Gender Immune Gap: The Defenses of Women

Women can ward off infection better than men. But there is more to a fit immune system, as BRIGITTE editor Antje Kunstmann has. What exactly?

It sounds a bit absurd at first, but it’s still true: many are now as healthy as never before. Distance, hygiene and contact restrictions not only protect against corona. Cold viruses also have a hard time. The Robert Koch Institute reports fewer norovirus infections, the flu epidemic has practically failed, and pharmacies even sell significantly less drugs against lice. “I can’t remember ever having survived a winter so infection-free,” said an acquaintance the other day.

It’s different for me: I actually can’t remember the last time I had a cough and runny nose or was otherwise ill. “That definitely speaks for a fit immune system,” confirms Professor Monika Brunner-Weinzierl from the University Children’s Clinic at Otto von Guericke University Magdeburg. What exactly is going to be different for me compared to a person susceptible to infection is not exactly known. The immunologist is currently looking for it in a large-scale study. In order to be able to filter out the decisive parameter among the many players in our immune system and in their finely balanced network of relationships, the scientists also rely on the help of artificial intelligence.

At the moment, therefore, there is only one thing to say: “Your immune system was also concerned with infections in the past – you can’t avoid all of them. If you haven’t noticed anything, it means that your immune responses are switched on and off again very effectively . ”

Gas and brakes: a healthy defense needs both

However, I don’t really know how I earned it. As far as nutrition and exercise are concerned, I would say that I live on an average healthy basis. So there is probably also a lot of luck involved. “There is definitely a genetic component,” says Monika Brunner-Weinzierl. That fits in with the fact that my children are also extremely rarely sick. Two of them missed exactly three days in their entire primary school.

Obviously, for familial reasons, we have, among other things, quite competent T cells. Monika Brunner-Weinzierl calls the white blood cells, which are named after their place of maturation, the thymus gland behind the breastbone, the central switching point of the immune system: If an intruder is detected, they decide how to proceed. And then they step on the accelerator, for example, by telling the so-called B cells to produce antibodies and other T cells to kill virus-containing cells in the body. For people who are seriously ill with Covid-19, it seems to be more of a problem.

So far, no precise marker is known that could be used to assess its course before an infection, but the T cells at least offer approaches to treatment. Monika Brunner-Weinzierl and her team have developed a therapeutic approach to remove these seriously ill T cells, make them fitter in the laboratory with virus components – repairing the accelerator, so to speak – and then returning the patient to the patient. “They can practically heal themselves,” says the immunologist.

But just like a car that, if it only accelerates, flies out of a curve at some point, the immune system also needs effective brakes. What their failure means can also be seen in the intensive care units. “Some people affected have what is known as a cytokine storm – cytokines are proteins that mediate immune responses and inflammatory processes,” says Monika Brunner-Weinzierl. “You can no longer detect the virus, but instead of shutting it down, the immune system reacts more and more violently and then also against the body itself.”

Immune murmur: When the immune system is getting old

Unfortunately, one cannot rest on a healthy immune system. “Its clout decreases continuously with increasing age”, says Monika Brunner-Weinzierl. “You won’t be spared from that either.” Even now, in my mid-40s, my thymus only provides a tenth of the amount of cells compared to puberty, and at some point it will dry up completely. In addition, the instructions that the cells give each other to conduct the defense concert are becoming more and more of a murmur, as the US immunologist Janko Nikolich-Zugich calls it. “Instead of reacting quickly and precisely to a virus with lots of new T cells, the immune system relies more and more on its memory,” says the expert.

Sometimes that doesn’t matter: with mumps and measles, for example, the defense plans that were made in my childhood (one I had at preschool age, the other I am vaccinated against) will probably fit my life. “But many pathogens develop strategies to escape the immune system. For example, a slightly modified influenza virus can trigger the flu again.” Even a completely new virus such as SARS-CoV-2, an older immune system has less to oppose. “That is why almost 85 percent of corona patients in intensive care units are over 70,” says the immunologist.

