RESUMEN
BACKGROUND: Models that incorporate patterns of multiple cytokine responses to allergens, rather than individual cytokine production, may better predict sensitization and asthma. OBJECTIVE: To characterize the patterns of peripheral blood mononuclear cells' (PBMCs) cytokine responses to house dust mite (HDM) allergens among children from two population-based birth cohorts using machine learning techniques. METHODS: PBMCs collected at 8 years of age from the UK Manchester Asthma and Allergy Study (n = 268) and at 14 years of age from the Australian Raine Study (n = 1374) were cultured with HDM extract (10 µg/ml). Cytokine expression (IL-13, IL-5, IFN-γ, and IL10) was measured in the supernatant. Cytokine patterns were identified using a Gaussian mixture model clustering, and classification stability was assessed by bootstrapping. RESULTS: A six-class model indicated complex latent structure of cytokine expression. Based on the characteristics of each class, we designated them as follows: 'Nonresponders' (n = 905, 55%); 'IL-10 responders' (n = 49, 3%); 'IFN-γ and IL-13 medium responders' (n = 56, 3.4%); 'IL-13 medium responders' (n = 351, 21.4%); 'IL-5 and IL-13 medium responders' (n = 77, 4.7%); and 'IL-13 and IL-5 high responders' (n = 204, 12.4%). 'IL-13 and IL-5 high responders' were at much higher risk of HDM sensitization and asthma compared to all other classes, with 88% of children assigned to this class being sensitized and 28.5% having asthma. CONCLUSION: Using model-based clustering, we identified several distinct patterns of cytokine response to HDM and observed interplay between cytokine expression level, cytokine patterns (especially IL-13 and IL-5), and clinical outcomes. 'IL-13 and IL-5 high responders' class was strongly associated with HDM sensitization. However, among HDM-sensitized children, one-third showed no PBMC response to HDM, and the majority of HDM-sensitized children did not have asthma or wheeze. Our findings suggest that positive HDM 'allergy tests' and asthma are associated with a broad range of immunophenotypes, which may have important implications for the use of cytokine-targeted treatment approaches.
Asunto(s)
Citocinas/metabolismo , Hipersensibilidad/epidemiología , Hipersensibilidad/metabolismo , Alérgenos/inmunología , Antígenos Dermatofagoides , Australia/epidemiología , Niño , Estudios de Cohortes , Femenino , Humanos , Hipersensibilidad/inmunología , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Masculino , Evaluación del Resultado de la Atención al Paciente , Vigilancia en Salud PúblicaRESUMEN
BACKGROUND: Presymptomatic immaturity in neonatal T-cell function is a consistent antecedent of allergic disease, including reduced responsiveness to polyclonal activation. METHODS: To elucidate the underlying mechanisms, we examined for differences in T-cell gene expression in longitudinal samples collected at birth and at 1 year of age in children with (n = 30) and without IgE-mediated food allergy (n = 30). We employed a low-level soluble anti-CD3 stimulus to activate the T-cell receptor (TCR) and surveyed gene expression by DNA microarray in purified CD4(+) T-cells. Allergen-specific responses were assessed in parallel functional studies. RESULTS: At birth, the allergic group showed a reduced number of genes up regulated in response to anti-CD3 treatment on the microarray and a reduced lympho proliferative capacity, suggesting clear differences in T-cell signalling pathways. Polymerase chain reaction (PCR) validation of candidate genes confirmed significantly lower expression of a number of genes in the allergic group including RELB, NFKB2, LIF and FAS. By 12 months of age, there were marked changes in the anti-CD3 response in all infants, culminating in upregulation of cytokine genes (IL-5, IL-13, IL-17 and IL-22). Neonatal differences were no longer apparent. Instead, the allergic group, all symptomatic by this age, showed differential expression of T-cell lineage pathways including GATA-3, MAL and FcER1 in unstimulated T-cells. Allergen stimulation induced significantly higher cytokines production (IL-5, IL-13 and IFNγ) in the allergic group. CONCLUSION: Although transient, suboptimal neonatal T-cell activation pathways that signal through the NF-κB complex may affect the developmental transition of T-cell phenotypes in the periphery shortly after birth and may increase the risk of food allergy.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Hipersensibilidad a los Alimentos/genética , Hipersensibilidad a los Alimentos/inmunología , Regulación de la Expresión Génica , Activación de Linfocitos/genética , Alérgenos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Análisis por Conglomerados , Citocinas/biosíntesis , Citocinas/inmunología , Femenino , Perfilación de la Expresión Génica , Humanos , Lactante , Recién Nacido , Masculino , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de SeñalRESUMEN
