RESUMO
BACKGROUND: Early-life exposures to geohelminths may protect against development of wheeze/asthma and atopy. OBJECTIVE: To study the effect of maternal geohelminths and infections in children during the first 5 years on atopy, wheeze/asthma and airways reactivity/inflammation at 8 years. METHODS: Birth cohort of 2404 neonates followed to 8 years in rural Ecuador. Data on wheeze/asthma were collected by questionnaire and atopy by skin prick test (SPT) reactivity to 9 allergens. We measured airways reactivity to bronchodilator, fractional exhaled nitric oxide (FeNO) and nasal eosinophilia. Stool samples were examined for geohelminths by microscopy. RESULTS: 1933 (80.4%) children were evaluated at 8 years. Geohelminths were detected in 45.8% of mothers and 45.5% of children to 5 years. Frequencies of outcomes at 8 years were as follows: wheeze (6.6%), asthma between 5 and 8 years (7.9%), SPT (14.7%), airways reactivity (10%) and elevated FeNO (10.3%) and nasal eosinophilia (9.2%). Any maternal geohelminth was associated with reduced SPT prevalence (OR 0.72). Childhood Trichuris trichiura infections during the first 5 years were associated with reduced wheeze (OR 0.57) but greater parasite burdens with Ascaris lumbricoides at 5 years were associated with increased wheeze (OR 2.83) and asthma (OR 2.60). Associations between maternal geohelminths and wheeze/asthma were modified by atopy. Parasite-specific effects on wheeze/asthma and airways reactivity and inflammation were observed in non-atopic children. CONCLUSIONS: Our data provide novel evidence for persistent effects of in utero geohelminth exposures on childhood atopy but highlight the complex nature of the relationship between geohelminths and the airways. Registered as an observational study (ISRCTN41239086).
Assuntos
Asma , Hipersensibilidade Imediata , Asma/epidemiologia , Asma/etiologia , Criança , Equador/epidemiologia , Feminino , Humanos , Hipersensibilidade Imediata/epidemiologia , Recém-Nascido , Sons Respiratórios/etiologia , Testes CutâneosRESUMO
BACKGROUND: IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that α-Gal sensitization is prevalent but has been little investigated. OBJECTIVE: We sought evidence for the cause(s) of α-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya. METHODS: IgE to α-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG4 to α-Gal and antibodies to regionally representative parasites were assessed in a subset of children. RESULTS: In Ecuador (32%) and Kenya (54%), α-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had α-Gal specific IgE. Levels of α-Gal specific IgG4 were not high in Ecuador, but were greater than in children from the United States. CONCLUSIONS: These results suggest that in areas of the developing world with endemic parasitism, α-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.
Assuntos
Dissacarídeos/imunologia , Hipersensibilidade Alimentar/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Adolescente , Adulto , Animais , Ascaris/imunologia , Ascaris/isolamento & purificação , Criança , Pré-Escolar , Dieta , Equador/epidemiologia , Fezes/parasitologia , Feminino , Hipersensibilidade Alimentar/sangue , Hipersensibilidade Alimentar/epidemiologia , Hipersensibilidade Alimentar/parasitologia , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Quênia/epidemiologia , Masculino , Prevalência , Carne Vermelha , Trichuris/isolamento & purificação , Virginia/epidemiologia , Adulto JovemRESUMO
Asthma is a common cause of emergency care attendance in low- and middle-income countries (LMICs). While few prospective studies of predictors for emergency care attendance have been undertaken in high-income countries, none have been performed in a LMIC.We followed a cohort of 5-15-year-old children treated for asthma attacks in emergency rooms of public health facilities in Esmeraldas City, Ecuador. We collected blood and nasal wash samples, and performed spirometry and exhaled nitric oxide fraction measurements. We explored potential predictors for recurrence of severe asthma attacks requiring emergency care over 6â months' follow-up.We recruited 283 children of whom 264 (93%) were followed-up for ≥6â months or until their next asthma attack. Almost half (46%) had a subsequent severe asthma attack requiring emergency care. Predictors of recurrence in adjusted analyses were (adjusted OR, 95% CI) younger age (0.87, 0.79-0.96 per year), previous asthma diagnosis (2.2, 1.2-3.9), number of parenteral corticosteroid courses in previous year (1.3, 1.1-1.5), food triggers (2.0, 1.1-3.6) and eczema diagnosis (4.2, 1.02-17.6). A parsimonious Cox regression model included the first three predictors plus urban residence as a protective factor (adjusted hazard ratio 0.69, 95% CI 0.50-0.95). Laboratory and lung function tests did not predict recurrence.Factors independently associated with recurrent emergency attendance for asthma attacks were identified in a low-resource LMIC setting. This study suggests that a simple risk-assessment tool could potentially be created for emergency rooms in similar settings to identify higher-risk children on whom limited resources might be better focused.
