Featured Research

from universities, journals, and other organizations

Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis

Date:
March 22, 2012
Source:
Brigham and Women's Hospital
Summary:
Medical professionals have suggested that the hygiene hypothesis explains the global increase of allergic and autoimmune diseases in urban settings. However, neither biologic support nor a mechanistic basis for the hypothesis has been directly demonstrated. Until now.

This concept of exposing people to germs at an early age (i.e., childhood) to build immunity is known as the hygiene hypothesis.
Credit: © Joanna Zielinska / Fotolia

Previous human studies have suggested that early life exposure to microbes (i.e., germs) is an important determinant of adulthood sensitivity to allergic and autoimmune diseases such as hay fever, asthma and inflammatory bowel disease.

Related Articles


This concept of exposing people to germs at an early age (i.e., childhood) to build immunity is known as the hygiene hypothesis.

Medical professionals have suggested that the hygiene hypothesis explains the global increase of allergic and autoimmune diseases in urban settings. It has also been suggested that the hypothesis explains the changes that have occurred in society and environmental exposures, such as giving antibiotics early in life.

However, neither biologic support nor a mechanistic basis for the hypothesis has been directly demonstrated. Until now.

Researchers at Brigham and Women's Hospital (BWH) have conducted a study that provides evidence supporting the hygiene hypothesis, as well as a potential mechanism by which it might occur.

The study was published online in the journal Science on the Science Express Web site on March 22, 2012.

The researchers studied the immune system of mice lacking bacteria or any other microbes ("germ-free mice") and compared them to mice living in a normal environment with microbes.

They found that germ-free mice had exaggerated inflammation of the lungs and colon resembling asthma and colitis, respectively. This was caused by the hyperactivity of a unique class of T cells (immune cells) that had been previously linked to these disorders in both mice and humans.

Most importantly, the researchers discovered that exposing the germ-free mice to microbes during their first weeks of life, but not when exposed later in adult life, led to a normalized immune system and prevention of diseases.

Moreover, the protection provided by early-life exposure to microbes was long-lasting, as predicted by the hygiene hypothesis.

"These studies show the critical importance of proper immune conditioning by microbes during the earliest periods of life," said Richard Blumberg, MD, chief for the BWH Division of Gastroenterology, Hepatology and Endoscopy, and co-senior study author, in collaboration with Dennis Kasper, MD, director of BWH's Channing Laboratory and co-senior study author. "Also now knowing a potential mechanism will allow scientists to potentially identify the microbial factors important in determining protection from allergic and autoimmune diseases later in life."

In light of the findings, the researchers caution that further research is still needed in humans.

This research was supported by the National Institutes of Health, Crohns Colitis Foundation of America, Harvard Digestive Diseases Center, Medizinausschuss Schleswig-Holstein, and Deutsche Forschungsgemeinschaft.


Story Source:

The above story is based on materials provided by Brigham and Women's Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Olszak, D. An, S. Zeissig, M. P. Vera, J. Richter, A. Franke, J. N. Glickman, R. Siebert, R. M. Baron, D. L. Kasper, R. S. Blumberg. Microbial Exposure During Early Life Has Persistent Effects on Natural Killer T Cell Function. Science, 2012; DOI: 10.1126/science.1219328

Cite This Page:

Brigham and Women's Hospital. "Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis." ScienceDaily. ScienceDaily, 22 March 2012. <www.sciencedaily.com/releases/2012/03/120322142157.htm>.
Brigham and Women's Hospital. (2012, March 22). Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis. ScienceDaily. Retrieved April 19, 2015 from www.sciencedaily.com/releases/2012/03/120322142157.htm
Brigham and Women's Hospital. "Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis." ScienceDaily. www.sciencedaily.com/releases/2012/03/120322142157.htm (accessed April 19, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, April 19, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Our Love Of Puppy Dog Eyes Explained By Science

Our Love Of Puppy Dog Eyes Explained By Science

Newsy (Apr. 17, 2015) — Researchers found a spike in oxytocin occurs in both humans and dogs when they gaze into each other&apos;s eyes. Video provided by Newsy
Powered by NewsLook.com
Dr. Oz Under Fire For 'Quack Treatments' Yet Again

Dr. Oz Under Fire For 'Quack Treatments' Yet Again

Newsy (Apr. 17, 2015) — Ten doctors signed a letter urging Columbia University to drop Dr. Oz as vice chair of its department of surgery, saying he plugs "quack" treatments. Video provided by Newsy
Powered by NewsLook.com
Scientists Find Link Between Gestational Diabetes And Autism

Scientists Find Link Between Gestational Diabetes And Autism

Newsy (Apr. 17, 2015) — Researchers who analyzed data from over 300,000 kids and their mothers say they&apos;ve found a link between gestational diabetes and autism. Video provided by Newsy
Powered by NewsLook.com
Video Messages Help Reassure Dementia Patients

Video Messages Help Reassure Dementia Patients

AP (Apr. 17, 2015) — Family members are prerecording messages as part of a unique pilot program at the Hebrew Home in New York. The videos are trying to help victims of Alzheimer&apos;s disease and other forms of dementia break through the morning fog of forgetfulness. (April 17) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins