Degree Of Bronchial Hyperresponsiveness Research Articles

Based on what parameters is safe to discontinuate inhaled corticosteroids in children with asthma?

Objective Remission of childhood asthma has not been widely studied. Patients in clinical remission continue to have some degree of bronchial hyperresponsiveness (BHR). The aim of this study was to investigate whether clinical parameters and lung function test are good parameters for discontinuation of inhaled corticosteroids (ICS) in asthmatic children, including patients with persistent BHR, as measured by the methacholine challenge test (MCT). Methods One year after discontinuation of inhaled corticosteroids (ICS), MCT was performed in a group of 40 asthmatic children to confirm or exclude BHR. In all patients, ICS treatment was discontinued based on the same parameters: symptoms, spirometry, daily PEF, and negative bronchodilator test. After achieving complete asthma control for at least 6 to 12 months, ICS treatment was stepped down and discontinued. Clinical course and spirometry were followed up after ICS discontinuation. Results Positive MCT was found in 50% of the patients. There was no statistically significant difference between the positive and negative MCT groups in age at initiation and discontinuation of ICS therapy, duration of ICS therapy, duration of stepping down period, FEV1, and PEF at the time of withdrawal of ICS and one year later. ICS treatment had to be restarted in two patients from the positive MCT group, due to recurrence of asthma symptoms. Conclusion Clinical parameters, normal spirometry, daily PEF values, and a negative bronchodilator test are good parameters for discontinuing ICS treatment in asthmatic children, even in patients with persistent BHR. Children should continue to be monitored, as symptoms may recur.

Predicting the course of asthma from childhood until early adulthood.

Purpose of reviewTo communicate recent insights about the natural history of childhood asthma, with a focus on prediction of persistence and remission of childhood asthma, up to early adulthood.Recent findingsLung function around the age of 8–9 years is the strongest predictor: obstructive lung function predicts asthma persistence up to early adulthood, whereas normal lung function predicts remission. The ability to predict asthma remission improves when lung function is combined with blood eosinophil levels and degree of bronchial hyperresponsiveness. Interventions, such as inhaled corticosteroids and immunotherapy do not appear to alter the course of asthma. Epigenetic studies have revealed potential novel biomarkers of asthma remission, such as micro-RNA patterns in blood. Specifically, lower serum levels of mi-R221-5p, which is associated with lower IL-6 release and eosinophilic inflammation, predict remission. Higher levels of blood DNA-methylation of a CpG site in Peroxisomal Biogenesis Factor 11 Beta were associated with asthma remission.SummaryLung function, allergic comorbidity and polysensitization in childhood predict the course of asthma. Recent epigenetic studies have provided a better understanding of underlying pathological processes in asthma remission, which may be used to improve prediction or develop novel treatments aimed at altering the course of asthma.

Genome-wide association study identifies BTNL2 associated with atopic asthma in children.

Asthma is a heterogeneous disease characterized by chronic airway inflammation with a genetic predisposition. Butyrophilin-like 2 (BTNL2) is a member of the immunoglobulin superfamily that plays an important role in regulating T cell activation and immune homeostasis. Here, we aimed to investigate the association of the genetic variants of BTNL2 with childhood asthma and asthma-related traits by utilizing extreme asthma phenotypes and employing a genome-wide association study. Our study included 243 children with well-defined moderate to severe atopic asthma and 134 healthy children with no history of allergic diseases and allergic sensitization. DNA from these subjects was genotyped using AxiomTM Genome-Wide Array Plates. Although no single nucleotide polymorphisms (SNPs) reached a genome-wide threshold of significance, 3 SNPs, rs3817971, rs41355746, and rs41441651, at BTNL2 were significantly associated with moderate to severe atopic asthma after performing Bonferroni correction. These SNPs were also associated with the risk of allergic sensitization toward house dust mites and the presence and degree of bronchial hyperresponsiveness. Thus, we identified that BTNL2 was associated with atopic moderate to severe persistent asthma in Korean children, and this may play an important role in disease development and susceptibility.

