By Nicholas Weiler, UCSF
A particular pattern of microbes living in a baby’s gut during its first month of life may directly impact the developing immune system, leading to a higher risk of allergies and asthma later in childhood, according to a study by researchers at UC San Francisco and the Henry Ford Health System in Detroit.
The findings highlight the importance of developing early interventions to improve microbial health in young infants.
The new paper, published Sept. 12, in Nature Medicine, shows that the gut microbes present in some one-month-old infants predict a three-fold higher risk of developing allergic reactions by age two and asthma by age four.
The paper demonstrates that the perturbed microbial ecosystem present in these at-risk babies produces molecules that reduce the abundance of a key type of immune cell known to help prevent allergy.
The researchers surmise that having fewer of these cells leads to a hyperactive immune system and eventually to chronic asthmatic inflammation of the lungs.
Co-senior author Susan Lynch, PhD, a UCSF associate professor of medicine, says she believes the discovery represents an opportunity to develop new treatments that could stave off allergies and asthma before they become established.
“If we are to prevent disease development, we need to intervene early,” Lynch said. “Currently, children are typically six or seven years old when they are diagnosed with asthma, which has no cure and has to be managed through medication. But if the genesis of the disease is visible as a disruption of gut microbiota in the very earliest stages of postnatal life, it raises an exciting question: could we reengineer the community of microbes in at-risk infants to prevent allergic asthma from developing?”
Numerous studies in recent years have tied early exposure to beneficial microbes in the environment to a host of positive health effects. Breast-feeding, vaginal births (as opposed to C-sections) and even having dogs in the household during the first year of life are all associated with protective effects against allergies and asthma.
Recently, researchers at the University of British Columbia reported that three-month-old infants with low levels of four key types of gut bacteria were significantly more likely to show early warning signs of asthma at their first birthdays than infants with normal levels of these bugs.
“We have been working for over a decade, trying to figure out why some children get asthma and allergies and some don’t,” said co-senior author Christine Cole Johnson, PhD, MPH, who is chair of public health sciences in the Henry Ford Health System. “It seems that the microbial communities within the body could be the keystone to understanding this and a number of different immune diseases.”
Since 2003, Johnson’s lab has been tracking a variety of early life risk factors for asthma in a racially and socio-economically diverse population of infants born in and around Detroit. In this study – the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study (WHEALS) – Henry Ford researchers conducted repeated follow-up appointments during the first year of life, then tested the infants for allergies at the age of twoand for asthma around their fourth birthdays.
For the rest of this article, go to www.ucsf.edu/news/2016/09/404071/newborn-gut-microbiome-predicts-later-allergy-and-asthma-study-finds