<p>The aim was to study the prevalence of asthma, eczema, allergy and respiratory symptoms among pupils in Shanxi province, China, in relation to home and school environment and outdoor air pollution. In one study there was a low prevalence of self-reported asthma, eczema and pollen or pet allergy among pupils (9-20y). Rural childhood and consumption of fruit and fish were negatively associated with asthma or allergy, while current urban residency and consumption of hamburgers tended to be risk factors. In another study in junior high school pupils, similar low prevalence of asthma and allergy was found. Compared with pupils at the same age in Uppsala, Sweden, asthma and allergy were less common while daytime attacks of breathlessness were more common in Chinese pupils. Parental asthma or allergy was a predictor of asthma symptoms. Factors in the home environment such as new floor, new furniture and ETS exposure were risk factors for asthma symptoms. Crowdedness, dust amount, CO₂, temperature and air humidity were negatively associated with respiratory symptoms. Microbial chemical components like muramic acid and ergosterol, markers for bacteria and fungi, were negatively associated with wheeze or daytime attacks of breathlessness. The associations with endotoxin varied depending on the length of 3-hydroxy fatty acids of the lippopolysaccharides (LPS). Among outdoor air pollutants, SO₂ and formaldehyde were positively associated with asthma symptoms or respiratory infections. In addition, indoor SO₂, NO₂ and formaldehyde were positively associated with asthma symptoms and respiratory infections. In conclusion, rural childhood and dietary factors can be protective for asthma and allergy. ETS and chemical emissions from new material at home can be risk factors for asthmatic symptoms. In the school environment, factors of indoor origin seemed to be generally protective for respirator symptoms while factors of outdoor origin seemed to be risk factors.</p>

The aim was to study the prevalence of asthma, eczema, allergy and respiratory symptoms among pupils in Shanxi province, China, in relation to home and school environment and outdoor air pollution. In one study there was a low prevalence of self-reported asthma, eczema and pollen or pet allergy among pupils (9-20y). Rural childhood and consumption of fruit and fish were negatively associated with asthma or allergy, while current urban residency and consumption of hamburgers tended to be risk factors. In another study in junior high school pupils, similar low prevalence of asthma and allergy was found. Compared with pupils at the same age in Uppsala, Sweden, asthma and allergy were less common while daytime attacks of breathlessness were more common in Chinese pupils. Parental asthma or allergy was a predictor of asthma symptoms. Factors in the home environment such as new floor, new furniture and ETS exposure were risk factors for asthma symptoms. Crowdedness, dust amount, CO2, temperature and air humidity were negatively associated with respiratory symptoms. Microbial chemical components like muramic acid and ergosterol, markers for bacteria and fungi, were negatively associated with wheeze or daytime attacks of breathlessness. The associations with endotoxin varied depending on the length of 3-hydroxy fatty acids of the lippopolysaccharides (LPS). Among outdoor air pollutants, SO2 and formaldehyde were positively associated with asthma symptoms or respiratory infections. In addition, indoor SO2, NO2 and formaldehyde were positively associated with asthma symptoms and respiratory infections. In conclusion, rural childhood and dietary factors can be protective for asthma and allergy. ETS and chemical emissions from new material at home can be risk factors for asthmatic symptoms. In the school environment, factors of indoor origin seemed to be generally protective for respirator symptoms while factors of outdoor origin seemed to be risk factors.

Allergic diseases are influenced by genetics and the environment. Maternal allergy appears to confer a higher risk for allergic sensitization than paternal allergy, suggesting an in utero influence. A decrease in particular infections or a lower exposure to microbial components during infancy is suggested to contribute to the high allergy prevalence in affluent societies. Toll-like receptors (TLR) 2 and 4 recognize peptidoglycan (PGN) and LPS respectively, are expressed on e.g. monocytes, and have been implicated in modulating the risk of IgE-sensitization. This thesis aimed to study the influence of maternal allergy and early microbial exposure on monocyte function and allergic sensitization during childhood. Blood samples from children participating in a prospective allergy cohort were used. Two-year old infants with allergic mothers had lower IL-6 production and reduced activation of the TLR-signalling intermediate p38-MAPK in response to PGN than children with non-allergic mothers. In 5-year old children, allergic disease and not maternal allergy influenced monocytic TLR2-regulation. Five-year olds who were seropositive for Epstein-Barr virus (EBV) at 2-years of age had a lower risk of persistent IgE-sensitization while EBV contraction after 2-years of age related to a higher risk of IgE-sensitization. Upon in vitro stimulation, NK cells from EBV+ 2-year olds produced lower IFN-g levels. EBV+ 2-year olds had also lower systemic IFN-g. In comparison to CD14++CD16- monocytes, CD14+CD16+ cells induced NK-cell IFN-g more potently in vitro, and EBV+ infants tended to have lower proportions of these CD14+CD16+ monocytes. This thesis highlights the importance of early-life microbial (EBV) exposure for a proper allergy-protective immunity. Also, maternal allergic heredity appears to influence monocytic microbial responses in early infancy. All these aspects relate to altered monocyte functionality, which suggest that they could have a role in allergic sensitization.