Small airway dysfunction in patients with cough variant asthma: a retrospective cohort study

BackgroundCough variant asthma (CVA) is one of the special populations of asthma. The aim of the study was to compare small airways, the degree of bronchial hyperresponsiveness (BHR) and airway inflammatory subtypes between CVA and classic asthma (CA), and investigate the relationship between these markers to determine the accuracy as indicators of CVA.MethodsA total of 825 asthmatic patients participated in the study and 614 were included. 614 patients underwent spirometry and a bronchial challenge with methacholine and 459 patients performed induction sputum cell test.ResultsThe number of CVA patients showed less small airway dysfunction than those of CA patients (p < 0.005). The degree of small airways dysfunction was higher in the CA group compared with the CVA group (p < 0.001). Small airways dysfunction was severer in the eosinophilic airway inflammatory subtype compared with other subtypes (p < 0.05).The area under curve of MMEF, FEF50 and FEF75 (% predicted) was 0.615, 0.621, 0.606, respectively. 0.17mcg of PD20 and 4.7% of sputum eosinophils was the best diagnostic value for CVA with an AUC of 0.582 and 0.575 (p = 0.001 and p = 0.005, respectively).ConclusionsThe eosinophilic airway inflammatory subtype may be increased small airway dysfunction. The value of small airways, BHR and induction sputum cells in CVA prediction, which reflected significant, but not enough to be clinically useful.

Effect of overweight or obesity on lung function and asthma severity in prepubertal asthmatic children

Purpose: Cluster analysis on pediatric asthma identifying a cluster characterized by obesity, females, and puberty showed that obe-sity is an independent risk factor for severe asthma in this cluster. In the present study, we aimed to investigate the effect of over-weight/obesity on lung function and asthma severity in prepubertal asthmatic children. Methods: One hundred fifty-five prepubertal children (aged 6-10) with asthma were enrolled and divided into 2 groups: the over-weight/obese group (body mass index [BMI] ≥85th percentile, n=44) and the normal BMI group (<85th percentile, n=111). We re-viewed their medical records and analyzed whether there were any differences in clinical features, lung function and degree of bron-chial hyperresponsiveness (BHR) between the 2 groups. The clinical factors associated with asthma severity were also investigated. Results: There was no difference in clinical features between the 2 groups. Pulmonary function tests showed that only forced vital capacity in 1 second/forced vital capacity (FEV1/FVC) was significantly lower in the overweight/obese group than in the normal BMI group (P=0.032). There was no difference in dysanapsis and BHR between the 2 groups. There were significantly more children with moderate-to-severe asthma in the overweight/obese group compared to the normal BMI group (P=0.018). In multivariate logistic regression analysis, overweight/obesity has been identified as an independent risk factor of affecting asthma severity (odds ratio, 2.44; P=0.018), in addition to the already known risk factor, FEV1. Conclusion: Our study showed that overweight/obese prepubertal asthmatic children had lower FEV1/FVC than those with normal BMI. It also suggests that overweight/obesity may be an independent risk factor for severe asthma before puberty. (Allergy Asthma Respir Dis 2021;9:231-237)

Small Airways Dysfunction and Bronchial Hyper-Responsiveness in Cough Variant Asthma.

BackgroundCough variant asthma (CVA) is one kind of atypical asthma. The study was to compare spirometric parameters of small airways and the degree of bronchial hyper-responsiveness (BHR) between CVA and classic asthma (CA), and examine the relationship between BHR and small airways to determine the accuracy of these markers as indicators of CVA.MethodsA total of 825 asthmatic patients were screened for the study, and 614 were included. All patients performed spirometry and underwent a bronchial challenge with methacholine.ResultsThe number of small airways dysfunctions in the CVA group was less than those of the CA group with MMEF% predicted (70% vs 80.91%, P=0.002) and FEF50% predicted (62.71% vs 73.5%, P=0.004). The degree of small airways dysfunction was less in the CVA group compared with the CA group (P<0.001). Significant positive correlations were observed between the FEV1 level below 20% of the baseline value (PD20) and MMEF% predicted (r=0.282, P<0.001), FEF50% predicted (r=0.2522, P<0.001), and FEF75% predicted (r=0.2504, P<0.001) in patients with CVA. The area under curve (AUC) of MMEF, FEF50, and FEF75 (% predicted) was 0.615, 0.621, and 0.606, respectively. In addition, 0.17 mcg of PD20 was the best diagnostic value for CVA, with an AUC of 0.582 (P=0.001).ConclusionSmall airway dysfunction is milder in CVA. The value of BHR combined with small airways in CVA prediction, which was significant, but not enough to be clinically useful.

