Heightened immunity to cold makes the asthma flare-up, according to a new study conducted by the University of Michigan.
It states that nutritional supplements, cold remedies and fortified foods that claim to stave off colds by augmenting the immune system may be harmful for asthma patients.
The researchers suggested that tempering the immune response rather than enhancing it might be a better strategy when combating cold symptoms.
They conducted a test on mice, showing 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 the infection.
"You often hear that people want to boost their immunity to prevent and fight colds. 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," said Marc B. Hershenson, professor of pediatrics and communicable diseases and director of the division of pediatric pulmonology.
"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," he added.
The study appears online ahead of print in the journal PLoS Pathogens, currently available online.