Differential effects of respiratory syncytial virus and adenovirus on mononuclear cell cytokine responses

Comparison of clinical characteristics and inflammatory cytokines between hypoxemic and non-hypoxemic human adenovirus 55 pneumonia

Background

Human adenovirus (HAdV) can cause severe community-acquired pneumonia, but there are few studies on the associated cytokine patterns. The purpose of this study was to analyze the relationship between inflammatory cytokine and severity of adenovirus pneumonia.

Methods

This was a prospective observational study. We evaluated pneumonia patients admitted to the Armed Forces Capital Hospital in Korea. On admission, blood samples were acquired from patients who showed signs of pneumonia. HAdV infection was diagnosed using Real-Q RV detection Kit, and types of HAdV were confirmed by nucleotide blast analysis. We used enzyme-linked immunosorbent assays (ELISAs) to quantify the serum levels of cytokines [interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, γ-interferon (IFN-γ), and IL-10]. We evaluated clinical characteristics and cytokine patterns.

Results

Of 74 pneumonia patients, respiratory specimens from 43 tested positive for HAdV-55, and the other 31 tested negatives. The length of hospital stay was significantly longer in the HAdV group. The serum concentrations of IL-6, IL-8, IL-10, and IFN-γ were all significantly higher in the HAdV group. Of the 43 HAdV pneumonia patients, 6 evidenced PaO₂/FiO₂ (PF) ratio <300, and 37 did not. Compared to the non-hypoxemic group, the hypoxemic group showed significantly lower lymphocyte and monocyte counts, and increased IL-6 and IFN-γ concentrations. Logistic regression analysis showed that the IL-6, IL-10, and IFN-γ were significantly associated with hypoxemia in the HAdV group. The IL-6, and IFN-γ levels correlated significantly with the PF ratio.

Conclusions

We found that the levels IL-6, IL-10, and IFN-γ were significantly associated with hypoxemia in patients with HAdV-55 pneumonia.

Human adenovirus type 7 infection causes a more severe disease than type 3

Background

Human adenovirus type 3 (HAdV-3) and 7 (HAdV-7) cause significant morbidity and develop severe complications and long-term pulmonary sequelae in children. However, epidemiologic reports have suggested that nearly all highly severe or fatal adenoviral diseases in children are associated with HAdV-7 rather than HAdV-3. Here, we conduct in-depth investigations to confirm and extend these findings through a comprehensive series of assays in vitro and in vivo as well as clinical correlates.

Methods

A total of 8248 nasopharyngeal aspirate (NPA) samples were collected from hospitalized children with acute respiratory infections in Children’s Hospital of Chongqing Medical University from June 2009 to May 2015. Among 289 samples that tested positive for HAdVs, clinical data of 258 cases of HAdV-3 (127) and HAdV-7 (131) infections were analyzed. All HAdV-positive samples were classified by sequencing the hexon and fiber genes, and compared with clinical data and virological assays. We also performed in vitro assays of virus quantification, viral growth kinetics, competitive fitness, cytotoxicity and C3a assay of the two strains. Mouse adenovirus model was used to evaluate acute inflammatory responses.

Results

Clinical characteristics revealed that HAdV-7 infection caused more severe pneumonia, toxic encephalopathy, respiratory failure, longer mean hospitalization, significantly lower white blood cell (WBC) and platelet counts, compared to those of HAdV-3. In cell culture, HAdV-7 replicated at a higher level than HAdV-3, and viral fitness showed significant differences as well. HAdV-7 also exhibited higher C3a production and cytotoxic effects, and HAdV-7-infected mice showed aggravated pathology and higher pulmonary virus loads, compared to HAdV-3-infected mice. Macrophages in BALF remained markedly high during infection, with concomitant increase in pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, and IL-6), compared HAdV-3 infection.

Conclusions

These results document that HAdV-7 replicates more robustly than HAdV-3, and promotes an exacerbated cytokine response, causing a more severe airway inflammation. The findings merit further mechanistic studies that offer the pediatricians an informed decision to proceed with early diagnosis and treatment of HAdV-7 infection.

Severity of Respiratory Syncytial Virus Lower Respiratory Tract Infection With Viral Coinfection in HIV-Uninfected Children

Background.

Molecular diagnostics enable sensitive detection of respiratory viruses, but their clinical significance remains unclear in pediatric lower respiratory tract infection (LRTI). We aimed to determine whether viral coinfections increased life-threatening disease in a large cohort.

Methods.

Molecular testing was performed for respiratory viruses in nasopharyngeal aspirates collected from children aged <5 years within 24 hours of hospital admission during sentinel surveillance for severe acute respiratory illness (SARI) hospitalization conducted in South Africa during February 2009–December 2013. The primary outcome was life-threatening disease, defined as mechanical ventilation, intensive care unit admission, or death.

Results.

Of 2322 HIV-uninfected children with respiratory syncytial virus (RSV)–associated LRTI, 1330 (57.3%) had RSV monoinfection, 38 (1.6%) had life-threatening disease, 575 (24.8%) had rhinovirus, 347 (14.9%) had adenovirus (ADV), and 30 (1.3%) had influenza virus. RSV and any other viral coinfection was not associated with severe disease (odds ratio [OR], 1.4; 95% confidence interval [CI], OR, 0.74; 95% CI, .39–1.4), ADV coinfection had increased odds of life-threatening disease (adjusted OR, 3.4; 95% CI, 1.6–7.2; P = .001), and influenza coinfection had increased odds of life-threatening disease and prolonged length of stay (adjusted OR, 2.1; 95% CI, 1.0–4.5; P = .05) compared with RSV monoinfection.

Conclusions.

RSV coinfection with any respiratory virus is not associated with more severe disease when compared to RSV alone in this study. However, increased life-threatening disease in RSV-ADV and RSV-influenza coinfection warrants further study.

Clinical characteristics and factors predicting respiratory failure in adenovirus pneumonia

Background and objective

Limited data exist regarding factors predicting respiratory failure (RF) in non‐immunocompromised patients with adenovirus (AdV) pneumonia.

Methods

We described characteristics of AdV pneumonia (n = 91) versus non‐AdV pneumonia (n = 55) and compared clinico‐laboratory and radiological characteristics in patient groups categorized by RF.