The usefulness of bronchial challenge tests in the diagnosis of occupational asthma

Bronchial hyperresponsiveness (BHR) is the individual ability to respond with bronchoconstriction to a variety of specific and nonspecific stimuli which do not cause these symptoms among healthy subjects. Bronchial hyperresponsiveness is one of the hallmark features of asthma. The degree of bronchial hyperresponsiveness is variable among individuals with asthma and may correlate to its severity (the more severe asthma the higher bronchial hyperreactivity). Bronchial hyperresponsiveness is evaluated by performing bronchial provocation test (BPT). Provocation tests are classified - according to their mechanisms - into direct and indirect tests. Direct challenge tests are highly sensitive and they are used primarily to rule out asthma. In contrast, provocation tests with indirect stimuli are less sensitive but more specific to the direct tests; they are used generally to confirm the diagnosis of asthma and they allow for more accurate conclusions about inflammatory lesions in the case of a patient. Bronchial provocation tests play a significant role in occupational medicine. They are particularly relevant to be performed prior to employment, during periodic examinations, and to diagnose and monitor both occupational asthma and work-related asthma. This article presents selected bronchial provocation tests and their usefulness in the diagnosis of occupational asthma. Med Pr 2018;69(4):457-471.

Dyspnea Perception During Induced Bronchoconstriction Is Complicated by the Inhaled Methacholine in Children With Clinical Asthma.

PurposeDyspnea is not widely utilized as an indicator of asthma provocation despite its universal presentation. We hypothesized that dyspnea severity was proportionate with the lung function decline, methacholine dose-step, and the degree of bronchial hyperresponsiveness (BHR).MethodsWe retrospectively analyzed 73 children's bronchial provocation test data with an assessment of dyspnea at every dose-step. Dyspnea severity was scored using a modified Borg (mBorg) scale. A linear mixed effect analysis was performed to evaluate the relationship between the mBorg scale, the percentage fall in the forced expiratory volume in 1 second (FEV1) (ΔFEV1%), the methacholine dose-step, and the degree of BHR (BHR grade).ResultsSubjects were divided into 5 BHR groups based on their last methacholine dose-steps. The mBorg scores did not differ significantly among BHR groups (P=0.596, Kruskal-Wallis test). The linear mixed effect analysis showed that ΔFEV1% was affected by the methacholine dose-step (P<0.001) and BHR grade (P<0.001). The mBorg score was affected by the dose-step (P<0.001) and BHR grade (P=0.019). We developed a model to predict the mBorg score and found that it was affected by the methacholine dose-step and ΔFEV1%, elevating it by a score of 0.039 (χ2 [1]=21.06, P<0.001) and 0.327 (χ2 [1]=47.45, P<0.001), respectively. A significant interaction was observed between the methacholine dose-step and ΔFEV1% (χ2 [1]=16.20, P<0.001).ConclusionsIn asthmatic children, inhaled methacholine, as well as the degree of BHR and lung function decline, may affect dyspnea perception during the bronchial provocation test. If we wish to draw meaningful information from dyspnea perception, we have to consider various complicating factors underlying it.

Specific inhalation challenge: the relationship between response, clinical variables and lung function

IntroductionThe specific inhalation challenge (SIC) is considered the gold standard for the diagnosis of occupational asthma (OA). However, its use is not standardised, and the intensity of exposure is regulated...

Association between menarche and increased bronchial hyper-responsiveness during puberty in female children and adolescents.