But we can at least give the immune system a helping hand. “Studies show that through exercise the telomeres of the T-cells, the protective caps of the chromosomes, which shrink with every cell division, become longer again. The cells can then divide more again and react better.” Diet also influences how quickly our immune system ages (see interview on p. 94).

Advantage of the double X: What influence does gender have

In general, the biological clock ticks significantly louder in women, but the opposite is true for the immune system. “The thymus ages a little faster in men,” says Professor Sabine Oertelt-Prigione from Radboud University in Nijmegen in Holland. And that’s not the only gender immune gap. “Our immune system is more plastic than that of a man. That means it changes more in the course of life.” After all, it must be able to tolerate a foreign body in its own four walls for almost ten months.

“On the one hand, the immune response can therefore slow down quite a bit, but on the other hand it can also be more violent,” says the gender doctor. This has disadvantages – autoimmune diseases, so if the immune system falsely shoots itself into one’s own body, are more common in women – but it also has advantages when it comes to defending against viruses and bacteria. Because female sex hormones are largely responsible for this, our immune system even knows cycle fluctuations. “The second half tends to be more susceptible to infections,” says Sabine Oertelt-Prigione. And unfortunately also after menopause, when the hormonal immune protection wears off.

Both of our X chromosomes are retained, however, and they contain a large number of genes that are important for the immune system. If some of them are faulty, women benefit from having a second version in reserve. “We see this importance particularly clearly at Corona.” The blueprint for the so-called ACE2 receptor, which the coronavirus can use to enter lung cells, is also on the X chromosome. 60 percent of the fatalities are men.

So should we women take a back seat when it comes to vaccinating? “No,” says the doctor. Age and previous illnesses played a bigger role. In addition, if you want to prevent chains of infection, you actually have to vaccinate women first. “We now know from many countries that they are often infected more often than men. Who is the teacher? Is there at the cash register? Does the nursing staff?” Staying healthy is not just a question of biology.

For me that means: Yes, I haven’t been sick in the last few years and can therefore describe my immune system as fit. If I were an educator and surrounded every day by more than a dozen toddlers, each with a dozen infections per year, things would probably look different.

Together you are less sick

Anyone who wants to get on the track of what influences our immune system should generally not stop at the level of T cells, messenger substances and receptors. It has long been assumed that the brain cannot influence the immune system at all, because this ultimately consists of a large number of different cells that are constantly wandering around the body. But then it was discovered that almost all of them have receptors for molecules with which the brain also communicates, namely for neurotransmitters and hormones. Adrenaline and northern renaline have an influence, as does the stress hormone cortisol. And so not only pathogens occupy our defenses, but also our feelings, how happy we are or how stressed we are.

The US psychologist Sheldon Cohen showed particularly impressively what stress means for susceptibility to infections by dripping cold and flu viruses into the noses of volunteers and then looking at how those who got sick afterwards differ from those who stayed healthy . Those with the most stress were infected 2.16 times more often and the more likely, the longer the stress persisted subjectively (in comparison: too little exercise only increased susceptibility by a factor of 1.8).

Cohen also found the most effective stress buffer: social support. People with only a few interpersonal relationships who were hardly socially integrated were more than four times more susceptible to infection.

I think my defenses are pretty good at this point: I can’t switch off stress, but I’ve learned to focus on the next step. It never takes me long to relax. I can probably suppress well – definitely a successful way of coping. And last but not least, I have a sustainable social network when I’m on the ropes.

Nevertheless, I found the last few months exhausting. I missed my parents, my friends, my colleagues. Could that have weakened my defenses? Sheldon Cohen at least speculates that contact restrictions and lockdown, which should actually contain Corona, could have made us more susceptible to the virus. Nobody knows yet whether this is really the case. Nevertheless, the findings of psychoneuroimmunology are reason enough to pay special attention to yourself and each other right now.

By the way, I have often been asked what special things I take or do to keep my defenses fit. Like there’s this one thing that optimizes the immune system. “In view of its complexity, this is certainly too simple,” says Monika Brunner-Weinzierl. There is no area of ​​our life that is not influenced. We cannot control a lot of it, but we can control others. The only real miracle cure is then: diversity.

Nothing is more important than health

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BRIGITTE 07/2021