Why Does Flu Trigger Asthma?
Study suggests new therapeutic targets for virally-induced asthma attacks
BOSTON, May 29, 2011 /PRNewswire-USNewswire/ — When children with asthma get the flu, they often land in the hospital gasping for air. Researchers at Children’s Hospital Boston have found a previously unknown biological pathway explaining why influenza induces asthma attacks. Studies in a mouse model, published online May 29 by the journal Nature Immunology, reveal that influenza activates a newly recognized group of immune cells called natural helper cells – presenting a completely new set of drug targets for asthma.
If activation of these cells, or their asthma-inducing secretions, could be blocked, asthmatic children could be more effectively protected when they get the flu and possibly other viral infections, says senior investigator Dale Umetsu, M.D., Ph.D., of Children’s Division of Immunology.
Although most asthma is allergic in nature, attacks triggered by viral infection tend to be what put children in the hospital, reflecting the fact that this type of asthma isn’t well controlled by existing drugs.
“Virtually 100 percent of asthmatics get worse with a viral infection,” says Umetsu. “We really didn’t know how that happened, but now we have an explanation, at least for influenza.”
Natural helper cells were first, very recently, discovered in the intestines and are recognized to play a role in fighting parasitic worm infections as part of the innate immune system (our first line of immune defense).
“Since the lung is related to the gut – both are exposed to the environment – we asked if natural helper cells might also be in the lung and be important in asthma,” Umetsu says.
Subsequent experiments, led by first authors Ya-Jen Chang, Ph.D., and Hye Young Kim, Ph.D., in Umetsu’s lab, showed that the cells are indeed in the lung in a mouse model of influenza-induced asthma, but not in allergic asthma. The model showed that influenza A infection stimulates production of a compound called IL-33 that activates natural helper cells, which then secrete asthma-inducing compounds.
“Without these cells being activated, infection did not cause airway hyperreactivity, the cardinal feature of asthma,” Umetsu says. “Now we can start to think of this pathway as a target – IL-33, the natural helper cell itself or the factors it produces.”
Personalized medicine in asthma?
The study adds to a growing understanding of asthma as a collection of different processes, all causing airways to become twitchy and constricted. ”In mouse models we’re finding very distinct pathways,” Umetsu says.
Most
Article source: PRNewswire
Related posts:
- Novel Therapy Improves Immune Function in Teen with Rare Disease
- An Advance for a Newborn Vaccine Approach
- Bill Paves Way for Asthma Management Programs in Schools Nationwide
- Gene that Mediates Response to Key Cancer Drugs Frequently Mutated in Young Leukemia Patients who Relapse
- Time To Stimulate, Not Limit, Pediatric Subspecialist Training
Did you enjoy this post? Why not leave a comment below and continue the conversation, or subscribe to my feed and get articles like this delivered automatically to your feed reader.
