RESUMEN
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.
Asunto(s)
Disacáridos/inmunología , Hipersensibilidad a los Alimentos/inmunología , Inmunoglobulina E/inmunología , Inmunoglobulina G/inmunología , Adolescente , Adulto , Animales , Ascaris/inmunología , Ascaris/aislamiento & purificación , Niño , Preescolar , Dieta , Ecuador/epidemiología , Heces/parasitología , Femenino , Hipersensibilidad a los Alimentos/sangre , Hipersensibilidad a los Alimentos/epidemiología , Hipersensibilidad a los Alimentos/parasitología , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina G/sangre , Kenia/epidemiología , Masculino , Prevalencia , Carne Roja , Trichuris/aislamiento & purificación , Virginia/epidemiología , Adulto JovenRESUMEN
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.
Asunto(s)
Alérgenos/inmunología , Asma/complicaciones , Asma/inmunología , Inmunoglobulina E/sangre , Infecciones por Picornaviridae/inmunología , Pyroglyphidae/inmunología , Rhinovirus , Animales , Estudios de Casos y Controles , Niño , Epítopos/inmunología , Espiración , Femenino , Humanos , Masculino , Óxido Nítrico/análisis , Infecciones por Picornaviridae/complicaciones , Infecciones por Picornaviridae/diagnóstico , Ruidos Respiratorios/etiología , Rhinovirus/genética , Rhinovirus/inmunología , RiesgoRESUMEN
OBJECTIVE: To examine whether early child care exposure influences the risk for development of asthma. STUDY DESIGN: Longitudinal data from 939 children and their families from the National Institute of Child Health and Development Study of Early Child Care and Youth Development were analyzed. Exposure to other children in the primary child care setting as an infant (before 15 months) and as a toddler (16-36 months) were assessed as risk factors for persistent or late-onset asthma by age 15 via logistic regression. RESULTS: The number of children in the child-care environment when the child was a toddler was significantly associated with odds of asthma, even after adjusting for respiratory illnesses and other risk factors (P < .05). The fewer the children exposed to as toddlers, the higher the probability of persistent or late-onset asthma by age 15. CONCLUSIONS: This study supports the theory of a protective effect of exposure to other children at an early age, especially as a toddler, on the risk of asthma. This effect appears to be independent of the number of reported respiratory tract illnesses, suggesting that other protective mechanisms related to the number of children in the child care environment may be involved.