Latent adenovirus infection in COPD

New Insights to Adenovirus-Directed Innate Immunity in Respiratory Epithelial Cells

The nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) family of transcription factors is a key component of the host innate immune response to infectious adenoviruses and adenovirus vectors. In this review, we will discuss a regulatory adenoviral protein encoded by early region 3 (E3) called E3-RIDα, which targets NFκB through subversion of novel host cell pathways. E3-RIDα down-regulates an EGF receptor signaling pathway, which overrides NFκB negative feedback control in the nucleus, and is induced by cell stress associated with viral infection and exposure to the pro-inflammatory cytokine TNF-α. E3-RIDα also modulates NFκB signaling downstream of the lipopolysaccharide receptor, Toll-like receptor 4, through formation of membrane contact sites controlling cholesterol levels in endosomes. These innate immune evasion tactics have yielded unique perspectives regarding the potential physiological functions of host cell pathways with important roles in infectious disease.

Viral Profile of COPD Exacerbations According to Patients

Background :

To compare the differences between elderly and non-elderly patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) due to viral infections.

Methods :

Patients with chronic obstructive pulmonary disease (COPD) exacerbation were recruited and classified as elderly (>65 years) and non-elderly (≤ 65 years). Sputum and oropharyngeal samples were assessed, PCR for respiratory viruses and cultures for common pathogens were performed.

Results :

247 patients (median age: 69.3±9.5 years) were recruited and categorized into group A: non-elderly patients [n=81 (32.8%), median age 58±5.99] and group B: elderly patients [n=166 (67.2%), median age 74.8±4.8] years. In 133 (53.8%) patients a viral infection was identified and in 34 (13.8%) a bacterial pathogen was isolated from cultures. In 18 (7.3%) patients a double infection (bacterial+viral) was identified. In group B, the presence of cardiac failure (46.6% vs 28.3%, p<0.001), renal failure (10.5% vs 4%, p=0.03), bacterial co-infection (13.8% vs 7.4%, p=0.04), influenza vaccination rates (45.5% vs 215, p<0.001), and longer hospital stay (8.4±4.4 vs 7.5±3.2 days, p=0.02) were higher than group A. The overall rate of viral infections did not differ according to age. A trend to higher rates of infection with parainfluenza 3 [19 (20%) patients in group B vs3 (7.5%) patients in group A, p=0.04] was observed in older patients.

Conclusion :

No differences on the rate and type of viral infections were noted for elderly vs non elderly patients. However, they tended to have more bacterial co-infections that led to AECOPD and longer hospitalization stays compared to non-elderly patients.

Adenovirus-specific IgG maturation as a surrogate marker in acute exacerbations of COPD

BACKGROUND

B cells in airways and lung parenchyma may be involved in COPD evolution; however, whether their pathogenic role is beneficial or harmful remains controversial. The objective of this study was to investigate the maturation of adenovirus-specific immunoglobulins in patients with COPD with respect to clinical outcome.

METHODS

The presence of adenovirus-specific immunoglobulins during acute exacerbation of COPD (AECOPD) was analyzed at exacerbation and 2 to 3 weeks later. Patients with detectable adenovirus-specific IgM and low IgG avidity were grouped into fast and delayed IgG maturation. The clinical outcome of both groups was evaluated.

RESULTS

Of 208 patients, 43 (20.7%) had serologic evidence of recent adenovirus infection and were grouped by fast IgG maturation (26 patients) and delayed IgG maturation (17 patients). Baseline characteristics, AECOPD therapy, and duration of hospitalization were similar in both groups, but the AECOPD recurrence rate within 6 months was higher (P = .003), and there was a trend for earlier AECOPD-related rehospitalizations (P = .061) in the delayed IgG maturation group. The time to rehospitalization or death within 2 years was shorter in patients with delayed IgG maturation (P = .003). Adenovirus-specific IgG maturation was an independent predictor of the number of AECOPD recurrences within 6 months (P = .001) and the occurrence of hospitalization or death within 2 years (P = .005).

CONCLUSIONS

Delayed immunoglobulin avidity maturation following COPD exacerbation is associated with worse outcomes.

TRIAL REGISTRY

ISRCTN Register; No.: ISRCTN77261143; URL: www.isrctn.org.

