Eosinophilic airway inflammation and the prognosis of childhood asthma

BACKGROUND: Eosinophilic airway inflammation is a key pathophysiological feature of asthma that can predict treatment response. However, the prognostic value of sputum eosinophilia is not established. OBJECTIVE: The aim of this study was to determine the influence of induced sputum eosinophilia on the prognosis of childhood asthma. METHODS: A cohort of children with asthma was evaluated by induced sputum analysis at inception and classified as having either eosinophilic asthma (EA) (sputum eosinophils >2.5%) or non-eosinophilic asthma (NEA). After a mean follow-up period of 5 years, eligible subjects (n=83) were contacted and 69 subjects (33 EA, 36 NEA) evaluated. The children had a mean age of 15.9 years, and 61% were male. RESULTS: Children with EA reported more wheeze during the follow-up period (27% vs. 6% wheezed most years; P<0.0001), increased night waking during the past 12 months (28% vs. 3% reported weekly waking; P=0.01), and greater impairment of quality of life due to asthma (P=0.04). Subsequent beta2-agonist use was increased in children with EA (P=0.02), although there was no difference in corticosteroid use. In EA, subsequent forced expiratory volume in 1 s/forced vital capacity was lower (79% vs. 86%; P=0.01) and grass pollen allergy was more prevalent (77% vs. 27%; P=0.006). CONCLUSION: In children, eosinophilic airway inflammation is associated with deteriorating asthma over time. This is consistent with the hypothesis that airway inflammation has an adverse impact on the prognosis of childhood asthma, and suggests a role for monitoring inflammation in asthma management.     

Eosinophilic inflammation, remodeling of lower airway, bronchial responsiveness and cough reflex sensitivity in non-asthmatic subjects with nasal allergy

BACKGROUND: It has been reported that nasal allergy influences the lower airway inflammation and functions. We elucidated whether nasal allergy would contribute to lower airway inflammation and functions. METHODS: 266 subjects aged 21-39 years were interviewed with special emphasis on history of asthma and nasal allergies (perennial allergic rhinitis (PAR) and seasonal allergic rhinitis (Japanese cedar pollinosis; PO)). Symptomatic subject was defined when nasal symptoms were present during a 3-week study period. Pulmonary function, provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20), capsaicin cough threshold defined as capsaicin concentration eliciting 5 or more coughs (C5) and eosinophil percentage in hypertonic saline-induced sputum were measured. RESULTS: Based on the interview, 232 subjects without asthma were divided into symptomatic (n = 25) and asymptomatic (n = 22) PAR, PO on-season (n = 15) and off-season (n = 36), and non-nasal allergy subjects (control) (n = 134). Sputum eosinophils were significantly greater in symptomatic PAR than another four groups (p < 0.01). FEV1/FVC ratio was significantly lower in PAR than control (p < 0.05). Maximum mean expiratory flow was lower in PAR than control (asymptomatic: p < 0.05, symptomatic: p = 0.06). C5 was not different among groups. PAR tended to have a lower PC20 compared to control (symptomatic: p = 0.078; asymptomatic: p = 0.086). CONCLUSIONS: These results suggest that eosinophilic inflammation occurred in symptomatic period of PAR may contribute to development of lower airway remodeling and bronchial hyperresponsiveness. Reversely, PO may not be associated with lower airway eosinophilic inflammation or abnormal bronchial functions. Nasal allergy dose not influence the cough reflex sensitivity.     