Bronchial hyper-responsiveness (BHR) is a key feature of asthma. The degree of BHR in children may be altered by several factors. We evaluated the prevalence of BHR according to age and gender in pediatric and adolescent population and analyzed the associated factors for gender differences. Among the 2,067 subjects, methacholine challenge tests were performed in 1,820 children from one elementary and one middle school in Seoul, Korea. A total of 1,725 subjects between 6 and 14 years old were included in the analysis. The prevalence of BHR, defined as a provocative concentration that induced a 20% reduction of FEV1 (PC20 ) that was less than 8 mg/ml, was evaluated according to age and gender. Gender differences associated with BHR prevalence at each age were calculated and multiple logistic regression analyses were performed to identify factors associated with BHR by gender. The prevalence of BHR (PC20 ≤ 8 mg/ml) for each gender decreased with age (P < 0.001). Although the prevalence of BHR linearly decreased in males with age, females showed an increase after 11 years of age. BHR in males was associated with a younger age (aOR, 0.797; 95%CI, 0.678-0.925), a higher blood eosinophil counts (%) (aOR, 1.160; 95%CI, 1.047-1.284), atopy (aOR, 2.091; 95%CI, 1.003-4.359), and a lower FEV1 /FVC ratio (aOR, 0.947; 95%CI, 0.901-0.995), and FEF25-75% (aOR, 0.980; 95%CI, 0.961-0.999). In females, BHR was significantly associated with a younger age (aOR, 0.845; 95%CI, 0.747-0.957), lower FEV1 (%) (aOR, 0.961; 95%CI, 0.938-0.984), and menarche (aOR, 3.674; 95%CI, 1.226-11.012). BHR declined with age in the Korean pediatric population. A younger age and reduced lung function were common factors related to BHR in both genders. Additionally, atopy was related to BHR in males, whereas sexual maturation was related to BHR in females. These findings have important clinical implications for evaluating of childhood BHR and asthma related to gender. Pediatr Pulmonol. 2016;51:1040-1047. © 2016 Wiley Periodicals, Inc.

Concordance between bronchial hyperresponsiveness, fractional exhaled nitric oxide, and asthma control in children.

Previous studies on association between level of asthma control, markers of airway inflammation and the degree of bronchial hyperresponsiveness (BHR) have yielded conflicting results. Our aim was to determine the presence and severity of BHR and the concordance between BHR, asthma control, and fractional exhaled nitric oxide (FeNO) in children with asthma on therapy. In this cross-sectional observational study, children (aged 6-18 years) with asthma on British Thoracic Society (BTS) treatment steps 2 or 3, underwent comprehensive assessment of their asthma control (clinical assessment, spirometry, asthma control test [ACT], Pediatric Asthma Quality of Life Questionnaire [PAQLQ]), measurement of FeNO and BHR (using mannitol dry powder bronchial challenge test [MCT], Aridol™, Pharmaxis, Australia). Fifty-seven children (63% male) were studied. Twenty-seven children were on BTS treatment step 2 and 30 were on step 3. Overall, 25 out of 57 (43.8%) children had positive MCT. Of note, 9 out of 27 (33.3%) children with clinically controlled asthma had positive MCT. Analyses of pair-wise agreement between MCT (positive or negative), FeNO (>25 or ≤25 ppb) and clinical assessment of asthma control (controlled or partially controlled/uncontrolled) showed poor agreement between these measures. A substantial proportion of children with asthma have persistent BHR despite good clinical control. The concordance between clinical assessment of asthma control, BHR and FeNO was observed to be poor. Our findings raise concerns in the context of emerging evidence for the role of bronchoconstriction in inducing epithelial stress that may drive airway remodeling in asthma. Pediatr Pulmonol. 2016;51:1004-1009. © 2016 Wiley Periodicals, Inc.

Assessment of Bronchial Hyperrespinsiveness to Methacholine in Children with Atopic Dermatitis

The methacholine challenge test (MCT) is commonly used to assess a bronchial hyperresponsiveness (BHR). Many studies have shown the importance for BHR in children with bronchial asthma, but BHR in children with atopic dermatitis (AD) is poorly defined. The aim of this study is to identify the BHR in children with AD and investigate the correlation between the degree of BHR and the severity of AD.

