[Truncated abstract] The last few decades have witnessed an increase in the prevalence, morbidity and economic burden associated with asthma and allergic disease. This rising incidence cannot be completely explained by changes in genetic factors or by improvements in diagnostic procedures. Environmental factors, particularly those associated with a westernised lifestyle, are considered to be involved in this increase. In the late 1980’s Strachan was the first to link environmental factors with allergic disease, this theory became to be known as the ‘hygiene hypothesis’. This hypothesis links the “cleaner” more “healthy ” environment we now live in, with an increased risk of developing allergic disease. This effect is highlighted by studies linking farm and animal exposure (rich in microbial compounds) during early life with a decrease in allergic disease. Since then numerous studies have been undertaken to ascertain the factors present in the microbe rich environment, which elicit this protective effect. Many studies have revolved around endotoxin, however microbial components (mainly from Gram-positive bacteria) which signal through Toll-like receptor 2 (TLR2), have also shown that they can alter the allergic immune response. In mice models TLR2 has been shown to both exacerbate and inhibit allergic disease. The above research highlights the need for further studies into the effect of TLR2 ligands, and to define the mechanisms by which they exert their effects in human allergic disease. These mechanisms will be relevant to understanding the pathogenesis of allergy, but also might provide novel ways to treat allergy. The aims of the study outlined in this thesis were to determine whether in vitro exposure to TLR2 ligands could modify the established immune response to house dust mite allergen (HDM), and to examine the mechanisms by which this occurs. ... The addition of glucocorticoids to LTA enhanced the ability of this TLR2 ligand to inhibit IL-5 and IL-13 production by HDM-activated blood mononuclear cells. In conclusion, this study shows that TLR2 ligands have the ability to inhibit the Th2 response to mite allergen in previously sensitized individuals by an as yet unknown mechanism. However the findings described herein do provide an impetus for future studies designed to uncover novel mechanisms by which allergic responses can be ameliorated, and may open new treatment modalities.

House dust mites are a major source of allergens in house dust and, thus, the main trigger of perennial allergic respiratory diseases [1,2,3,4,5]. Scientific research on the life cycle, diet, and reproductive behavior of dust mites and on the biology of mite allergens has uncovered mechanisms leading to the development of respiratory allergies and suggests measures that can minimize exposure to dust mite allergens. Here, we discuss the evidence linking house dust mite exposure and respiratory allergies and present the efficacy of avoidance measures and their scientific evidence.

<p>The overall aims of our studies were to identify risk factors for respiratory symptoms and asthma in indoor environment but even to look at some personal risk factors such as body mass index and gastroesophageal reflux. The study population is based on participants of the European Community Respiratory Health Survey I and II. </p><p> In the first study, water damage and visible moulds were reported in 7.4% and 17% of the homes respectively. The combination of water damage and visible moulds was independently associated with attacks of breathlessness when resting and after activity and also to long term cough. In the second study, the prevalence of nocturnal GER increased with higher BMI and the same pattern could be seen for habitual snoring. Reported onset of asthma, wheeze and night-time symptoms increased in prevalence along with the BMI gradient. In the multivariable analysis, obesity and nocturnal GER were independent risk factors for onset of asthma, wheeze and night-time symptoms. Habitual snoring was an independent risk factor for onset of wheeze and night-time symptoms, but not for onset of asthma. In the third study, a total of 18% of the subjects reported indoor dampness in the last 12 months and 27% of the subjects reported indoor dampness since the previous survey. Respiratory symptoms and asthma were significantly more prevalent in individuals exposed to indoor dampness and indoor dampness was a risk factor for respiratory symptoms and asthma after adjusting for possible confounders. Indoor dampness was an independent risk factor for onset of respiratory symptoms but not for asthma onset. Remission of respiratory symptoms was less likely to occur if subjects reported indoor dampness. In the fourth study, the lowest prevalence of atopy and the lowest levels of all indoor allergens, bacteria and moulds were found in Iceland. A positive association was found, between cat allergen exposure and asthma symptoms and between bronchial hyperresponsiveness and the amount of viable mould in indoor air.</p>

The overall aims of our studies were to identify risk factors for respiratory symptoms and asthma in indoor environment but even to look at some personal risk factors such as body mass index and gastroesophageal reflux. The study population is based on participants of the European Community Respiratory Health Survey I and II. In the first study, water damage and visible moulds were reported in 7.4% and 17% of the homes respectively. The combination of water damage and visible moulds was independently associated with attacks of breathlessness when resting and after activity and also to long term cough. In the second study, the prevalence of nocturnal GER increased with higher BMI and the same pattern could be seen for habitual snoring. Reported onset of asthma, wheeze and night-time symptoms increased in prevalence along with the BMI gradient. In the multivariable analysis, obesity and nocturnal GER were independent risk factors for onset of asthma, wheeze and night-time symptoms. Habitual snoring was an independent risk factor for onset of wheeze and night-time symptoms, but not for onset of asthma. In the third study, a total of 18% of the subjects reported indoor dampness in the last 12 months and 27% of the subjects reported indoor dampness since the previous survey. Respiratory symptoms and asthma were significantly more prevalent in individuals exposed to indoor dampness and indoor dampness was a risk factor for respiratory symptoms and asthma after adjusting for possible confounders. Indoor dampness was an independent risk factor for onset of respiratory symptoms but not for asthma onset. Remission of respiratory symptoms was less likely to occur if subjects reported indoor dampness. In the fourth study, the lowest prevalence of atopy and the lowest levels of all indoor allergens, bacteria and moulds were found in Iceland. A positive association was found, between cat allergen exposure and asthma symptoms and between bronchial hyperresponsiveness and the amount of viable mould in indoor air.