Vitamin D has been linked in some studies with atopy- and asthma-associated phenotypes in children with established disease, but its role in disease inception at the community level is less clear. The aim of the present study was to investigate associations between vitamin D status and biological signatures indicative of allergy and asthma development in children aged 6 and 14 years in Perth, WA, Australia (latitude 32° S). Serum vitamin D was assayed in 989 6-yr-olds and 1,380 14-yr-olds from an unselected community birth cohort; 689 subjects were assessed at both ages. Vitamin D levels were assessed as a risk modifier for respiratory and allergic outcomes at both ages, using previously ascertained phenotypic data. The predictive value of vitamin D levels at age 6 yrs for development of clinical phenotypes at age 14 yrs was also examined. Serum vitamin D levels in children of both ages were negatively associated with concurrent allergic phenotypes; sex stratification revealed that this association was restricted mainly to males. Furthermore, vitamin D levels at age 6 yrs were significant predictors of subsequent atopy/asthma-associated phenotypes at age 14 yrs. In an unselected community setting, children (particularly males) with inadequate vitamin D are at increased risk of developing atopy, and subsequently bronchial hyperresponsiveness (BHR) and asthma. In a large unselected cohort, males with inadequate vitamin D at 6 and 14 yrs of age had increased atopy and BHR. Low vitamin D at age 6 yrs was a predictor of atopy and asthma at 14 yrs of age.
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Asma/sangre , Vitamina D/sangre , Adolescente , Alérgenos/sangre , Animales , Asma/fisiopatología , Hiperreactividad Bronquial/sangre , Niño , Femenino , Humanos , Hipersensibilidad/sangre , Inmunoglobulina E/sangre , Estudios Longitudinales , Masculino , Valor Predictivo de las Pruebas , Prevalencia , Pyroglyphidae , Pruebas de Función Respiratoria , Ruidos Respiratorios/fisiopatología , Rinitis/sangre , Factores de Riesgo , Factores Sexuales , Australia Occidental/epidemiologíaRESUMEN
Bacterial colonisation of the airways is associated with increased risk of childhood asthma. Immunoglobulin (Ig)E against bacterial antigens has been reported in some asthmatics, suggesting a role for bacterial-specific type-2 immunity in disease pathogenesis. We aimed to investigate relationships between bacterial-specific IgE amongst teenagers and asthma susceptibility. We measured titres of IgE against Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus in 1,380 teenagers, and related these to asthma symptomatology and immunophenotypes. IgE titres against S. aureus-derived enterotoxins were highest amongst atopics and were associated with asthma risk. Surprisingly, IgE titres against H. influenzae and S. pneumoniae surface antigens were higher, not stratified by atopy and independently associated with decreased asthma risk. The positive association between type-2 immunity to S. aureus and asthma phenotypes probably reflects IgE-mediated effector cell activation via enterotoxin super antigens which are secreted in soluble form. The contrasting benign nature of type-2 immunity to H. influenzae and S. pneumoniae antigens may reflect their lower availability in soluble forms that can crosslink IgE receptors. We theorise that instead they may be processed by antigen presenting cells and presented to type-2 memory cells leading to mucosal secretion of interleukin (IL)-4/IL-13, a mechanism widely recognised in other tissues to attenuate T-helper-1 associated bacterial-induced inflammation.
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Asma/inmunología , Asma/microbiología , Células Th2/citología , Adolescente , Hiperreactividad Bronquial , Femenino , Haemophilus influenzae/inmunología , Humanos , Sistema Inmunológico , Inmunoglobulina E/inmunología , Inflamación , Masculino , Fenotipo , Espirometría/métodos , Staphylococcus aureus/inmunología , Streptococcus pneumoniae/inmunología , Factores de TiempoRESUMEN
Anti-viral innate immune responses may be impaired in asthma, although the mechanisms are not well understood. Toll-like receptors (TLRs) 7 and 3 are particularly relevant for initiating responses to common respiratory viruses, as they recognise single-stranded viral RNA and double-stranded viral RNA, respectively. The aim of the present study was to investigate TLR7 and TLR3 function in 14-yr-old adolescents with asthma. Blood mononuclear cells obtained from 17 atopic asthmatics, 29 atopic, non-asthmatics and 21 healthy, non-atopic individuals, were stimulated with the TLR7 agonist imiquimod and the TLR3 agonist poly I:C. Expression of anti-viral molecules was measured by real-time PCR. Concentrations of interferon-gamma-inducible cytokine protein (IP)-10 and interleukin (IL)-6 were measured by ELISA. TLR7-induced myxovirus resistance protein A and 2'5' oligoadenylate synthetase mRNA expression and protein levels of IP-10 were significantly lower in asthma subjects compared with healthy subjects (p = 0.041, p = 0.003 and p = 0.001 respectively). There was a significant negative correlation between total serum immunoglobulin E and IP-10 following TLR7 stimulation. However, TLR3-induced responses did not vary with asthma or atopy. IL-10 mRNA and IL-6 protein synthesis were similar in asthmatic and control subjects. In conclusion, TLR7 function is reduced in adolescents with asthma and this may contribute to susceptibility to respiratory viral infections.
