How the body resists SARS-CoV-2
An Australian research team documented for the first time how the immune system defends itself against the new corona virus. The researchers found that the human immune system is surprisingly well prepared for novel pathogens such as SARS-CoV-2.
Researchers at the Peter Doherty Institute for Infection and Immunity in Melbourne, Australia, carried out detailed studies on one of the first patients to develop COVID-19 in Australia. The research team paid particular attention to how the immune system reacts to the new disease. It turned out that the body is not as defenseless as initially thought. The results were recently presented in the renowned journal “Nature Medicine”.
Who is the patient?
The patient examined was a 47-year-old woman who returned from the particularly badly affected city of Wuhan in China. Eleven days after entering the country, she developed symptoms such as fatigue, sore throat, dry cough, stabbing chest pain when inhaled, slight difficulty in breathing and fever. Otherwise the patient was healthy and did not suffer from any underlying illness. The victim was treated in a clinic in Melbourne.
The treating team took blood samples at four different times during the course of the disease and analyzed them. This enabled mapping to show the body’s ability to fight the new virus and recover from the infection.
Flu experiences helped with the documentation
“We examined the full range of the immune response in this patient, using the knowledge that we have built up over many years by examining the immune response in patients who have been hospitalized with flu,” explains Dr. Oanh Nguyen, one of the study’s authors. According to the researchers, this is the first time that a broad immune response to COVID-19 has been reported.
Recovery could be predicted
“Three days after the patient was admitted, we saw large populations of several immune cells, which are often a clear sign of recovery during a seasonal flu infection, so we predicted that the patient would recover in three days, whichever happened,” explains Nguyen.
The body was able to defeat COVID-19 in seven days
A team led by Katherine Kedzierska, laboratory manager at the Doherty Institute, managed to map the exact immunological response to SARS-CoV-2. Accordingly, the first sign of a measurable immune response was an increase in antibody-producing cells. These were detectable on the seventh day after the onset of the disease. At this point, the detectable viruses had already disappeared from the smears. This rise peaked on the eighth day.
This is how the immune system defends itself against SARS-CoV-2
According to the researchers, during the period in which antibody-producing cells rose, there was also an increase in follicular T helper cells, which are essential for the sustained production of highly effective antibodies. In addition, an increase in CD8-positive T cells has been documented, the task of which is to destroy infectious cells. It was also observed that the so-called CD4 cells, which also belong to the T helper cells, rose.
At the same time, the number of so-called monocytes (CD16 + CD14 +) in the blood, which are able to penetrate tissue and then turn into macrophages (phagocytes), decreased. According to laboratory manager Kedzierska, this is a sign that these cells are being increasingly recruited to eliminate the consequences of pneumonia.
Flu-like immune response
“We have shown that although COVID-19 is caused by a new virus, in an otherwise healthy person, a robust immune response across different cell types is associated with clinical recovery, similar to the flu,” sums up Professor Kedzierska. This is an incredible step forward in understanding what drives the recovery of COVID-19.
Great progress in understanding the disease
Researchers and health professionals can use the mechanisms outlined to understand immune responses in larger COVID-19 cohorts and to identify what is missing from those who have fatal consequences. The research team hopes that these findings will provide the basis for understanding why some people die from COVID-19 and others show almost no symptoms. (vb)
Graduate editor (FH) Volker Blasek
- Peter Doherty Institute: COVID-19: the immune system can fight back (published: March 17th, 2020), doherty.edu.au
- Katherine Kedzierska, Irani Thevarajan, Thi H. O. Nguyen, et al .: Breadth of concomitant immune responses prior to patient recovery: a case report of non-severe COVID-19; in: Nature Medicine, 2020, nature.com
This article contains general information only and should not be used for self-diagnosis or treatment. He can not substitute a visit at the doctor.