Results

All 91 AdV pneumonia patients presented with acute respiratory symptoms and radiological infiltrations and had significantly lower levels of white blood cell counts and platelet counts compared with non‐AdV pneumonia. Of them, 67 patients had mild pneumonia without RF (non‐RF), 14 patients had no RF at admission but progressed to RF during hospitalization (progressed to RF) and 10 patients had RF at admission (initial RF). Initial monocyte percentage and absolute monocyte counts in RF patient groups (progressed to RF and initial RF) were significantly lower than those of non‐RF patients (both P < 0.001), and the differences among progressed to RF and initial RF patients were not significant. Chest computed tomography findings such as dominant pattern or distribution, clinical symptoms, and bacterial or viral co‐infections other than AdV were not discriminable between patients who had RF and those who did not. On univariate analysis, initial monocytopenia, multilobar infiltrations and pleural effusion were associated with RF. However, on multivariable analysis, only initial monocytopenia remained significant (P = 0.004) for predicting RF.

Conclusion

Our data suggest that initial monocytopenia may help to predict RF during the course of AdV pneumonia in non‐immunocompromised patients.

We described the characteristics of adenovirus (AdV) pneumonia in non‐immunocompromised adult patients and evaluated factors predicting the occurrence of respiratory failure (RF). Our data suggest that initial monocytopenia may help to predict RF during an AdV pneumonia in non‐immunocompromised adult patients.

Facile and rapid detection of respiratory syncytial virus using metallic nanoparticles

Background

Respiratory syncytial virus (RSV) causes severe respiratory infection in infants, children and elderly. Currently, there is no effective vaccine or RSV specific drug for the treatment. However, an antiviral drug ribavirin and palivizumab is prescribed along with symptomatic treatment. RSV detection is important to ensure appropriate treatment of children. Most commonly used detection methods for RSV are DFA, ELISA and Real-time PCR which are expensive and time consuming. Newer approach of plasmonic detection techniques like localized surface plasmon resonance (LSPR) spectroscopy using metallic nanomaterials has gained interest recently. The LSPR spectroscopy is simple and easy than the current biophysical detection techniques like surface-enhanced Raman scattering (SERS) and mass-spectroscopy.

Results

In this study, we utilized LSPR shifting as an RSV detection method by using an anti-RSV polyclonal antibody conjugated to metallic nanoparticles (Cu, Ag and Au). Nanoparticles were synthesized using alginate as a reducing and stabilizing agent. RSV dose and time dependent LSPR shifting was measured for all three metallic nanoparticles (non-functionalized and functionalized). Specificity of the functionalized nanoparticles for RSV was evaluated in the presence Pseudomonas aeruginosa and adenovirus. We found that functionalized copper nanoparticles were efficient in RSV detection. Functionalized copper and silver nanoparticles were specific for RSV, when tested in the presence of adenovirus and P. aeruginosa, respectively. Limit of detection and limit of quantification values reveal that functionalized copper nanoparticles are superior in comparison with silver and gold nanoparticles.

Conclusions

The study demonstrates successful application of LSPR for RSV detection, and it provides an easy and inexpensive alternative method for the potential development of LSPR-based detection devices.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0167-z) contains supplementary material, which is available to authorized users.

Postinfectious bronchiolitis obliterans in children: the South American contribution

Postinfectious bronchiolitis obliterans (PIBO) is an infrequent chronic lung that causes irreversible obstruction and, or, obliteration of the smaller airways. This review particularly focuses on more than 30 studies from South America.

CONCLUSION

The initial PIBO event occurs in the early years of life and is strongly associated with adenovirus infection and the need for mechanical ventilator support. Treatment requires a multidisciplinary strategy. Multicentre studies are needed to determine progression, optimal management and long-term follow-up.

Cross-sectional study of the relationship of peripheral blood cell profiles with severity of infection by adenovirus type 55

Background

The immunologic profiles of patients with human adenovirus serotype 55 (HAdV-55) infections were characterized in subjects diagnosed with silent infections (n = 30), minor infections (n = 27), severe infections (n = 34), and healthy controls (n = 30) during a recent outbreak among Chinese military trainees.

Methods

Blood was sampled at the disease peak and four weeks later, and samples were analyzed to measure changes in leukocyte and platelet profiles in patients with different severities of disease. Differential lymphocyte subsets and cytokine profiles were measured by flow cytometry and Luminex xMAP®, and serum antibodies were analyzed by ELISA and immunofluorescence staining.

Results

Patients with severe HAdV infections had higher proportions of neutrophils and reduced levels of lymphocytes (p < 0.005 for both). Patients with minor and severe infections had significantly lower platelet counts (p < 0.005 for both) than those with silent infections. The silent and minor infection groups had higher levels of dendritic cells than the severe infection group. Relative to patients with silent infections, patients with severe infections had significantly higher levels of IL-17⁺CD4⁺ cells, decreased levels of IL-17⁺CD8⁺ cells, and higher levels of IFN-γ, IL-4, IL-10, and IFN-α2 (p < 0.001 for all comparisons).

Conclusions

Patients with different severities of disease due to HAdV-55 infection had significantly different immune responses. These data provide an initial step toward the identification of patients at risk for more severe disease and the development of treatments against HAdV-55 infection.

Predictors of severity and mortality in children hospitalized with respiratory syncytial virus infection in a tropical region

INTRODUCTION

Respiratory syncytial virus (RSV) is one of the leading causes of acute lower respiratory infection (ALRI) in infants and young children. Although ALRI is a major public health problem in developing countries located in tropical areas, studies about RSV epidemiology in these regions are scarce.

METHODS

In a retrospective cohort study, we investigated the epidemiology and predictive variables that reflect disease severity and mortality in young children hospitalized with ALRI due to RSV in Colombia, South-America, during a 2-year period (2009-2011).

RESULTS

Of a total of 6,344 children with a diagnosis of ALRI, we selected 2,147 (33.8%) that were positive for RSV. After controlling for pre-existing conditions, we found that independent predictors of severe disease in our population included age <6 months (RR 2.01; CI 95% 1.70-2.38; P < 0.001), prematurity (RR 1.61; CI 95% 1.20-2.17; P = 0.001), congenital heart disease (RR 2.03; CI 95% 1.16-3.54; P = 0.013), and mixed RSV-adenovirus infection (RR 2.09; CI 95% 1.60-2.73; P < 0.001). Multivariate analysis identified that cancer (RR 31.60; CI 95% 5.97-167.13; P < 0.001) is a predictor of mortality in our RSV-infected pediatric population independently of age and other co-morbidities.

CONCLUSIONS

RSV is an important cause of ALRI in infants and young children living in tropical regions, especially during the rainy season. The identified predictors of severe disease and mortality should be taken into account when planning interventions to reduce the burden of ALRI in young children living in these regions.