Small airway dysfunction is associated to excessive bronchoconstriction in asthmatic patients.

BackgroundWe investigated whether a relationship between small airways dysfunction and bronchial hyperresponsiveness (BHR), expressed both in terms of ease of airway narrowing and of excessive bronchoconstriction, could be demonstrated in asthma.Methods63 (36 F; mean age 42 yr ± 14) stable, mild-to-moderate asthmatic patients (FEV1 92% pred ±14; FEV1/FVC 75% ± 8) underwent the methacholine challenge test (MCT). The degree of BHR was expressed as PD20 (in μg) and as ∆FVC%. Peripheral airway resistance was measured pre- and post-MCT by impulse oscillometry system (IOS) and expressed as R5-R20 (in kPa sL−1).ResultsAll patients showed BHR to methacholine (PD20 < 1600 μg) with a PD20 geometric (95% CI) mean value of 181(132–249) μg and a ∆FVC% mean value of 13.6% ± 5.1, ranging 2.5 to 29.5%. 30 out of 63 patients had R5-R20 > 0.03 kPa sL−1 (>upper normal limit) and showed ∆FVC%, but not PD20 values significantly different from the 33 patients who had R5-R20 ≤ 0.03 kPa sL−1 (15.8% ± 4.6 vs 11.5% ± 4.8, p < 0.01 and 156(96–254) μg vs 207 (134–322) μg, p = 0.382). In addition, ∆FVC% values were significantly related to the corresponding pre- (r = 0.451, p < 0.001) and post-MCT (r = 0.376, p < 0.01) R5-R20 values.ConclusionsOur results show that in asthmatic patients, small airway dysfunction, as assessed by IOS, is strictly associated to BHR, expressed as excessive bronchoconstriction, but not as ease of airway narrowing.

Risk factors influencing bronchial hyperresponsiveness to methacholine in school age and adolescence of atopic dermatitis

Purpose: Many studies have shown the importance for bronchial hyperresponsiveness (BHR) in children with bronchial asthma and allergic rhinitis. However, studies have not been done in BHR in school age and adolescence with atopic dermatitis (AD). Methods: The patients with history of bronchial asthma were excluded and methacholine challenge test (MCT) was performed in 103 children with atopic dermatitis. The positive of MCT result is defined as provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (PC20)≤8 mg/mL. According of the level of PC20, the patients were divided into two groups. Results: The group 1 (BHR+) was observed in 43 of all patients (41.7%). Of two groups, significant differences were observed in age, body mass index. No significant differences were observed in the number of male, SCORing Atopic Dermatitis (SCORAD) index, admission history, smoking exposure history, other allergic disease, parental allergic disease. The group 1 (BHR+) have higher levels of total eosinophil count compared with the group 2 (BHR-) (629.8±360.5/μL vs. 470.2±253.9/μL, P=0.01). But no significant association was found between severity of BHR and SCORAD score, total immunoglobulin E, total eosin ophil count and eosinophil cationic protein (r=0.008, P=0.961; r=-0.217, P=0.162; r=0.225, P=0.147; r=-0.032, P=0.841). The list of allergen is that the house dust mite, tree, weed, food, animal hair, and fungus. The house dust mite has correlation with bronchial hypersensitivity statistically and the any of allergen groups, either. Conclusion: No significant relationship was observed between degree of BHR and allergy laboratory finding, severity of AD.

The role of epigenetics in the developmental origins of allergic disease

To review current research findings in the field of epigenetics pertaining to the developmental origins of allergic disease. We examined original research and review articles identified from MEDLINE, OVID, and PubMed that addressed the topic of interest, using the search terms atopy, allergy, asthma, development, IgE, origins, and cord blood paired with epigenetic(s). Relevant references from each article were also procured for review. Articles were selected based on their relevance to the contributory role of epigenetic modifications in asthma and other atopic diseases. There is increasing evidence pointing to the influence of prenatal and early life exposures on the development of allergic disease. A growing body of literature supports the theory that transient environmental pressures can have permanent effects on gene regulation and expression through epigenetic mechanisms. Histone modifications have been associated with degree of bronchial hyperresponsiveness and corticosteroid resistance in asthma. Epigenetic mechanisms can operate independently in various cell types; recent studies have suggested a role in the differentiation of human T cells. Murine studies have revealed that a maternal diet rich in methyl donors can enhance susceptibility to allergic inflammation in the offspring, mediated through increased DNA methylation. Murine studies have also implicated epigenetically modified dendritic cells in the transmission of allergic risk from mothers to offspring. The current literature offers exciting data to support a role for epigenetics in the development and persistence of asthma and allergic rhinitis. However, further human studies are necessary to explore these mechanisms and assess future clinical applicability.