Prevalence and quantitation of adenovirus DNA from human tonsil and adenoid tissues

In this study, real-time PCR was used to quantify adenovirus DNA in cell suspensions prepared from 106 right and left tonsils and 10 adenoids obtained from 57 patients who underwent routine tonsillectomies and/or adenoidectomies. Eighty-four (72.4%) tonsils and adenoids samples were positive for HAdV by real-time PCR. The viral load ranged from 2.8 × 10(2) to 2.6 × 10(6) copies/10(7) cells and varied up to sixfold between the right and left tonsils. In some cases, only one tonsil was positive and the viral load was lower in older children. Seventy-eight of 84 positive samples could be typed by sequencing of the hexon L1 region. Species C (types 1, 2, and 5) were detected in 84.1% of the patients followed by types 3 and 7 of species B (6.8%), HAdV-E4 (6.8%), and HAdV-F41 (2.3%). In one patient adenovirus C2 was found in the left tonsil and adenovirus C5 in the right tonsil. No DNA methylation was detected in either the E1A promoter or the major late promoter region of adenovirus DNA from six tonsils and adenoids samples and two clinical isolates.

Virus reactivation: a panoramic view in human infections

Viruses are obligate intracellular parasites, relying to a major extent on the host cell for replication. An active replication of the viral genome results in a lytic infection characterized by the release of new progeny virus particles, often upon the lysis of the host cell. Another mode of virus infection is the latent phase, where the virus is 'quiescent' (a state in which the virus is not replicating). A combination of these stages, where virus replication involves stages of both silent and productive infection without rapidly killing or even producing excessive damage to the host cells, falls under the umbrella of a persistent infection. Reactivation is the process by which a latent virus switches to a lytic phase of replication. Reactivation may be provoked by a combination of external and/or internal cellular stimuli. Understanding this mechanism is essential in developing future therapeutic agents against viral infection and subsequent disease. This article examines the published literature and current knowledge regarding the viral and cellular proteins that may play a role in viral reactivation. The focus of the article is on those viruses known to cause latent infections, which include herpes simplex virus, varicella zoster virus, Epstein-Barr virus, human cytomegalovirus, human herpesvirus 6, human herpesvirus 7, Kaposi's sarcoma-associated herpesvirus, JC virus, BK virus, parvovirus and adenovirus.

Susceptibility of the aging lung to environmental injury

With an ever-increasing number of elderly individuals in the world, a better understanding of the issues associated with aging and the environment is needed. The respiratory system is one of the primary interfaces between the body and the external environment. An expanding number of studies suggest that the aging pulmonary system (>65 years) is at increased risk for adverse health effects from environmental insult, such as by air pollutants, infection, and climate change. However, the mechanism(s) for increased susceptibility in this subpopulation are not well understood. In this review, we provide a limited but comprehensive overview of how the lung ages, examples of environmental exposures associated with injury to the aging lung, and potential mechanisms underlying the increased vulnerability of the aging lung to injury from environmental factors.

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.

In vivo potential effects of adenovirus type 5 E1A and E1B on lung carcinogenesis and lymphoproliferative inflammation

Triggering uncontrolled cellular proliferation, chronic inflammation, and/or disruption of p53 activity is critical for tumorigenesis initiated by latent viral oncogenes. The adenovirus type 5 (Ad5) early genes E1A and E1B can maintain lifelong latency in the lungs of patients with chronic pulmonary diseases. To determine the in vivo effects of the latent Ad5 E1A and E1B oncogenes, we have examined the influence of Ad5 E1A and E1B gene products on mouse lung carcinogenesis and inflammation by generation and characterization of lung-specific transgenic mouse models. Here, we show that either the Ad5 E1A 243-amino-acid (aa) protein or the E1B 58-kDa protein was dominantly expressed in the transgenic lung. Preferential expression of Ad5 E1A 243-aa protein alone was not sufficient to induce lung carcinogenesis but resulted in low-grade cellular proliferation and high-grade lymphoproliferative inflammation in the lung. The presence of Ad5 E1B dramatically enhanced the expression of the E1A 243-aa protein, in addition to impairing p53 and apoptosis response, resulting in uncontrolled cellular proliferation, lymphoproliferative inflammation, and metastatic carcinomas in the lung after a period of latency. Our studies may provide clues to understanding the potential in vivo biological effects of Ad5 E1A and E1B latent in the lung and a new scope for assessing in vivo functions of viral genes latent in the infection target tissue.

