RESUMEN
A 10-year national program to improve prevention and management of allergic diseases and asthma was implemented in Finland (population 5.5. million) in 2008-2018. The main aim was to reduce the long-term burden of these conditions. The strategy was changed from traditional avoidance to tolerance and resilience of the population. Health was endorsed instead of medicalization of mild symptoms. Disease severity was reevaluated, and disabling clinical manifestations were given high priority. For health care, 5 quantitative goals and 1 qualitative goal were set. For each of the goals, specific tasks, tools, and outcome evaluation were stipulated. During the program, 376 educational sessions gathered 24,000 health care participants. An information campaign targeted the lay public, and social media was used to contact people. In the 10 years of the program, the prevalence of allergic diseases and asthma leveled off. Asthma caused fewer symptoms and less disability, and 50% fewer hospital days. Food allergy diets in day care and schools decreased by half. Occupational allergies were reduced by 45%. In 2018, the direct and indirect costs of allergic diseases and asthma ranged from 1.5 billion to 1.8 billion, with the 2018 figures being 30% less than in the respective figures in 2007. The Finnish proactive and real-world intervention markedly reduced the public health burden of allergic disorders. The allergy paradigm was revisited to improve management with systematic education.
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Asma , Costo de Enfermedad , Hipersensibilidad a los Alimentos , Programas Nacionales de Salud/economía , Asma/economía , Asma/epidemiología , Asma/terapia , Costos y Análisis de Costo , Finlandia/epidemiología , Hipersensibilidad a los Alimentos/economía , Hipersensibilidad a los Alimentos/epidemiología , Hipersensibilidad a los Alimentos/terapia , Humanos , Tiempo de Internación , PrevalenciaRESUMEN
BACKGROUND: The relationship of airway hyperresponsiveness to airway remodeling and inflammation in infants with wheeze is unclear. OBJECTIVE: To investigate airway hyperresponsiveness, remodeling and inflammation in infants with wheeze and troublesome breathing. METHODS: Inclusion criteria were as follows: full-term, 3-23 months of age; doctor -diagnosed wheeze and persistent recurrent troublesome breathing; without obvious structural defect, suspicion of ciliary dyskinesia, cystic fibrosis, immune deficiency or specified use of corticosteroids. Airway hyperresponsiveness (AHR) was evaluated by performing a methacholine bronchial challenge test combined with whole body plethysmography and rapid thoracoabdominal compression. Endobronchial biopsies were analysed for remodeling (thickness of reticular basement membrane and amount of airway smooth muscle) and for inflammation (numbers of inflammatory cells). Correlation analyses were performed. RESULTS: Forty-nine infants fulfilled the inclusion criteria for the present study. Median age was 1.06 years (IQR 0.6; 1.5). Lung function was impaired in 39/49 (80%) children, at the median age of 1.1 years. Methacholine challenge was successfully performed in 38/49 children. Impaired baseline lung function was correlated with AHR (P = .047, Spearman). In children with the most sensitive quartile of AHR, the percentage of median bronchial airway smooth muscle % and the number of bronchial mast cells in airway smooth muscle were not significantly higher compared to others (P = .057 and 0.056, respectively). No association was found between AHR and thickness of reticular basement membrane or inflammatory cells. Only a small group of children with both atopy and AHR (the most reactive quartile) had thicker airway smooth muscle area than non-atopics with AHR (P = .031). CONCLUSIONS AND CLINICAL RELEVANCE: These findings do not support the concept that AHR in very young children with wheeze is determined by eosinophilic inflammation or clear-cut remodeling although it is associated with impaired baseline lung function. The possible association of increased airway smooth muscle area among atopic children with AHR remains to be confirmed.
