North American children may be 'too clean'

Oct 29 2010

Rising levels of allergic asthma and eczema in North American children have Canadian scientists wondering if there is such a thing as being "too clean." "We see auto-immune diseases like asthma and eczema increasing rapidly in North American children, but we don't see the same effect in children in the developing world," says Dr. B. Brett Finlay, a Professor in the Michael Smith Laboratories at the University of British Columbia.

This has led Dr. Finlay to embark on a new project called the Impact of the Microbiota on Immune Development and Disease that will look at microbiota (a kind of bacteria or microorganism that lives in or on our body) and its potential link to auto-immune illnesses in children. Scientists will look at the increasing evidence that intestinal microbiota, the bacteria that live in our gut, has an impact on immune development and disease, including asthma and eczema.

"The so-called 'hygiene hypothesis' is the idea that we are killing off good bacteria along with bad bacteria with some of our habits, whether it is bleaching countertops or antibiotic use in early childhood," says Finlay. "If these intestinal bacteria play a role in preventing auto-immune diseases, then our desire to be ultra-clean may mean that kids aren't getting the bacteria they need to have strong immune systems later in life."

Finlay has assembled an interdisciplinary team to study the intestinal microbiota. Sequencing the microbiota populations should allow researchers to identify the various types that are living in the gut. The team will then examine mice models and track the health development of young Canadian children enrolled in the Canadian Healthy Infant Longitudinal Development Study (CHILD) in order to both better understand the role microbiota plays in the immune system, and ultimately find new information to treat asthma and other illnesses.

"It's the kind of sensitivity that genomics can bring to revealing the complex nature of our immune system that makes projects like this one so exciting," says Dr. Alan Winter, President and CEO of Genome BC, one of the funders of the project. "This type of project has relevance on an international scale, so we are excited to see BC researchers once more taking a leading role on such a critical issue."

The five year project is funded in part by the Canadian Institutes of Health Research (CIHR) and Genome BC, each contributing $1.875 million and $625,000 respectively. The initiative is part of the Canadian Microbiome Initiative, which was created to provide an opportunity for Canadian researchers to contribute to international efforts to gain an understanding of the role of the human microbiome in health and disease. The goal will be to gain a genetic understanding of the bacteria that lives in and on the human body, specifically those found orally, on the skin, the gut, nasal/lung and vaginally.

The project team includes Dr. Kelly McNagny, who looks at asthma in mice, Dr. William Mohn, a microbial ecologist, Dr. Tobias Kollman who studies pediatric infectious diseases and is a clinician and developmental immunologist, Dr. Richard Moore who specializes in genome sequencing, Dr. Stuart Turvey, a pediatric immunologist and CHILD Co-PI and Dr. Kieran O'Doherty, an applied ethicist. The data created from the project will be used in the CHILD longitudinal study, which will look at immune analysis based on samples taken from children from birth until one year of age.

Source: http://www.genomebc.ca/