Exposing infants to indoor molds strengthens their immune systems

Environmental health scientists at the University of Cincinnati (UC) have confirmed what scientists have till now suspected - that early-life exposure to certain indoor fungal components (molecules) can help build stronger immune systems, and may protect against future allergies.

Washington, May 1 : Environmental health scientists at the University of Cincinnati (UC) have confirmed what scientists have till now suspected - that early-life exposure to certain indoor fungal components (molecules) can help build stronger immune systems, and may protect against future allergies.

The UC team found that infants who were exposed to high levels of indoor fungal components-known as fungal glucans-were nearly three times less likely to wheeze compared with infants exposed to low levels.

Study lead author and environmental health scientist Yulia Iossifova says exposure to high levels of these molecules may also protect against allergy development in high-risk infants.

"The immune system's protective effects only appear to occur when there are high levels of microbial exposure. Cleaner environments do not have enough microbial components to trigger the immune system response," Iossifova said.

This epidemiological study is the first to suggest that early-life exposure to high levels of indoor fungal glucans can have a positive impact on the human immune system.

"Fungi are a diverse group of microorganisms, so species differ in their glucan content and allergenic proteins. Some fungi also contain mycotoxins that can contribute to disease," adds Tiina Reponen, PhD, professor of environmental health and corresponding author of the study.

"Exposure to indoor molds during infancy may be associated with respiratory symptoms, such as persistent coughing and wheezing,"he said.

The UC-led team analyzed the effects of microbial exposures to both fungal glucans and endotoxins in infants.

Scientists said early-life exposure to common microbial components-like bacterial endotoxins and fungal glucans-can stimulate the body's immune system to produce infection- and allergy-fighting substances. Iossifova said that people should avoid overusing antibacterial sprays and soaps to clean their bodies and homes.

"Certain microbes can have helpful affects in the body," she explains, "but antibacterial disinfectants can't discriminate between helpful and harmful microbes-they destroy them all," Iossifova said.

"This eliminates the natural competition among bacteria and fungi, so the surviving microbes are often the infectious ones that can develop resistance to drugs designed to eliminate them.," she said

Iossifova said further research is needed to determine how early microbial exposures affect the development of certain allergic conditions-including asthma, dermatitis and hay fever-later in life.

The UC team reports their findings in the May 2007 edition of the scientific journal Allergy.

ANI