Viral respiratory infections in association with asthma and sinusitis: a review

Human airway and lung microbiome at the crossroad of health and disease (Review)

The evolving field of the microbiome and microbiota has become a popular research topic. The human microbiome is defined as a new organ and is considered a living community of commensal, symbiotic and pathogenic microorganisms within a certain body space. The term 'microbiome' is used to define the entire genome of the microbiota. Bacteria, archaea, fungi, algae and small protists are all members of the microbiota, followed by phages, viruses, plasmids and mobile genetic elements. The composition, heterogeneity and dynamics of microbiomes in time and space, their stability and resistance, essential characteristics and key participants, as well as interactions within the microbiome and with the host, are crucial lines of investigation for the development of successful future diagnostics and therapies. Standardization of microbiome studies and harmonized comparable methodologies are required for the transfer of knowledge from fundamental science into the clinic. Human health is dependent on microbiomes and achieved by nurturing beneficial resident microorganisms and their interplay with the host. The present study reviewed scientific knowledge on the major components of the human respiratory microbiome, i.e. bacteria, viruses and fungi, their symbiotic and parasitic roles, and, also, major diseases of the human respiratory tract and their microbial etiology. Bidirectional relationships regulate microbial ecosystems and host susceptibility. Moreover, environmental insults render host tissues and microbiota disease-prone. The human respiratory microbiome reflects the ambient air microbiome. By understanding the human respiratory microbiome, potential therapeutic strategies may be proposed.

The effect of infectious agents on the prevalence of allergies

PURPOSE

The role of infectious agents in allergy development is ambivalent. On one hand, there are reports of an association between a previous infection (especially a viral respiratory tract infection) and developing hypersensitivity to inhaled allergens, which in turn may increase the risk of developing allergic reactions. On the other hand, there are reports emphasizing a protective effect of a number of infectious agents against allergy development. The aim the study was to find possible associations between a past infectious or parasitic disease and an allergic condition.

MATERIAL AND METHODS

The study population was a group of 18,648 subjects. The study, which was a part of the project: 'Implementation of a System for the Prevention and Early Detection of Allergic Diseases in Poland', was conducted in 9 selected regions of Poland and used the ECRHS and ISAAC questionnaires adapted for Europe. The following statistical tools were used: Pearson's chi-squared test, Fisher's exact test, and logistic regression.

RESULTS

This research was an attempt to clear association between a history of measles or viral hepatitis and the likelihood of developing asthma, especially in males (χ² = 5.29; p<0.05). Past parasitic disease showed a clear association with a suspected allergic rhinitis in various groups of patients (differing both in terms of sex and age).

CONCLUSIONS

A history of some forms of either infectious or parasitic diseases has a measurable effect on the risk of developing allergies.

Relationship between Olfactory Acuity and Peak Expiratory Flow during Postoperative Follow-up in Chronic Rhinosinusitis Associated with Asthma

Objectives

The link between nasal and bronchial disease has been studied extensively for chronic rhinosinusitis and asthma. The concept of “united airway allergy” has become widely accepted in the past decade. We evaluated the relationship between the upper and lower airways during follow-up after endoscopic sinus surgery by monitoring sinonasal and pulmonary functions.

Methods

Thirty-nine subjects with chronic rhinosinusitis associated with bronchial asthma were entered in this study. A self smell test using stick-type odorant materials was carried out daily to evaluate postoperative recurrence of sinonasal disease. Each patient was assessed for peak expiratory flow (PEF) 3 times daily.

Results

The average (±SD) scores of initial symptoms were 8.3 ± 2.2, which was significantly decreased to 1.5 ± 1.4 by 3 months after operation. During postoperative follow-up, 25 of 39 patients showed no decrease in PEF, whereas the other 14 patients had at least 1 episode of a significant decline in PEF. In the postoperative course, with respect to the self smell test, 24 patients showed no aggravation of smell, but 15 patients had episode(s) of decreased olfaction. Twelve patients demonstrated worsening on the smell test concomitant with a decreased PEF. A discrepancy between olfactory acuity and pulmonary function was recognized in 5 patients. There were 22 patients with a good prognosis of parameters of both the upper and lower airways.

Conclusions

Daily monitoring of both upper and lower respiratory tract functions clearly revealed dual relationships, indicating that worsening of sinusitis accompanies asthma exacerbation. Appropriate measures of the upper and lower airways following endoscopic sinus surgery can be used to predict patient outcome.