Canine atopic dermatitis (CAD) is a common dermatosis, defined as a genetic-based disease, which predisposes to cutaneous inflammation and pruritus, mediated by class IgE immunoglobulins directed against specific antigens in most cases. Clinical diagnosis may be later complemented by skin allergic and/or serological tests (ELISA). The aim of these tests is to identify possible allergens in order to enable the clinicians to select candidate antigens for allergen specific immunotherapy. This work aimed to identify the sensitization profile of 58 dogs with atopic dermatitis diagnosis. All animals were submitted to intradermic test (IDT) and screened for the presence of antibodies against different allergens using a serologic test. House dust mites are described as the most frequent allergens in all continents. However, the positivity to C. dactylon is not commonly described and may be characteristic for the region. With this work it was possible to identify the main allergens involved in the immunologic response of atopic dogs residing in Rio Grande do Sul, pointing to the importance to include C. dactylon in screening tests for allergy. / A dermatite atópica canina (DAC) é uma dermatose comum, definida como uma doença de cunho genético que predispõe à inflamação e ao prurido cutâneo, mediada por imunoglobulinas da classe IgE dirigidas contra antígenos específicos na maior parte dos casos. O diagnóstico da DAC é clínico e pode ser posteriormente complementado por testes alérgicos cutâneos e/ou sorológicos. O objetivo desses testes é identificar possíveis alérgenos e, com isso, possibilitar ao clínico a seleção de antígenos candidatos para a imunoterapia alérgeno-específica. No presente trabalho buscou-se identificar o perfil de sensibilização de 58 cães diagnosticados com dermatite atópica. Todos os animais foram submetidos ao teste intradérmico (TID) e à detecção de anticorpos específicos para diferentes alérgenos através de teste sorológico (ELISA). Os ácaros domiciliares são descritos como os alérgenos mais frequentes em todos os continentes. Entretanto, a positividade ao C. dactylon não é usualmente descrita e pode ser característica da região. Com esse trabalho foi possível identificar os principais alérgenos envolvidos na resposta imunológica de cães atópicos residentes no Rio Grande do Sul, ressaltando-se a importância da inclusão do extrato de C. dactylon em testes alérgicos.

