What causes overactive immune system allergies


News reporter: "The pollen report, valid until Wednesday evening. Due to the high levels of solar radiation, there is an increased flight of grass pollen. The allergenic load from mugwort and rye pollen is also high."

When it is green and blooming, many people would like to escape their "lovely" environment. Every fifth German is overly sensitive to pollen. Anyone who dares to venture into "hostile" nature can protect themselves with masks that provide allergy sufferers with pollen-free air. Filters prevent the microscopic tormentors from coming into contact with the mucous membranes of the nose, eyes or airways.

Often only a few thousandths of a millimeter in size, these tiny pieces cannot harm most people. Those who suffer from hay fever, on the other hand, react to the pollen of one or more flowering plants. The bizarrely shaped structures are fought by the immune system as if they were pathogenic parasites. A multitude of symptoms such as coughing or shortness of breath make life difficult for allergy sufferers, as well as dripping noses, swollen mucous membranes and watery eyes.

Upon contact with the pollen, certain cells of the immune system, the mast cells, release histamine. This substance, which is also contained in nettles, causes the inflammation with its annoying side effects.

When allergens such as pollen get into the human body, some are over-sensitive, while others are not. Why is not exactly known. On the other hand, you know how the "career" of an allergy sufferer will develop. Cells in the skin or mucous membrane that have absorbed allergens show parts of them on their surface. If T helper cells recognize alleged pathogens in these profiles, a false alarm occurs.

The T cells divide and organize the production of suitable antibodies. These IgE antibodies dock on the mast cells and receive reception like antennas. Now people are sensitized to a specific allergen. With every further contact with the allergen, the defense goes astray. The mast cells become active.

If an allergen bridges two neighboring antibodies, the mast cell releases the messenger substance histamine in order to get rid of the annoying intruders. The mucous membrane turns red and swells. One possible therapy: antihistamines block the messenger substances, the symptoms subside.

The easiest way to prevent allergic reactions is to avoid contact with the allergens. Regardless of whether they are of natural origin, from traffic emissions or from industrial production.

A number of disused salt or ore mines are now places of refuge for allergy sufferers. The health resorts of the Baden-Württemberg town of Aalen have also adapted to the overly sensitive clientele. The mining underworld of bygone days offers a precious commodity: clean air, free from allergens. A natural exchange of air takes place in the cool, damp tunnels underground, which quickly removes all suspended matter to the outside. Otherwise, similarly favorable conditions can only be found in the mountains or by the sea.

The patients, who usually undergo a three-week cure, mostly suffer from hay fever, asthma or neurodermatitis. They spend two hours a day in the Heilstollen. For many, the allergic symptoms alleviate after the first week. With a longer duration of therapy, they often subside to such an extent that medication can sometimes be dispensed with. The treatment continues to have an effect for a long time. But if the exposure to allergens then exceeds a certain threshold, the signs of the disease increase again.

Scenes from the Middle Ages. By today's standards, our ancestors lived in extremely unsanitary conditions. Humans and animals shared the simple dwellings. Parasites, viruses and bacteria were omnipresent and constantly challenged the immune system. Allergies were rare.

As the standard of living has risen, allergies have increased dramatically. Some scientists see the cause in today's "sterile lifestyle". Defense mechanisms against parasites are constantly under-challenged and are instead directed against harmless substances. There are several arguments in favor of this theory. Because allergies rarely occur in less developed countries. The human immune system, which has arisen in the course of evolution, has adapted to life in nature. Different defense strategies have developed, depending on whether bacteria, viruses or parasites are to be fought.

The immune system has not yet adapted to modern industrial societies with few parasites. One hypothesis states that environmental pollution contributes significantly to the increased susceptibility to allergies. Air pollutants are suspected of damaging the respiratory tract and thus making pollen easier to access the immune system. As plausible as the explanation may sound, hard facts are still pending. In the light of more recent findings, the theory could even more or less vanish into thin air.

The turning point came to the rescue of scientists. The opening of the borders in 1989 not only brought freedom to East Germans. With the fall of the wall, a new field for research opened up. Doctors examined preschool children who had grown up under significantly worse environmental conditions during the GDR era. The surprising result: the little ones had significantly fewer allergies than their western peers. In contrast to these, the GDR children attended the day nursery much earlier. Infections with worms also trained the immune system. This is how some researchers explain the lower susceptibility to allergies.

Consultation hour at the Department of Dermatology at the University of Freiburg. Reddened, itchy spots in the crooks of the arm are caused by neurodermatitis. Patients with this type of allergy are usually hypersensitive to several substances. Questions about the living conditions at home and when the symptoms occur provide information on which substances can be considered as triggers of the allergy.

Patient: "Yes, mostly in spring, that's why I'm here now, because things have been getting worse since March."


Doctor: "Is it only in spring or also in summer or autumn?"


Patient: "Mainly in spring, but I notice it in summer too, so it's never completely gone, unless I'm at the seaside."

Solutions that contain allergens from pollen, mite excrement or animal hair in as pure a form as possible help in the criminal search for clues. A kind of "perpetrator profile" is created from the patient's information, which contains all substances suspected of being allergic.

In the prick test, the selected extracts are dripped onto pre-numbered areas of the skin. The immune reactions that are later visible on the skin are partly hereditary. Children of parents with allergies are affected more often than average. So that the substances can also work, they are scratched into the skin. It takes about half an hour until the result of the histamine release can be seen. Swellings show which substances caused an allergic reaction.

Doctor: "Your histamine control is positive, then you have a reaction to cat hair, then you have reacted to timothy grass, very strong, to rye and to mugwort."