Serum Amyloid A, Properdin, Complement 3, and Toll-Like Receptors are Expressed Locally in Human Sinonasal Tissue

Background

There is a growing appreciation of the role that nasal mucosa plays in innate immunity. In this study, the expression of pattern recognition receptors known as toll-like receptors (TLRs) and the effector molecules complement factor 3 (C3), properdin, and serum amyloid A (SAA) were examined in human sinonasal mucosa obtained from control subjects and patients with chronic rhinosinusitis (CRS).

Methods

Sinonasal mucosal specimens were obtained from 20 patients with CRS and 5 control subjects. Messenger RNA (mRNA) was isolated and tested using Taqman real-time polymerase chain reaction with primer and probe sets for C3, complement factor P, and SAA. Standard polymerase chain reaction was performed for the 10 known TLRs. Immunohistochemistry was performed on the microscopic sections using antibodies against C3

Results

Analysis of the sinonasal sample mRNA revealed expression of all 10 TLRs in both CRS samples and in control specimens. Expression of the three effector proteins was detected also, with the levels of mRNA for C3 generally greater than SAA and properdin in CRS patients. No significant differences were found in TLR or innate immune protein expression in normal controls. Immunohistochemical analysis of sinonasal mucosal specimens established C3 staining ranging from 20 to 85% of the epithelium present.

Conclusion

These studies indicate that sinonasal mucosa expresses genes involved in innate immunity including the TLRs and proteins involved in complement activation. We hypothesize that local production of complement and acute phase proteins by airway epithelium on stimulation of innate immune receptors may play an important role in host defense in the airway and, potentially, in the pathogenesis of CRS.

An unusual exostotic lesion of the maxillary sinus from Roman Lincoln

This report provides a differential diagnosis of an exostotic bony lesion within the left maxillary sinus of a Romano-British (3rd to 4th century AD) adult male from Newport, Lincoln. Macroscopic, radiographic, and cone beam computed tomography (CBCT) analyses suggest that the lesion is likely of odontogenic origin. The overall size of the lesion and areas of sclerosis and radiolucency, together with its hypothesised odontogenic origin, suggest that the lesion represents a chronic exostotic osteomyelitic reaction to the presence of odontogenic bacteria. While modern case studies of odontogenic maxillary sinus osteomyelitis are noteworthy, published cases of this condition are extremely rare in an archaeological context and may be underreported due to the enclosed nature of the sinuses. Such infections may have serious implications for individual and population health, and non-destructive investigation should be considered in cases where significant maxillary caries are present.

Allergic rhinitis is associated with open-angle glaucoma: a population-based case-control study

BACKGROUND

Despite many reports linking allergic rhinitis (AR) to problems of the eye, the relationship between AR and open-angle glaucoma (OAG) has not been studied. The purpose of this epidemiology study was to provide an estimation of the association of OAG with AR by using a population-based data set in Taiwan.

METHODS

We retrieved our study sample for this case-control study from the Longitudinal Health Insurance Database 2000. We extracted 7063 subjects with OAG as cases and 21,189 matched controls (three controls per case). We used conditional logistic regression analyses to calculate the odds ratio (OR) and corresponding 95% confidence interval (CI) to describe the association between OAG and having previously been diagnosed with AR.

RESULTS

A chi-squared test showed that there was a significant difference in the prevalence of prior AR between cases and controls (28.8% versus 22.3%; p < 0.001). A conditional logistic regression analysis suggested that the OR of having previously been diagnosed with AR for cases was 1.40 (95% CI, 1.31∼1.48; p < 0.001) compared with controls after adjusting for monthly income, geographic region, urbanization level, hypertension, diabetes, asthma, coronary heart disease, hyperlipidemia, and hypothyroidism. It also revealed that OAG was consistently and significantly associated with prior AR across all age groups. In particular, subjects aged 50∼59 years had the highest OR for prior AR among cases compared with controls (OR, 1.77; 95% CI, 1.53∼2.06; p < 0.001).

CONCLUSION

This outcome research found that there was an association between AR and OAG.

Airway surface mycosis in chronic TH2-associated airway disease

BACKGROUND

Environmental fungi have been linked to TH2 cell-related airway inflammation and the TH2-associated chronic airway diseases asthma, chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), and allergic fungal rhinosinusitis (AFRS), but whether these organisms participate directly or indirectly in disease pathology remains unknown.

OBJECTIVE

To determine the frequency of fungus isolation and fungus-specific immunity in patients with TH2-associated and non-TH2-associated airway disease.