Asunto(s)
Remodelación de las Vías Aéreas (Respiratorias)/inmunología , Asma , Ruidos Respiratorios/inmunología , Asma/diagnóstico , Asma/inmunología , Asma/patología , Eosinófilos/inmunología , Eosinófilos/patología , Femenino , Humanos , Lactante , Inflamación/diagnóstico , Inflamación/inmunología , Inflamación/patología , Masculino , Cloruro de Metacolina/administración & dosificación , Músculo Liso/inmunología , Músculo Liso/patologíaRESUMEN
BACKGROUND: Asthma, allergic conditions, and COPD overlap, but the effect of them and their combinations on disease severity, need for drugs, use of healthcare, and costs is poorly known. OBJECTIVE: To study how different allergic diseases co-occur in asthma and allergy patients and evaluate the use of medication well as drug and healthcare costs. METHODS: Nationwide Allergy Barometer Survey was carried out in the Finnish pharmacies during 1 week in September 2016. Altogether, 956 patients (5-75 years) who purchased asthma or allergy drugs with prescription participated in 351 pharmacies. RESULTS: Of the participants, 78% reported physician-diagnosed asthma, 57% allergic rhinitis, 24% atopic eczema, 21% food allergy, 20% allergic conjunctivitis, 8% anaphylaxis, and 8% COPD. One-third of the patients had at least three conditions, and multimorbidity was common across all age groups. Disease severity increased with the number of coexisting conditions, and asthma severity also with age. Patients with asthma alone used on average 3.8 drugs with the annual costs of EUR 661. This increased to 4.9 drugs and EUR 847 in asthmatics with multimorbidity. For all participants, costs of drugs and healthcare services together during the preceding year were on average EUR 1,214, of which 56% were drug costs. The costs doubled to EUR 2,714 in 65 subjects (7%) who had both asthma and COPD. CONCLUSIONS: In asthma and allergy, multimorbidity and polypharmacy are major concerns. Disease severity, drug use, and costs increased with multimorbid conditions. To reduce the burden, allergy management should be better integrated and more comprehensive.
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Asma/epidemiología , Hipersensibilidad/epidemiología , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Asma/economía , Niño , Preescolar , Comorbilidad , Costos y Análisis de Costo , Utilización de Medicamentos , Finlandia/epidemiología , Humanos , Hipersensibilidad/economía , Persona de Mediana Edad , Farmacia , Enfermedad Pulmonar Obstructiva Crónica/economía , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios , Adulto JovenAsunto(s)
Asma/fisiopatología , Pulmón/efectos de los fármacos , Contaminación por Humo de Tabaco/efectos adversos , Adolescente , Niño , Preescolar , Femenino , Humanos , Pulmón/fisiopatología , Masculino , Pruebas de Función Respiratoria , Factores de Tiempo , Contaminación por Humo de Tabaco/estadística & datos numéricosRESUMEN
INTRODUCTION: Early origins of chronic obstructive pulmonary disease have been recognized. Impulse oscillometry (IOS) is suitable for assessment of lung function also in preschool children, and some novel indices have been connected to assessment of small airway function. However, limited data exist on the sensitivity of these new indices to detect lung function deficits in young symptomatic children. METHODS: IOS measurements of 103 healthy preschool children were evaluated to establish reference equations for the difference between respiratory resistance at 5 and 20 Hz (R5-20), the relative difference of R5-20 (R5-20%), and area under the reactance curve (AX). Thereafter, IOS results of children with late-onset troublesome lung symptoms (n = 20), a history of early wheeze (n = 37), or a history of bronchopulmonary dysplasia (BPD, n = 8) were compared to healthy children. RESULTS: None of the patient groups differed from healthy regarding respiratory resistance at 5 Hz (R5), and only children with a history of BPD differed from healthy regarding respiratory reactance at 5 Hz (X5). In contrast, z-scores of R5-20, R5-20%, and AX were significantly higher in all patient groups than in healthy children (P < 0.001), showing improved sensitivity (20-55%) compared to R5 and X5 (5-6%). CONCLUSION: R5-20, R5-20%, and AX are superior to conventional IOS parameters in distinguishing children with current or past lower respiratory tract symptoms from healthy, and may prove valuable for screening early lung function deficits. Pediatr Pulmonol. 2017;52:598-605. © 2016 Wiley Periodicals, Inc.