Adenovirus respiratory infection in hospitalized children in Hong Kong: serotype-clinical syndrome association and risk factors for lower respiratory tract infection

Lower respiratory tract infections (LRTI) caused by adenovirus can be severe with resultant chronic pulmonary sequelae. More than 50 serotypes have been recognized; however, the exact association of serotype with clinical phenotype is still unclear. There have been no reports on the adenovirus serotype pattern in Hong Kong, and their relationships with disease manifestations and complications are not known. Clinical and epidemiological data on 287 children (<6 years old) admitted with adenovirus respiratory infections from 2001 to 2004 were reviewed. Common presenting symptoms included fever (97.9 %) and cough and rhinitis (74 %). Extra-pulmonary manifestations were present in 37.3 %. The clinical picture mimicked bacterial infection for its prolonged high fever and neutrophilic blood picture. Forty-two patients (14.6 %) had LRTI, either pneumonia or acute bronchiolitis, but none had severe acute respiratory compromise. Children aged 1 to 2 years old were most at risk for adenovirus LRTI (adjusted p = 0.0165). Serotypes 1 to 7 could be identified in 93.7 % of the nasopharyngeal specimens, with serotypes 2 and 3 being the most prevalent. Different serotypes showed predilection for different age groups and with different respiratory illness association. The majority of acute bronchiolitis (71.4 %) were associated with serotype 2 infection, and this association was statistically significant (p < 0.0001). Serotype 3 infection accounted for over half of the pneumonia cases (57-75 %) in those aged 3-5 years old. Only one patient developed mild bronchiectasis after serotype 7 pneumonia. Children aged 1 to 2 years old were the at-risk group for adenovirus LRTI, but respiratory morbidity was relatively mild in our locality. There was an apparent serotype-respiratory illness association.

Adenoviruses types, cell receptors and local innate cytokines in adenovirus infection

Adenovirus is a common infectious pathogen in both children and adults. It is a significant cause of morbidity in immunocompetent people living in crowded living conditions and of mortality in immunocompromised hosts. It has more recently become a popular vehicle for gene therapy applications. The host response to wild-type infection and gene therapy vector exposure involves both virus entry receptor and the innate immune systems. Cell-mediated recognition of viruses via capsid components has received significant attention, principally thought to be regulated by the coxsackievirus-adenovirus receptor (CAR), CD46, integrins and heparin sulfate-containing proteoglycans. Antiviral innate immune responses are initiated by the infected cell, which activates the interferon response to block viral replication, while simultaneously releasing chemokines to attract neutrophils and NK cells. This review discusses the innate immune response primarily during wild-type adenovirus infection because this serves as the basis for understanding the response during both natural infection and exposure to adenovirus vectors.

Cytokine patterns associated with a serotype 8 fowl adenovirus infection

This study examined cytokine gene expression patterns associated with fowl adenovirus (FAdV) infection. The selected cytokine mRNA was quantified by quantitative real-time reverse transcription-PCR in spleen, liver, and cecal tonsil during the course of infection of chickens with a serotype 8 FAdV (FAdV-8). Compared to uninfected chickens, infected birds had higher mRNA expression of interleukin (IL)-18 and IL-10 in spleen and liver, respectively. Interferon gamma (IFN-γ) mRNA expressed in spleen and liver of infected chickens was significantly upregulated, while the expression of IL-8 mRNA in spleen and liver of infected chickens was significantly downregulated. There was no significant difference between infected and uninfected groups in terms of cytokine gene expression in cecal tonsil. These results indicate that these four cytokines might play an important role in driving the immune responses following FAdV-8 infection.

[Post-infectious bronchiolitis obliterans]

Post-infectious bronchiolitis obliterans (BO) is characterized by inflammatory and fibrotic lesions of small airways following a pulmonary infection and leading to some degree of airway obstruction. It represents a rare cause of chronic obstructive pulmonary disease, and is probably underestimated, especially when the lesions affect small areas of the lungs. The clinical features differ between children and adults. In children, adenovirus is the most frequently involved infectious agent, especially the more virulent serotypes 3, 7 and 21. The clinical and radiological signs vary widely and the functional outcome depends on the extent of the lung injury. The diagnosis is based on the medical history, the CT-scan and functional data. The treatment is symptomatic. The most severe forms may result in chronic respiratory insufficiency. In adults, the frequency of obstructive injuries of the small airways in the context of lung infection is unclear. Parenchymal lesions are often present, resulting in BO with organizing pneumonia. These lesions alter the clinical presentation and the radiographic features of the initial infectious disease and often prove difficult to diagnose and manage. Several authors have published clinical cases describing presumed efficacy of systemic corticosteroids but the data are scarce.

Local interleukin-10 production during respiratory syncytial virus bronchiolitis is associated with post-bronchiolitis wheeze

Background

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants. Following RSV bronchiolitis, 50% of children develop post-bronchiolitis wheeze (PBW). Animal studies have suggested that interleukin (IL)-10 plays a critical role in the pathogenesis of RSV bronchiolitis and subsequent airway hyperresponsiveness. Previously, we showed that ex vivo monocyte IL-10 production is a predictor of PBW. Additionally, heterozygosity of the single-nucleotide polymorphism (SNP) rs1800872 in the IL10 promoter region was associated with protection against RSV bronchiolitis.

Methods

This study aimed to determine the in vivo role of IL-10 in RSV pathogenesis and recurrent wheeze in a new cohort of 235 infants hospitalized for RSV bronchiolitis. IL-10 levels in nasopharyngeal aspirates (NPAs) were measured at the time of hospitalization and the IL10 SNP rs1800872 genotype was determined. Follow-up data were available for 185 children (79%).

Results

Local IL-10 levels during RSV infection turned out to be higher in infants that later developed physician diagnosed PBW as compared to infants without PBW in the first year after RSV infection (958 vs 692 pg/ml, p = 0.02). The IL10 promoter SNP rs1800872 was not associated with IL-10 concentration in NPAs.

Conclusion

The relationship between high local IL-10 levels during the initial RSV infection and physician diagnosed PBW provides further evidence of the importance of the IL-10 response during RSV bronchiolitis.

Swyer-James syndrome with peculiar course and ipsilateral pulmonary vein defect

Swyer-James syndrome (SJS) is a rare disease probably resulting from bronchiolitis obliterans. The radiological findings of this entity are characterized by hyperlucent appearance of one or more lobes of a unilateral lung, decreased lung volume, diminished ipsilateral hilar shadow and hardly visible arterial structure on chest radiography. We report a 50-year-old patient, who had unilateral right lower lung hyperlucency on chest radiography. However, the patient reported a history of pulmonary atelectasis of lobus centralis dexter in the course and the corresponding affliction of ipsilateral pulmonary vein, that rendered the diagnosis more complicated. The radiological and pathological features of this syndrome, as well as differential diagnosis were also discussed.