Lung tissue and tumour-infiltrating T lymphocytes in patients with non-small cell lung carcinoma and chronic obstructive pulmonary disease (COPD): moderate/severe versus mild stage of COPD

Cytotoxic CD8+ T cells have been suggested to be key players in the pathogenesis of chronic obstructive pulmonary disease (COPD). We wanted to investigate the phenotype of lung tissue T lymphocytes (LTL) and tumour-infiltrating T lymphocytes (TIL) in smokers with peripheral non-small cell lung carcinoma (NSCLC) with moderate/severe versus mild COPD. Lung tissue and tumour samples were obtained from patients with moderate/severe stage of COPD (n = 10) and from patients with mild stage of COPD (n = 7) at lung resection for a solitary peripheral NSCLC, processed and analysed by flow cytometry. The flow-cytometric results showed that lung tissue T cells, regardless of the severity of COPD, were mostly of the activated phenotype, expressed the CXCR3 chemokine receptor characteristic of type 1 T cells, and did neither significantly differ in the expression of activation markers (CD69, CD25 and HLA-DR), differentiation markers (CD27 and CD28) and chemokine receptors (CXCR3 and CCR4) between the selected groups, nor showed any significant correlation with lung function measured as forced expiratory volume in 1 s (FEV1) or TLCO. Compared with LTL, a significantly greater proportion of TIL expressed the activation markers CD69 and CD25, but a lower proportion showed a fully differentiated CD27- 28- phenotype. We conclude that lung LTL patterns are similar in NSCLC patients with moderate/severe or mild stages of COPD, and are not significantly related to lung function. LTL and TIL possess different phenotype characteristics. The majority of tumour tissue T cells are activated, but it seems that their process of differentiation is incomplete.

Acute and latent adenovirus in COPD

INTRODUCTION

The COPD airway is infiltrated with CD8+ T cells, which has led to a virus being implicated in its pathogenesis. Some investigators have suggested a role for the persistence of the adenovirus E1A in bronchial epithelial cells. We examined respiratory tract specimens from COPD patients for the presence of E1A DNA and mRNA using real-time PCR.

METHODS

Nucleic acid extraction was performed on sputum specimens from patients with COPD. Copy numbers for GAPDH, and adenovirus 5 E1A DNA and mRNA were determined using a quantitative real-time PCR assay. All samples were screened for the adenovirus hexon gene using nested PCR.

RESULTS

One hundred and seventy-one patients, 80 male, aged 68.9+/-9.8 years with COPD were recruited. One hundred and thirty-six were seen during an exacerbation when admitted to hospital, 33 of whom were reviewed when clinically stable along with an additional 35 stable COPD patients. Ten patients in the exacerbation group were positive for the adenovirus hexon gene (7%), as were four in the stable group (6%). Only two patients in the exacerbation group were positive for adenovirus 5 E1A. Only one patient in the stable COPD group had detectable E1A DNA/mRNA and also tested positive for the adenovirus hexon gene.

CONCLUSION

Adenovirus is detected in similar frequencies in exacerbated and stable COPD patients. Adenovirus E1A DNA is infrequently detected in respiratory secretions from patients with COPD. Our data suggest that the persistence of adenovirus 5 E1A in lung cells of sputum samples in patients with COPD occurs infrequently.

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.

Pulmonary immunity to viral infection: adenovirus infection of lung dendritic cells renders T cells nonresponsive to interleukin-2

Adenovirus (Ad) infection has been identified as predisposing hosts to the development of pulmonary disease through unknown mechanisms. Lung dendritic cells (DCs) are vital for initiating pulmonary immune responses; however, the effects of Ad infection on primary lung DC have not been studied. In contrast to the effects on bone marrow- and monocyte-derived DCs, the current study shows that Ad infection of murine BALB/c lung DCs in vitro and in vivo suppresses DC-induced T-cell proliferation. The effect of Ad on DCs was not due to a downregulation of major histocompatibility complex or costimulatory molecules. Analysis of the production of interleukin-12 (IL-12), alpha interferon (IFN-alpha), and IFN-gamma by the Ad-infected DCs shows no significant differences over noninfected control lung DCs. Ad-induced suppression was not due to a deficiency of IL-2 or other DC-secreted factors and was dependent on viral protein synthesis, as UV irradiation of Ad abrogated the suppressive effect. Results suggest that Ad-infected DCs induce T cells to be nonresponsive to IL-2 during primary coculture, as the addition of IL-2 in secondary cultures recovered T-cell proliferation. In vivo studies supported in vitro results showing that Ad infection resulted in lung T cells with decreased proliferative ability. This study demonstrates that Ad infection induces local immunoincompetence by altering DC-T-cell interactions.