METHODS

Sinus lavage fluid and blood were collected from sinus surgery patients (n = 118) including patients with CRSwNP, patients with CRS without nasal polyps, patients with AFRS, and non-CRS/nonasthmatic control patients. Asthma status was determined from medical history. Sinus lavage fluids were cultured and directly examined for evidence of viable fungi. PBMCs were restimulated with fungal antigens in an enzyme-linked immunocell spot assay to determine total memory fungus-specific IL-4-secreting cells. These data were compared with fungus-specific IgE levels measured from plasma by ELISA.

RESULTS

Filamentous fungi were significantly more commonly cultured in patients with TH2-associated airway disease (asthma, CRSwNP, or AFRS: n = 68) than in control patients with non-TH2-associated disease (n = 31): 74% vs 16%, respectively (P < .001). Both fungus-specific IL-4 enzyme-linked immunocell spot (n = 48) and specific IgE (n = 70) data correlated with TH2-associated diseases (sensitivity 73% and specificity 100% vs 50% and 77%, respectively).

CONCLUSIONS

The frequent isolation of fungi growing directly within the airways accompanied by specific immunity to these organisms only in patients with TH2-associated chronic airway diseases suggests that fungi participate directly in the pathogenesis of these conditions. Efforts to eradicate airway fungi from the airways should be considered in selected patients.

Respiratory viral infection in the chronic persistent phase of chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The role of respiratory viral infection in the pathogenesis of chronic rhinosinusitis (CRS) has been rarely studied and remains controversial. The aim of this study was to explore the prevalence of respiratory viruses in the chronic status of CRS.

STUDY DESIGN

A case-control prospective study.

METHODS

Fifty-three control subjects, and 67 CRS with nasal polyp (CRSwNP) and 61 CRS without nasal polyp (CRSsNP) patients without signs of acute viral infection were enrolled. Epithelial cells scraped from the middle nasal meatus were tested for the nucleic acid of nine common respiratory viruses using polymerase chain reaction assay. The clinical disease severity was compared between subjects with and without viral infection.

RESULTS

The overall detection rate of viral infection was 75.47%, 68.66%, and 73.77% in controls, CRSwNP, and CRSsNP, respectively, and no significant difference among studied groups was observed. There was no significant difference in detection rate of any specific individual virus or multiple viruses among the groups studied either. Visual analog scale scores of symptoms, computed tomography scores, or endoscope scores did not show obvious difference between subjects with and without viral infection.

CONCLUSIONS

Although a high frequency of viral infection could be observed in the middle nasal meatus, no increase of frequency of viral infection could be demonstrated in chronic persistent phase of CRSsNP and CRSwNP. The contribution of the interaction between viral infection and host immunity to the pathogenesis of CRS remains to be determined.

LEVEL OF EVIDENCE

3b. Laryngoscope, 124:832-837, 2014.

Effects of rhinovirus species on viral replication and cytokine production

BACKGROUND

Epidemiologic studies provide evidence of differential virulence of rhinovirus species (RV). We recently reported that RV-A and RV-C induced more severe illnesses than RV-B, which suggests that the biology of RV-B might be different from RV-A or RV-C.

OBJECTIVE

To test the hypothesis that RV-B has lower replication and induces lesser cytokine responses than RV-A or RV-C.

METHODS

We cloned full-length cDNA of RV-A16, A36, B52, B72, C2, C15, and C41 from clinical samples and grew clinical isolates of RV-A7 and RV-B6 in cultured cells. Sinus epithelial cells were differentiated at the air-liquid interface. We tested for differences in viral replication in epithelial cells after infection with purified viruses (10(8) RNA copies) and measured virus load by quantitative RT-PCR. We measured lactate dehydrogenase (LDH) concentration as a marker of cellular cytotoxicity, and cytokine and/or chemokine secretion by multiplex ELISA.

RESULTS

At 24 hours after infection, the virus load of RV-B (RV-B52, RV-B72, or RV-B6) in adherent cells was lower than that of RV-A or RV-C. The growth kinetics of infection indicated that RV-B types replicate more slowly. Furthermore, RV-B released less LDH than RV-A or RV-C, and induced lower levels of cytokines and chemokines such as CXCL10, even after correction for viral replication. RV-B replicates to lower levels also in primary bronchial epithelial cells.

CONCLUSIONS

Our results indicate that RV-B types have lower and slower replication, and lower cellular cytotoxicity and cytokine and/or chemokine production compared with RV-A or RV-C. These characteristics may contribute to reduced severity of illnesses that has been observed with RV-B infections.