Airway inflammation in nasal polyposis: immunopathological aspects of relation to asthma

BACKGROUND: Nasal polyposis (NP) is a chronic inflammatory disorder of the upper respiratory tract, which is often coexist with asthma. However, the pathogenesis of especially in patients with NP is still a matter of debate. OBJECTIVE: To better understand the immunopathologic mechanism involved in this relationship, we investigated the inflammatory cell profiles in bronchial and nasal tissues of patients with NP alone and with concomitant asthma. METHODS: Seventeen patients with NP (six male, 11 female, age range: 19-63, mean age: 38.29+/-13.27 years) were selected for the study. Subjects were divided into two groups based on the presence of asthma or bronchial hyper-responsiveness (BHR). NP without BHR (Group 1) (n=8), NP and asthma or BHR (Group 2) (n=9). All patients underwent atopy evaluation including detailed history, skin prick test (SPT), total and specific IgE determination in sera. None of the subjects had taken inhaled, nasal or oral corticosteroids for at least 1 month before the study. Respiratory symptoms of asthmatic patients were controlled with only short acting beta(2)-agonist inhaler drugs as needed. NP tissue, nasal and bronchial mucosa biopsies were taken from all patients using fiberoptic endoscopy. CD3, CD8, CD16, CD68, AA1 (mast cell tryptase), human leucocyte antigen-DR (HLA-DR) and eosinophil peroxidase (EPO) expressing cells in specimens were determined by immunohistochemical methods. Positively staining inflammatory cell types were counted. Subepithelial lamina propria and periglandular areas were separately evaluated. RESULTS: No significant difference was found in polyp tissue, nasal and bronchial CD3(+), CD8(+), CD16(+), CD68(+), AA1(+), HLA-DR(+) and EPO(+) positive cells between groups. There were significantly higher numbers of CD8(+), CD16(+), HLA-DR(+), EPO(+) cells in the polyp tissue and nasal mucosa vs. the bronchial mucosa in all groups (P<0.05). However, CD8(+) cells were significantly increased in the polyp tissue and bronchial mucosa of patients with NP alone when compared with the patients with both asthma and NP (P<0.05). CD3(+), CD68(+) and CD16(+) cell counts were tended to be higher within the nasal polyp tissue of patients with isolated NP compared with counts within nasal and bronchial mucosa of patients with NP and asthma. Also, patients with isolated NP showed more HLA-DR(+) cells in the nasal polyp tissue and nasal mucosa than those of patients with NP and asthma. Immunoreactivity for EPO(+) eosinophils within the nasal and bronchial mucosa was more prominent in patients with NP and asthma compared with patients with NP alone. The number of EPO(+) eosinophils within the polyp tissue, nasal and bronchial mucosa was higher in the skin prick test negative (SPT -ve) group than the SPT positive (SPT +ve) ones. CONCLUSIONS: Our results demonstrate that infiltration of inflammatory cells in the nasal and the lower airways do not remarkably differ between patients with NP alone who has no evidence of BHR and asthmatic patients with NP. However, patients with SPT-ve NP reveal more intense eosinophilic inflammation in the entire respiratory mucosa.     

Quality of life in nasal polyposis.

BACKGROUND: Nasal polyposis (NP) is a frequent inflammatory chronic disease of the upper respiratory tract, which may impair quality of life (QOL). The NP impact, which is frequently associated with lower respiratory disorders, has never before been studied. OBJECTIVE: We initiated this prospective study to establish internal validity and reliability of the generic SF-36 questionnaire in NP and to determine to what level daily functioning becomes impaired as a result of NP. METHODS: Forty-nine consecutive patients with NP were included. They were assessed for the severity of nasal symptoms and underwent pulmonary function tests. The QOL profiles in patients with NP were compared with those of patients with perennial rhinitis (n = 111) and healthy subjects (n = 116). RESULTS: Cronbach's coefficient alpha demonstrated the high reliability and validity of the SF-36 questionnaire for patients with NP (alpha =.89). NP impaired QOL more than perennial allergic rhinitis (P <.05). The impairment of QOL was greater when NP was associated with asthma (P <.05). SF-36 scores appeared highly correlated to pulmonary function (FEV1, maximal midexpiratory flow, forced vital capacity), suggesting relationships between QOL in NP and associated bronchial obstruction. Severity of nasal symptoms were not related to QOL scales. In addition, sequential evaluations of QOL, nasal symptoms, and pulmonary function were performed 10 months after the first evaluation in 28 patients with NP. These evaluations demonstrated that NP treatment either with nasal steroids or endonasal ethmoidectomy significantly improved both nasal symptoms and QOL without significant change of pulmonary function. CONCLUSION: Our study clearly demonstrated that the SF-36 questionnaire presented a high internal validity and reliability in patients with NP. NP impaired QOL to a greater degree than perennial allergic rhinitis. QOL improvement after NP treatment is related to nasal symptoms improvement.     