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Displasia Broncopulmonar/diagnóstico , Pulmón/fisiopatología , Oscilometría/métodos , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Resistencia de las Vías Respiratorias/fisiología , Displasia Broncopulmonar/fisiopatología , Niño , Preescolar , Femenino , Humanos , Masculino , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Pruebas de Función RespiratoriaAsunto(s)
Asma/diagnóstico , Biomarcadores/sangre , Dipeptidil Peptidasa 4/sangre , Eosinófilos/inmunología , Antígeno Ki-1/sangre , Células TH1/inmunología , Células Th2/inmunología , Alérgenos/inmunología , Asma/inmunología , Biomarcadores/metabolismo , Proteína C-Reactiva/metabolismo , Niño , Quimioterapia Combinada , Femenino , Fluticasona/uso terapéutico , Humanos , Activación de Linfocitos , Masculino , Ruidos Respiratorios , Xinafoato de Salmeterol/uso terapéutico , Espirometría , Resultado del TratamientoRESUMEN
BACKGROUND: Associations between early deficits of lung function, infant airway disease, and outcome at school age in symptomatic infants are still unclear. OBJECTIVE: To report follow-up data on a unique cohort of children investigated invasively in infancy to determine predictive value of airway disease for school-aged respiratory outcomes. METHODS: Fifty-three infants previously studied using bronchoscopy and airway conductance were approached at 8 years of age. Symptoms, lung volumes, and airway responsiveness were reassessed. Data on lifetime purchase of asthma medication were obtained. Lung function was compared with that of 63 healthy nonasthmatic children. RESULTS: Forty-seven children were reevaluated. Physician-diagnosed asthma was present in 39 children (83%). Twenty-five children (53%) had current and 14 children (30%) had past asthma. No pathologic feature in infancy correlated with any outcome parameter. As expected, study children had significantly reduced lung function and increased airway responsiveness compared with healthy controls, and very early symptoms were risk factors for reduced lung function. Current asthma was associated with reduced infant lung function and parental asthma. Reduced lung function in infancy was associated with purchase of inhaled corticosteroids when 6 to 8 and 0 to 8 years of age. CONCLUSION: The lack of predictive value of any pathologic measure in infancy, reported here for the first time to our knowledge, demonstrates that pathologic processes determining the inception of asthma, which are as yet undescribed, are different from the eosinophilic inflammation associated with ongoing disease.
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Remodelación de las Vías Aéreas (Respiratorias)/fisiología , Asma/epidemiología , Hiperreactividad Bronquial/epidemiología , Pulmón/fisiopatología , Antiasmáticos/uso terapéutico , Asma/tratamiento farmacológico , Asma/inmunología , Hiperreactividad Bronquial/fisiopatología , Broncoscopía , Niño , Preescolar , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Inflamación/inmunología , Rendimiento Pulmonar , Masculino , Pronóstico , Ventilación Pulmonar , Pruebas de Función Respiratoria , Mecánica Respiratoria , Encuestas y CuestionariosAsunto(s)
Asma/sangre , Dermatitis Atópica/sangre , Dipeptidil Peptidasa 4/sangre , Antígeno Ki-1/sangre , Asma/tratamiento farmacológico , Asma/patología , Biomarcadores/sangre , Broncodilatadores/uso terapéutico , Budesonida/uso terapéutico , Preescolar , Dermatitis Atópica/tratamiento farmacológico , Dermatitis Atópica/patología , Eccema/sangre , Eccema/patología , Humanos , Lactante , Pulmón/fisiopatología , Pruebas de Función Respiratoria , Células TH1/inmunología , Balance Th1 - Th2 , Células Th2/inmunologíaRESUMEN
BACKGROUND: Airway hyperresponsiveness (AHR) is a hallmark of asthma but its assessment is usually restricted to older children who are capable of performing the maneuvers involved in spirometry. In younger children, a feasible option to perform the lung function measurement is impulse oscillometry (IOS), which requires less cooperation. OBJECTIVE: To evaluate whether assessment of AHR by IOS could differentiate children with various obstructive symptoms from one another. METHODS: One hundred twenty-one children (median age 6.0 years, range 3.7-8.1 years) were examined: 31 with probable asthma characterized by current troublesome lung symptoms, 61 with a history of early wheezing disorder (recurrent wheezing ≤24 months of age), 15 with a history of bronchopulmonary dysplasia, and 14 healthy controls. Indirect AHR was assessed by exercise and mannitol challenge tests, and direct AHR was assessed with methacholine using IOS. AHR to exercise was defined as an increase of at least 40% in respiratory resistance at 5 Hz. In the mannitol and methacholine challenges, the dose causing an increase of 40% in respiratory resistance at 5 Hz was calculated. RESULTS: AHR to exercise was good at differentiating children with current troublesome lung symptoms from those in the other groups (P < .001). AHR to methacholine separated children with current troublesome lung symptoms, early wheezing disorder, and bronchopulmonary dysplasia from the controls (P < .001), whereas the mannitol test did not distinguish among the study groups (P = .209). CONCLUSION: The methacholine and exercise challenge tests with IOS identify children with probable asthma characterized by troublesome lung symptoms and therefore may represent a practical aid in the evaluation of AHR in young children.