Post infectious bronchiolitis obliterans in children

Bronchiolitis Obliterans (BO) is an infrequent chronic and obstructive lung disease secondary to an insult to the terminal airway and its surroundings. In children, the most common presentation is the post-infectious variant, closely related to a severe viral infection in the first three years of life. However, the increase in the number of lung and bone-marrow transplants has also been followed by an increase in post-transplant BO. Post-transplant BO is progressive while post-infectious BO does not seem to be, but both forms share some common pathways that result in a characteristic histopathology of bronchiolar obliteration. This review covers up-to-date evidence on epidemiology, diagnosis, treatment and prognosis of post-infectious bronchiolitis obliterans, including areas of controversy that need to be addressed in future studies.

Different cytokine signatures in children with localized and invasive adenovirus infection after stem cell transplantation

HAdV infection is a dangerous complication after pediatric SCT. In this study, we aimed at determining the cytokine profile in plasma samples in case of HAdV infection after SCT to gain more knowledge about the HAdV-specific immune response. In this prospective study, 47 pediatric SCT recipients were included in three yr. By using particle-based MIA, 17 different cytokines were analyzed in 41 plasma samples of patients with a localized HAdV infection (presence of HAdV in feces, urine or throat detected by culture) and patients with invasive HAdV infection (HAdV viremia in blood, detected by PCR). In patients with invasive HAdV infection, but not in patients with localized HAdV infection, the pro-inflammatory cytokines IL1beta, IL6, IL8, IL12, IFNgamma, TNFalpha, and also IL17, MIP1alpha, OSM, and IP10 were produced. The simultaneous release of the cytokines IL1beta, IL17, IL18, OSM, MIP1alpha, and IP10 was related to invasive HAdV infections. We also show that cytokine signatures can be helpful to differentiate invasive HAdV infection from GvHD and EBV infections. In conclusion, after SCT, children with invasive HAdV infection have a different cytokine profile compared with patients with a localized HAdV infection.

Clinical features, adenovirus types, and local production of inflammatory mediators in adenovirus infections

BACKGROUND

Adenovirus infection manifests in many ways, with respiratory and gastrointestinal symptoms predominating.

METHODS

We performed a retrospective chart review on children evaluated at our center who had a nasal wash culture positive for adenovirus. Archived nasal washes were retrieved. Polymerase chain reaction for 15 respiratory viruses was performed on these samples. Patients who were coinfected with another virus were excluded. Adenovirus typing was performed using polymerase chain reaction primers directed at the conserved hexon gene. Bead proteomics was used to measure concentrations of inflammatory mediators.

RESULTS

Seventy-eight patients were infected only with adenovirus. The clinical diagnosis was upper respiratory infection in 60%, pneumonia in 18%, febrile seizure in 8%, and bronchiolitis in 6%. Subgroup-C and B1 infections were most common. Seventy percent of patients with upper respiratory infection and all 5 patients with bronchiolitis had a subgroup-C infection; pneumonia was caused by subgroup-B1 and C viruses. Compared with asymptomatic control patients, adenovirus infected patients had higher nasal wash concentrations of interleukin (IL)-1alpha, IL-6, inducible protein-10, macrophage inflammatory protein-1alpha, tumor necrosis factor alpha, monokine induced by gamma interferon, and interferon-alpha (P < 0.05). In addition, we found that IL-8 and IL-1alpha (P < 0.05) were higher in the nasal washes obtained from hospitalized patients than in nonhospitalized patients.

CONCLUSIONS

Adenovirus infection causes an array of clinical disease and is associated with local production of several proinflammatory cytokines. The observation that nasal wash IL-8 and IL-1alpha concentrations were higher in patients requiring hospitalization suggests that these mediators contribute to disease severity.

Comparison of cytokine responses in nasopharyngeal aspirates from children with viral lower respiratory tract infections

Aim: To determine whether nasopharyngeal aspirates (NPAs) cytokine response is different according to the causative viruses in children with lower respiratory tract infections (LRTI).

Methods: NPAs from 277 children with LRTI caused by respiratory virus were evaluated. Based on the proven viral agents, LRTI patients were divided into four groups. Levels of IL‐4, IL‐5 and IFN‐γ were determined by ELISA.

Results: Patients with influenza virus infection demonstrated significantly lower IL‐4 and IL‐5 levels than those with other three groups. Patients with respiratory syncytial virus (RSV) infection showed an increase in production of IL‐4 and IL‐5, and a decrease in the IFN‐γ level when compared to patients with influenza virus infection. Interestingly, a similar Th2 response was seen in patients with parainfluenza virus or adenovirus infection.

Conclusion: These results demonstrate that respiratory viruses can induce different local cytokine responses. However, Th2 biased responses are not unique for RSV but seem to be predominant in respiratory viruses of young children.

Serum interferon-gamma, interleukin-4, and interleukin-6 in infants with adenovirus and respiratory syncytial virus infection

BACKGROUND

To characterize adenoviral (ADV) infection, the clinical symptoms, laboratory findings and serum cytokine concentrations were evaluated in ADV patients and compared with those in patients with respiratory syncytial virus (RSV) infections.

METHODS

A total of 63 patients who had been diagnosed with ADV infections or RSV on an antigen detection test were enrolled in the present study between December 2002 and March 2004. Forty patients had RSV infection and 23 patients had ADV infection. Serum cytokine (interleukin [IL]-4,6 and interferon [IFN]-gamma) concentrations were analyzed. Concentration of IL-6 in both infection groups was analyzed regardless of whether the patients had been given steroids (dexamethaxone or prednisolone). In addition, IL-6 levels were measured on day 1 and 4 of hospitalization.

RESULTS

A strong inflammatory response was observed in patients with ADV infection. Serum IL-6 levels in patients with ADV infection on day 4 of hospitalization were significantly higher than those in patients without steroids treatment or in patients with RSV infection. IL-4, and IFN-gamma were not significantly different.

CONCLUSION

Patients with ADV infections who were given steroids had a temporary increase of IL-6, which might have indicated the development of a severe clinical course if not been administered.

