Bronchial hyperresponsiveness and airway inflammation in adolescents with asymptomatic childhood asthma

Evaluation of barometric whole-body plethysmography for therapy monitoring in cats with feline lower airway disease

OBJECTIVES

Feline lower airway disease (FLAD) is a common respiratory condition in cats. Traditionally, response to therapy is monitored only by evaluation of clinical signs and radiographic examination of the lungs. Barometric whole-body plethysmography (BWBP) is considered a non-invasive, well-tolerated form of measuring airway reactivity in cats. The aim of the study was to assess pulmonary function testing by BWBP for non-invasive evaluation of response to therapy in cats with FLAD and to investigate whether BWBP parameters correlate with clinical severity.

MATERIAL AND METHODS

The prospective study included 25 client-owned cats, diagnosed with FLAD on the basis of their medical history, clinical signs, radiographic findings, and bronchoalveolar lavage fluid (BALF) examination. At three time points (day 0, 14, and 60), a standardised owner questionnaire, a clinical examination and BWBP measurements were carried out. Results of the questionnaire and the clinical examination were evaluated using a clinical 12-point score. Individual therapy was administered to all patients after diagnosis, based on the severity of disease and compliance of the cat.

RESULTS

The total clinical score significantly improved over the entire study period (p<0.001). Significant improvement was detected for the frequency of coughing (p = 0.009), respiratory distress (p = 0.001), lung auscultation findings (p = 0.002), and general condition and appetite (p = 0.045). The BWBP parameter Penh, an indicator of bronchoconstriction, improved significantly under initial therapy between day 0 and 14 (p = 0.009). A significant correlation between Penh and the severity of auscultation findings was seen on day 0 (r = 0.40; p = 0.013).

CONCLUSION

The study supports the role of Penh as a non-invasive parameter for monitoring initial treatment response in cats with FLAD. Further studies are needed to address whether other BWBP parameters might be suitable for non-invasive therapy monitoring of FLAD. Clinical evaluation is always essential in cats with FLAD to evaluate treatment response.

Accelerated decline in lung function in adults with a history of remitted childhood asthma

AIM

A significant number of children with asthma show remission in adulthood. Although these adults are often diagnosed with chronic obstructive pulmonary disease in later life, the effect of clinically remitted childhood asthma on the decline in lung function during adulthood is uncertain. We examined whether clinical remission of childhood asthma was associated with an accelerated decline in lung function in apparently non-asthmatic adults.

METHODS

Here, 3584 participants (mean age, 48.1 years; range, 35-65 years) who did not have adulthood asthma and other lung diseases and had normal lung function at the baseline visit were included. They were categorised as follows: those with remitted childhood asthma (n=121) and healthy controls (n=3463) according to their self-reported childhood asthma history. Spirometry was performed at baseline and follow-up visits.

RESULTS

The mean follow-up time was 5.3 years. Multivariate regression analysis showed that remitted childhood asthma and smoking were independently associated with a rapid decline in forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC). Besides, smoking was an independent predictor of a rapid decline in the FEV₁/FVC. The annual decline in FEV₁ and FVC was significantly greater in participants with remitted childhood asthma than in healthy controls, and the differences remained significant after adjusting for the propensity score.

CONCLUSION

A history of clinically remitted childhood asthma is an independent risk factor for accelerated decline in lung function in adults. Remitted childhood asthma and smoking may additively accelerate the development of obstructive lung disease.

Feline Asthma: Diagnostic and Treatment Update

Asthma is an important allergic lower-airway disease in cats affecting approximately 1% to 5% of the pet cat population. New diagnostics are being developed to help better differentiate asthma from other lower-airway diseases and improve monitoring. In addition, new treatments are being developed to help in refractory cases or in those cases in which traditional therapeutics are contraindicated. This article discusses potential pitfalls in the diagnosis of asthma. In addition, current literature investigating new diagnostic tests and therapies for feline asthma is reviewed.