Infection with respiratory syncytial virus influences FasL-mediated apoptosis of pulmonary γδ T cells in a murine model of allergen sensitization

BACKGROUND

It has been reported that adoptive transfer of γδ T cells increases the cellular infiltration, especially eosinophils, in the lungs of allergic mice, suggesting that γδ T cells may play a proinflammatory role in allergic airway inflammation. Respiratory syncytial virus (RSV) infection can decrease the number of Th2-type γδ T cells. However, the underlying mechanisms remain unknown.

METHODS

BALB/c mice were inoculated intranasally with RSV before or after sensitization to OVA. The amounts of Th1/Th2 cytokines as well as the levels of specific antibodies were determined by ELISA. The apoptotic death of pulmonary γδ T cells was analyzed by flow cytometry.

RESULTS

Adoptive transfer of γδ T cells increased the production of Th2 cytokines in the lungs and allergy-related antibodies in the serum, further confirming that γδ T cells act as pro-inflammatory cells or a promoter for the development of allergic asthma. RSV infection before sensitization to OVA enhanced apoptotic death of pulmonary γδ T cells. The percentage and absolute number of FasL-expressing γδ T cells in the lungs of allergic mice were elicited significantly by prior RSV infection. Blocking FasL with monoclonal antibody diminished apoptotic death of γδ T cells, suggesting that FasL is important for RSV-induced apoptosis of pulmonary γδ T cells.

CONCLUSIONS

This work provides evidence that RSV infection suppresses the subsequent development of OVA-induced allergic responses partly by enhancing FasL-mediated apoptosis of pulmonary γδ T cells.

Treatment of chronic rhinosinusitis using erythromycin phonophoresis

Bacterial biofilms have been implicated in many chronic infective diseases, including chronic rhinosinusitis (CRS). Therapeutic ultrasound enhances the breakdown of bacterial biofilms and is clinically effective in CRS treatment, while phonophoresis has also been utilized for antibiotic delivery through the skin. The objective of this case report is to describe the results of a novel treatment, erythromycin phonophoresis, in a woman with CRS. A 31-year-old woman with a 7-month history of CRS refractory to conventional medical management was treated with erythromycin phonophoresis to both maxillary sinuses. Individual sinus symptom severity was assessed and sinus CT scans were obtained both pretreatment and posttreatment. After treatment, the total sinusitis symptom score improved from 12 to 0 and the CT scan showed almost complete disease resolution. At 5-month follow-up, the patient reported sustained improvement. Erythromycin phonophoresis has potential as an effective treatment for CRS.

Rhinovirus upregulates matrix metalloproteinase-2, matrix metalloproteinase-9, and vascular endothelial growth factor expression in nasal polyp fibroblasts

OBJECTIVES/HYPOTHESIS

Upregulation of matrix metalloproteinase (MMP) and vascular endothelial growth factor (VEGF) has been suggested to have an important role in the pathogenesis of nasal polyps (NPs). The aim of this study was to investigate the effect of rhinovirus (RV) infection on the expression of MMPs, tissue inhibitor of metalloproteinase (TIMP)-1, and VEGF in NP fibroblasts.

METHODS

NP fibroblasts (5 x 10(5) cells/mL) obtained from patients with chronic rhinosinusitis with nasal polyps (CRSwNP) were infected with RV serotype 16 (RV-16) for 4 hours. The RV-16 infection was confirmed by seminested reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization. After 48 hours, MMP-2, MMP-9, TIMP-1, and VEGF protein levels were measured from culture supernatants by enzyme-linked immunosorbent assay. The changes in the expression of MMP-2, MMP-9, TIMP-1, and VEGF mRNA were assayed by RT-PCR.

RESULTS

RV-16 infection significantly enhanced the gene and protein expressions of MMP-2, MMP-9, and VEGF in NP fibroblasts, whereas TIMP-1 expression was not significantly affected by RV-16. MMP-2, MMP-9, and VEGF protein expression increased by 2.39-, 2.99-, and 3.02-fold, respectively, in RV-infected NP fibroblasts compared to noninfected controls. RV-16 infection also significantly upregulated the expression of MMP-2, MMP-9, and VEGF mRNA by 1.27-, 1.70-, and 1.53-fold, respectively, compared to control levels.

CONCLUSIONS

These in vitro findings suggest that RV infection may contribute to the pathogenesis of NP formation in patients with CRSwNP.

Clarithromycin inhibits rhinovirus-induced bacterial adhesions to nasal epithelial cells

OBJECTIVES/HYPOTHESIS

We investigated the inhibitory effects of clarithromycin (CM) on the rhinovirus (RV)-induced expression of fibronectin (Fn) and carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), which act as major receptors for Staphylococcus aureus and Haemophilus influenzae, respectively. We further investigated the effects of CM on secondary S. aureus and H. influenzae adhesions to RV-infected primary human nasal epithelial cells (HNECs).