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Asma/inmunología , Receptor Toll-Like 3/fisiología , Receptor Toll-Like 7/fisiología , Adolescente , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Receptor Toll-Like 3/biosíntesis , Receptor Toll-Like 7/biosíntesisRESUMEN
BACKGROUND: Increasing evidence suggests that patterns of T-cell immunity to inhalant allergens in genetically diverse human populations are more heterogeneous than previously assumed, and that covert differences in expression patterns might underlie variations in airway disease phenotypes. We tested this proposition in a community sample of children. METHODS: We analysed data from 172 individuals who had been recruited antenatally to a longitudinal birth cohort study. Of the 194 birth cohort participants, data from the 147 probands (age range 8.6-13.5 years) who consented to blood collection were included along with data from 25 consenting siblings (mean age 11 years [range 7.4-17.4]). We ascertained clinical phenotypes related to asthma and allergy. We measured T-cell responses to allergens and mitogens, together with blood eosinophils and IgE/IgG antibodies, and assessed associations between these indices and clinical phenotypes. FINDINGS: Atopy was associated with allergen-specific T-helper (Th)2 responses dominated by interleukin 4, interleukin 5, interleukin 9, interleukin 13, whereas interleukin 10, tumour necrosis factor alpha, and interferon gamma responses were common to both atopics and non-atopics. The wheal size from skin prick with allergen was positively associated with in-vitro interleukin 5 and interferon gamma responses, and negatively associated with interleukin 10. Asthma, especially in atopics, was strongly associated with eosinophilia/interleukin 5, and bronchial hyper-responsiveness (BHR) was associated with eosinophilia plus polyclonal interferon gamma production. BHR in non-atopics was associated with elevated allergen-specific and polyclonal interleukin 10 production. INTERPRETATION: Parallel immunological and clinical profiling of children identified distinctive immune response patterns related to asthma and wheeze compared with BHR, in atopics non-atopics. Immunological hyper-responsiveness, including within the Th1 cytokine compartment, is identified as a hallmark of BHR. RELEVANCE TO PRACTICE: These findings highlight the heterogeneity of immune response patterns in asthmatic children, including those with seemingly homogeneous Th2-driven atopic asthma. Further elucidation of the covert relationships between wheezing phenotypes and underlying immunophenotypes in this age group will potentially lead to more effective treatments for what is an unexpectedly heterogeneous collection of disease subtypes.
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Asma/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Adolescente , Animales , Asma/fisiopatología , Hiperreactividad Bronquial , Niño , Eosinofilia , Humanos , Hipersensibilidad Inmediata/inmunología , Interleucinas/metabolismo , Fenotipo , Pyroglyphidae/inmunología , Ruidos Respiratorios , Pruebas CutáneasRESUMEN
(CA)n simple repeats in DNA were examined at 17 loci in 18 human squamous cell carcinomas of the esophagus and compared with those in normal esophageal tissue from the same patients. Six loci were examined in 32 esophageal papillomas that had been induced by N-nitrosomethylbenzylamine in BD VI rats. Length-altered CA repeats were found in two human tumors and four rat papillomas. Loss of heterozygosity was observed in three human tumors; two rat papillomas had lost microsatellite bands that are common in inbred BD VI rats. Both (CA)n microsatellite length alteration and loss of heterozygosity were clustered at certain loci in the human tumor samples and in the chemically induced rat esophageal tumors. Our findings indicate that genomic instability that results in alteration of repeated sequences not only occurs in human tumors but may also be a consequence of chemical carcinogenesis in rodents.