[Adenoviral respiratory diseases in healthy children: a study of 116 hospital cases]

Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other diseases. Diagnosis may be difficult to achieve.The clinical findings for 116 children hospitalised with adenoviral infection were studied retrospectively. In 71 children, the diagnosis was based on detection of adenovirus antigen in the nasopharyngeal specimens and in 71 children on viral culture. The clinical picture of adenoviral infection was characterised by high-grade (mean 39°1C) and prolonged fever (mean duration 4,3 days). Upper respiratory and lower respiratory symptoms were the most common infections. Twelve had been admitted to the hospital due to febrile convulsions, 6 had meningitis. Laboratory findings varied from normal values to values seen in bacterial infections. Thus it was difficult to distinguish adenoviral disease from a bacterial disease. Fifty-nine children were referred to the hospital due to infection unresponsive to antimicrobial therapy.Symptoms of respiratory infection caused by adenovirus may range from the common cold syndrome to pneumonia, croup and bronchiolitis. Adenoviruses can be responsible for severe consequences, even in previously healthy children. Studies of the molecular mechanisms of viral infections of the airways could provide important insights into the nature of the inflammatory process involved in asthma and chronic obstructive pulmonary disease. Most infections are mild and require no therapy or only symptomatic treatment. There are at present time no recognised antiviral agents that are effective in treating serious adenovirus disease. The rapid detection of adenovirus antigen in nasopharygeal specimens proved to have a great clinical value in the diagnosis.

Molecular characterization of hospital-acquired adenovirus infantile respiratory infection in Chile using species-specific PCR assays

BACKGROUND

Adenovirus serotypes 7, 2 and 1 are the second most common cause of viral acute lower respiratory tract infection (ALRI) requiring hospitalization in Chile. Nosocomial outbreaks have high secondary attack and lethality rates, and call for rapid and specific diagnosis.

OBJECTIVE

We compared the results obtained on ALRI specimens by immunofluorescence (IFA) and virus isolation, plus restriction enzyme digestion (RFLP) typing, with universal, species-specific and 7h-specific PCR typing of adenovirus. A second objective was to determine the type of adenovirus implicated in nosocomial infection and nosocomial cross-infection rates.

METHODS

Infants hospitalized for ALRI in the Roberto del Río Children's Hospital (Santiago, Chile) in 1995-1996 had nasopharyngeal aspirates obtained at admission and tested by IFA and virus isolation. Adenovirus isolates were identified by RFLP. When an index case was identified, samples were collected from contacts for 2 consecutive days and twice weekly thereafter for 2 weeks. Further typing of adenovirus isolates was undertaken with universal, species-specific and 7h-specific PCR performed in 2003 on the stored frozen samples.

RESULTS

Fifteen index cases of adenovirus and their 65 contacts were identified. The nosocomial secondary attack rate using PCR was estimated as 46%. PCR had a higher sensitivity (98.7%) compared to virus isolation (90%) and IFA (50%) and facilitated identification of adenovirus strains more easily and accurately than RFLP (91.6% versus 55.8%). Fifty-three percent of the contacts had severe outcomes. The case fatality rate was 16.6% and was associated with adenovirus 7h.

CONCLUSIONS

Prompt, rapid and sensitive methods to identify adenovirus infection are necessary, especially for hospital-acquired adenovirus infections, because of their ease of spread and high fatality rate.

Cytokine induction by respiratory syncytial virus and adenovirus in bronchial epithelial cells

In order to broaden our knowledge of the primary immune responses to respiratory syncytial virus (RSV) and adenovirus infections, we compared the concentrations of interleukin (IL)-6, IL-8, and regulated on activation, normal T cell expressed and secreted (RANTES) produced in vitro during RSV and adenovirus infections of bronchial epithelial cells. We infected BEAS-2B cells-a human bronchial epithelial cell line-with RSV, adenovirus serotype 3, or serotype 7 and measured the concentrations of IL-6, IL-8, and RANTES in the cell culture supernatants. When the multiplicity of infection (MOI) was 1, RSV induced the production of markedly higher concentrations of IL-6, IL-8, and RANTES than the adenovirus. When the MOI of the adenovirus was increased to 100, the production of IL-6 and IL-8 increased. However, the amounts produced were still lower than those produced by RSV with the MOI of 1. There was no statistically significant increase in the production of RANTES in spite of the MOI of the adenovirus was increased to 100. Adenovirus serotype 7 induced the production of considerably more IL-6 and IL-8 than serotype 3 in the MOI of 100. However, neither adenovirus serotype triggered an increase in the production of RANTES in spite of the MOI of 100. This demonstrates that RSV could have a superior capacity to stimulate the production of IL-6, IL-8, and RANTES in the bronchial epithelial cells. This study may help to explain the differences in the clinical outcomes of RSV and adenovirus infections.

Interaction of monocytic cells with respiratory syncytial virus results in activation of NF-kappaB and PKC-alpha/beta leading to up-regulation of IL-15 gene expression

Respiratory syncytial virus (RSV) is a major human respiratory pathogen, particularly for infants. RSV is also a powerful inducer of cytokines, one of which is IL-15, an important immunoregulatory cytokine. IL-15 plays a key role in NK and T cell development and differentiation and also regulates NK cell/macrophage interaction, as well as monocyte/macrophage and granulocyte function. We have shown previously that different viruses up-regulate IL-15 gene expression in human PBMCs. Recently, we found that RSV induces the expression of IL-15 mRNA in the monocytic line THP-1. The signaling pathway involved in such virus-induced up-regulation of IL-15 has not yet been identified. We report here a study describing this mechanism. Because of the involvement of the protein kinase C (PKC) and the transcription factor NF-kappaB in the regulation of others cytokines by RSV as well as the involvement of NF-kappaB in the transactivation of IL-15, our hypothesis was that RSV induced the expression of IL-15 in THP-1 cells through the PKC and NF-kappaB activation. We demonstrate here that RSV-induced up-regulation of IL-15 expression in THP-1 cells involves the phosphorylation of PKC-alpha/beta. Further, inhibition of PKC by different specific inhibitors blocks this up-regulation. Using the electromobility shift assay, we show that the activated form of NF-kappaB binds to the IL-15 promoter sequence. We further confirm, using an ELISA assay, the involvement of p65 in the transcription of IL-15. This study, demonstrating the ability of RSV to induce IL-15 expression, might explain, at least in part, the exacerbated, inflammatory response triggered by RSV infection.

Synergistically Upregulated Interleukin-10 Production in Cocultures of Monocytes and T Cells after Stimulation with Respiratory Syncytial Virus

BACKGROUND

Respiratory syncytial virus (RSV) is known as a causal factor of severe bronchiolitis in young children. It has also been detected in patients with chronic obstructive pulmonary disease (COPD), a disease that is associated with an increased number of T cells in the bronchial mucosa. Here, we investigated the potential direct interaction between RSV and T cells and its impact on cytokine response.

