Academic literature on the topic 'Environmental sensitisation'

IntroductionAllergic sensitisation to fungi such as Aspergillus are associated to poor clinical outcomes in asthma, bronchiectasis and cystic fibrosis; however, clinical relevance in COPD remains unclear.MethodsPatients with stable COPD (n=446) and nondiseased controls (n=51) were prospectively recruited across three countries (Singapore, Malaysia and Hong Kong) and screened against a comprehensive allergen panel including house dust mites, pollens, cockroach and fungi. For the first time, using a metagenomics approach, we assessed outdoor and indoor environmental allergen exposure in COPD. We identified key fungi in outdoor air and developed specific-IgE assays against the top culturable fungi, linking sensitisation responses to COPD outcomes. Indoor air and surface allergens were prospectively evaluated by metagenomics in the homes of 11 COPD patients and linked to clinical outcome.ResultsHigh frequencies of sensitisation to a broad range of allergens occur in COPD. Fungal sensitisation associates with frequent exacerbations, and unsupervised clustering reveals a “highly sensitised fungal predominant” subgroup demonstrating significant symptomatology, frequent exacerbations and poor lung function. Outdoor and indoor environments serve as important reservoirs of fungal allergen exposure in COPD and promote a sensitisation response to outdoor air fungi. Indoor (home) environments with high fungal allergens associate with greater COPD symptoms and poorer lung function, illustrating the importance of environmental exposures on clinical outcomes in COPD.ConclusionFungal sensitisation is prevalent in COPD and associates with frequent exacerbations representing a potential treatable trait. Outdoor and indoor (home) environments represent a key source of fungal allergen exposure, amenable to intervention, in “sensitised” COPD.

ObjectivesLittle is known about risk factors for new onset and loss of atopic sensitisation in adulthood. The aim is to examine the longitudinal effect of quantitatively assessed endotoxin exposures on changes in specific allergen sensitisation in young adults.MethodsThe cohort consisted of 1113 young Danish farmers and rural controls, with a mean age of 19 years at baseline. Sensitisation to birch pollen, grass pollen, cat dander and house dust mite was measured by specific IgE levels in serum samples from baseline and at 15 years’ follow-up. Changes in sensitisation were analysed in relation to cumulative endotoxin exposure during follow-up, considering early life farm exposure.ResultsEndotoxin exposure during follow-up was significantly associated with less new onset of specifically grass and birch pollen sensitisation. For the highest versus lowest quartile of cumulative endotoxin exposure, the OR for new-onset IgE sensitisation was 0.35 (0.13–0.91) for birch and 0.14 (0.05–0.50) for grass. On the other hand, loss of pollen sensitisation showed a positive, although mostly non-significant, association with increased levels of endotoxin exposure. Endotoxin exposure was not associated with significant changes in cat dander and house dust mite sensitisation.ConclusionsHigh exposure to endotoxin during young adulthood appears to protect against new onset of pollen sensitisation, independent of childhood farm exposure.

Few biological theories of manic-depressive illness have focused on the longitudinal course of affective dysfunction and the mechanisms underlying its often recurrent and progressive course. The authors discuss two models for the development of progressive behavioural dysfunction—behavioural sensitisation and electrophysiological kindling—as they provide clues to important clinical and biological variables relevant to sensitisation in affective illness. The role of environmental context and conditioning in mediating behavioural and biochemical aspects of this sensitisation is emphasised. The sensitisation models provide a conceptual approach to previously inexplicable clinical phenomena in the longitudinal course of affective illness and may provide a bridge between psychoanalytic/psychosocial and neurobiological formulations of manic-depressive illness.

This study was performed to induce atopic dermatitis (AD) using nongenetically predisposed Beagle dogs. Five healthy Beagle dogs were used. Twice weekly for 12 weeks, the dogs were painted on the axillae and groin with a solution of Dermatophagoides farinae (D. farinae). Each dog was thereafter placed in a cage where a house dust mite (HDM) solution was applied on the bottom of the cage. The dog remained in the cage for 3 h daily for 3 consecutive days for the environmental exposure to HDM. Serum samples were collected at 0 week and 6 weeks after sensitisation, and at 0 h and 72 h after the environmental exposure. During the environmental exposure, skin biopsies were obtained at 0 h, 36 h, and 72 hours. After the first environmental exposure, no dog had any marked clinical sign. An additional sensitisation was subsequently administered for 10–13 weeks. Three of the five dogs developed pruritic dermatitis with skin lesions after the second exposure. The histopathology of the lesions revealed severe infiltration of inflammatory cells and dermal oedema. The levels of D. farinae-specific IgE were also elevated. This study demonstrated that AD could be induced by epicutaneous sensitisation with HDM in nongenetically predisposed dogs.