Rhinovirus-induced IFNβ expression is NFκB-dependent and regulated by the macrophage microenvironment

Macrophages play an important role in asthma pathogenesis both in the inflammatory and resolution phase of the disease. Macrophages can acquire different polarisation states dependent on their microenvironment. It is yet unclear through which mechanism the microenvironment affects the anti-viral response in macrophages. We hypothesized that the macrophage microenvironment regulates rhinovirus-induced IFNβ expression. Murine bone marrow-derived monocytes and human differentiated THP-1 cells were stimulated with M-CSF or GM-CSF and IFNγ or IL-4/IL-13, respectively, to mimic a Th1 or Th2 environment. Macrophages were infected with rhinovirus and gene and protein levels of IFNβ and pattern recognition receptor expression were measured. In subsequent experiments an IκB kinase inhibitor was used to study the involvement of NFκB. Both murine and human M1-like macrophages exhibited higher levels of IFNβ and pattern recognition receptors after rhinovirus infection than M2-like macrophages. Blockage of NFκB resulted in a lower expression of rhinovirus-induced IFNβ in human M1-like macrophages while inducing a higher expression in M2-like macrophages, suggesting that the interferon response towards viral infection was mediated by NFκB. These findings could contribute to a better understanding of mechanisms causing reduced anti-viral responses at viral-induced exacerbations in asthma.

Cytokine production by PBMC and serum from allergic and non-allergic subjects following in vitro histamine stimulation to test fexofenadine and osthole anti-allergic properties

FXF is a third-generation antihistamine drug and osthole is assumed a natural antihistamine alternative. This paper compares peripheral blood mononuclear cell (PBMC) incubation with FXF and osthole, by studying FXF, osthole and histamine cytokine secretion in PBMC in vitro cultures. Mabtech kits determined the interleukins IL-1β, IL-4, IL-10, IL-13 and TNF-α. The influence of the above active substances on cytokine secretion in PBMC's and serum was assessed: cytokines were IL-1β, IL-4, IL-10, IL-13 and TNF-α; and cytokine levels secreted by untreated PBMCs in pure culture medium formed the absolute control (ctrl). We determined that osthole affects PBMC cytokine secretion to almost precisely the same extent as FXF (IL-1β, IL-4, IL-10 and TNF). In addition osthole had greater IL-13 blocking ability than FXF. Moreover, we observed significantly decreased IL-4 level in histamine/osthole theatment compared to histamine alone. Meanwhile, FXF not significantly decrease the level of IL-4 increased by histamine. This data indicates osthole's strong role in allergic inflamation. All results confirm our hypothesis that osthole is a natural histamine antagonist and therefore can be beneficially used in antihistamine treatment of conditions such as allergies.

Clinically remitted childhood asthma is associated with airflow obstruction in middle-aged adults

BACKGROUND AND OBJECTIVE

While adult asthma has been shown to be a risk factor for COPD, the effect of remitted childhood asthma on adult lung function has not been clarified. The aim of this study was to examine whether remitted childhood asthma is a risk factor for airflow obstruction in a middle-aged general population.

METHODS

A total of 9896 participants (range: 35-60 years) from five healthcare centres were included in the study. The participants were classified into four categories based on the presence or absence of physician-diagnosed childhood/adulthood asthma and asthma symptoms as follows: healthy controls (n = 9154), remitted childhood asthma (n = 287), adulthood-onset asthma (n = 354) and childhood-adulthood asthma (n = 101).

RESULTS

The prevalence of respiratory symptoms was similar in both the participants with remitted childhood asthma and healthy controls. The prevalence of airflow obstruction (forced expiratory volume in 1 s (FEV₁ )/forced vital capacity (FVC) < 0.7) was significantly higher in the participants with remitted childhood asthma, those with adult-onset asthma and those with childhood-adulthood asthma (5.2%, 14.4% and 16.8%, respectively) compared with healthy controls (2.2%). Multivariate logistic regression showed that remitted childhood asthma was independently associated with airflow obstruction. Among the participants with remitted childhood asthma, ever-smokers had significantly lower FEV₁ /FVC than never-smokers.