METHODS

Purified human peripheral blood T cells were stimulated with RSV in vitro and analyzed by flow cytometry and fluorescence microscopy. Cytokine expression and release were measured in T cell cultures and in cocultures with peripheral blood monocytes as well as with alveolar macrophages from bronchoalveolar lavage fluid by quantitative real-time PCR and ELISA.

RESULTS

It was shown that RSV adhered to the surface of T cells. Stimulation of purified T cells with RSV led to a significant increase in interleukin (IL)-10 mRNA expression after 24 h. Moreover, in cocultures of T cells with monocytes or alveolar macrophages, IL-10 production was synergistically upregulated 24 h after stimulation with RSV.

CONCLUSION

These results suggest that RSV can cause an excessive IL-10 response leading to downregulation of antiviral defense mechanisms and reduced elimination of respiratory pathogens when antigen-presenting cells and T cells are simultaneously present on the site of infection. This effect may possibly contribute to high frequencies of respiratory pathogens found in patients with chronic inflammatory airway diseases associated with increased local T cell influx such as COPD.

Human Metapneumovirus Elicits Weak IFN-γ Memory Responses Compared with Respiratory Syncytial Virus

Human metapneumovirus (MPV) is a recently discovered pathogen that causes repeated lower respiratory tract infections beginning in infancy. The prevalence, nature and control of human regulatory responses to MPV are unknown. In this study, we develop and optimize systems to evaluate MPV-driven cytokine responses. Using primary culture of human PBMC from previously exposed adults, MPV-stimulated responses were directly compared with those elicited by genetically and clinically similar respiratory syncytial virus (RSV). Intense IL-6 production was evident following culture with infectious or inactivated RSV. MPV elicited IL-6 responses averaging 3.5-fold more intense (p < 0.001). Virus-dependent expression of IL-11, IL-12, IFN-alpha, and other innate immunity cytokines differed little between MPV and RSV. When examining adaptive immunity, RSV infection elicited strong IFN-gamma responses by all 60 adults. In marked contrast, MPV elicited IFN-gamma in a lower frequency of adults (p < 0.002) and at levels averaging 6-fold weaker (p < 0.001). These Th1-dominated responses were CD4, CD8, CD86 dependent, and were closely paralleled by strong virus-driven IL-10 and CCL5 production. For MPV and RSV, Th2 (IL-5, IL-13) responses were sporadic, occurring in 10-40% of the population. Thus, MPV and RSV, although both ubiquitous and leading to very high levels of infection, seroconversion, and clinically similar presentation in the population, evoke distinct innate and adaptive T cell-dependent cytokine responses. Although both viruses yield Th1-dominated responses with strong IL-10 and CCL5 production, MPV restimulation results in markedly more robust IL-6 and significantly weaker adaptive cytokine responses, in both prevalence and intensity, than does RSV.

T helper 1/T helper 2 cytokine imbalance in respiratory syncytial virus infection is associated with increased endogenous plasma cortisol

OBJECTIVE

Cellular immunity has classically been described as the defense mechanism for viral infections. The development of cellular or humoral immune responses will depend on a repertoire of cytokines produced by numerous cells, including CD4+ and CD8+ T cells. These lymphocytes can be subdivided into 2 subsets, T helper 1 (Th1) and Th2, on the basis of the cytokine profiles they synthesize. Type 1 T cells produce interferon gamma (IFN-gamma), an essential cytokine in the viral cell-mediated immune response. Th2 cells selectively produce interleukin 4 (IL-4) and IL-5 that participate in the development of humoral immunity and have a prominent role in immediate-type hypersensitivity. An imbalance in the Th1/Th2 cytokine immune response has been related to pathogenesis of the respiratory syncytial virus (RSV) bronchiolitis and to the severity of the infection. Glucocorticosteroids have a role in inhibiting the IFN-gamma response, acting directly on T cells or indirectly through IL-12. In this way, an increase in plasma cortisol would induce a decrease in the Th1 products with the imbalance between Th1/Th2 cytokines and a shift to Th2 response. We hypothesized that there is a relationship among endogenous cortisol response in acute RSV infection, severity of illness, and decreased Th1 cytokine response.

METHODS

We studied 42 infants under 12 months of age during an acute RSV infection. Twenty-one infants with a median age of 6 months had a severe illness and required hospitalization, whereas 21 with mild diseases with a median age of 7 months were under ambulatory control. All of them had bronchial obstruction evidenced by wheezing and/or hyperinflation on chest radiograph and positive RSV antigen detected by indirect immunofluorescence in nasopharyngeal aspirates. The control group included 21 infants in good health matched by age and gender with median age of 6 months that required blood tests for minor surgery. They were evaluated during a non-RSV epidemic period. Heparinized blood was collected on enrollment from all participating children at 9 am for total leukocyte and differential cell count, determination of lymphocyte subsets, and for intracellular detection of cytokines in single cells; mononuclear cells were cultured to determine in the supernatant cytokine production. In addition, 1 mL of plasma was separated and kept frozen at -20 degrees C for cortisol assay. In the supernatant of the cultured peripheral blood mononuclear cells (PBMCs), we quantified IL-12, IFN-gamma, IL-4, IL-5, and IL-10. Lymphocyte phenotypes and CD4+ and CD8+ T cells with intracellular IL-4, IL-10, and IFN-gamma were analyzed by triple-color immunofluorescence of single cells on a FACScan flow cytometer.

RESULTS

Infants with severe illness had significantly higher plasma cortisol levels than infants with mild disease, and in both groups of infected infants, those were higher than in the control group. A significantly decreased IL-12 and IFN-gamma production by PBMCs and a fall in the percentage of CD4+ T cells expressing IFN-gamma were observed only in the severely affected infants. IL-12 concentrations were 2 pg/mL in severe illness versus 13 pg/mL in mildly infected infants and 12 pg/mL in controls. PBMCs from infants with severe illness produced less IFN-gamma than mildly infected infants and than controls when compared with severe illness. No differences between the 3 groups of infants were observed during the acute phase of the disease for IL-4, IL-5, and IL-10. IL-12 and IFN-gamma production had an inverse correlation with plasma cortisol levels. During severe RSV bronchiolitis, infants developed lymphopenia, and significantly lower eosinophil counts and percentages and absolute counts of CD4+ and CD8+ T cells. Eighty days postinfection, all values had returned to normal levels.