Eosinophilic inflammation in asthma

BACKGROUND AND METHODS. The importance of eosinophils in the pathogenesis of bronchial asthma is not established. In an attempt to evaluate the role of eosinophilic inflammation in asthma, we compared 10 normal subjects with 43 patients with chronic asthma, 19 of whom had severe disease as assessed by a clinical scoring method described by Aas and by pulmonary-function tests. Eosinophils were counted in peripheral blood and bronchoalveolar-lavage fluid, and in biopsy specimens obtained from the patients and post mortem from 8 subjects without asthma, but not from the 10 normal controls. Eosinophil cationic protein was titrated by radioimmunoassay in the bronchoalveolar-lavage fluid from all subjects and studied by immunohistochemistry in the biopsy specimens. RESULTS. There was a significant increase in the number of peripheral-blood eosinophils in the patients that was correlated with the clinical severity of asthma (P less than 0.001) and pulmonary function (P less than 0.03). Levels of eosinophils and eosinophil cationic protein were increased in the bronchoalveolar-lavage fluid from the patients and were also correlated with the severity of asthma (P less than 0.001 and P less than 0.002, respectively). Hematoxylin-eosin staining of bronchial-biopsy specimens showed that intraepithelial eosinophils were present only in patients with asthma. Immunohistochemical analysis of eosinophil cationic protein revealed that normal subjects had only a few nondegranulated eosinophils deep in the submucosa, whereas all the patients had degranulated eosinophils beneath the basement membrane and among epithelial cells. In some patients there was a relation between the presence of degranulated eosinophils and epithelial damage. CONCLUSIONS. Eosinophilic inflammation of the airways is correlated with the severity of asthma. These cells are likely to play a part in the epithelial damage seen in this disease.     

Mucociliary clearance,airway inflammation and nasal symptoms in urban motorcyclists

OBJECTIVES:There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution.METHODS:In total, 25 non-smoking commercial motorcyclists, aged 18-44 years, were included in this study. These drivers work 8-12 hours per day, 5 days per week, driving on urban streets. Nasal mucociliary clearance was measured by the saccharine transit test; airway acidification was measured by assessing the pH of exhaled breath condensate; and airway symptoms were measured by the Sino-nasal Outcome Test-20 questionnaire. To assess personal air pollution exposure, the subjects used a passive-diffusion nitrogen dioxide (NO₂) concentration-monitoring system during the 14 days before each assessment. The associations between NO₂ and the airway outcomes were analyzed using the Mann-Whitney test and the Chi-Square test. Clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01976039","term_id":"NCT01976039"}}NCT01976039.RESULTS:Compared with clearance in healthy adult males, mucociliary clearance was decreased in 32% of the motorcyclists. Additionally, 64% of the motorcyclists had airway acidification and 92% experienced airway symptoms. The median personal NO₂ exposure level was 75 mg/m³ for these subjects and a significant association was observed between NO₂ and impaired mucociliary clearance (p = 0.036).CONCLUSION:Non-smoking commercial motorcyclists exhibit increased airway symptoms and airway acidification as well as decreased nasal mucociliary clearance, all of which are significantly associated with the amount of exposure to air pollution.     

