Der Spiegel (Germany): slaughter in the body

When came to visit the grandchildren, Waltraud B. Snitkin loved to sing the folk song Komm, lieber Mai (“Come, dear may”) and watch from the window playing in the backyard children. But in April, Waltraud B. Snitkin started coughing, high fever, and she died soon after. She was 91 years old.

Waltraud B. — one of the 400 thousand people died from the coronavirus, a new type is an insidious disease that affects not only the lungs but also the heart, brain, blood vessels. It is amazing that some do not notice the disease.

Why this happens remains a big mystery, or “the one million dollar question”, says Bernd Salzberger, infectious diseases of the University hospital in Regensburg. “The peculiarity of Sars-Cov-2 is that it can cause severe inflammation,” explains the doctor.

The fact that some patients with the coronavirus, the immune system activates cells that circulate in the blood and develop in the so-called macrophages when they come into the infected tissue. If they recognize a pathogen or damaged cell, then sent directly to them, surround them and absorb. Therefore they are also called “eating cells”, or phagocytes.

In General, this “garbage collection” in their own body — a good thing, but the virus cells often can do little to oppose. The fact that the immune system activates a “devouring cells” in infectious diseases, unusual and can cause problems.

The body does not realize that the worst is over

In severe coronavirus immune system apparently sends signals that cause inflammation to get rid of the pathogen, and to mobilize new phagocytes, although infection has long been suppressed and the antibodies block the virus. The body at this point doesn’t understand that the worst is over, and continues all the forces to fight off the virus with life-threatening consequences.

This phenomenon is known also by the example of the pathogen MERS — another coronavirus and close relative of Sars-CoV-2. In the case of MERS, or middle East respiratory syndrome, this excessive response that met most often. That’s why deaths from MERS were often higher than covid-19.

What causes the inflammatory response is unclear. “Must be some switch that says Salzberger. We still do not know exactly which factors play a role.” First studies show that certain parameters contribute to the severe course of the disease. These include older age, obesity, high blood pressure and diabetes.

What factors have the greatest impact, it is not always possible clearly to trace. “In older people the immune system is more prone to inflammatory reactions,” notes Thomas Kamradt, President of the German society of immunology and Director of the Institute of immunology of the University clinic of Jena. They are also more likely to suffer from high blood pressure and excess weight. It is therefore not surprising that these diseases occur in many patients with covid-19.

Information about 4,1 thousand patients with covid-19 in new York showed that people with obesity, i.e. body mass index over 30, often were treated in the hospital. For 50 years old male 1,80 m this corresponds to a weight of approximately 96 kg. the Risk of falling in the hospital or even death increases with body mass index of 30 four times, and when the index is more than 40 six times.

It is known that adipose tissue may contribute to the development of inflammatory processes. There is a theory: if the pillow is too fat increases rapidly, it is poorly supplied with oxygen, and mobilized “devouring cells.” Increases the risk of chronic inflammation and cancer. Whether these processes role in the coronavirus, while it is safe no one can say.

Probably to the disease have the value and genetic factors. Certain gene mutations may contribute to the development of an overreaction of the immune system. When the so-called hemophagocytic syndrome some natural killers of the immune system defective.

Although they can recognize the infected tissue and send signal substances that attract other helpers of the immune system, but I can’t “disable” malicious cells. This can cause life-threatening chain reaction in which the immune system attacks healthy cells.

In the case of other diseases it is known that in certain groups of patients, they are heavier, not only in the elderly. During the swine flu pandemic in 2009 was seriously ill a lot of very young people. “What are the factors that then affected, we could not figure out,” says Salzberger. This was too few samples of affected patients.

Why men get sick more often?

With the coronavirus situation is different. Across the country hospitals have collected data and samples of patients, and now they can explore. The first results will be published next year, and perhaps earlier, Salzberger.

“One of the questions which we are engaged: why men get sick more often in severe form, than women?” reports Salzberger. He suggests that genetic changes in X-chromosome may play a role. Women have two of them. If one has an error, the other chromosome can often compensate. Men have one X chromosome and one Y chromosome.

“The better we understand the immune response, the more potential vaccines”. In very rare cases, active immunization, in which is introduced a weak form of the pathogen, can cause severe or incorrect reaction of the immune system. Will there be a vaccine for the coronavirus, and when, is not clear. Worldwide conducted relevant research.

According to the findings of a recent study presented in the Cell, the coronavirus enters the body through the nose. But different patients have the disease is quite different. Many patients initially affected by the infection of the oropharynx. A cough, sore throat, some much fever.

Further, the infection may descend into the lower respiratory tract, i.e. the lungs. In this case, the patient’s condition is deteriorating. This disease was the British Prime Minister Boris Johnson.

Others did not notice the infection. According to research, almost half of those infected with the coronavirus had symptoms. However, it is not always clear whether they were without symptoms at the time of the survey, and then they all appeared, or did not have symptoms at all.

When asymptomatic, the virus apparently spreads into the oropharynx as extensively as in people who get sick. High probability that the infected can still long time to infect others, probably even more than two weeks.

The immune system reacts and asymptomatic

The problem is that such asymptomatic course rarely diagnosed, because the test primarily people with typical complaints. Those who have no symptoms often become aware of the fact that she was infected accidentally, for example when testing all employees of a hospital or the passengers of a cruise ship.

“Probably the human immune system responds to asymptomatic — suggests immunologist Kamradt. — It’s not notice.” Symptoms such as a cough, fever and inflammation are not the cause of viral infection and the body’s attempt to get rid of the pathogen.

According to one theory, the reaction of the immune system may depend on how many viruses simultaneously stormed the body. After contact with a particularly high dose of a virus, for example, if someone sneezed directly in the face in a small room, the body can begin to defend themselves more actively, and the risk of severe increases.

Not even noticing the infection, some can get immunity for some time. Other diseases it is known that the body produces antibodies, even when asymptomatic. How long does the immunity in the case of covid-19, it is not clear, because the pathogen appeared not so long ago.

“I will be surprised if the immunity is not at all,” says immunologist Kamradt. Although it was already reported about a possible re-infection, it is likely that those people have not yet fully recovered when doing a new test. “I don’t know of any cases when someone was sick months later,” says Kamradt. In the case of related causative agent of SARS (SARS), the proportion of antibodies capable of neutralizing the virus gradually decreased after two years. Perhaps in the case of covid-19 immunity appears for the same period.

It is also unclear whether asymptomatic without consequences for the organism. Some passengers of the cruise liner Diamond Princess c who test positive for coronavirus were told that they had no symptoms. However, they revealed changes in the lungs characteristic of covid-19. But it is unclear whether the coronavirus is the cause of these changes.

Despite all the uncertainty, one thing is for sure: the new coronavirus can be fatal. Waltraud B. was the last link in our family, tells her granddaughter Maria: “I miss her very much”.