METHODS

Cells were pretreated with 10 microM CM 24 hours before RV-16 infection and for 48 hours thereafter. The expression levels of Fn and CEACAMs were assayed by reverse transcriptase-polymerase chain reaction and Western blotting. Bacterial adhesion to cells was assessed by confocal microscopy and the fluorescence intensity of adherent bacteria was analyzed using Image-Pro Plus 5.1 (Media Cybernetics, Bethesda, MD).

RESULTS

Clarithromycin significantly inhibited the RV-induced gene and protein expression of Fn and CEACAMs in HNECs. Compared with RV-infected cells, CM treatment significantly reduced the adhesion levels of S. aureus and H. influenzae in RV-infected HNECs to the levels seen in noninfected control cells.

CONCLUSIONS

These findings indicate that CM has the potential to prevent secondary bacterial infections in RV-infected HNECs by inhibiting the expression of Fn and CEACAM, thereby interfering with bacterial adhesion.

Double-stranded RNA poly(I:C) enhances matrix metalloproteinase mRNA expression in human nasal polyp epithelial cells

CONCLUSION

The significant up-regulation of matrix metalloproteinase (MMP)-9 mRNA, which is not modulated by tissue inhibitor of metalloproteinase (TIMP)-1, is an additional source of increased proteolytic activity in virus-infected upper airways that might contribute to the exacerbation of chronic rhinosinusitis with nasal polyps.

OBJECTIVES

Chronic rhinosinusitis is often exacerbated by viral infection. We hypothesized that a disruption of the mechanisms that regulate the activity of MMPs during viral infection is one possible mechanism responsible for the exacerbation. In the present study we attempted to achieve a better understanding of MMP expression in nasal epithelial cells after viral infection.

MATERIALS AND METHODS

Human nasal epithelial cells were isolated from nasal polyp specimens obtained during endoscopic endonasal surgery in chronic rhinosinusitis patients. We investigated the expression of MMP-2, MMP-9, and TIMP-1 mRNA in primary human nasal polyp epithelial cells after dsRNA stimulation.

RESULTS

Among the genes whose expression was evaluated, only expression of MMP-9 mRNA increased significantly after dsRNA stimulation.

Involvement of Toll-like receptors in the immune response of nasal polyp epithelial cells

Recognition systems employed by airway epithelial cells to respond to microbial exposure include the action of Toll-like receptors (TLRs). We investigated the presence and function of TLR2, 3, and 4 in primary cultures of human nasal polyp epithelial cells. dsRNA stimulation significantly enhanced the expression and secretion of RANTES, IP-10, IL-8, and GM-CSF. LPS also exhibited stimulatory action, but it was much weaker than dsRNA. Peptidoglycan had no significant stimulatory action on the genes. Flow cytometry showed that the nasal polyp epithelial cell mainly expressed TLR3 in an intracellular compartment, but expression of TLR2 and TLR4 was very low on both the cell surface and in the cell. The immune response of primary nasal polyp epithelial cells induced by TLR3 could not be blocked by anti-TLR3 antibody. Among the TLR ligands evaluated, dsRNA, the ligand for TLR3, mediated the strongest pro-inflammatory effects in primary nasal polyp epithelial cells.

The effects of maternal employment on child injuries and infectious disease

This article presents estimates of effects of maternal paid work and nonmaternal child care on injuries and infectious disease for children aged 12 to 36 months. Mother-child fixed-effects estimates are obtained by using data from the NICHD Study of Early Child Care. Estimates indicate that maternal employment itself has no statistically significant adverse effects on the incidence of infectious disease and injury. However, greater time spent by children in center-based care is associated with increased rates of respiratory problems for children aged 12 to 36 months and increased rates of ear infections for children aged 12 to 24 months.

[Current management of acute pediatric rhinosinusitis in France]

Un groupe de médecins généralistes et multidisciplinaire de spécialistes contribue à définir les différentes formes de sinusites ou rhinosinusites aiguës de l'enfant à partir des principaux symptômes et signes cliniques. Le rôle des pathologies associées telles que l'allergie, les troubles immunitaires est envisagé. L'incidence, la présentation clinique et la prise en charge des complications sont présentées. Les indications des examens radiologiques et biologiques sont analysées. La prise en charge médicale en particulier, la place et le type des antibiotiques sont discutés. Des propositions de prise en charge selon des situations cliniques rencontrées en pratique sont présentées.

