MADISON - For some asthma sufferers, the common cold can trigger worsening asthma symptoms, leading to heavier reliance on inhalers and perhaps even trips to the emergency room for more aggressive breathing help.
Why does asthma worsen in some people when they catch a cold, while others have much less trouble?
University of Wisconsin Asthma and Pulmonary Clinical Research investigators are working to pinpoint answers to critical questions - is it something about the particular cold virus that triggers the asthma exacerbation, or does a person's individual immune response determine whether asthma symptoms will worsen?
The average person gets two or three colds a year. And when someone with asthma comes to the doctor's office with worsening asthma symptoms, it's often found that the person also has the "common cold" virus, also known as rhinovirus (RV).
"What is not well known is, when asthma patients get a cold, who is going to get in trouble?" says Nizar Jarjour, MD, primary investigator of the Viral Induced Asthma Exacerbations (VIAX) study. "Is it a particular virus - one that is more virulent? Or is it the type of patient? The difference could be in their immune response - how they fight the virus."
The common cold and immune system response
When a person catches a cold, the immune system typically works quickly, clearing the virus within a few days. But in some people, the immune system may not be able to function as aggressively.
"Therefore, you could have a growth of the virus to higher quantities," explains Dr. Jarjour.
If a person's antiviral response is not very robust, multiplication of the cold virus could stimulate the development of white blood cells called neutrophils that "specialize" in fighting infections.
"A little bit is helpful, but too many neutrophils could be harmful," Dr. Jarjour says. "The injury to the bronchial tubes from too many neutrophils could be one of the mechanisms to the exacerbation of asthma."
In asthma exacerbation, symptoms worsen and patients need to use their inhalers more often. Some patients may even need to come to an emergency room for additional treatment, such as prednisone; a small number of patients may even wind up in an intensive care unit on a breathing machine.
Study seeks people in early cold stages
The $2 million study is sponsored by the National Institutes for Health (NIH) and is being conducted over a four-year period. The study will enroll 85 adults age 18-45 with mild or moderate asthma who are in the beginning stages of a cold. A control group of 15 adults without asthma or allergies is also being sought.
For all study participants, timing is a critical element.
"We want them to come in as quickly as they can while they still have cold symptoms," says Mary Jo Jackson, RN, study coordinator.
Time is of the essence because studies have shown that if a person's asthma is going to get worse, it will happen within three to five days of the onset of a cold. Also, many pieces of information must be gathered for the study's purposes while the participant is actively experiencing cold symptoms.
Participation in the study involves an initial visit of about two hours, which includes gathering the patient's health history and administering breathing tests to gauge lung function. In subsequent visits, patients will be scheduled for various imaging tests, including a PET scan, a CT scan and an MRI.
The imaging portion of the study will allow investigators to look at the thickness of the airway walls, how well the person's breathing tubes are working, and how the cells lining the airways are different when the participant has a cold.
"With the imaging tests, we're taking it one step further to find out the mechanism of these exacerbations," Dr. Jarjour explains. "Even if a breathing test is normal, there could still be abnormalities in the airways that we'll be able to see on the imaging."
Altogether, study participants will have up to 11 outpatient visits over about a six- to 12-week period. Participants will receive financial compensation for each visit completed during the study.
How to enroll in the study