IntroductionWe evaluated a classroom-based sensitisation intervention that was designed to reduce demand-side barriers affecting referrals to a school counselling programme. The sensitisation intervention was offered in the context of a host trial evaluating a low-intensity problem-solving treatment for common adolescent mental health problems.MethodsWe conducted a stepped-wedge, cluster randomised controlled trial with 70 classes in 6 secondary schools serving low-income communities in New Delhi, India.The classes were randomised to receive a classroom sensitisation session involving a brief video presentation and moderated group discussion, delivered by a lay counsellor over one class period (intervention condition, IC), in two steps of 4 weeks each. The control condition (CC) was whole-school sensitisation (teacher-meetings and whole-school activities such as poster displays). The primary outcome was the proportion of students referred into the host trial. Secondary outcomes were the proportion of students who met mental health caseness criteria and the proportion of self-referred adolescents.ResultsBetween 20 August 2018 and 9 December 2018, 835 students (23.3% of all students) were referred into the host trial. The referred sample included 591 boys (70.8%), and had a mean age of 15.8 years, SD=0.06; 194 students (31.8% of 610 with complete data) met mental health caseness criteria. The proportion of students referred in each trial conditionwas significantly higher in the IC (IC=21.7%, CC=1.5%, OR=111.36, 95% CI 35.56 to 348.77, p<0.001). The proportion of self-referred participants was also higher in the IC (IC=98.1%, CC=89.1%, Pearson χ2 (1)=16.92, p<0.001). Although the proportion of referred students meeting caseness criteria was similar in both conditions (IC=32.0% vs CC=28.1%), the proportion weighted for the total student population was substantially higher in the IC (IC=5.2%, CC=0.3%, OR=52.39, 95% CI 12.49 to 219.66,p<0.001).ConclusionA single, lay counsellor-delivered, classroom sensitisation session increased psychological help-seeking for common mental health problems among secondary school pupils from urban, low-income communities in India.Trial registration numberNCT03633916.

HISTORICAL PERSPECTIVE: It has recently been shown that intensive prophylactic dietary and environmental control measures during early infancy may reduce the incidence and/or postpone the onset of atopic disease. In order to institute this prophylactic regime, early identification of the infants genetically "at risk" for atopic disease is essential, since sensitisation begins at birth, or even during intra-uterine life. European and Scandinavian studies have shown that a raised concentration of cord blood serum immunoglobulin E (CBsIgE) is an excellent predictive marker for the subsequent development of atopic disease. Other potential predictive atopic markers such as cord blood eosinophils, platelets and anti-cow's milk serum IgG have also been suggested as having possible predictive relevance for newborns in terms of the development of subsequent atopic disease. PROBLEM DEFINITION: Most of the work in this field has been done on Caucasian neonates, in Westernised, First World countries. In South Africa, it has been shown that the Black adult ethnic group has serum immunoglobulin E concentrations (sIgE) which are significantly higher than that found in the South African White adult ethnic group. Furthermore, it has been suggested that the elevated sIgE in the adult Blacks may be raised independently of allergic disease. It is, therefore, important to ascertain whether this elevation of sIgE in Black South African adults is evident already at birth in the cord blood sera of Black South African newborns. If so, it is imperative to ascertain whether any such elevation is reflective of a high genetic load for atopy in these Black newborns, and furthermore whether these Black newborns are consequently "high-risk" for the development of subsequent atopic disease, as has been previously reported in the literature for White newborns. Arising from an awareness of these specific South African problems, the following hypothesis was developed. HYPOTHESIS: The hypothesis states that: "Black South African newborns without an atopic family history (aFH) have significantly higher CBslgE values than similar White and Mixed newborns. An aFH does not influence the CBsIgE values in the Black newborns, as it does in the White and Mixed newborns. The CBsIgE values in Black newborns are not, furthermore, predictive for the development of subsequent atopy in infancy, as they are in the other ethnic groups". A description of the three South African ethnic groups considered in this study is provided in Section IV, (Pg. 74). AIMS OF THE STUDY: The aims of the study were three-fold: 1. To test the hypothesis. 2. To assess the relevance of alternative cord blood markers (eosinophils, platelets and anti-cow's milk serum IgG) as predictive atopic markers in each of the three ethnic groups. 3. To provide epidemiological information with regard to genetic and environmental influences on CBslgE, cord blood total eosinophil counts (CBTEC's) cord blood platelet counts (CBPlC's) and cord blood anti-cow's milk serum IgG concentrations (CBacmlgG).