CONCLUSION

Clinically remitted childhood asthma is associated with airflow obstruction in middle-aged adults. Smoking and remitted childhood asthma may be additive factors for the development of airflow obstruction.

Update on feline asthma

This article provides an overview of recent advances in the diagnosis and treatment of feline asthma. The authors discuss the potential pitfalls in the diagnosis of feline asthma. In addition, current literature investigating new therapies for the treatment of feline asthma is reviewed.

Peanut allergy and allergic airways inflammation

Asthma is a major risk cofactor for anaphylactic deaths in children with peanut allergy. Peanut allergy is generally thought to be a lifelong condition, but some children outgrow their coexistent asthma. It has recently been shown that children who have 'outgrown' their asthma symptoms may have ongoing eosinophilic airways inflammation. The need for regular inhaled corticosteroid treatment in peanut allergic children and adolescents who have outgrown their asthma is however unclear. The aims of our study were to look at fractional exhaled nitric oxide levels (FeNO), as a non-invasive marker of eosinophilic airways inflammation, in peanut allergic children and assess whether children with outgrown asthma had elevated levels. Children with peanut allergy were recruited at two pediatric allergy clinics in Belfast, UK. Exhaled nitric oxide levels (FeNO) were measured using the Niox Mino in all children. Of the 101 peanut allergic children who consented for enrollment in the study, 94 were successfully able to use the NIOX Mino. Age range was 4-15 yr (median 10 yr); 61% were boys. Thirty (32%) had never wheezed, 37 (39%) had current treated asthma, 20 (21%) had at least 1 wheezing episode within the last year but were not taking any regular asthma medication (wheeze no treatment), and 7 (7%) had outgrown asthma. All children with outgrown asthma had elevated levels of FeNO (> 35 ppb), and 75% of children defined as 'wheeze no treatment' had elevated FeNO levels (> 35 ppb). Outgrown asthma and children defined as 'wheeze no treatment' had higher levels of FeNO than those with no history of wheeze or current treated asthma (p = 0.003). In children with peanut allergy, we found that those who had outgrown asthma had elevated FeNO levels in keeping with ongoing eosinophilic airways inflammation.

A new look at the pathogenesis of asthma

Asthma is an inflammatory disorder of the conducting airways that has strong association with allergic sensitization. The disease is characterized by a polarized Th-2 (T-helper-2)-type T-cell response, but in general targeting this component of the disease with selective therapies has been disappointing and most therapy still relies on bronchodilators and corticosteroids rather than treating underlying disease mechanisms. With the disappointing outcomes of targeting individual Th-2 cytokines or manipulating T-cells, the time has come to re-evaluate the direction of research in this disease. A case is made that asthma has its origins in the airways themselves involving defective structural and functional behaviour of the epithelium in relation to environmental insults. Specifically, a defect in barrier function and an impaired innate immune response to viral infection may provide the substrate upon which allergic sensitization takes place. Once sensitized, the repeated allergen exposure will lead to disease persistence. These mechanisms could also be used to explain airway wall remodelling and the susceptibility of the asthmatic lung to exacerbations provoked by respiratory viruses, air pollution episodes and exposure to biologically active allergens. Variable activation of this epithelial-mesenchymal trophic unit could also lead to the emergence of different asthma phenotypes and a more targeted approach to the treatment of these. It also raises the possibility of developing treatments that increase the lung's resistance to the inhaled environment rather than concentrating all efforts on trying to suppress inflammation once it has become established.

