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Atopic Outcomes (atopic + outcome)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Human mid-gestation amniotic fluid contains interleukin-16 bioactivity

IMMUNOLOGY, Issue 4 2009
Catherine A. Thornton
Summary CD4-positive cells are detectable in the human fetal gastrointestinal tract from 11 weeks of gestation. Interleukin-16 (IL-16) is a chemoattractant for CD4+ cells and, via fetal swallowing of amniotic fluid, could mediate the influx of CD4+ cells into the fetal gut. We have shown that IL-16 was detectable in human amniotic fluid at 16,18 weeks of gestation (mid-pregnancy) but was not detectable at term (late pregnancy; > 37 weeks of gestation). Similarly, mid-pregnancy, but not late pregnancy, amniotic fluid contained chemotactic activity for CD4+ T cells, this activity was reduced by 58% in the presence of a neutralizing anti-IL-16 antibody. The levels of IL-16 in fetal plasma at 16,24 weeks of gestation were very high, and decreased significantly by 25,36 weeks but at > 37 weeks remained significantly higher than adult levels. IL-16 transcripts were detectable in whole tissue extracts of fetal gut, skin and placenta but not in amniocytes, and IL-16 immunoreactivity was detectable in cells within the lamina propria of the fetal gut and within the skin, where it was associated with the basement membrane. Neither IL-16 levels nor chemotactic activity for CD4+ T cells in mid-pregnancy amniotic fluid was related to atopic outcomes at 1 year of age. IL-16 might have an important role in the early development of the human immune system and/or in regulating fetal and maternal immunological responsiveness during pregnancy. [source]

The role of the intestinal microbiota in the development of atopic disorders

ALLERGY, Issue 11 2007
J. Penders
The prevalence of atopic diseases, including eczema, allergic rhinoconjunctivitis and asthma, has increased worldwide, predominantly in westernized countries. Recent epidemiological studies and experimental research suggest that microbial stimulation of the immune system influences the development of tolerance to innocuous allergens. The gastrointestinal microbiota composition may be of particular interest, as it provides an early and major source of immune stimulation and seems to be a prerequisite for the development of oral tolerance. In this review the observational studies of the association between the gut microbiota and atopic diseases are discussed. Although most studies indicated an association between the gut microbiota composition and atopic sensitization or symptoms, no specific harmful or protective microbes can be identified yet. Some important methodological issues that have to be considered are the microbiological methods used (traditional culture vs molecular techniques), the timing of examining the gut microbiota, the definition of atopic outcomes, confounding and reverse causation. In conclusion, the microbiota hypothesis in atopic diseases is promising and deserves further attention. To gain more insight into the role of the gut microbiota in the etiology of atopy, large-scale prospective birth cohort studies using molecular methods to study the gut microbiota are needed. [source]

A promoter polymorphism in the CD14 gene is associated with elevated levels of soluble CD14 but not with IgE or atopic diseases

ALLERGY, Issue 5 2004
M. Kabesch
Background:, A polymorphism in the promoter region of the CD14 gene, C-159T, has been shown to be associated with increased levels of soluble CD14 (sCD14) and decreased serum immunoglobulin E (IgE) and the expression of a more severe atopic phenotype in previous studies. Methods:, To test if these associations are consistently found in different populations and different age groups, we genotyped 2048 children of different age groups as well as 888 adults from different regions of Germany for the CD14 C-159T polymorphism. Results:, While an association between this promoter polymorphism and levels of sCD14 could be confirmed in our study population (CC: 1017 ng/ml vs TT: 1370 ng/ml, P = 0.03), no association between CD14 C-159T genotypes and IgE levels or the prevalence of atopic diseases was seen. Conclusions:, The lack of association between CD14 genotypes and IgE as well as atopic outcomes in this large German study population seems to indicate that CD14 genotypes may not directly be involved in the development of allergies during childhood. [source]

Determinants of endotoxin levels in living environments of farmers' children and their peers from rural areas

CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2004
M. Waser
Summary Background Lower frequencies of asthma and hayfever have been observed in children with contact to livestock. At school age, the amount of endotoxin measured in the dust of children's mattresses is inversely related to the occurrence of atopic asthma, hayfever and atopic sensitization both in children from farming and non-farming households. Objective The aim of the present study was to investigate which home and lifestyle characteristics of farm and non-farm families contribute to endotoxin levels measured in different indoor home environments. Methods In the framework of the Allergy and Endotoxin (ALEX) Study, endotoxin was measured in dust samples from the living room floor and the child's mattress of 319 farmers' families and 493 non-farming families, and in settled dust from stables. Endotoxin content of all dust samples was determined by a kinetic Limulus assay (Limulus - Amebocyte -Lysate test). Information about the child's activities on farms, home characteristics and cleaning behaviours was obtained from parental questionnaires. Results Endotoxin levels in stables did not predict the amount of endotoxin measured in floors or mattresses. However, a dose-dependent association between the child's activity on the farm and indoor home endotoxin levels was observed, both in farm and non-farm children. In non-farm children pet keeping and the frequency of floor cleaning were additionally associated with endotoxin levels, whereas in farm children parental farm activities, study area, time since last cleaning, the mattress type as well as younger age of the children contributed to increased microbial exposure. Conclusion These results demonstrate that regular contact to farm animals increases indoor home endotoxin concentrations, both in farm and non-farm children, and might thus explain the protective effect of contact to livestock on atopic outcomes. To assess children's individual exposure to a microbial environment, measures of mattress dust exposure are needed as stable endotoxin concentrations were not associated with indoor home levels. [source]