Paradoxical low nasal nitric oxide in nasal polyposis

BACKGROUND: Nitric oxide (NO) is synthesized in the respiratory tract. Three isoforms of NO synthase have been described in man, with the inducible form related to inflammatory disease. In the paranasal sinuses constitutive production of nitric oxide has been demonstrated, with levels of 20-25 p.p.m. being found in sinus puncture. Nasal polyposis is a chronic inflammatory condition in which inducible nitric oxide synthase (iNOS) expression is elevated in nasal polyp epithelium. OBJECTIVES: 1. Measurement of upper airway nitric oxide in nasal polyposis patients compared with those with allergic rhinitis, and with normal controls. 2. To assess the effect of polyp treatment on nasal NO levels. METHODS: NO levels (parts per billion) were measured in nasal and pulmonary exhaled air using a LR 2000 Logan Sinclair nitric oxide gas analyser. This utilizes the chemiluminescence principle. Eighty-two patients were studied: 44 with rhinitis, but without polyps, and 38 with nasal polyps. NO levels were compared with those of 20 normal controls. In 23 further polyp patients, levels were measured pre- and post-treatment and the changes were compared with alterations in polyp size, as assessed by rigid nasendoscopy. RESULTS: Nasal NO levels were significantly lower (Kruskal-Wallis, P = 0.000, chi2 = 27.5, d.f. = 3) in patients with polyps than those found in uncomplicated allergic rhinitis. NO levels were correlated directly with extent of polyposis as graded by the Lund-McKay index. Successful treatment, with reduction in polyp volume, was associated with a rise in NO levels (P = 0.042). CONCLUSION: NO levels are low in nasal polyposis, despite high levels of iNOS, possibly related to blockage of the ostiomeatal complex and failure of NO generated constitutively in the sinuses to reach the nasal airway. A rise in the NO levels is seen with successful polyp treatment, and is proportional to the reduction in endoscopically assessed polyp size, suggesting that with both medical and surgical therapy, the ostiomeatal complex obstruction is decreasing. We propose the following scenario. Nasal NO levels are the result of two processes: inducible NO production by inflamed nasal mucosa plus constitutive sinus mucosal production, detectable in normals. In uncomplicated allergic rhinitis with patent sinus ostia NO levels tend to be elevated, but when inflammation is sufficient to obstruct sinus ostia (as in nasal polyps), NO levels fall because sinus NO makes the major contribution.     

Fluticasone propionate downregulates nasal fibroblast functions involved in airway inflammation and remodeling

BACKGROUND: Besides being highly effective in the treatment of allergic and nonallergic rhinitis with eosinophilia, intranasal corticosteroids appear to be useful in reducing nasal polypoid lesions and the likelihood of polyp recurrence after surgery. We evaluated the ability of fluticasone propionate to downregulate fibroblast functions related to nasal inflammation and remodeling. METHODS: Primary nasal polyp tissue-derived fibroblasts were stimulated with tumor necrosis factor (TNF)-alpha or interleukin (IL)-4 or basic fibroblast growth factor (bFGF) in the presence of fluticasone propionate (0.1-100 nM). Fibroblast proliferation, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 expression and eotaxin release were then evaluated. RESULTS: As compared with unstimulated cultures, a significant increase in fibroblast proliferation was observed when the cells were stimulated with bFGF (p < 0.05), but not with TNF-alpha or IL-4 (p > 0.05). TNF-alpha induced an upregulation of ICAM-1 expression (p < 0.05), which was not seen in fibroblasts cultured in the presence of IL-4 or bFGF. No changes in VCAM-1 expression were induced by TNF-alpha, IL-4 or bFGF, whereas both TNF-alpha and IL-4 increased eotaxin release (p < 0.05). Both bFGF-induced fibroblast proliferation and TNF-alpha-induced ICAM-1 expression were significantly reduced by fluticasone, starting at the dose of 1 and 10 nM, respectively (p < 0.05). Fluticasone at concentrations of 1-100 nM effectively inhibited eotaxin release by TNF-alpha- or IL-4-stimulated fibroblasts (p < 0.05). CONCLUSIONS: The pharmacologic activity of fluticasone in patients with chronic upper airway inflammatory disease may include inhibition of resident fibroblast functions involved in airway inflammation and remodeling.     

