Having a warm nose helps fight colds better
The arrival of winter always rhymes with cold season.
It is well known, the arrival of winter always rhymes with cold season. Among the factors favoring these common respiratory infections are more frequent gatherings indoors and viruses surviving better in the drier air between four walls. But as to whether low temperatures actually weaken our immune system (and if so how), there is less certainty.
A study published in the Journal of Allergy and Clinical Immunology details a new way our bodies attack intruders. And this method works best when it's hot.
These findings could help develop new treatments for the common cold and other viruses, Mansoor Amiji, a professor at Northeastern University and co-author of the work, told AFP.
The starting point is a previous study he conducted in 2018, which found that cells in the nose release extracellular vesicles (EVs) – a cloud of tiny bacteria-attacking particles at the time of inhalation.
The best analogy is that of the hornet's nest, explains Mansoor Amiji.
“Like hornets defending a nest under attack, EVs fly in swarms to attach to invaders and kill them .
—Mansoor Amiji, Northeastern University
Researchers then asked two questions: Are EVs also secreted when a virus is present? And if so, is their response affected by temperature?
- Cold infections are very common.
- An adult suffers from two to five colds a year.
- Colds are infections of the upper respiratory tract (nose, nasal passages, and throat).
- There are more than 200 viruses that can cause the common cold.
- In adults, rhinoviruses, of which there are more than 100 varieties, are the main family of cold-causing virus.
For their tests, the scientists used the nasal mucosa of volunteers (who were undergoing an operation to remove polyps) and a substance reproducing a viral infection.
Result: EVs are well produced against viruses.
To answer the second question, the nasal mucous membranes were divided into two groups, with the cells cultured in the laboratory at either 37°C or 32°C. C.
These temperatures were chosen based on tests showing that the temperature inside the nose drops about 5°C when the outside air drops from 23°C to 4°C.
Under normal body temperature conditions, EVs were good at fighting off viruses, presenting them with decoys to which they clung, instead of cell receptors that x27; they would normally have aimed.
But with reduced temperature, EV production was less abundant, and they were found to be less effective against the viruses tested: two rhinoviruses and a coronavirus (non-COVID), common during winter.
There has never been a very compelling reason why there is a clear increase in viral infectivity during the colder months, said in a press release Benjamin Bleier, co- study author and surgeon at Harvard University School of Medicine.
is the first quantitatively and biologically plausible explanation that has been developed.
—Benjamin Bleier, Harvard University
This work could help develop treatments to boost natural EV production so they can better fight off colds – or even the flu and COVID-19, according to Mansoor Amiji. This is an area of research that interests us enormously, and we will undoubtedly continue on this path.