Understanding Rhinovirus Infections and Asthma
Dr. Ellen Foxman can’t shake the memory of her son struggling during an asthma attack. It’s that moment every parent dreads, witnessing their child in distress, and for her, it prompted a more profound question about the science behind it.
She was aware that her son had asthma and recognized that rhinovirus, which is commonly responsible for colds, often triggers wheezing in asthma sufferers. “In fact, rhinovirus infection is the most common trigger of asthma attacks,” noted Foxman, who works as an associate professor at Yale School of Medicine.
What really piqued her interest was why rhinovirus led to severe asthma symptoms in some individuals but merely caused mild symptoms in others. “Here’s a virus that often causes no symptoms in many, while for some, it leads to life-threatening respiratory issues. It’s fascinating,” she explained.
Foxman and her team at Yale have identified a significant factor that influences these varied responses: the speed at which nasal cells react to the virus. The body’s interferon response varies among individuals—which can impact symptoms dramatically. When this response is delayed or suppressed, it can lead to heightened mucus production and inflammation, according to their recent study published in Cell Press Blue. These interferons play a crucial role in stopping the virus from spreading.
“They’re real cells, and growing them exposed to air for four weeks leads to a tissue that closely resembles the nose’s lining,” Foxman elaborated.
They then infected these cells with rhinovirus, using a method to observe thousands of cells simultaneously and examining the defenses activated in both infected and nearby cells. They found that a prompt interferon response confined the rhinovirus to less than 2% of nasal cells, potentially resulting in mild symptoms like a few sniffles. But in scenarios where this response was blocked, about 30% of cells became infected, which also led to increased mucus and inflammation.
Yet, a lingering question remained: What causes some people’s interferon responses to falter, which leads to increased inflammation and symptoms? Foxman pointed out that further research involving real individuals could shed light on this issue.
For now, she regards the study as a foundational step toward understanding the nasal response to rhinovirus infections. There’s potential for future treatments aimed at controlling inflammation and mucus production.
Dr. Dan Barouch from Beth Israel Deaconess Medical Center emphasized that while the study is enlightening, its findings need real-world validation. “People may have varying interferon response levels. Generally, those with a strong initial response may experience only mild symptoms and recover quickly. In contrast, those lacking this robust response could suffer from more severe infections,” he explained, adding that it’s still unclear how individuals can enhance their own interferon responses.
Additionally, Dr. Larry Anderson from Emory University pointed out that this phenomenon isn’t limited to rhinovirus. He mentioned that various factors—like the presence of certain bacteria, genetics, existing health conditions, and previous immunity—could all influence how a viral infection impacts someone.
