Features

Michael Glenwood

Asthma's Inner World (continued)

A Proof of Concept

Wills-Karp’s findings demonstrate something that no scientist has shown before, says Richard Markham, MD, a Bloomberg School professor of Molecular Microbiology and Immunology and an expert in sequencing technology essential to much microbiome research.

“They suggest for the first time that the presence of a single species of bacteria has influence on whether an individual can develop asthma,” he says.

Markham and Wills-Karp add that asthma may not be the only disease that follows this pattern. Th17 cells have also been associated with arthritis, multiple sclerosis, Crohn’s disease and other autoimmune conditions. The microbiota may underlie those diseases as well.

Her results, says Wills-Karp, “are proof of concept.” One big unknown is whether the human disease truly does parallel the mouse pattern. Patients with severe asthma do have elevated levels of Th17 cells, scientists have found. But no one has shown that the clostridia-related bacteria underlie those cases.

“our purest, sweet necessity: the air.”
—Mary Oliver

Wills-Karp is starting to address this question in a study with Stacey Burgess, PhD, a former student and now an infectious disease researcher at the University of Virginia. The pair will examine whether the clostridia-related bacteria are more prevalent in children with asthma. This and Wills-Karp’s other studies could help guide the way toward new asthma treatments—perhaps a drug that dampens or eliminates the clostridia-related bacteria or a new and improved probiotic.

Of course, preventing asthma in the first place would be even better. Here, too, growing knowledge about the microbiome might offer some guidance. Research implies that microbially rich environments reduce asthma risk. So does it make sense to raise your kids on a farm or simply not wash off the pacifier after it falls on the floor, five-second rule or no? The New York Times Magazine recently ran a story on  the microbiome; the opening photo showed a baby slathered in mud, mouthing a  grimy toy car that was clenched in a dirt-encrusted fist.

Wills-Karp won’t go so far as to endorse muddy playtime, although she observes that there is an evolutionary argument to be made for this practice: “Kids when they are young touch everything and put it all in their mouths. Maybe there’s a reason for that.” She would, however, advise germ-phobic parents to temper their fear, saying, “I would tell parents not to go overboard with the hand sanitizers. Babies do need some kind of exposure to the environment.’”

Greater understanding of the microbiome’s role in asthma may help scientists refine such prevention strategies, as well as develop new treatments for those already afflicted. The microbiota may contribute a little or a lot to asthma, says Wills-Karp. “We don’t yet know. Microbiome research is in the early stages.”

The microbiome mystery continues.