Airway microbiota and bronchial hyperresponsiveness in patients with suboptimally controlled asthma

Improvement in lung function after macrolide antibiotic therapy has been attributed to reduction in bronchial infection by specific bacteria. However, the airway might be populated by a more diverse microbiota, and clinical features of asthma might be associated with characteristics of the airway microbiota present. We sought to determine whether relationships exist between the composition of the airway bacterial microbiota and clinical features of asthma using culture-independent tools capable of detecting the presence and relative abundance of most known bacteria. In this pilot study bronchial epithelial brushings were collected from 65 adults with suboptimally controlled asthma participating in a multicenter study of the effects of clarithromycin on asthma control and 10 healthy control subjects. Acombination of high-density 16S ribosomal RNA microarray and parallel clone library-sequencing analysis was used to profile the microbiota and examine relationships with clinical measurements. Compared with control subjects, 16S ribosomal RNA amplicon concentrations (a proxy for bacterial burden) and bacterial diversity were significantly higher among asthmatic patients. In multivariate analyses airway microbiota composition and diversity were significantly correlated with bronchial hyperresponsiveness. Specifically, the relative abundance of particular phylotypes, including members of the Comamonadaceae, Sphingomonadaceae, Oxalobacteraceae, and other bacterial families were highly correlated with the degree of bronchial hyperresponsiveness. The composition of bronchial airway microbiota is associated with the degree of bronchial hyperresponsiveness among patients with suboptimally controlled asthma. These findings support the need for further functional studies to examine the potential contribution of members of the airway microbiota in asthma pathogenesis.

Association of polymorphisms in CASP10 and CASP8 with FEV1/FVC and bronchial hyperresponsiveness in ethnically diverse asthmatics

Several chromosomal regions have been identified using family-based linkage analysis to contain genes contributing to the development of asthma and allergic disorders. One of these regions, chromosome 2q32-q33, contains a gene cluster containing CFLAR, CASP10 and CASP8. These genes regulate the extrinsic apoptosis pathway utilized by several types of immune and structural cells that have been implicated in the pathogenesis of asthma. To assess the role of genetic variation in CFLAR, CASP10 and CASP8 in asthma and related phenotypes in individuals of diverse ethnic backgrounds. We tested 26 single nucleotide polymorphisms (SNPs) in the CFLAR, CASP10 and CASP8 gene cluster for association with asthma and related phenotypes in African-American, non-Hispanic whites, and Hispanic case-control populations (cases, N=517, controls, N=644). Five CASP10 SNPS were associated with forced expiratory volume in 1 s (FEV(1))/forced expiration volume capacity (FVC) in the African-American subjects with asthma (P=0.0009-0.047). Nine SNPs, seven in CASP10 and two in CASP8, were also associated with the degree of bronchial hyperresponsiveness (BHR) (as determined by PC(20)) in race-specific analysis, predominately in the Non-Hispanic white cases. Two SNPs, rs6750157 in CASP10 and rs1045485 in CASP8 were modestly associated with asthma in the African-American (P=0.025) and Hispanic (P=0.033) populations, respectively. These data suggest a role for CASP10 as a potential modifier of the asthma phenotype, specifically with measures of airway obstruction and BHR.

