Heightened Immunity To Colds Makes Asthma Flare-Ups Worse, U-M Research Shows

Tempering the immune response — rather than enhancing it — in asthma patients might be a better strategy when combating cold symptoms

People often talk about “boosting” their immunity to prevent and fight colds. Nutritional supplements, cold remedies and fortified foods claim to stave off colds by augmenting the immune system.

A new University of Michigan study shows this strategy might actually be flawed. The results may hold important implications for individuals with asthma, who often experience life-threatening flare-ups due to infections with cold viruses.

The study, using a novel mouse model, shows that, in the airways, the immune response to the common cold is actually maladaptive. Mice that were engineered to have a reduced innate immune response to the common cold actually showed less – not more – airway inflammation and bronchoconstriction (airway spasm) following infection.

The results of this study appeared online ahead of print in the journal PLoS Pathogens, currently available online. Marc B. Hershenson, M.D., professor of pediatrics and communicable diseases and director of the division of pediatric pulmonology, is the study’s senior author.

“You often hear that people want to boost their immunity to prevent and fight colds,” says Hershenson. “However, boosting the immune response could increase inflammation. Up to now there have been no convincing data supporting the theory that the immune response might be deleterious. In our study, we offer the first direct evidence that limiting the immune response reduces the manifestations of rhinovirus infection.”

“In our model, cold-induced asthma flare-ups were caused by the body’s immune response to the virus, not the virus itself. Chemicals produced by the immune system inflame cells and tissues, causing asthma symptoms such as cough and wheeze,” Hershenson explained.

Hershenson and his group hypothesized that limiting the immune response to viral infection would actually reduce their symptoms. Using a rhinovirus 1B, a cold virus strain that replicates in mouse lungs, they infected mice deficient in MDA5 and TLR3 – two receptors that trigger the protective defenses of the immune system against viruses and other pathogens.

MDA5-deficient mice showed a delayed defensive response to the infection, leading to a small increase in the level of virus in the lungs. Nevertheless, these mice showed less airway inflammation and bronchoconstriction following infection compared to wild-type mice. TLR3-deficient mice also showed diminished airway responses.

In addition, MDA5- and TLR3-null mice that were made asthmatic by exposure to allergen showed decreased airway inflammatory and contractile responses in response to rhinovirus infection compared to normal mice. These results suggest that, in the context of rhinovirus infection, reducing the mouse’s innate immune system led to reduced inflammatory signaling pathways and reduced airways inflammation and hyper-responsiveness.

“This study shows that, once you have a cold, elements of the immune response actually make the symptoms worse,” Hershenson adds. “A better strategy might be to modulate the immune response in asthma patients with colds.”

Contacts and sources:

Written by Margarita Wagerson

University of Michigan Health System

Authors: Qiong Wang, Ph.D., David J. Miller, M.D., Ph.D., Emily R. Bowman, Deepti R. Nagarkar, Ph.D., Dina Schneider, Ph.D., Ying Zhao, Marisa J. Linn, Adam M. Goldsmith, Ph.D., J. Kelley Bentley, Ph.D., Umadevi S. Sajjan, Ph.D, Marc B. Hershenson, M.D., all of the University of Michigan

Funding: National Institutes of Health

Disclosures: None

Citation: Wang Q, Miller DJ, Bowman ER, Nagarkar DR, Schneider D, et al. (2011) MDA5 and TLR3 Initiate Pro-Inflammatory Signaling Pathways Leading to Rhinovirus-Induced Airways Inflammation and Hyperresponsiveness. PLoS Pathog 7(5): e1002070. doi:10.1371/journal.ppat.1002070

The University of Michigan C.S. Mott Children’s Hospital is consistently ranked as one of the best hospitals in the country. It was nationally ranked in all ten pediatric specialties in the U.S. News Media Group’s 2011 edition of “America’s Best Children’s Hospitals” including third in the country for heart and heart surgery. In November, the hospital moves to a new 1.1 million square feet, $ 754 million state-of-the-art facility that will be home to cutting-edge specialty services for newborns, children and women.

Allergy Season: What Makes It Worse

May 2011 – Are the drugs you take for allergy making you gain weight?

Whether you are a Climate Change believer or not, allergies do seem to be coming on earlier in the year, and are causing more problems for more people.

I always advise to look at your environment and your diet as both these areas have a major impact on allergy.  I think it will be interesting to see how the increase in GMO crops and that pollen will start to affect people.

Remember too that cell phone and other wireless devices that are so popular contribute to this problem by creating electrolytically charged pollen and pollutant particles which makes it easier for these to stick to the mucous membrane lining inside your respiratory system.  This finding from a decade ago also shows correlation to increasing asthma rates.

There are several excellent approaches to natural allergy therapy, find out more here -

and if you’d like a personal program designed specifically for you contact us for this clinical service.

