House dust mites may be the primary trigger for allergy-associated respiratory problems in tropical urban environments

July 30, 2014
House dust mites may be the primary trigger for allergy-associated respiratory problems in tropical urban environments
The house dust mite, a common but invisible presence in many homes, is a major trigger of allergic respiratory problems in Singapore. Credit: Eraxion/iStock/Thinkstock

City life can be an assault on the senses—quite literally, in the case of allergies. The steady increase in global urbanization is mirrored by a growing prevalence of allergy-associated respiratory problems. Potential triggers include insects, mold, pollen and animal hair, but now A*STAR researchers have uncovered a single culprit with a disproportionate role in allergy onset in tropical urban settings1.

Allergies arise when the body mounts an to a foreign molecule that it mistakenly perceives as a threat. Whenever the body encounters that trigger—for example, a pollen grain—it produces large numbers of antibodies against the trigger. The resulting can cause symptoms including asthma and rhinitis. Olaf Rotzschke and colleagues from the Singapore Immunology Network and De Yun Wang of the National University of Singapore began their study by surveying the antibody responses of 206 volunteers to a dozen common allergic triggers.

Remarkably, the great majority of these Singapore-born individuals responded to one particular antigen: the tiny found in many homes (see image). This trend remained clear even after the researchers expanded their cohort to look at a larger group of individuals. "According to our study, 80 per cent of Singaporeans respond to the mite, with roughly 40 per cent developing and 15 per cent developing asthma," says Rotzschke. "Globally these are among the highest figures reported so far."

The allergic reaction appears to be a consequence of the Singaporean urban environment. When the researchers examined newly arrived Chinese immigrants, fewer than 30 per cent mounted a strong antibody response against dust mites; in contrast, for immigrants who had lived in Singapore eight years or longer, the response rate was indistinguishable from lifelong Singapore residents. "This phenomenon of gradual acquisition of an allergic reaction has been shown in other countries for other allergens as well," explains Rotzschke. However, in temperate regions in Western countries, the most common allergic trigger is pollen, suggesting that this dust-mite-associated sensitization may be more characteristic of tropical cities like Singapore.

By identifying a single target, the findings could be used to provide relief to of allergy sufferers. But the existence of such a large population with a shared, strong response to a single antigen has broader implications for research as well, notes Rotzschke. "We are currently planning a functional analysis of immune pathways in combination with genome-wide genetic studies to better characterize the molecular and genetic basis of allergies," he says.

Explore further: New treatments for hay fever and house dust mite allergy successfully tested

More information: Andiappan, A. K., Puan, K. J., Lee, B., Nardin, A., Poidinger, M. et al. "Allergic airway diseases in a tropical urban environment are driven by dominant mono-specific sensitization against house dust mites." Allergy 69, 501–509 (2014). DOI: 10.1111/all.12364

Related Stories

Basis of allergic reaction to birch pollen identified

June 5, 2014

In Austria alone around 400,000 people are afflicted by a birch pollen allergy and its associated food intolerances. Why so many people have allergic reactions to birch pollen has still not been completely explained. It is ...

Recommended for you

Epigenomic changes are key to innate immunological memory

August 31, 2015

A research team led by Keisuke Yoshida and Shunsuke Ishii of the RIKEN Molecular Genetics Laboratory has revealed that epigenomic changes induced by pathogen infections, mediated by a transcription factor called ATF7, are ...

Team finds early inflammatory response paralyzes T cells

August 18, 2015

In a discovery that is likely to rewrite immunology text books, researchers at UC Davis have found that early exposure to inflammatory cytokines, such as interleukin 2, can "paralyze" CD4 T cells, immune components that help ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.