Detection of rhinovirus in turbinate epithelial cells of chronic sinusitis

BACKGROUND

In contrast to the well-established association of rhinovirus (RV) with acute sinusitis, little is known about the role of RV infections in the pathogenesis of chronic sinusitis. Therefore, we assayed the nasal cavity mucosae of chronic sinusitis patients lacking signs of acute viral infection for the presence of RV.

METHODS

Nasal lavage fluids and turbinate epithelial cells from 39 sinusitis patients and 27 control subjects were tested. Turbinate epithelial cells were collected using a Rhino-probe mucosal curette. Picornavirus was assayed by an initial reverse-transcription polymerase chain reaction (PCR), and picornavirus-positive samples were assayed by nested reverse-transcription PCR to detect RV.

RESULTS

All lavage fluids from both groups, as well as control epithelial cells, were negative for picornavirus. In contrast, 8 of 39 (21%) epithelial cell samples from sinusitis patients were positive for picornavirus. RV-specific nested-PCR revealed that all eight of these samples were positive for RV.

CONCLUSION

The detection of RV in the turbinate epithelial cells of chronic sinusitis patients suggests that RV may be important in the pathogenesis of chronic sinusitis.

Molecular characterization of a variant rhinovirus from an outbreak associated with uncommonly high mortality

BACKGROUND

Human rhinoviruses (HRVs) are the most frequent cause of acute upper respiratory tract infection, however, they are also known to replicate in the lower respiratory tract and associate with more severe respiratory illnesses. An outbreak of HRV occurred in a long-term facility in Santa Cruz, California with unusually high morbidity and mortality.

OBJECTIVES

To identify viral characteristics associated with this unique outbreak, genetic relationships between these clinical isolates (SCRVs) and prototype strains of rhinovirus were investigated.

STUDY DESIGN

Sequence homology and phylogenetic analyses of the SCRV VP4/VP2 region were performed in conjunction with all HRV prototypes. Due to the importance of the 5'noncoding region (NCR) and the structural genes to viral replication and host immune responses, respectively, we focused on a segment of the HRV genome which includes these regions. Molecular models of SCRV were also assessed.

RESULTS

SCRV showed closest similarity to HRV82 with some divergence from the prototype. Amino acid differences were concentrated within predicted neutralization epitopes within VP2, VP3 and VP1.

CONCLUSION

Sequence analyses and differences in cell culture growth characteristics suggest that this virus is a variant of HRV which has distinctive properties from its respective prototype strain.

Incidência de infecção viral do trato respiratório em asma aguda atendida em sala de emergência

OBJETIVO: Avaliar a incidência de infecção viral em asma aguda em pacientes atendidos em setor de adultos de um serviço de emergência. MÉTODOS: Conduzimos um estudo de coorte de pacientes que se apresentaram com asma aguda no setor de adultos do Serviço de Emergência do Hospital de Clínicas de Porto Alegre (idade > 12 anos). Um aspirado nasofaríngeo foi obtido para detecção de antígenos com a técnica de coloração de imunofluorescência indireta para os vírus sincicial respiratório, adenovírus, influenza e parainfluenza tipos 1, 2, 3 e 4. Foram coletados dados referentes a características demográficas, história médica pregressa, crise que levou à atual visita ao serviço de emergência e desfechos da crise. RESULTADOS: No período de março a julho de 2004, 49 pacientes foram examinados para infecção viral do trato respiratório. Foram identificados vírus respiratórios em 6 pacientes (3 com adenovírus, 2 com influenza A e 1 com parainfluenza tipo 1). Os pacientes com infecção viral do trato respiratório apresentaram média de idade de 61,7 ± 11,5 anos, enquanto que os pacientes sem infecção viral apresentaram média de idade de 41,7 ± 20,9 anos (p = 0,027). Não houve outras diferenças significativas quanto às características clínicas e desfechos. CONCLUSÃO: Este estudo mostra uma incidência de 12,24% de infecção viral do trato respiratório na asma aguda em pacientes com idade igual ou maior que doze anos atendidos em sala de emergência, o que confirma a infecção viral como um desencadeante nessa faixa etária.