Pathogenesis of nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory condition that affects a large proportion of the population world‐wide and is associated with high cost of management and significant morbidity. Yet, there is a lack of population‐based epidemiologic studies using current definitions of CRSwNP, and the mechanisms that drive pathogenesis in this disease remain unclear. In this review, we summarize the current evidence for the plethora of factors that likely contribute to CRSwNP pathogenesis. Defects in the innate function of the airway epithelial barrier, including diminished expression of antimicrobial products and loss of barrier integrity, combined with colonization by fungi and bacteria likely play a critical role in the development of chronic inflammation in CRSwNP. This chronic inflammation is characterized by elevated expression of many key inflammatory cytokines and chemokines, including IL‐5, thymic stromal lymphopoietin and CCL11, that help to initiate and perpetuate this chronic inflammatory response. Together, these factors likely combine to drive the influx of a variety of immune cells, including eosinophils, mast cells, group 2 innate lymphoid cells and lymphocytes, which participate in the chronic inflammatory response within the nasal polyps. Importantly, however, future studies are needed to demonstrate the necessity and sufficiency of these potential drivers of disease in CRSwNP. In addition to the development of new tools and models to aid mechanistic studies, the field of CRSwNP research also needs the type of robust epidemiologic data that has served the asthma community so well. Given the high prevalence, costs and morbidity, there is a great need for continued research into CRS that could facilitate the development of novel therapeutic strategies to improve treatment for patients who suffer from this disease.     

Continuous positive airway pressure (CPAP) induces early nasal inflammation

STUDY OBJECTIVES: To assess whether noninvasive application of nCPAP is a mechanical stimulus inducing early nasal inflammation. DESIGN: Prospective controlled animal study. SETTING: University laboratory. PATIENTS OR PARTICIPANTS: 32 male Sprague-Dawley rats (250-300 g). INTERVENTIONS: The rats were anesthetized and subjected to nCPAP=10 cm H2O and sham-CPAP through a mask for 3 h and 5 h (n=8 each). MEASUREMENTS AND RESULTS: After nCPAP or sham, nasal scraping was carried out to detect neutrophils, and septum and dorsal nasal concha were excised to assess gene expression of inflammatory markers by real time PCR. Percentage of neutrophils in nucleated cells in the nasal scrapings was significantly (P = 0.006) higher after 5 h of nCPAP (3.51% +/- 0.73%; m +/- SEM) than in the sham group (1.12% +/- 0.39%). When compared with sham, the mRNA of macrophage inflammatory protein-2 (MIP-2) in nasal tissue was significantly overexpressed after both 3 h (2.28-fold +/- 0.43-fold; P = 0.034) and 5 h (5.56-fold +/-1.88-fold; P = 0.002) of nCPAP=10 cm H2O. No significant changes were found in the gene expressions of tumor necrosis factor-alpha, nerve growth factor and tachykinin-1 receptor. CONCLUSIONS: The compression applied by nCPAP (10 cm H2O, 5 h) on the nasal wall of healthy rats is a mechanical stimulus that triggers an early inflammatory process mediated by MIP-2, resulting in neutrophil extravasation.     

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.     

Antifungal immune reactivity in nasal polyposis

As a fungal etiology has been proposed to underlie severe nasal polyposis, the present study was undertaken to assess local antifungal immune reactivity in nasal polyposis. For this purpose, microbial colonization, along with the pattern of T helper 1 (Th1)/Th2 cytokine production and Toll-like receptor (TLR) expression, was evaluated in patients with nasal symptoms and with and without polyposis and in healthy subjects. The results show that Th2 reactivity was a common finding for patients with nasal polyposis regardless of the presence of microbes. The production of interleukin-10 was elevated in patients with bacterial and, particularly, fungal colonization, while both TLR2 expression and TLR4 expression were locally impaired in microbe-colonized patients. Eosinophils and neutrophils, highly recruited in nasal polyposis, were found to exert potent antifungal effector activities toward conidia and hyphae of the fungus and to be positively regulated by TLR2 or TLR4 stimulation. Therefore, a local imbalance between activating and deactivating signals to effector cells may likely contribute to fungal pathogenicity and the expression of local immune reactivity in nasal polyposis.     