Assuntos
Asma/epidemiologia , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Equador/epidemiologia , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Humanos , Masculino , Recidiva , Medição de Risco , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Despite the high asthma rates described in Latin America, asthma risk factors in poor urban settings are not well established. We investigated risk factors for acute asthma among Ecuadorian children. METHODS: A matched case-control study was carried out in a public hospital serving a coastal city. Children with acute asthma were age- and sex-matched to non-asthmatics. A questionnaire was administered, and blood, as well as stool, and nasopharyngeal swabs were collected. RESULTS: Sixty cases and 119 controls aged 5-15 were evaluated. High proportions of cases were atopic with population-attributable fractions for atopy of 68.5% for sIgE and 57.2% for SPT. Acute asthma risk increased with greater titers of mite IgE (3.51-50 kU/l vs. <0.70kU/l - OR 4.56, 95% CI 1.48-14.06, p = 0.008; >50kU/l vs. <0.70kU/l - OR 41.98, 95% CI: 8.97-196.39, p < 0.001). Asthma risk was significantly independently associated with bronchiolitis (adj. OR: 38.9, 95% CI 3.26-465), parental educational level (adj. OR 1.26, 95% CI: 1.08-1.46), and presence of sIgE (adj. OR: 36.7, 95% CI: 4.00-337), while a reduced risk was associated with current contact with pets (adj. OR: 0.07, 95% CI: 0.01-0.56). Rhinovirus infection was more frequent in cases (cases 35.6% vs. controls 7.8%, p = 0.002). None of the cases were on maintenance therapy with inhaled corticosteroids and most relied on emergency department for control. CONCLUSIONS: A high proportion of children presenting to a public hospital with acute asthma were allergic to mite, particularly at high IgE titer. Poor asthma control resulted in overuse of emergency care.
Assuntos
Asma/epidemiologia , Saúde da População Urbana , Doença Aguda , Adolescente , Distribuição por Idade , Alérgenos/efeitos adversos , Alérgenos/imunologia , Animais , Antiasmáticos/uso terapêutico , Asma/diagnóstico , Asma/tratamento farmacológico , Asma/imunologia , Biomarcadores/sangue , Estudos de Casos e Controles , Criança , Pré-Escolar , Progressão da Doença , Equador/epidemiologia , Serviço Hospitalar de Emergência , Feminino , Hospitais Públicos , Humanos , Imunoglobulina E/sangue , Testes Imunológicos , Exposição por Inalação/efeitos adversos , Proteínas de Insetos/imunologia , Modelos Logísticos , Masculino , Ácaros/imunologia , Análise Multivariada , Razão de Chances , Prognóstico , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/imunologia , Infecções Respiratórias/virologia , Fatores de RiscoRESUMO
BACKGROUND: The relevance of allergic sensitization, as judged by titers of serum IgE antibodies, to the risk of an asthma exacerbation caused by rhinovirus is unclear. OBJECTIVE: We sought to examine the prevalence of rhinovirus infections in relation to the atopic status of children treated for wheezing in Costa Rica, a country with an increased asthma burden. METHODS: The children enrolled (n= 287) were 7 through 12 years old. They included 96 with acute wheezing, 65 with stable asthma, and 126 nonasthmatic control subjects. PCR methods, including gene sequencing to identify rhinovirus strains, were used to identify viral pathogens in nasal washes. Results were examined in relation to wheezing, IgE, allergen-specific IgE antibody, and fraction of exhaled nitric oxide levels. RESULTS: Sixty-four percent of wheezing children compared with 13% of children with stable asthma and 13% of nonasthmatic control subjects had positive test results for rhinovirus (P< .001 for both comparisons). Among wheezing subjects, 75% of the rhinoviruses detected were group C strains. High titers of IgE antibodies to dust mite allergen (especially Dermatophagoides species) were common and correlated significantly with total IgE and fraction of exhaled nitric oxide levels. The greatest risk for wheezing was observed among children with titers of IgE antibodies to dust mite of 17.5 IU/mL or greater who tested positive for rhinovirus (odds ratio for wheezing, 31.5; 95% CI, 8.3-108; P< .001). CONCLUSIONS: High titers of IgE antibody to dust mite allergen were common and significantly increased the risk for acute wheezing provoked by rhinovirus among asthmatic children.