Airway hyper-responsiveness in young adults with asthma that remitted either during or before adolescence

BACKGROUND AND OBJECTIVE

More than 50% of patients with childhood asthma enter clinical remission by puberty, although 40-50% of these people will probably develop asthma symptoms during early adulthood. The mechanism of relapsing asthma in early adulthood remains unclear. This study determined the characteristics of young adults whose asthma remitted either during or before adolescence.

METHODS

A comparative study was performed on 24 students whose childhood asthma had gone into clinical remission by puberty (remission group), 25 atopic students with no history of asthma (atopy group) and 19 non-atopic students without allergic diseases (control group). Examinations included spirometry, levels of serum-specific IgE-antibodies, airway responsiveness to methacholine, exhaled nitric oxide (eNO) and evidence of airway inflammation in induced sputum.

RESULTS

Airway responsiveness (P < 0.01), eosinophil counts in sputum (P < 0.05) and the prevalence of sensitization to Dermatophagoides forinae (P < 0.01) were significantly higher, and FEF(25-75%) and FEF(75%) (P < 0.01) were significantly lower in the remission group than in the atopy and control groups. Furthermore, 50% and 33% of the remission group had airway hyper-responsiveness (AHR) and sputum eosinophilia, respectively. The eNO levels in the remission (P < 0.01) and atopy (P < 0.05) groups were significantly higher than in controls. Remission group members with AHR had a significantly longer period of childhood asthma, a shorter period of remission and greater airway eosinophilic inflammation than those without AHR (P < 0.05).

CONCLUSION

One half of young adults with childhood asthma that remitted either during or before adolescence continued to have evidence of AHR and airway eosinophilic inflammation, and might be at risk of future relapse.

Asthma in humans and cats: is there a common sensitivity to aeroallegens in shared environments?

Cats spontaneously develop eosinophilic airway inflammation and airway hyperreactivity that is very similar to human allergic asthma. In addition, household cats share environmental exposures to aeroallergens with humans. We review the scientific literature concerning the pathophysiology of feline asthma, including similarities to human asthma and evidence regarding environmental aeroallergen triggers. Results of pathophysiological studies suggest important similarities between human and feline responses to inhaled allergens. Only a few studies were found that examined the development of disease in cats to environmental aeroallergens. Limited evidence suggests that some environmental allergens can cause disease in both cats and humans. It appears that there is a need for greater communication between human and animal health professionals regarding environmental causes of asthma. Specifically, additional research into linkages between human and feline asthma using both molecular techniques and clinical epidemiological approaches could lead to improved understanding of the environmental risks. Finally, there should be consideration of use of naturally affected and/or experimentally induced (using clinically relevant allergens) asthmatic cats in preclinical trials for novel therapeutic interventions.

The validity of induced sputum and bronchoalveolar lavage in childhood asthma

There are a number of useful direct airway sampling procedures to help diagnose and monitor asthma in patients. However, non-invasive techniques are the ideal, especially in children, given the necessity of safe and repeatable measurements to monitor treatment efficacy and disease progression. Bronchoalveolar lavage (BAL) may be too invasive for clinical use in children, while questions still surround the utility of induced sputum (IS). More novel techniques, such as fractional exhaled nitric oxide (FE(NO)) and exhaled breath condensate (EBC), are still unproven. Eosinophilic airway inflammation is a major feature of childhood asthma, and it has been revealed as a major treatment target with inhaled corticosteroids. Moreover, treatment protocols governed by sputum eosinophil counts may be more efficacious - by reducing the frequency and severity of exacerbations - than treatment based on clinical symptoms and other traditional objective measures of lung function. The selection of an appropriate airway inflammation monitoring technique must take everything into consideration, including safety, reproducibility, repeatability, sensitivity to treatment, and the overall clinical/research goals.

Granulocyte-macrophage colony-stimulating factor expression in induced sputum and bronchial mucosa in asthma and COPD

Background:

Granulocyte–macrophage colony-stimulating factor (GM-CSF) has been implicated as an important mediator in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). However, the expression of GM-CSF and its receptor in airway samples in asthma and COPD across disease severity needs to be further defined.