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Hiperreactividad Bronquial/diagnóstico , Pruebas de Provocación Bronquial , Oscilometría/métodos , Asma/diagnóstico , Asma/fisiopatología , Displasia Broncopulmonar/complicaciones , Niño , Preescolar , Ejercicio Físico , Femenino , Volumen Espiratorio Forzado , Humanos , Pulmón/fisiopatología , Masculino , Manitol , Cloruro de MetacolinaRESUMEN
BACKGROUND: The respiratory outcomes after preterm birth have changed, and it is unclear whether increased airway hyperresponsiveness (AHR) later in childhood is associated with airway inflammation. OBJECTIVE: To investigate the association between AHR and fractional exhaled nitric oxide (FeNO), including the alveolar concentration of nitric oxide, in school-age children with very low birth weight (VLBW). METHODS: Twenty-nine children with VLBW, 33 children with a history of early wheeze, and 60 healthy controls underwent a FeNO measurement and bronchial challenge test with histamine. Atopy was assessed with skin prick tests. RESULTS: Children with VLBW had well-preserved baseline lung function but significantly increased AHR, expressed as the dose response slope (P < .001). Geometric mean FeNO levels were similar between VLBW children and healthy controls, and a history of bronchopulmonary dysplasia had no effect. In the VLBW and early wheeze groups, AHR was associated with FeNO (r = 0.47, P = .01, and r = 0.43, P = .013, respectively), but in a stratified analysis, this association was significant only in atopic individuals. By using the multiple flow FeNO technique, the bronchial nitric oxide flux rather than alveolar nitric oxide concentrations were associated with AHR in both children with early wheeze and VLBW. CONCLUSION: We conclude that in VLBW children AHR is related to FeNO but only in atopic individuals. Similar to children with early wheeze, this association is dependent on bronchial flux rather than alveolar nitric oxide concentration. It is likely that AHR is modified by atopic inflammation rather than by inflammatory process due to prematurity.
Asunto(s)
Hiperreactividad Bronquial/fisiopatología , Recién Nacido de muy Bajo Peso , Neumonía/fisiopatología , Hiperreactividad Bronquial/epidemiología , Niño , Femenino , Humanos , Recién Nacido , Masculino , Neumonía/etiología , Pruebas de Función RespiratoriaRESUMEN
BACKGROUND: Exposure to tobacco smoke is a well-known risk factor for childhood asthma and reduced lung function, but the effect on airway inflammation in preschool-aged children is unclear. OBJECTIVE: To examine the effect of parental smoking on lung function and fractional concentration of exhaled nitric oxide (Feno) in relation to both parental reports and children's urine cotinine concentrations in preschool-aged children with multiple-trigger wheeze. METHODS: A total of 105 3- to 7-year-old children with multiple-trigger wheeze and lung function abnormalities were recruited. Lung function was assessed by impulse oscillometry, and Feno measurements were performed. Exposure to tobacco smoke was determined by parental reports and measurement of children's urinary cotinine concentrations. RESULTS: Forty-three percent of the children were exposed to environmental tobacco smoke according to parental reports. The Feno level was significantly higher in children with a smoking mother (n = 27) than in children with a nonsmoking mother (23.4 vs 12.5 ppb, P = .006). The Feno level expressed as z score and the cotinine level correlated significantly (P = .03). Respiratory resistance at 5 Hz was higher in children exposed to maternal smoking than in others (0.99 vs 0.88 kPas/L, P = .005). Urinary cotinine concentrations reflected well parental reports on their daily smoking and increased relative to the number of cigarettes smoked in the family (P < .01). Atopy was found in 75% of the children, but it was not associated with the Feno value (P = .65). CONCLUSION: Maternal smoking was associated with increased Feno value and poorer lung function in steroid-naive preschool children with multiple-trigger wheeze. Larger controlled trials are needed to generalize the results.
