Do you feel like you’re the only one who gets hit by every bug going around? While you’re no stranger to freshers' flu, your flatmates seemingly never get ill? A new study from Yale researchers sheds light on this age-old mystery, suggesting that the answer lies in the body’s first line of defence: your nasal passage.
When the most widespread cause of common colds, rhinovirus, enters your body through the nasal passage, the cells in your nose activate an extensive range of antiviral defences to stop the virus from spreading. In a new study published by the journal Cell Press Blue, researchers found that one of these early cellular responses is key in determining whether a person becomes ill, as well as the severity of their symptoms. Crucially, they found that the body’s reaction is more important than the rhinovirus itself.
Our study advances the paradigm that the body’s responses to a virus, rather than the properties inherent to the virus itself
Ellen Foxman
“Our study advances the paradigm that the body’s responses to a virus, rather than the properties inherent to the virus itself, are hugely important in determining whether or not a virus will cause illness and how severe the illness will be, “ says author Ellen Foxman of Yale School of Medicine.
Central to the coordinated cellular response to rhinovirus are interferons, antiviral proteins that interfere with the virus’s ability to enter cells and replicate. When nasal cells detect rhinovirus, they release interferons not only in infected cells, but also in neighbouring uninfected cells, quickly containing the virus. Interestingly, this occurs absent of any immune system cells.
To study this process, the research team built a lab-grown model of human nasal tissue, growing nasal stem cells and exposing the tissue surface to air to best resemble human nasal passages and lung airways. When the researchers blocked the interferon response, the virus spread rapidly, which, in a living person, would lead to an individual becoming sick.
When the interferon response is delayed, weak, or disrupted, the virus has more opportunities to replicate, triggering inflammation and excess mucus, the classic symptoms of the common cold.
When the interferon response is delayed, weak, or disrupted, the virus has more opportunities to replicate, triggering inflammation and excess mucus, the classic symptoms of the common cold. This study explains why even when exposed to the same virus, some people get hit hard by colds and flus, while others seem completely fine. The speed and strength of the interferon response makes all the difference in how quickly your body can fight off the virus.
So, next time someone accuses you of being melodramatic when faced with the same cold, remember that the difference may lie in biology, not willpower.