Methods:

Sputum GM-CSF was measured in 18 control subjects, 45 subjects with asthma and 47 subjects with COPD. Enumeration of GM-CSF+ cells in the bronchial submucosa and airway smooth muscle bundle was performed in 29 control subjects, 36 subjects with asthma and 10 subjects with COPD.

Results:

The proportion of subjects with measurable GM-CSF in the sputum was raised in those with moderate (7/14) and severe (11/18) asthma, and in those with COPD GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II (7/16), III (8/17) and IV (7/14) compared with controls (1/18) and those with mild asthma (0/13); p = 0.001. The sputum GM-CSF concentration was correlated with the sputum eosinophilia in subjects with moderate to severe asthma (r_s = 0.41; p = 0.018). The median (interquartile range) GM-CSF+ and GM-CSFR+ cells/mm² of submucosa was increased in severe asthma (1.4 (3.0) and 2.1 (8.4)) compared with those with mild to moderate asthma (0 (2.5) and 1.1 (5)) and healthy controls (0 (0.5) and 0 (1.6)), (p = 0.004 and p = 0.02, respectively).

Conclusions:

The findings support a potential role for GM-CSF in asthma and COPD and suggest that overexpression of GM-CSF in sputum and the bronchial mucosa is a particular feature of severe asthma.

Sputum eosinophilia, airway hyperresponsiveness and airway narrowing in young adults with former asthma

BACKGROUND

30-80% of outgrown asthma subjects develop symptoms again later in life. We investigated inflammation and function of lower airway in adolescents with former asthma.

METHODS

326 never-smoking young adults (mean age 24.0 years) were interviewed with special emphasis on history of asthma. Diagnosis of asthma was based on GINA guidelines. Former asthma subjects consisted of ones with a history of physician-diagnosed childhood asthma, who had been free of asthma symptoms without the use of medication for at least 10 years prior to the study. Provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (FEV(1))(PC(20)) and eosinophil percentage in induced sputum were measured.

RESULTS

31 subjects were former asthma subjects (FBA), 11 subjects were current asthma subjects (CBA) and 284 subjects had no history of asthma (non-BA). PC(20) and FEV(1)/FVC ratio were significantly lower in the FBA group than in the non-BA group (P < 0.01). Maximal mid-expiratory flow (MMF) was significantly lower in the FBA group than in the non-BA group (P < 0.05). Sputum eosinophil percentage was significantly increased in the FBA group compared with the non-BA group (P < 0.01). PC(20) was significantly lower in the CBA group than in the FBA and non-BA groups (P < 0.01). FEV(1), FEV(1)/FVC ratio and MMF were significantly lower in the CBA group than in the FBA group (P < 0.05, P < 0.05 and P < 0.05, respectively) and the non-BA group (P < 0.01, P < 0.01 and P < 0.05, respectively). Sputum eosinophils were significantly higher in the CBA group than in the FBA and non-BA groups (P < 0.01).

CONCLUSIONS

This study shows that subjects with long-term outgrown asthma continue to have airway eosinophilic inflammation, airway hyperresponsiveness and airway narrowing.

Airway hyperresponsiveness is dissociated from airway wall structural remodeling

BACKGROUND

Nonasthmatic eosinophilic bronchitis (EB) has emerged as a useful tool to study the structural and inflammatory mechanisms of airway hyperresponsiveness (AHR) in asthma. We have previously shown that vascular remodeling and reticular basement membrane (RBM) thickening are present in EB. However, it is not known whether other features of structural remodeling including increased airway smooth muscle (ASM) mass, matrix deposition, and glandular hyperplasia are also present in EB.

OBJECTIVES

We sought to determine whether structural remodeling occurs in EB and is associated with AHR and airflow limitation.

METHODS

Forty-two patients with asthma, 21 patients with EB, and 19 healthy volunteers were recruited. ASM area, RBM thickness, collagen 3 deposition, glandular area, mast cells, and granulocytes were assessed in bronchial biopsy samples.