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Neumonía/fisiopatología , Ruidos Respiratorios/fisiopatología , Contaminación por Humo de Tabaco/efectos adversos , Niño , Preescolar , Cotinina/orina , Femenino , Humanos , Hipersensibilidad/diagnóstico , Hipersensibilidad/metabolismo , Hipersensibilidad/fisiopatología , Masculino , Madres , Óxido Nítrico/metabolismo , Oscilometría , Neumonía/etiología , Neumonía/metabolismo , Ruidos Respiratorios/etiología , Pruebas Cutáneas , FumarRESUMEN
BACKGROUND: Relationships between early deficits of lung function, infant airway pathology and outcome in symptomatic infants are unclear. A study was undertaken to determine the associations between early lung function, airway histology and inflammation in symptomatic infants with the continuance of respiratory symptoms, lung function and subsequent use of inhaled asthma medication at the age of 3 years. METHODS: 53 children who underwent lung function measurements and bronchoscopy following referral to a specialist children's hospital for recurrent lower respiratory symptoms at a mean age of 1 year were followed up at 3 years of age. Assessments were made of respiratory symptoms during the previous year, lung function by oscillometry and atopy by skin prick testing. Individual data on the purchase of asthma medications were obtained from the Social Insurance Institution for the 12 months preceding the follow-up visit. RESULTS: 50 children (94%) were re-evaluated, of whom 40 had ongoing airway symptoms. 11/39 (28%) who underwent successful oscillometry had reduced lung function, 31/50 (62%) used inhaled corticosteroids (ICS) regularly and 12/50 (24%) used ICS intermittently. Abnormal lung function at infancy was associated with ongoing airway symptoms (p<0.001) and with the purchase of ICS (p=0.009) and ß agonists (p=0.002). Reticular basement membrane thickness in infancy and the numbers of mucosal mast cells, but not eosinophils, correlated significantly with the amount of ICS purchased at 3 years (p=0.003 and p=0.018, respectively). CONCLUSIONS: Reduced lung function, thickening of the reticular basement membrane and increased density of mucosal mast cells in infancy are associated with respiratory morbidity and treatment needs at age 3 years in this highly selected group of children.
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Remodelación de las Vías Aéreas (Respiratorias)/fisiología , Asma/fisiopatología , Pulmón/fisiopatología , Antiasmáticos/uso terapéutico , Asma/tratamiento farmacológico , Asma/patología , Membrana Basal/patología , Biopsia , Bronquios/patología , Broncodilatadores/uso terapéutico , Broncoscopía , Budesonida/uso terapéutico , Femenino , Estudios de Seguimiento , Humanos , Hipersensibilidad Inmediata/fisiopatología , Lactante , Masculino , Pronóstico , Mucosa Respiratoria/patología , Ruidos Respiratorios/fisiopatología , Pruebas CutáneasRESUMEN
OBJECTIVE: To characterize symptoms, pulmonary function tests (PFT) and bronchial responsiveness (BR) in adolescents after repaired esophageal atresia with tracheoesophageal fistula and correlate these with endobronchial biopsy findings. STUDY DESIGN: After a primary operation, 31 patients underwent endoscopies and bronchoscopies at the age of <3, 3 to 7, and >7 years. A questionnaire on respiratory and esophageal symptoms was sent to patients at a mean age of 13.7 years (range, 9.7-19.4). The questionnaire was completed by 27 of 31 patients (87%), and 25 of the 31 patients (81%) underwent clinical examination and pulmonary functioning tests. Endobronchial biopsies were analyzed for reticular basement membrane (RBM) thickness and inflammatory cells. RESULTS: The prevalence of current respiratory and esophageal symptoms was 41% and 44%, respectively. "Doctor-diagnosed asthma" was present in 22% of patients. A restrictive and obstructive spirometric defect was observed in 32% and 30% of patients, respectively. Increased bronchial responsiveness, detected in 24% of patients, was weakly associated with current respiratory symptoms and low forced vital capacity. Mean exhaled nitric oxide was within predicted range. RBM thickness increased slightly with age, whereas inflammatory cell counts varied from normal to moderate, with intraindividual variation. CONCLUSION: Inflammation of the airways in adolescents with a history of tracheoesophageal fistula, even in the presence of atopy, does not lead, in most cases, to the type of chronic inflammation and RBM changes seen in asthma.
