Exposure to dirt in childhood boosts immunity

Hygiene hypothesis that says exposing infants to germs in order to boost immunity has got reinforcement from a new study. Researchers of Brigham and Women's Hospital (BWH) have found evidence supporting this concept for the first time.

The researchers at the hospital studied the immune system of 'germ-free mice' and compared them to mice living in a real environment with microbes, reports the journal Science.

The researchers observed that 'germ-free mice' had exaggerated inflammation of the lungs and colon that appeared like asthma and colitis, respectively, caused by the hyperactivity of a unique class of T cells (immune cells).

These cells of immune system had been previously associated to these disorders in both mice and humans, a university statement says.

Apart from these, researchers found that exposure to the germ-free mice to microbes during their first weeks of life, but not when exposed later in adult life, resulted in a normal immune system and disease prevention.

In addition, the protection gained by early-life exposure to microbes was long-lasting, as prescribed by the hygiene hypothesis.

"These studies show the critical importance of proper immune conditioning by microbes during the earliest periods of life," Richard Blumberg, chief for the BWH Division of Gastroenterology, Hepatology and Endoscopy, and study co-author, working with Dennis Kasper, director of BWH's Channing Lab has been quoted as saying.

--with inputs from IANS