CONCLUSIONS

In this study, we demonstrate that during the acute phase of RSV infection, there is an increase in the level of plasma cortisol that is parallel to the decrease in IL-12 and IFN-gamma production. These findings suggest an association between increased plasma cortisol and a decreased Th1-type response. The increase in plasma cortisol was greater in infants with the more severe symptomatology in association with a lower level of IL-12 and IFN-gamma production. The potential causative role of endogenous cortisol in the imbalance of the Th1/Th2 response observed during severe RSV infection requires additional investigation. Our results suggest that the immunologic changes observed in the more severely ill patients may be partially explained by the increased levels of plasma cortisol. This finding should be taken into consideration when systemic steroids are prescribed to infants infected with the RSV because there is still controversy regarding the efficacy of systemic steroid use in severe bronchiolitis.

Levels of Th1 and Th2 cytokines in children with post-infectious bronchiolitis obliterans

BACKGROUND

Post-infectious bronchiolitis obliterans (BO) is a chronic obstructive airway disease associated with inflammation and fibrosis of the small airways; it is more common in children who have had acute viral bronchiolitis. No previous studies have reported the immune response of BO. Unbalanced Th1/Th2 immune response might be one of the risk factors for developing this illness.

AIM

To compare the production of interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 in peripheral blood mononuclear cell cultures in children with BO and in healthy children.

METHODS

From March 2003 to October 2003, children with BO and healthy children were selected from the paediatric outpatient clinics in our centre. Peripheral blood was collected and mononuclear cells were separated and cultured (96 hours) with 1% phytohaemagglutinin stimulation. The supernatant was stored and cytokine levels were measured through ELISA.

RESULTS

IFN-gamma, IL-4 and IL-10 levels were not significantly different between the groups studied. Family history of atopy was significantly associated with subjects with BO (p=0.02).

CONCLUSIONS

Our results suggest that unbalanced peripheral blood Th1/Th2 immune response of children with post-infectious BO might not be associated with its pathophysiology. Further studies are required to better understand the role of risk factors, including viral genotype, viral load or tissue repair abnormalities in the development of post-infectious BO.

Respiratory syncytial virus nonstructural protein 2 specifically inhibits type I interferon signal transduction

Human respiratory syncytial virus (RSV) inhibits type I interferon-induced gene expression by decreasing expression of signal transducer and activator of transcription (Stat)2. To identify the RSV protein that mediates effects on Stat2, airway epithelial cells were infected with vaccinia virus vectors that express single RSV proteins. Expression of RSV nonstructural (NS)2 protein alone was sufficient to decrease Stat2 levels. Furthermore, decreasing RSV NS2 levels using RNA interference in respiratory epithelial cells inhibited the RSV-mediated decrease in Stat2 expression. Airway epithelial cells were also infected with equivalent inoculums of RSV without or with single gene deletions of NS1 or NS2. RSV infection without NS2 expression did not result in decreased Stat2 levels or loss of type I interferon-dependent signaling, indicating that NS2 expression is necessary for RSV effects on Stat2. Taken together, our results indicate that NS2 regulates Stat2 levels during RSV infection, thereby modulating viral effects on interferon-dependent gene expression.

Single versus dual respiratory virus infections in hospitalized infants: impact on clinical course of disease and interferon-gamma response

BACKGROUND

Dual respiratory viral infections are frequently associated with lower respiratory tract illness in infants. This study aimed to determine the impact of a dual respiratory viral infection on specific aspects of the infant's immune response and the clinical course of illness.

METHODS

A prospective study was performed with 772 infants hospitalized from October 2000 through July 2004. Sensitive polymerase chain reaction methodology revealed the presence of a single respiratory virus in 443 (57%) of 772 cases, whereas dual infections were identified in 153 (20%) of cases. From 250 infants with confirmed respiratory viral infection, fresh heparinized blood was analyzed for interferon-gamma (IFN-gamma) responses by flow cytometry. Of these, 191 patients had a single infection with respiratory syncytial virus (RSV), rhinoviruses, adenoviruses or influenza viruses; and 59 patients had a dual infection with RSV and rhinoviruses, RSV and adenoviruses, influenza viruses and rhinoviruses or adenoviruses and rhinoviruses. The clinical features and peripheral lymphocyte IFN-gamma responses were compared among infants with single or dual infections.

RESULTS

It was found that dual infections with non-RSV respiratory viruses induced peripheral blood mononuclear cell IFN-gamma responses that mimic those of single infections, whereas coinfection with RSV was associated with reduced IFN-gamma responses and a more severe clinical course of lower respiratory tract disease.

CONCLUSIONS

The results indicate that the clinical characteristics and the IFN-gamma response differ significantly in single and dual respiratory viral infection, depending on the nature of the simultaneously detected viruses. In dual infections, RSV involvement was associated with a decreased IFN-gamma response in peripheral blood mononuclear cell and an increase in severity of illness.

Decreased interferon-gamma response in respiratory syncytial virus compared to other respiratory viral infections in infants

An inappropriate interferon-gamma response has been implicated in the pathogenesis of severe respiratory syncytial virus (RSV) lower respiratory tract illness (LRTI). To assess whether this is unique for RSV primary LRTI compared to a first non-RSV LRTI, intracellular interferon-gamma was determined by flow cytometry in peripheral blood mononuclear cells from 32 infants with a primary RSV infection, 28 with a first non-RSV LRTI due to adenoviral, parainfluenzaviral and rhinoviral infection and 13 healthy infants. Interferon-gamma responses were increased significantly during adenoviral, parainfluenzaviral and the majority of the rhinoviral infections, but remained low during RSV and severe rhinoviral infection. Low interferon-gamma responses were associated with a more severe clinical course of LRTI. This indicates that depending on the nature of the viral pathogen, respiratory virus infections in infants differ significantly with regard to the quantity of the interferon-gamma production and that this may contribute to the clinical course of the disease.

Discrepancy between cytokine production from peripheral blood mononuclear cells and nasal secretions among infants with acute bronchiolitis

BACKGROUND

Many studies have measured cytokine production derived from peripheral blood mononuclear cells (PBMCs) to evaluate the immune response in acute bronchiolitis (AB), but no previous reports have examined the association between PBMC release of cytokines and concomitant airway immune response.

OBJECTIVE

To determine whether interferon-gamma (IFN-gamma), interleukin 4 (IL-4), and IL-10 levels from PBMCs are associated with concurrent cytokine release in the airways of infants with AB.

