Since the epidemic prevention and control has been fully relaxed, there seem to be more and more people in Xiaoyang, and basically all of me and my colleagues around me have been infected. Studies have pointed out that a disordered immune response in the olfactory system is the r

Since the epidemic prevention and control was fully relaxed, there seem to be more and more Xiaoyang people . Basically, I and my colleagues around me have been infected. Although it will take a few days, the damage to the human body is not as serious as imagined.

However, there is an obvious feeling that my sense of smell seems to have failed. Is this the legendary sequelae? American scientists have solved the mystery for us.

Research published this week in the journal Science Translational Medicine shows that the cause of the long-term sequelae of loss of smell after recovery from new coronavirus pneumonia may be found.

Research points out that a disordered immune response in the olfactory system is the reason why some infected people still cannot smell smell for a long time after the symptoms of COVID-19 disappear. Some patients have been troubled by this for as long as 16 months.

Compared with people with a normal sense of smell, people with long-term loss of smell have fewer olfactory neurons, which are the cells in the nasal cavity that detect odors and transmit messages to the brain.

Study co-author Brad Goldstein, a sinus surgeon at Duke University, said that patients with the sequelae of anosmia have about 75% fewer olfactory neurons than healthy people. He said: "We believe that the decrease in olfactory neurons is almost certainly related to inflammation."

Loss of smell is a common symptom after patients recover from COVID-19, but its causes vary widely, including which virus variant causes the disease.

Gosden said that he and his colleagues are trying to find the key to the defects or changes in the bodies of people with long-term smell loss. "If we don't know what is broken, it is difficult to know how to fix it." The

research team sampled cells from nine patients with anosmia and compared them with cells from 15 healthy controls. Two of the healthy groups did not develop symptoms of anosmia after recovering from the epidemic.

The results found that people who had lost their sense of smell for a long time had more T cells, a type of white blood cell that plays an important role in the nasal immune response.

Gosden said T cells produce interferon-gamma, which is associated with inflammation, and support cells that respond to it.

Supporting cells protect and nurture olfactory neurons. Without supporting cells, olfactory neurons cannot survive.

research points out that the new coronavirus will not directly infect olfactory neurons, but will attack the supporting cells that protect olfactory neurons.

In addition, people who have lost their sense of smell have fewer specific anti-inflammatory cells and more of the unique inflammatory cells .

COVID-19 researchers say the study strengthens evidence that inflammation may be a culprit in COVID-19 symptoms.

Cheng-Ying Ho, co-author of the study and associate professor of pathology at Johns Hopkins University (JHU) School of Medicine, said neuroinflammation may cause loss of smell or other neurological symptoms related to COVID-19, such as brain fog.