RESULTS

Nonasthmatic eosinophilic bronchitis and asthma were associated with a significant increase in ASM mass and RBM thickness compared with healthy subjects. In contrast, we did not observe any significant differences in collagen 3 deposition in the lamina propria and ASM or the % area of glands in the lamina propria. Univariate analysis demonstrated that mast cell numbers in the ASM were the only feature of remodeling associated with AHR (beta = -0.51; P = .004). Stepwise linear regression revealed that a combination of mast cell numbers in the ASM (beta = -0.43) and disease duration (beta = -0.25; model-adjusted R(2) = 0.26; P = .027) best modeled AHR.

CONCLUSION

Mast cell localization to the ASM bundle, but not structural remodeling of the airway wall, is associated with AHR in asthma.

Retrospective characterization of airway reversibility in patients with asthma responsive to bronchodilators

BACKGROUND

National and international asthma guidelines recommend the use of reversibility to assist in the diagnosis of asthma.

SCOPE

This retrospective pooled analysis assessed the reversibility characteristics of a large cohort of patients (n = 30 816) selected from 106 clinical trials conducted by GlaxoSmithKline in which bronchodilator reversibility (> or = 12%) was required for participation in the trials.

FINDINGS

Patients (n = 1434) with a baseline forced expiratory volume in 1 second (FEV1) between 40% and < 50% at screening had a mean reversibility of 42% and those (n = 550) with a baseline FEV1 between 90% and < 100% had a mean reversibility of 18%. In general, the lower the patient's baseline lung function, the higher the reversibility. Further, in a subset of studies (n = 7; 1477 patients) that provided reversibility data at study baseline and endpoint, the mean reversibility for patients receiving placebo or fluticasone propionate (FP) was 26%. At study completion, nearly 30% fewer patients receiving placebo were shown to be reversible and approximately half of the patients receiving fluticasone propionate were no longer reversible.

CONCLUSION

This analysis shows that airway reversibility is affected by asthma severity as measured cross-sectionally by spirometry, pharmacotherapeutic interventions, including placebo, and time. Additional studies are needed to confirm this finding in broader populations as studies in this analysis were limited to those conducted in the US by GlaxoSmithKline.

Once versus twice daily budesonide metered-dose inhaler in children with mild to moderate asthma: effect on symptoms and bronchial responsiveness

BACKGROUND

Simplifying dosing regimens could improve both adherence and asthma-related morbidity. However, there is little information on the effectiveness of once-daily budesonide, administered through a metered dose inhaler (MDI) plus spacer, on asthma symptoms and pulmonary function in asthmatic children.

METHODS

The aim of this study was to compare the effect of once-daily versus twice-daily doses of inhaled budesonide on symptoms, lung function and bronchial hyperresponsiveness (BHR) in asthmatic children. This study was a randomized, single-blind, parallel clinical trial. Patients received budesonide from an MDI either 800 microg as a daily dose or fractionated in 400 microg twice a day for 12 weeks. Statistical analysis was performed using tests for independent and paired samples.

RESULTS

In both groups, asthma symptoms significantly decreased. However, the improvement in asthma symptoms, decrease in BHR and treatment adherence were significantly greater in the once-daily group than in the twice-daily group (p < 0.05). No significant differences were found between the two groups in spirometric parameters, morning peak expiratory flow or plasma cortisol values.

CONCLUSIONS

Once-daily administration of 800 microg of inhaled budesonide administered by MDI plus spacer was more effective in controlling symptoms and improving BHR than fractionating the dose to 400 microg twice daily. The differences observed in this study could have been due to the greater adherence to treatment in patients in the once-daily group.

