering the entire viral genome to determine the types of cell infected by the virus. The PCR analysis showed that a 675 base pair target sequence of the E1A region of the adenovirus was present in most of the lungs studied with greater copy numbers in the smokers with airways obstruction in both paraffin-embedded (p less than 0.002) and frozen lung tissue (p less than 0.016), whereas the E3/19K region showed no difference between the groups. When sufficient copy numbers were present to localize the DNA by ISH it was found in epithelial cells of the smokers who had airways obstruction. These data are consistent with a current model of adenoviral integration into host DNA and suggest that the E1A region of the adenovirus may contribute to the pathogenesis of COPD.