Exhaled nitric oxide levels and airway responsiveness to adenosine 5'-monophosphate in subjects with nasal polyposis

BACKGROUND:It is widely appreciated that asthma is an inflammatory disease of the airways associated with airway hyperresponsiveness, and that nasal polyposis and asthma are related diseases. The objective of this study was to determine differences in exhaled nitric oxide (ENO) levels and airway responsiveness to adenosine 5'-monophosphate (AMP) between nonasthmatic patients with nasal polyposis and healthy controls. METHODS: Twenty patients without asthma with nasal polyposis and 16 healthy control subjects were enrolled in the study. Participants were challenged with increasing concentrations of AMP and methacholine. ENO was measured with the single-exhalation method. RESULTS: Bronchoconstriction in response to AMP was detected in 7 (35%) subjects with nasal polyposis. The geometric mean (95% CI) of ENO for subjects with nasal polyposis was 33.1 parts per billion (ppb) (24.0-45.7 ppb) compared with 12.3 ppb (8.5-18.2 ppb) for the healthy controls (p = 0.0002). ENO values were significantly higher in atopic than in nonatopic subjects with nasal polyposis [51.3 ppb (32.3-83.2 ppb) vs. 24.5 ppb (16.2-37.1 ppb), p = 0.02]. Nonatopic subjects with nasal polyposis also had higher concentrations of ENO than healthy control subjects (p = 0.016). CONCLUSIONS: Inhaled AMP causes airway narrowing in a significantly higher proportion of nonasthmatic subjects with nasal polyposis than in healthy controls. Furthermore, increased concentrations of ENO are detected in atopic and nonatopic subjects with nasal polyposis. These results suggest that bronchial inflammation is present in nonasthmatic subjects with nasal polyposis.     

Repeatability of allergen-induced airway inflammation.

BACKGROUND: Allergen inhalation challenge is a useful clinical model to investigate the effects of asthma therapies on allergen-induced airway responses; however, the repeatability of allergen-induced airway inflammation is not known. OBJECTIVE: The purpose of this study was to investigate the repeatability of allergen-induced increases in sputum eosinophils. This information will allow the prediction of the number of subjects required in studies evaluating asthma therapies. METHODS: Seventeen subjects completed 2 allergen challenges using the same dose of allergen, at least 3 weeks apart. Allergen-induced airway responses were measured for 7 hours after challenge. Differential cell counts from induced sputum were determined the day before and 7 and 24 hours after challenge; methacholine PC20 was measured the day before and 24 hours after challenge. RESULTS: The intraclass correlation coefficient for maximum percent late fall in FEV1 was 0.32 and for the area of the late response was 0.61. The sample size predicted to be necessary to observe 50% attenuation of the maximum percent late fall in FEV1 and the late area under the curve with a power of 0.95 was 9 subjects. The intraclass correlation coefficient for percent of allergen-induced sputum eosinophils was 0.60 at 7 hours and 0.53 at 24 hours after challenge. With a randomized cross-over study design, the sample size predicted to be necessary to observe 50% attenuation of allergen-induced percent of eosinophils with a power of 0.95 was 5 subjects. CONCLUSION: Allergen inhalation challenge with measurements of sputum eosinophils is a noninvasive and reliable method for evaluating the anti-inflammatory effects of asthma therapies.     

Histamine metabolism is altered in nasal polyposis

Inflammation Research -