A new USDA-led study finds a warming planet makes for more pollen and a longer, more intense allergy season in many parts of the United States.

By Leah Zerbe

If you’re planning a vacation during prime hay fever season—summer and fall—opt for a spot near water, where pollen counts tend to be lower.

RODALE NEWS, EMMAUS, PA—Given the millions of allergy sufferers held hostage by the drippy noses, burning, watery eyes, and continuous sneezing sessions it induces, ragweed may be one of the most hated plants on the planet. And a new the U.S. Department of Agriculture (USDA)-led study published in the Proceedings of the National Academy of Sciences confirms what many allergy sufferers and allergists have already been noticing—hay fever season caused by ragweed seems to be getting more intense and lasting longer.

The study is the latest to make the connection between climate change and a more potent allergy season. (Allergy-related issues cost the United States about $ 21 billion a year, so a warming planet affects economics, too.) “The main takeaway is that we are already seeing a significant increase in the season length of ragweed; and that this increase in season length is associated with a greater warming at northern latitudes, consistent with the Intergovernmental Panel on Climate Change projections regarding climate change,” explains lead study author Lewis Ziska, PhD, research plant physiologist with USDA’s Crop Systems and Global Change Lab.

THE DETAILS: Researchers used ragweed pollen and temperature data recorded between the late 1990s and 2005 in 10 different locations in the U.S. and Canada and found that in all but two of the areas analyzed, the ragweed pollen season increased—in some cases by nearly a month. The lengthening of the allergy season coincides with an increase in warmer, frost-free days. Researchers noticed a general trend—the ragweed allergy season grew longest in the higher latitudes of the northern United States and Canada. Winnipeg, Ontario, allergy sufferers endured a 27-day-longer ragweed pollen season in 2005 compared to just 16 years earlier. In the U.S., Fargo, ND, and Minneapolis, MN, experienced a more than two-week increase in ragweed allergy season, with LaCrosse and Madison, WI, not far behind.

WHAT IT MEANS: Climate change threatens human health in a number of ways, but allergies may be the most immediate, easy-to-recognize ailment thus far. And our increasingly chaotic climate’s allergy-accelerating properties are already afflicting millions of people. Ragweed is one of the most common weed allergens, affecting about 10 percent of the population. Among allergy sufferers, nearly a third endure hay fever misery brought on by ragweed pollen. Under normal circumstances, a single ragweed plant creates 1 million pollen grains; but a climate change–charged, more CO2-rich environment boosts that number to upwards of 3 to 4 million pollen grains per plant, according to Clifford Bassett, MD, medical director of Allergy and Asthma Care of New York and a member of the public-education committee at the American College of Allergy, Asthma and Immunology. (Don’t your eyes water just thinking of it?)

And scientists are also suspect of other potentially climate change–infused weed species. Ziska says there are concerns that other specific plant allergens are worsening due to climate change. His research group is working with Rutgers University in New Jersey and the Environmental Protection Agency to begin assessing pollen production and season length for other annual weeds like lambsquarters, mugwort, and plaintain, in addition to ragweed.

Consuming less, using less energy, eating organic, and demanding that clean energy subsidies replace incentives to fund dirty fossil fuels like coal, oil, and natural gas that make us sick are all important tactics to help stabilize global climate and protect our health. It’s also important to realize that we’ve already set ourselves up for a lifetime of climate-related problems. Here’s how to deal with the allergy aspect as we all work to keep things from getting worse.

Here are some solutions to think about now, before ragweed allergies strike later this year:

• Make sure you’re actually allergic to ragweed. It may sound silly, but allergists recommend being tested to confirm you’re allergic to what you actually think is making you sneeze. If ragweed is really making your life miserable (the longer you’re exposed to the allergen, the worse the symptoms become), consider getting allergy shots. The ongoing climate shift could be a cue to reassess your antiallergy options. “It might make people who previously had mild ragweed seasons to consider interventions they hadn’t though of before, like getting ragweed allergy shots,” says study coauthor Jay Portnoy, MD, chief of allergy, asthma, and immunology at Children’s Mercy Hospitals and Clinics in Kansas City, MO.

• Plan vacations accordingly. For many people, February still marks the cold season, months away from hay fever hell. But take your ragweed allergy into consideration as you plan this year’s summer or fall getaway. Dr. Bassett notes that pollen counts are generally lower around water. So if you vacation during prime ragweed season—summer and fall, or year-round in places like Florida or Hawaii—plan some time on the beach or around rivers and lakes for some ragweed relief.

• Create better indoor air. Now’s the perfect time to grow your own houseplants for free. They should be flourishing by ragweed season. While houseplants can’t rid your air of pollens you’re allergic to, certain houseplants can counteract indoor air pollution that further aggravates your allergy problem.