Effect of weed pollen on children's hospital admissions for asthma during the fall season

The authors analyzed temporal variations in asthma hospital admissions for New Jersey children (0-14 years of age) over a 3-year period. Significant spikes in children's asthma hospital admissions occurred during late September and early October of each of the 3 years of the study. The authors report on an in-depth analysis of the fall peak periods, in an effort to determine whether there was an association between children's asthma hospital admissions and environmental variables. Hospital admission peaks occurred approximately 3 weeks after school started and before heating systems were turned on in New Jersey public schools. They also preceded the point at which schools begin to report increased absences that are due to infectious illnesses. An examination of environmental variables showed only weed pollen as a statistically significant predictor of children's asthma hospital admissions during the fall peaks (p < .001). The counseling of parents about children's exposure to pollen and possible ways to reduce such exposure should be part of the asthma management protocols for children living in high-pollen environments.

The bronchial lavage of pediatric patients with asthma contains infectious Chlamydia

There has been a worldwide increase in the incidence of asthma, and the disease has greatly impacted the public health care system. Chlamydia pneumoniae has been reported as a possible contributing factor in asthma. The organism has been detected by polymerase chain reaction (PCR) in bronchial tissue, but there has been no direct evidence of viability. To determine the frequency of viable Chlamydia in children, blood and bronchoalveolar lavage were collected from 70 pediatric patients undergoing flexible fiberoptic bronchoscopy. Forty-two of these patients had asthma, whereas the remaining patients had various respiratory disorders. Fifty-four percent (38) of the bronchoalveolar lavage samples were PCR-positive for Chlamydia, and 31% (22) of the PCR-positive samples were positive when cultured on macrophages. Twenty-eight samples (40%) and 14 samples (20%) of the PCR- and culture-positive samples, respectively, were from patients with asthma. Culture of the blood samples revealed that 24 (34.3%) of 70 were positive for Chlamydia compared with 8 (11%) of 70 matched nonrespiratory control subjects (p < 0.01); 17 (24%) of the positive blood cultures from the respiratory group were from patients with asthma. Elevation of total IgE was strongly associated with lavage culture positivity for Chlamydia. We therefore conclude that viable Chlamydia pneumoniae organisms are frequently present in the lung lavage fluid from this cohort of predominantly asthmatic pediatric patients.

Viruses in asthma exacerbations

PURPOSE OF REVIEW

Respiratory viruses are well recognized as major triggers of acute exacerbations of asthma in children and adults, resulting in frequent outpatients visits and hospitalizations. Clinical and epidemiologic evidence supports this association. The application of molecular diagnostic methods has improved understanding of viral epidemiology and the pathophysiological mechanisms involved in viral induced acute asthma. This article reviews publications since October 2002 for an update of the role of viruses in exacerbations of asthma.

RECENT FINDINGS

Respiratory viruses are present in most patients hospitalized for life-threatening asthma and acute non life-threatening asthma. Rhinovirus is the most common, but coinfection with other viruses may be important. Patients with asthma are not more susceptible to upper respiratory tract rhinovirus infections than healthy people but suffer from more severe consequences of the lower respiratory tract infection. Recent epidemiologic studies suggest that viruses provoke asthma attacks by additive or synergistic interactions with allergen exposure or with air pollution. An impaired antiviral immunity to rhinovirus may lead to impaired viral clearance and hence prolonged symptoms. Respiratory viral infections cause asthmatic exacerbations by triggering recruitment of Th2-type cells into the lungs. There is no specific antiviral strategy for prevention of respiratory-triggered asthma exacerbations, although clinical trials of potential antiviral agents are ongoing. Indirect prevention strategies focus on the reduction of overall airway inflammation to reduce the severity of the host response to respiratory viral infections.

SUMMARY

Respiratory viral infections are a major cause of morbidity and mortality in asthma. There is a lack of specific antiviral strategies in the prevention or reduction of viral-triggered asthma exacerbations. Recent advances in understanding of the epidemiology and immunopathogenesis of respiratory viral infection in asthma provide opportunities or identification of specific targets for antiviral agents and strategies for management and prevention.

Nutritional Supplements and Upper Respiratory Tract Illnesses in Young Children in the United States

Key Points

In the United States, children have lower blood levels than adults of eicosapentaenoic acid (EPA), an important ω-3 fatty acid that helps decrease inflammation; vitamin A, the “anti-infective” vitamin; and selenium (Se), a trace metal that is an intrinsic part of glutathione peroxidase, an important free-radical scavenging enzyme.

EPA, vitamin A, and Se are important in controlling inflammation and can be supplied by oral nutritional supplements.

Cod liver oil contains EPA (and other important ω-3 fatty acids), and vitamin A as well as vitamin D.

Fish oil contains ω-3 fatty acids (including EPA) but no vitamins.

Our clinical research demonstrates that daily supplementation with a flavored cod liver oil (which meets European purity standards) and a children’s multivitamin-mineral with trace metals, including Se, can decrease morbidity from upper respiratory tract illnesses, otitis media, and sinusitis in young children living in the United States.