Assuntos
Alérgenos/imunologia , Asma/complicações , Asma/imunologia , Imunoglobulina E/sangue , Infecções por Picornaviridae/imunologia , Pyroglyphidae/imunologia , Rhinovirus , Animais , Estudos de Casos e Controles , Criança , Epitopos/imunologia , Expiração , Feminino , Humanos , Masculino , Óxido Nítrico/análise , Infecções por Picornaviridae/complicações , Infecções por Picornaviridae/diagnóstico , Sons Respiratórios/etiologia , Rhinovirus/genética , Rhinovirus/imunologia , RiscoRESUMO
BACKGROUND: Geohelminth infections are highly prevalent infectious diseases of childhood in many regions of the Tropics, and are associated with significant morbidity especially among pre-school and school-age children. There is growing concern that geohelminth infections, particularly exposures occurring during early life in utero through maternal infections or during infancy, may affect vaccine immunogenicity in populations among whom these infections are endemic. Further, the low prevalence of allergic disease in the rural Tropics has been attributed to the immune modulatory effects of these infections and there is concern that widespread use of anthelmintic treatment in high-risk groups may be associated with an increase in the prevalence of allergic diseases. Because the most widely used vaccines are administered during the first year of life and the antecedents of allergic disease are considered to occur in early childhood, the present study has been designed to investigate the impact of early exposures to geohelminths on the development of protective immunity to vaccines, allergic sensitization, and allergic disease. METHODS/DESIGN: A cohort of 2,403 neonates followed up to 8 years of age. Primary exposures are infections with geohelminth parasites during the last trimester of pregnancy and the first 2 years of life. Primary study outcomes are the development of protective immunity to common childhood vaccines (i.e. rotavirus, Haemophilus influenzae type B, Hepatitis B, tetanus toxoid, and oral poliovirus type 3) during the first 5 years of life, the development of eczema by 3 years of age, the development of allergen skin test reactivity at 5 years of age, and the development of asthma at 5 and 8 years of age. Potential immunological mechanisms by which geohelminth infections may affect the study outcomes will be investigated also. DISCUSSION: The study will provide information on the potential effects of early exposures to geohelminths (during pregnancy and the first 2 years of life) on the development of vaccine immunity and allergy. The data will inform an ongoing debate of potential effects of geohelminths on child health and will contribute to policy decisions on new interventions designed to improve vaccine immunogenicity and protect against the development of allergic diseases. TRIAL REGISTRATION: Current Controlled Trials ISRCTN41239086.
Assuntos
Asma/imunologia , Eczema/imunologia , Helmintíase/imunologia , Hipersensibilidade/imunologia , Complicações Parasitárias na Gravidez/imunologia , Vacinas/imunologia , Asma/epidemiologia , Criança , Pré-Escolar , Equador/epidemiologia , Eczema/epidemiologia , Projetos de Pesquisa Epidemiológica , Feminino , Helmintíase/epidemiologia , Humanos , Hipersensibilidade/epidemiologia , Imunidade Inata/imunologia , Lactente , Recém-Nascido , Estudos Longitudinais , Modelos Imunológicos , Gravidez , Complicações Parasitárias na Gravidez/epidemiologia , Complicações Parasitárias na Gravidez/parasitologia , Testes CutâneosRESUMO
A nomenclatura proposta no relatório de outubro de 2003 do Comitê de Revisão de Nomenclatura da World Allergy Organization é uma atualização da Nomenclatura Revisada para Declaração da Situação da Alergia da Academia Européia de Alergologia e Imunologia Clínica (European Academy of Allergology and Clinical Immunology Revised Nomenclature for Allergy Position Statement), publicada em 2001. A nomenclatura pode ser usada independentemente do órgão alvo ou da faixa etária do paciente e se baseia nos mecanismos que desencadeiam e medeiam as reações alérgicas. Supõe-se que, conforme o conhecimento sobre as causas básicas e os mecanismos for se aprimorando, a nomenclatura virá a precisar de revisão
Assuntos
Humanos , Anafilaxia , Asma , Dermatite , Eczema , Hipersensibilidade , Imunoglobulina E , Rinite , Terminologia , Reações Antígeno-Anticorpo , Métodos , Técnicas e Procedimentos DiagnósticosRESUMO
The objective of this study was to evaluate risk factors for persistent wheezing in a group of 2-4-year-old children after an index-wheezing episode in infancy. Eighty infants who had been seen at the Emergency Department for an episode of acute wheezing were followed for 2 yr in this prospective study. Caregivers completed a questionnaire, and children underwent clinical evaluation and skin prick testing 2 yr following the index-wheezing episode. Detection of respiratory viruses and analysis of exposure to major indoor allergens were carried out at enrollment. Immunoglobin E antibodies were measured at the beginning of the study and at the end of follow-up, using the CAP system. Logistic regression analysis was performed to identify factors associated with persistent wheezing. Seventy-three children (44 boys) completed the study. After 2 yr, 38 (52%) reported three or more wheezing episodes in the past 12 months (persistent wheezers). Independent risk factors for persistence of wheezing were allergic sensitization and exposure to cockroach allergen in the kitchen. Breast-feeding for at least 1 month was a protective factor. A strong association between allergic sensitization and persistence of wheezing was found in a group of very young children living in a subtropical area.