METHODS

Infants with acute viral-associated first episode of wheezing who required hospitalization between May and September 2002 were recruited. Nasopharyngeal aspirates (NPAs) and PBMC samples were collected simultaneously. The concentrations of IFN-gamma, IL-4, and IL-10 in NPA and PBMC supernatants were determined by enzyme-linked immunosorbent assay.

RESULTS

Twenty infants with AB were enrolled in the study of whom 17 (85%) had positive NPA immunofluorescence results for viral detection and respiratory syncytial virus. Median total cell count and viability from NPA samples were 2.2 x 10(6) cells/mL (SD, 1.7 cells/mL) and 92% (SD, 6.0%), respectively. There was a significant correlation between IL-4 levels from NPA and PBMC samples (r = 0.5, P = .02); however, we did not find an association between IFN-gamma and IL-10 levels.

CONCLUSIONS

Cytokines produced by in vitro PBMCs may not necessarily reflect the concurrent cytokine pattern production at the mucosal surface in the respiratory tract of infants with AB. Further studies are required to determine whether peripheral blood is a reliable sample for airway inflammation evaluation and to explain the discrepancies of cytokine productions found in this study.

Specific Inhibition of Type I Interferon Signal Transduction by Respiratory Syncytial Virus

Respiratory viruses often express mechanisms to resist host antiviral systems, but the biochemical basis for evasion of interferon effects by respiratory syncytial virus (RSV) is poorly defined. In this study, we identified RSV effects on interferon (IFN)-dependent signal transduction and gene expression in human airway epithelial cells. Initial experiments demonstrated inhibition of antiviral gene expression induced by IFN-alpha and IFN-beta, but not IFN-gamma, in epithelial cells infected with RSV. Selective viral effects on type I IFN-dependent signaling were confirmed when we observed impaired type I, but not type II, IFN-induced activation of the transcription factor Stat1 in RSV-infected cells. RSV infection of airway epithelial cells resulted in decreased Stat2 expression and function with preservation of upstream signaling events, providing a molecular mechanism for viral inhibition of the type I IFN JAK-STAT pathway. Furthermore, nonspecific pharmacologic inhibition of proteasome function in RSV-infected cells restored Stat2 levels and IFN-dependent activation of Stat1. The results indicate that RSV acts on epithelial cells in the airway to directly modulate the type I IFN JAK-STAT pathway, and this effect is likely mediated though proteasome-dependent degradation of Stat2. Decreased antiviral gene expression in RSV-infected airway epithelial cells may allow RSV replication and establishment of a productive viral infection through subversion of IFN-dependent immunity.

Respiratory syncytial virus induces prostaglandin E2, IL-10 and IL-11 generation in antigen presenting cells

Bronchiolitis caused by respiratory syncytial virus (RSV) infection is a major cause of hospitalization in children under 1 years of age. The disease characteristically does not induce protective immunity. However, a mononuclear peribronchiolar and perivascular infiltrate during RSV infection is suggestive of an immune-mediated pathogenesis. Macrophages and dendritic cells (DCs) play an essential role in the initiation and maintenance of immune response to pathogens. To analyse interactions of RSV and immune cells, human cord blood derived macrophages and dendritic cells were infected with RSV. Both cells were found to be infected with RSV resulting in the activation of macrophages and maturation of dendritic cells as reflected by enhanced expression of several surface antigens. In the next set of experiments, generation of mediators was compared between cells infected with RSV, parainfluenza (PIV3) and influenza virus as well as ultracentrifuged virus free supernatant. Whereas the supernatant did not induce release of mediators, all three live virus infections induced IL-6 production from macrophages and DC. Influenza virus infection induced predominantly IL-12 p75 generation in DC. In contrast, RSV induced strong IL-11 and prostaglandin E2 release from both macrophages and DCs. In addition, RSV but not influenza and parainfluenza virus induced a strong IL-10 generation particularly from macrophages. Since IL-10, IL-11 and PGE2 are known to act immunosuppressive rather than proinflammatory, these mediators might be responsible for the delayed protective RSV specific immune response.

Pulmonary function changes and immunomodulation of cytokine expression by zafirlukast after sensitization and allergen challenge in brown Norway rats

BACKGROUND

The cysteinyl leukotrienes are known important mediators in bronchial asthma.

OBJECTIVE

Our purpose was to evaluate the effect of zafirlukast on the late-phase reaction, bronchial hyper-responsiveness (BHR) and T cell-related cytokine mRNA expression in ovalbumin (OA)-sensitized brown Norway rats (BNRs).

METHODS

Thirty BNRs were equally divided into three groups. Group I and II animals were sensitized and then provoked with OA. Zafirlukast was given intraperitoneally (i.p.) to group I animals prior to provocation. Group II animals received i.p. normal saline. Group III animals (controls) were not sensitized and breathed aerosolized saline. After OA provocation, the animals were anaesthetized. Pulmonary function tests (PFT) were performed at baseline and after varying doses of acetylcholine. Thereafter, bronchoalveolar lavage (BAL) was performed and the lungs were examined histologically. Total RNA was extracted from lung tissue and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using primers for IL-2, IL-4, IL-5, IL-6, IL-10, TNF-alpha, IFN-gamma, iNOS and beta-actin.

RESULTS

Group II OA-treated BNRs had worse PFT results, more severe bronchoconstriction in response to acetylcholine, and more severe inflammation in lung tissue than the other two groups. Group II had higher IL-2, IL-4, IL-10 and IFN-gamma cytokine levels in BAL fluid and higher IL-2, IL-4, IL-5, IL-6, IL-10, IFN-gamma, TNF-alpha and iNOS mRNA levels when compared with group I.

CONCLUSION

Zafirlukast is effective in preventing late-phase bronchoconstriction and BHR, reducing inflammatory response, and decreasing IL-2, IL-4, IL-5, IL-6, IL-10 and IFN-gamma and iNOS mRNA expression.

Large epidemic of respiratory illness due to adenovirus types 7 and 3 in healthy young adults

After 25 years of successful control through immunization, respiratory infections due to adenoviruses have reemerged to threaten the health of young adults in the military. Shortly after the loss of adenovirus vaccine supplies, a large outbreak of respiratory illness was observed at the United States Navy's sole basic training center. Laboratory testing confirmed 541 cases of adenovirus infection, including 378 cases due to serotype 7 and 132 cases due to serotype 3. This outbreak was remarkable because of its unique serotype distribution and the large amount of data available to describe demographic factors associated with infection. This was the largest outbreak of respiratory illness due to adenovirus types 7 and 3 documented in recent history, and it portends even greater challenges for young adults in the military in the postvaccine era.