These supplements can be used by practitioners on an individual basis, when clinically indicated; the supplements can be purchased in the United States without a prescription.

Socioeconomically disadvantaged children are at risk for micronutrient deficiencies. However, their families may not be able to afford to purchase these supplements, which are not available through Medicaid, The Special Supplemental Nutrition Program for Women, Infants and Children, or the Food Stamp Program.

If our results are confirmed in larger studies, a system change will be needed to provide these supplements to nutritionally vulnerable, socioeconomically disadvantaged children living in the United States.

History of ear infections and prevalence of asthma in a national sample of children aged 2 to 11 years: the Third National Health and Nutrition Examination Survey, 1988 to 1994

METHODS

We analyzed data on 7,538 children aged 2 to 11 years who participated in the Third National Health and Nutrition Examination Survey to examine the cross-sectional associations of history of ear infections with prevalence of ever-diagnosed asthma and the prevalence of wheezing in the last year in US children.

RESULTS

History of ear infections was significantly related to the lifetime prevalence of diagnosed asthma (prevalence odds ratio [POR], 1.57; 95% confidence interval [CI], 1.05 to 2.36) and to the prevalence of wheezing in the last year (POR, 1.70; 95% CI, 1.22 to 2.37) after controlling for potential confounding variables. The number of ear infections was linearly and significantly related to the risk of asthma and wheezing in the last year. Among children with no diagnosis of asthma, there was a significant association between a history of ear infections and any wheezing in the last year (adjusted POR, 1.55; 95% CI, 1.07 to 2.25).

CONCLUSIONS

Our study indicated strong and significant associations of a history of asthma and wheezing with the frequency of ear infections in a nationally representative sample of 7,538 children aged 2 to 11 years. These findings highlight the need for prospective studies to examine further the relationship between asthma and ear infections.

Clinical impact and diagnosis of human metapneumovirus infection

BACKGROUND

Acute respiratory infections are the most common illnesses experienced by people of all ages worldwide. A portion of hitherto unexplained viral respiratory tract illnesses (RTIs) can now be attributed to the human metapneumovirus (hMPV), which was discovered in 2001. Several surveys on the burden of disease of hMPV infection have been conducted in various study groups and with different diagnostic assays. To estimate the impact of hMPV infection in a hospital setting and in the community at large, we reviewed these surveys to establish the burden of disease of hMPV infection.

METHODS

Published data and our own additional unpublished data on the clinical impact of hMPV infection were reviewed.

RESULTS AND CONCLUSION

Worldwide, hMPV infections account for at least 5 to 7% of the RTI in hospitalized children, but immunocompromised and elderly individuals are also at risk. In the general community hMPV infections account for at least 3% of patients who visit a general practitioner for RTI. The seasonality of hMPV infections resembles that for respiratory syncytial virus and influenza virus infections, with recurrent epidemics during the winter months. Clinical symptoms and laboratory findings associated with hMPV infection exhibit a spectrum virtually indistinguishable from those associated with respiratory syncytial virus disease. The development of diagnostic assays must take into account the existence of two hMPV serotypes.

Prenatal cigarette smoke decreases lung cAMP and increases airway hyperresponsiveness

Epidemiologic studies suggest that in utero exposure to tobacco smoke, primarily through maternal smoking, increases the risk for asthma in children; however, the mechanism of this phenomenon is not clear. Cyclic adenosine monophosphate relaxes airway smooth muscles in the lung and acts as an antiasthmatic. In this study, we examined the effects of in utero cigarette smoke exposure of Balb/c mice on airway responsiveness, as determined by Penh measurements. Animals exposed prenatally but not postnatally to cigarette smoke exhibited increased airway hyperresponsiveness after a single intratracheal injection of Aspergillus fumigatus extract. The increased airway hyperresponsiveness was not associated with increased leukocyte migration or mucous production in the lung but was causally related to decreased lung cyclic adenosine monophosphate levels, increased phosphodiesterase-4 enzymatic activity, and phosphodiesterase-4D (PDE4D) isoform-specific messenger ribonucleic acid expression in the lung. Exposure of adult mice to cigarette smoke did not significantly alter airway responsiveness, cyclic adenosine monophosphate levels, or the phosphodiesterase activity. These results suggest that prenatal exposure to cigarette smoke affects lung airway reactivity by modulating the lung cyclic adenosine monophosphate levels through changes in phosphodiesterase-4D activity, and these effects are independent of significant mucous production or leukocyte recruitment into the lung.