Assuntos
Alérgenos/administração & dosagem , Aleitamento Materno , Baratas/imunologia , Hipersensibilidade/etiologia , Sons Respiratórios/etiologia , Animais , Brasil , Pré-Escolar , Feminino , Humanos , Hipersensibilidade/imunologia , Hipersensibilidade/prevenção & controle , Lactente , Masculino , Estudos Prospectivos , Sons Respiratórios/imunologia , Fatores de RiscoRESUMO
BACKGROUND: Risk factors for acute wheezing among children in subtropical areas are largely unknown. OBJECTIVE: To investigate the role of viral infections, allergen sensitization, and exposure to indoor allergens as risk factors for acute wheezing in children 0 to 12 years old. METHODS: One hundred thirty-two children 0 to 12 years of age who sought emergency department care for wheezing and 65 children with no history of wheezing were enrolled in this case-control study. Detection of respiratory syncytial virus antigen, rhinovirus and coronavirus RNA, adenovirus, influenza, and parainfluenza antigens was performed in nasal washes. Total IgE and specific IgE to mites, cockroach, cat, and dog were measured with the CAP system. Major allergens from mites, cockroach, cat, and dog were quantified in dust samples by ELISA. Univariate and multivariate analyses were performed by logistic regression. RESULTS: In children under 2 years of age, infection with respiratory viruses and family history of allergy were independently associated with wheezing (odds ratio, 15.5 and 4.2; P = .0001 and P = .008, respectively). Among children 2 to 12 years old, sensitization to inhalant allergens was the major risk factor for wheezing (odds ratio, 2.7; P = .03). High-level allergen exposure, exposure to tobacco smoke, and lack of breast-feeding showed no association with wheezing. CONCLUSIONS: Some risk factors for wheezing previously identified in temperate climates were present in a subtropical area, including respiratory syncytial virus infection in infants and allergy in children older than 2 years. Rhinovirus was not associated with wheezing and did not appear to be a trigger for asthma exacerbations.
Assuntos
Sons Respiratórios/etiologia , Alérgenos/administração & dosagem , Asma/etiologia , Asma/imunologia , Asma/virologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Eosinofilia/etiologia , Feminino , Humanos , Imunoglobulina E/sangue , Lactente , Recém-Nascido , Masculino , Sons Respiratórios/imunologia , Infecções Respiratórias/etiologia , Fatores de Risco , Clima Tropical , Viroses/complicações , Vírus/isolamento & purificaçãoRESUMO
OBJECTIVE: The purpose of this study was to evaluate differences in the relationship between asthma and immune responses to allergens in children living in rural and urban areas of Kenya. STUDY DESIGN: Children (mean age, 11 years) from Kabati (n = 136), a rural village, and Thika (n = 129), a small town, were studied by skin testing and serum immunoglobulin E (IgE) and immunoglobulin G (IgG) antibody measurement. Asthma was evaluated by symptoms, as well as spirometry before and after vigorous exercise to test for exercised-induced bronchospasm (EIB). School children from a study performed in Atlanta, Georgia, were used for comparison of anthropometric and immunologic results. RESULTS: Compared with the urban area of Kenya, children living in the rural area had a lower percentage of body fat, smaller and fewer skin test responses to allergens, a higher prevalence of IgE antibodies to Ascaris (67% vs 26%) and 10-fold higher total IgE. In the urban area of Kenya, there was a strong correlation between EIB and atopy determined both by IgE antibodies (P =.02) and skin tests (P =.002). By contrast, in the rural area, none of the 13 children with EIB were skin-test positive (vs 13/109 of children without EIB). CONCLUSIONS: Among the rural children, there was no association between immune responses to allergens and airway-related symptoms or reactivity. The association between asthma and atopy seen in the town of Thika may represent an important step in the increase in asthma seen both in urban Africa and in the West.