RESUMEN
We have examined age-related changes in the association between nonspecific bronchial hyperresponsiveness (BHR) and atopy in 494 second-generation Polynesian migrant children, aged 5 to 15 years. BHR (provocative dose of methacholine, less than or equal to 7.8 mumol, causing a 20% fall in FEV1) was present in 125 children (25.3%). Atopy (skin wheal, greater than or equal to 4 mm diameter) was present in 157 children (32%). BHR associated with atopy demonstrated a constant age-related frequency in the 7- to 15-year-old children that was influenced by a family history (FH) of asthma (FH, 50%; no FH, 34%; p = 0.051). BHR not associated with atopy demonstrated a marked decreasing frequency with age from 25% in 5- to 7-year-old children to 3% in 13- to 15-year-old children and was uninfluenced by an FH of asthma. We conclude that the differences in the frequency of BHR with age, together with the genetic influence on BHR associated with atopy, compared with the findings in nonatopic children, indicate distinct heterogeneity in the pathogenesis of BHR in these Tokelauan children. These differences may be important for understanding the relationships between nonspecific BHR, atopy, and asthma in children.
Asunto(s)
Asma/genética , Bronquios/fisiopatología , Hipersensibilidad/complicaciones , Adolescente , Asma/etnología , Asma/inmunología , Asma/fisiopatología , Pruebas de Provocación Bronquial , Niño , Preescolar , Estudios Transversales , Emigración e Inmigración , Femenino , Humanos , Masculino , Nueva Zelanda , Polinesia/etnología , Pruebas CutáneasRESUMEN
503 migrant Tokelauan children between five and 15 years resident predominantly in Porirua and the Hutt Valley were surveyed as part of a study of asthma prevalence in a recently migrant population. The survey consisted of domiciliary interview with parents, physical examination, assessment of bronchial hyperresponsiveness and atopy, by allergen skin prick testing. Forty-three children (8%) had a history of wheezy breathing or asthma. 160 children (32%) had evidence of increased airway responsiveness defined as a PD20 (provocative dose of methacholine causing a less than or equal to 20% fall in FEV1, of less than or equal to 12.2 mumoL methacholine). Of the 43 children with a history of asthma, 40 (93%) had evidence of bronchial hyperresponsiveness, 36 (84%) were atopic and 35 (81%) had both bronchial hyperresponsiveness and atopy. Forty-five children (9%) were found to be wheezing on the day of examination only 16 of these had a history of wheezing. Twenty seven of the wheezing children demonstrated bronchial hyperresponsiveness and 22 of these were atopic. Of the 18 children wheezing but with no evidence of bronchial hyperresponsiveness only six were atopic. These contrasting findings suggest differences in the cause of symptoms among the children. Regional differences were observed for the prevalence of symptoms and signs of asthma, bronchial hyperresponsiveness and atopy. Hutt Valley Tokelauan children exhibited a higher prevalence than the Porirua children. Migrants to the Hutt Valley and Porirua are from different atolls, and these differences raise the possibility of a genetic influence on the development of asthma.
Asunto(s)
Asma/epidemiología , Pruebas de Provocación Bronquial , Etnicidad , Hipersensibilidad Inmediata/epidemiología , Adolescente , Asma/diagnóstico , Asma/etnología , Bronquios/efectos de los fármacos , Bronquios/fisiología , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Hipersensibilidad Inmediata/etnología , Masculino , Cloruro de Metacolina , Compuestos de Metacolina , Nueva Zelanda , MigrantesRESUMEN
Six Polynesian children aged 8-14 years with recurrent lower respiratory infections and abnormal lung mucociliary clearance were assessed for immuno-deficiency. Measurements were made in these 6 children and in 21 healthy Polynesians of serum immunoglobulins (IgG, IgM, IgA) and complement components (C3, C4), leucocyte function tests, and T and B cell populations. A further 8 Polynesian bronchiectatics were tested for sputum secretory-IgA. There was no evidence of S-IgA deficiency and 4 had high levels. There was no evidence of immunodeficiency. Nasal epithelium was obtained from 6 children using a cytology brush and ciliated epithelium was obtained in only 4. The ultrastructure was normal although few cilia were examined.
Asunto(s)
Bronquiectasia/inmunología , Cilios/ultraestructura , Proteínas del Sistema Complemento/análisis , Inmunoglobulinas/análisis , Linfocitos/inmunología , Adolescente , Bronquiectasia/patología , Bronquiectasia/fisiopatología , Niño , Cilios/fisiología , Femenino , Humanos , Inmunoglobulina A Secretora/análisis , Pulmón/ultraestructura , Masculino , Moco/fisiología , Mucosa Nasal/ultraestructura , Polinesia , Esputo/inmunologíaRESUMEN
Ciliated bronchial or nasal epithelium from 20 Polynesian bronchiectatic patients was examined in an electron microscope. In all patients there was a partial or complete loss of dynein arms. Also, in many patients other ciliary abnormalities were present with a high proportion, often over 25%, of cilia affected. This contrasts with a control group where ciliary abnormalities were infrequent. Mucociliary clearance, measured by imaging 99mTc sulfide dust with a gamma camera, was either absent or markedly reduced in these bronchiectatic patients.
Asunto(s)
Bronquiectasia/patología , Cilios/ultraestructura , Mucosa Nasal/ultraestructura , Bronquios/ultraestructura , Bronquiectasia/epidemiología , Bronquiectasia/fisiopatología , Cilios/fisiología , Humanos , Pulmón/fisiopatología , Moco/fisiología , Nueva Zelanda , Polinesia/etnologíaRESUMEN
The prevalence of asthma has been studied in Tokelauan children aged 0--14 years in two environments--Tokelau and New Zealand. Only 11.0% of the 706 children examined in Tokelau were classified as asthmatic, whereas 25.3% of the 1,160 children seen in New Zealand were asthmatic. For those children examined in New Zealand there was no significant difference in the prevalence of asthma between those children who were born in New Zealand and those who were born in Tolelau.