Montelukast improves pulmonary function measured by impulse oscillometry in children with asthma (Mio study)

BACKGROUND

Systemic drugs-like oral montelukast can reach lower airways, whose inflammation plays a crucial role in the evolution of asthma, while inhaled drugs hardly reach them. The impulse oscillometry (IOS) technique is useful to evaluate both central and peripheral airways function.

OBJECTIVE

To measure the effect of oral montelukast on airways resistance evaluated by oscillometry in children with asthma.

METHODS

In an open study, respiratory function in 23 children with mild asthma and a positive bronchodilator response was assessed by spirometry and oscillometry. They took oral montelukast during 4 weeks and were again evaluated. As a control group, 23 similar patients with no preventive treatment underwent the same study.

MEASUREMENTS AND MAIN RESULTS

Children on oral montelukast showed improvements (measured in kPa s L(-1)) in all oscillometry parameters: mean 0.20 (22.4%) in total respiratory impedance Zrs5, 0.18 (21.8%) in total airway resistance Rrs5, 0.09 (17.8%) in central airway resistance Rrs20, and 0.09 (28.8%) in distal capacitive reactance Xrs5; the frequency of resonance Fres improved 2.3 Hz (8.7%) (P<0.05 in all cases). No changes were found in the control group. Expiratory flows showed no changes except for a small (0.23 L s(-1), 7.4%) but significant worsening of FEF25-75 in the control group.

CONCLUSIONS

Montelukast improves central and especially peripheral airways function in the first month of treatment, as evaluated by IOS, a technique based on tidal breathing analysis which is more sensitive than conventional forced spirometry.

Is mild asthma really 'mild'?

Current evidence suggests that patients with mild asthma are often under-recognised, and those that are diagnosed can remain with this initial classification and be treated accordingly, despite worsening of their condition. There is considerable overlap between mild and more severe asthma in terms of the underlying pathophysiology and poorly reversible airway changes, such as subepithelial fibrosis and airway wall remodelling, which are present very early in the progression of asthma in patients with normal lung function. Life-threatening exacerbations can also occur in patients with mild asthma. In view of these factors and given that asthma is a two-component disease (airway inflammation and smooth muscle dysfunction), recent studies have examined the effects of both early intervention with steroids and combination therapy comprising an inhaled steroid and a long acting beta(2)-agonist. These studies suggest that early intervention is likely to provide better asthma control and possibly prevent or delay the worsening of disease and fatalities in patients considered to be mild asthmatics.

Clinical implications of airway inflammation in mild intermittent asthma

OBJECTIVE

To determine whether inhaled corticosteroids should be prescribed to patients with milder forms of asthma and whether markers of airway inflammation should be considered when making therapy decisions.

DATA SOURCES

A PubMed search was performed of the English-language literature published in the preceding 10 years (January 1, 1993, through December 31, 2003) concerning epidemiology, pathophysiology, therapy, and prognosis of mild intermittent asthma, with asthma, mild, and intermittent as indexing terms.

STUDY SELECTION

All relevant studies including author's expert opinions were selected.

RESULTS

Several studies have addressed the question of a possible benefit of maintenance therapy (ie, inhaled steroids) in patients with mild intermittent asthma. Although a diminishing effect on airway inflammation has been widely demonstrated, even in patients with mild disease, the impact of inhaled steroids on the long-term prognosis is much less clear. For patients with mild disease who are long-term inhaled steroid users, alternative therapy strategies, including low-dose inhaled steroids and leukotriene receptor antagonists, have been advocated.

CONCLUSIONS

Mild intermittent asthma is a disease characterized not only by infrequent symptoms and normal lung function but also by chronic airway inflammation, possibly resulting in irreversible airflow limitation if left unattended. Therefore, maintenance therapy, such as (low-dose) inhaled steroids or leukotriene receptor antagonists, should be considered in patients with mild disease. Future studies should give more insight into the impact of prolonged anti-inflammatory therapy on the long-term prognosis of mild intermittent asthma patients. Whether results from these studies will justify a more aggressive treatment for these patients remains to be answered.