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Asma/diagnóstico , Bronquitis/diagnóstico , Atresia Esofágica/cirugía , Esófago/cirugía , Tráquea/cirugía , Fístula Traqueoesofágica/cirugía , Adolescente , Adulto , Anastomosis Quirúrgica/métodos , Asma/etiología , Asma/fisiopatología , Biopsia , Pruebas Respiratorias , Bronquitis/etiología , Bronquitis/fisiopatología , Broncoscopía , Niño , Endoscopía Gastrointestinal , Atresia Esofágica/complicaciones , Femenino , Estudios de Seguimiento , Flujo Espiratorio Forzado/fisiología , Humanos , Masculino , Óxido Nítrico/análisis , Ápice del Flujo Espiratorio/fisiología , Periodo Posoperatorio , Mucosa Respiratoria/patología , Estudios Retrospectivos , Encuestas y Cuestionarios , Factores de Tiempo , Fístula Traqueoesofágica/complicaciones , Resultado del TratamientoRESUMEN
BACKGROUND: Human rhinoviruses (HRVs) are a common cause of upper respiratory tract infections. There is growing evidence that HRVs are also important in lower respiratory tract infections and often induce asthma exacerbations. OBJECTIVE: We evaluated the presence of HRV in the lower respiratory tract by obtaining bronchial biopsies from infants with recurrent asthmalike respiratory symptoms. METHODS: A total of 201 steroid-naive infants age 3 to 26 months with recurrent respiratory symptoms for at least 4 weeks within the preceding 2 months were studied for lung function using body plethysmography. Bronchoscopy was performed in 68 children, and bronchial biopsies were available from 59 infants for HRV detection with in situ hybridization. RESULTS: Human rhinovirus was detected in 21 of 47 (45%) specimens. Abnormal lung function (decreased airways conductance) was found in 18 of 21 (86%) HRV(+) infants and in 15 of 26 (58%) HRV(-) infants (P = .037). Occurrence of a respiratory infection in the 6 weeks preceding bronchoscopy correlated with HRV positivity (P = .036). CONCLUSION: Human rhinovirus is frequently found in the lower airways in infants with recurrent respiratory symptoms, and the majority of these HRV(+) infants also showed increased airway resistance. CLINICAL IMPLICATIONS: Human rhinovirus is a common pathogen causing upper and lower respiratory symptoms. Follow-up of these infants will reveal whether the presence of HRV in the bronchial biopsy and abnormal lung function with recurrent respiratory symptoms predicts subsequent asthma.
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Asma/virología , Bronquios/virología , Infecciones por Picornaviridae/virología , Mucosa Respiratoria/virología , Rhinovirus/fisiología , Asma/patología , Asma/fisiopatología , Bronquios/patología , Bronquios/fisiopatología , Preescolar , Femenino , Humanos , Hibridación in Situ , Lactante , Masculino , Infecciones por Picornaviridae/patología , Infecciones por Picornaviridae/fisiopatología , Recurrencia , Mucosa Respiratoria/patología , Mucosa Respiratoria/fisiopatología , Rhinovirus/aislamiento & purificaciónRESUMEN
RATIONALE: We hypothesized that the epithelial reticular basement membrane (RBM) thickening and eosinophilic inflammation characteristic of asthma would be present in symptomatic infants with reversible airflow obstruction. METHODS: RBM thickness and numbers of inflammatory cells were determined in ultrathin sections of endobronchial biopsies obtained from 53 infants during clinical bronchoscopy for severe wheeze and/or cough. Group A: 16 infants with a median age of 12 months (range 3.4-26 months), with decreased specific airway conductance (sGaw) and bronchodilator reversibility; Group B: 22 infants with a median age of 12.4 months (5.1-25.9 months), with decreased sGaw but without bronchodilator reversibility; and Group C: 15 infants with a median age of 11.5 months (3.4-24.3 months) with normal sGaw. Additional comparisons were made with the following groups. Group D: 17 children, median age 10.3 years (6-16 years), with difficult asthma; Group E: 10 pediatric control subjects without asthma, median age 10 years (6-16 years); and Group F: nine adult normal, healthy control subjects, median age 27 years (21-42 years). MAIN RESULTS: There were no significant differences in RBM thickness or inflammatory cell number between the infant groups. RBM thickness was similar in the infants and Groups E and F. However, the RBM in all infant groups (Group A: median 4.3 microm [range 2.8-9.2 microm]; Group B: median 4.15 microm [range 2.7-5.8 microm]; Group C: median 3.8 microm [range 2.7-5.5 microm]) was significantly less thick than that in the older children with asthma (Group D: median 8.3 microm [range 5.3-12.7 microm]; p < 0.001). CONCLUSION: RBM thickening and the eosinophilic inflammation characteristic of asthma in older children and adults are not present in symptomatic infants with reversible airflow obstruction, even in the presence of atopy.