Factors Affecting Bronchial Hyperreactivity in Asthmatic Children

Bronchial hyperresponsiveness (BHR), the exaggerated airway narrowing in response to nonspesific stimuli, is a common characteristic of asthma. One hundred thirty-five children who were diagnosed asthma in the outpatient clinic of Gazi University Hospital, Pediatric Allergy and Asthma Department between January 2007 and January 2008 were retrospectively analysed from the asthma database of the division. BHR was not found to be different according to sex. Younger the age of the patient, more severe was BHR (p = 0.096, r = 0.164). Younger the age at onset of the symptoms, the more severe was the BHR (p < 0.001, r = 0.307). Patients who had an asthmatic first degree relative and who were exposed to passive smoking at home, had more severe BHR (p = 0.006 and p = 0.032, respectively). There were more hospitalizations among the asthmatic children with moderate-severe BHR (p = 0.027) however no correlation was found between chronic asthma severity and the degree of BHR). In this study we found that age, age at onset of symptoms, having a parent with asthma, exposure to tobacco smoke and baseline lung function are related to BHR measured at referral. Serum levels of Ig E or skin prick test positivity were not found to have any effect on BHR severity. Considering BHR severity, we could not reveal any relation between atopic and nonatopic children. However among atopic subjects, the ones with indoor allergen sensitization had more severe BHR.

Intensity of bronchial hyperresponsiveness and asthma relapse risk in the young adult

Background The evolution of asthma starting in childhood varies and depends on a series of factors (atopy, allergens, and environmental irritants, etc). Treatment may influence the evolution of the disease and even cause the symptoms to disappear. However, there remains a risk of relapse years later. Objectives To assess the role of bronchial hyperresponsiveness in asthma relapse in young adulthood in patients with symptoms that disappeared after treatment prescribed in childhood. Material and methods To determine the evolution of asthma and patients’ personal opinions, 78 patients were sent a questionnaire several years after having been discharged without symptoms in the previous 2 years, and without the need for medication. The methacholine test was used to evaluate bronchial hyperresponsiveness at discharge. The 40 patients who correctly completed the questionnaire were divided into three groups according to the methacholine dose required to obtain a 20 % decrease in forced expiratory volume in 1 second (PD20): group 1 (15 patients), < 1000 μg; group 2 (10 patients) between 1001 and 2000 μg; and group 3 (15 patients) > 2100 μg. The mean age at discharge was 16 years (range 13-25 years) versus 26 years at the time of response (range 18-33 years), with a similar distribution in all three groups. Age at disease onset, with estimation of severity, age at the first visit and at the start of treatment, and respiratory function were evaluated. Results Thirty of the interviewed patients considered themselves to be cured. Seven of the patients (three in group 1, one in group 2, and three in group 3) did not consider themselves to be cured, although their symptoms were minimal and they rarely used medication. Health status was described as “regular” with sporadic symptoms by one patient in each group. No correlation with methacholine response was observed. Conclusion No relationship was found between the degree of bronchial hyperresponsiveness and the risk of relapse in young adults who suffered asthma in childhood.

Relationship Among Pulmonary Function, Bronchial Hyperresponsiveness, and Atopy in Children with Clinically Stable Asthma

Pulmonary function testing plays a key role in the diagnosis and management of asthma in children. However, the literature does not clearly show whether children with clinically stable asthma have significantly reduced lung function when compared with normal children. We compared the lung function of 242 clinically stable asthmatic children who were initially diagnosed with mild intermittent or mild persistent asthma with the lung function of 100 nonasthmatic controls. The lung function was assessed using FEV1, FEV1/FVC, FEF25-75 and PEF. In addition, we measured bronchial hyperresponsiveness (BHR) using the provocation concentration of methacholine needed to produce a 20% fall in FEV1. All measures of pulmonary function were significantly decreased in the children with asthma. Pulmonary function was not influenced by atopy, serum IgE, or total eosinophil count (TEC). However, the likelihood ratio for trends revealed a significant association between our pulmonary parameters and the degree of BHR. Children with mild-to-severe BHR had greatly decreased lung function compared with those with normal BHR, the control group. In addition, a direct correlation was found between PC20 and our pulmonary parameters in asthmatic children. However, only atopic children with asthma had a significant correlation between PC20 and TEC. We found children with clinically stable asthma to have pulmonary obstruction, which associated strongly with their degree of BHR.