Indoor air quality is described as the chemical, physical and biological characteristics of air in a residential or occupational indoor environment. In residential settings, there are many contributions to indoor pollution levels namely; human activities, biological sources and outdoor air. There has been increased focus on house dust due to its potential to contain biological and chemical pollutants in indoor environments. These have the potential to cause harm to human health. The purpose of this study was to conduct toxicological analysis of house dust collected from inside selected Durban residential buildings. The objectives of this study were to isolate, identify and quantify mould occurrence in house dust samples; to measure the occurrence of heavy metals (arsenic, lead and mercury) in house dust; and to analyse the cytotoxicity of house dust on human lung bronchus carcinoma epithelial line (A549) and human lung bronchus virus transformed epithelial cell line (BBM). One hundred and five house dust samples were obtained from households that participated in the South Durban Health Study. In each home, a sample of settled dust was collected, using standardized protocols, then sieved and individually packed into polystyrene bags. The samples were taken from three surface areas namely; living room couches, bed mattresses, and carpets. Well documented methods were used for the isolation, identification and quantification of mould. The samples for heavy metals analysis were sent to Umgeni Water (chemistry laboratory, Pietermaritzburg) where standardised methods were used. Human cell lines were treated with five different dilutions of each house dust extract. Cell viability was assessed using the MTT assay. Toxic effects of house dust extract were analyzed, following house dust extract treatment and cells were stained with double dye (annexin-V- and propidium iodide) and analysed with flow cytometry, and fluorescent microscope. Cytokines were analysed by Microbionix (Neuried, German) using a Luminex®100 plate reader for multiplex human cytokines analysis. There were (n=128) mould types isolated and (n=105) were identified, of which (n=10) were predominately isolated moulds. This was further confirmed by Allerton Provincial Laboratory in Pietermaritzburg. Among the isolated genera in all three surface areas, Rhizopus spp and Penicillium spp were widely distributed throughout surface areas in greater proportion. The overall highest mean which was reported in this study and expressed in colony forming unit per gram (CFU/g) for Penicillium spp ranged (3400 - 62316 CFU/g) obtained from living room couches, followed by Rhizopus spp (5200 - 15990 CFU/g). The mould results were compared with the South African Occupational Health and Safety Act (OHSA) 85 of 1993 as amended suggested guidelines of 1,000, 000 CFU/g. The findings of this study suggest the moulds in the homes studied were below the suggested guideline. However, this does not imply that the indoor conditions are unsafe or hazardous. Instead, the findings act as an indicator of moulds presence indoors. The type of airborne mould, its concentration and extent of exposure and the health status of the occupants of a building will determine the health effects on an individual. Heavy metals were detected in the dust in the following ascending order: arsenic (As) ranged from 1.3 ug/g -18.4 ug/g (mean, 4.26 ug/g), lead (Pb) ranged from 28.0 - 872 ug/g (mean 171.66 ug/g), and mercury (Hg) ranged from 0.6 -19.0 ug/g (mean, 2.22 ug/g). The mean concentration of lead in the dust was within the range of Canadian National Classification guidelines on residential contamination (500 ug/g). There was numerous numbers of samples in this study that exceeded these guidelines. The mean concentration of arsenic was within residential soil guidelines (20 ug/g). Mercury was within limits when compared with Global Hg project guidelines of soil/residential (6.6 ug/g), thought some of samples were notably above this mean. The ability of house dust extract to lower the cell viability which was slightly above 80% (prior treatment) to less than 50% (post treatment) in both cells was observed in this study. The findings in this study showed that dust extract are toxic to human cell lines, and cells undergone a degree of apoptosis and necrosis 62% (A549) and 99% (BBM). The cytokines serve an important role in the non-specific defence external against insults. It was observed that A549 cells up-regulated the release of IL-6 and IL-8 pro-inflammatory cytokines and under-regulated the release of other cytokines analysed (IL-4, IL-13, and TNF-a). BBM cells released IL-4, IL-8 and IL-13 within limit of detection. The presence of moulds in these sampled indoor household dusts, which is comparable with findings elsewhere indoors, show that moulds act as an indicator for building conditions such as dampness, which supports mould growth. Individuals, whether they are sensitized or not, may develop allergic reactions towards spores, thus the elevated numbers of spores quantified in this study are of concern. Some of the heavy metals reported in this study were higher or marginally higher than international norms and guidelines. The findings in this study strongly suggest that house dust extract is toxic to human lung cell lines. It must be noted, however, that this study may not reflect all that happens when a human lung is exposed to house dust. The findings of this study could contribute to the development of South African indoor air guidelines. In conclusion further study needed to be undertaken with respect to air pollution disease such as allergic; the reason being this study shown the reduced expression of cytokines that are involved in allergic inflammation. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2009.

Notre volonté d'économiser l'énergie nous pousse à vivre dans un environnement confiné favorisant les acariens et les micro-organismes. L'objectif de la thèse est de caractériser la contamination en acariens et en micro-organismes des logements de patients présentant des pathologies respiratoires, d'évaluer l'influence des interactions acariens/moisissures sur l'exposition aux allergènes et de comprendre les facteurs favorisant la pollution biologique de l'air intérieur. Afin de disposer d'un outil commun aux acariens et aux micro-organismes, un modèle innovant de quantification des acariens pas qPCR a été mis au point. Les acariens de stockage sont sous-estimés et les mesures d'éviction doivent être appliquées à l'ensemble de l'habitat. L'observation des interactions acariens/moisissures a montré une vraie relation symbiotique: dispersion des moisissures et apports des nutriments essentiels aux acariens. La contamination des logements de producteurs laitiers atteint de BPCO a été comparée à celle de producteurs laitiers sains, de patients BPCO non­-agriculteurs et de sujets sains non-agriculteurs. L'exposition agricole est abondante et spécifique à certains micro­organismes caractéristiques de la ferme et la sensibilité IgG à Wallemia sebi est spécifique des producteurs laitiers BPCO Le suivi de l'impact du compostage sur la qualité biologique de l'air intérieur a démontré une augmentation des concentrations en acariens de stockage et certaines moisissures circonscrite au bio-seau. De nouveaux indicateurs communs aux acariens, aux moisissures et aux bactéries devraient nous permettre de progresser dans la détermination de la relation dose/effet. / Our will to save energy leads us to live in a confined environment providing the ideal conditions to mites and microorganisms development. The aim of the thesis is to characterize mites and microorganisms contamination of dwellings from patients suffering respiratory diseases, to estimate the influence of the interactions between various organic communities on the allergens exposure and to understand the factors increasing the biological pollution ofindoor air. To evaluate our exposition, we needed to quantify mites and microorganisms with a common tool and an innovative quantification mode! of domestic mites by qPCR was developed. The presence of storage mites is overemphasized in dwellings of allergie patients and the eviction measures of mites should be applied into any rooms of dwellings. The contamination of dairy fanners' dwellings suffering from COPD was compared with that ofhealthy dairy fanners, COPC patients non-farmers and healthy non-fanners. In dwellings, the dairy fanners' exposure was important and specific ofth1 fanning environment. The lgG sensitivity to Wallemia sebi was significantly specific of dairy fanners suffering from COPD. The impact of the composting on the biological air quality was evaluated and the concentrations in storage mites and some molds increased significantly only in a confined area around the waste bin. New common indicators of domestic mites, molds and bacteria should allow us to progress in the determination of the dose-response relationship for the different allergens and their possible synergie effects.