Exposure and sensitization to dust mite allergens among asthmatic children in Sao Paulo, Brazil

Abstract

A group of 20 mite allergic asthmatic children aged 6-12 years old, living in São Paulo, Brazil, was studied regarding their degree of sensitization to house dust mites and exposure to mite allergens in their homes. In 18 out of 20 houses at least one dust sample was obtained which contained greater than 10 micrograms Der p I/g of dust. The highest levels of Dermatophagoides pteronyssinus allergens, Der p I and Group II, were measured in bedding samples (geometric mean 38.4 and 36.6 micrograms/g, respectively), followed by bedroom floor, TV room and kitchen. Mite allergen levels in Brazilian houses were as high as those reported to be associated with sensitization and acute attacks of asthma in other parts of the world. In keeping with previous reports that D. farinae is rarely found in Brazil, Der f I was undetectable or found in very low levels (less than 0.5 micrograms/g). Levels of cat allergen Fel d I of greater than 8 micrograms/g of dust were obtained only in 2 houses only. Cockroach allergen Bla g I was detected in five out of 20 houses. Levels of IgE antibodies to D. pteronyssinus were greater than 200 RAST U/ml in 19 out of 20 children (geometric mean 1588 RAST U/ml). IgE antibodies to cat, cockroach, A. fumigatus, ragweed and rye grass pollens were undetectable or less than 80 RAST U/ml. IgE antibodies to the mite Blomia tropicalis were also measured, and levels greater than 200 RAST U/ml were observed in 13 out of 20 sera.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of damp and mould in the home on respiratory health: a review of the literature

“…It has been suggested that mechanical ventilation may have a major effect on indoor climate in cold regions but is unlikely to be effective in regions which have a humid outdoor climate for a significant part of the year (22,23). The finding that beds have higher Der p 1 levels than floors (12,24) and that bed, but not floor, levels arc associated with the severity of airway hyperresponsiveness (3) suggests that the microclimate that influences allergen exposure from beds may be more relevant to respiratory health than that which influences exposure from floors.…”

Assessment of personal and community-level exposures to particulate matter among children with asthma in Detroit, Michigan, as part of Community Action Against Asthma (CAAA).

“…Considerable research evidence suggests that both indoor and outdoor environmental exposures may be involved in the worldwide increase in asthma (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Some of the strongest associations have been found with indoor allergens such as dust mite and cockroach in children sensitized to that particular allergen (24)(25)(26)(27)(28)(29)(30)(31)(32). Exposure to environmental tobacco smoke, both in utero (15,19) and during childhood (17,18,20), also appears to play an important role in asthma causation and aggravation.…”

Intranasal sensitization with Blomia Tropicalis antigens induces allergic responses in mice characterized by elevated antigen-specific and non-specific serum ige and peripheral blood eosinophil counts

“…The mite has been ubiquitously found in common houses in tropical and subtropical areas 1,2,7,10,21,23 . Although there have been a few reports indicating the scarce distribution of the genus Blomia in mainland of Japan 18,20 , the authors and other investigators have recently reported that B. tropicalis is one of the major mite species found in Okinawa, a subtropical prefecture of Japan 14,26,27 .…”