While mugwort pollen is only found in the wild, other allergens come from the immediate living environment. Many people do not think that it could be the dust mites in their bedroom, whose faeces are the most common cause of allergies. The annoying sub-tenants also include cockroaches, which usually nestle in the household without being noticed. They are looking for warmth and food. Your excrement, whirled up with the vacuum cleaner or spread over the air conditioning, is not for sensitive people.

Pets, especially cats, are another source of allergens. Proteins in the skin and hair cause the symptoms. Intolerance to urine or saliva is less common. In line with the general trend, work-related allergies are on the rise. Widespread among farmers, the so-called farmer's lung. Dust from haying or threshing can lead to dangerous inflammation of the alveoli. Many a farmer had to give up his farm as a result.

The man in the mask is baker Josef Krieger. Thanks to the easy-to-carry device, which constantly supplies him with dust-free air, he can still do his job. Josef Krieger is allergic to rye flour. That almost meant the end of the business that has been in the family for generations. Josef Krieger loves his job. As the asthma attacks became more frequent, the doctors gave him the usual recommendation:

Baker: "So it was said that retraining is the only way away from my job. But since I definitely didn't want that, I looked for and found a way through this mask, which I've been wearing constantly for six years now. And that Values ​​get better from examination to examination, so I no longer have any complaints and can do my job, which is very important for me because it is a question of existence. "

Natural substances that float in the ambient air lead the allergen hit list. In second place, however, are substances that - mostly undetected - are hidden in food. They can cause gastrointestinal discomfort, headaches, skin reactions or even life-threatening shock.

Every food is made up of a large number of individual components. The same ingredients are often found in several foods. Some products contain chemical additives. All of this makes it difficult to unmask allergy-causing factors. Milk is found in many products. The earlier children start drinking milk, the more likely they are to develop intolerance. Babies should therefore be breastfed for as long as possible. This generally lowers the risk of allergies.

Wasps are usually harmless troublemakers. For some people, however, they can be dangerous, life threatening. The following scene, set in Switzerland, gives an impression of how severe allergic reactions can be. Immediately after the sting, the immune reaction sets in. Histamine from the mast cells and other messenger substances flood the body. First a tingling sensation in the hands, then more massive circulatory disorders.

Chaos breaks out in the body. The vessels expand so quickly that the blood pressure drops threateningly. It is only a matter of seconds before the man goes black. It shows all the symptoms of anaphylactic shock, which, if left untreated, can lead to death. In such a severe case, minutes count. It is best to call the ambulance immediately. Every year, for some patients, all help comes too late.

The first thing to do is to get the circulation going again and to stop the extreme histamine production. There are tried and tested active ingredients that rescue teams have with them. In principle, any allergen can cause a shock. This particularly affects people who are allergic to food and drugs.

Knocking and sucking, these are the typical hand movements of a rare professional group. The insect hunters target wasps, more precisely their main weapon. The animals' stings and poison bladders are removed in the laboratory. The wages of this arduous activity benefit those people who are extremely sensitive to wasp stings. The masks protect against inhalation of the poison and prevent the employees from becoming allergy sufferers themselves.

The allergen, which is used for desensitization, is obtained from the wasp venom. Starting with small doses that increase gradually, the patient becomes accustomed to the poison over the years. A reprogramming takes place. Other branches of the immune system, which react less violently to the allergen, gradually take over the defense. The test with a live wasp will show whether the therapy was successful. Your sting has no consequences. How desensitization works is not yet fully understood, but it is successful in many forms of allergy.

Prof. Schöpf: "In the case of severe pollen allergies, for example, it makes sense to carry out this desensitization at a relatively early age, because it can prevent the pollen allergy from changing floors, which means that it doesn't just cause a cold, which is comparatively harmless, albeit a relatively harmless one is uncomfortable, but spreads to the deeper levels of the bronchi, in the form of pollen asthma. And then of course it becomes dangerous.

A small part of human ingenuity is stored in these drawers: substances that enrich our everyday lives, but to which we also owe some "charming" side effects. When cosmetics, washing powder, paints or solvents come into contact with the skin, the immune system sounds the alarm in some people. If a contact allergy is suspected, only a test can clarify which substances are not tolerated.

While the allergens considered so far - pollen or wasp venom - trigger an immediate reaction, the immune response to contact allergens takes place with a delay. Itchy eczema only develops weeks after exposure to hypersensitive people. The patients would like to get out of their skin.

The skin, which modern Homo sapiens likes to adorn with all sorts of fashionable items, is more than a simple protective cover. It forms a fantastic early warning system which, however, often triggers false alarms in allergy sufferers. Jewelry, perfumes, cosmetics or clothes, anything that comes into direct contact with the skin can cause inflammation. Those who pay attention to these symptoms and consistently avoid contact allergens will soon feel good in their skin again.

Eczema. More and more small children are affected. In addition to hereditary factors, too short a period of breastfeeding and excessive hygiene contribute to this form of allergy. Silja Beckmann has also suffered from neurodermatitis since she was a child. Typical of the chronic disease: It occurs in episodes, often without a clearly identifiable cause. In atopic dermatitis, mental stress and external influences work together, which one often cannot avoid. Stress, heat, water or your own sweat can increase the inflammation of the skin. As with Silja Beckmann, there are usually intolerances to several allergens.


There are star-shaped Langerhans cells in the skin of every person. These guardians of the immune system identify foreign intruders with their antenna-like antibodies. Skin examinations show that atopic dermatitis sufferers have an extremely large number of docking points for IgE antibodies. This large number of recipients make the Langerhans cells extremely sensitive. You can still discover the slightest traces of a substance.

A few allergens are sufficient to activate the Langerhans cells. They fire off messenger substances that promote inflammation. In addition, profiles of the allergen are presented. If a T helper cell detects such an allergen fragment, it docks and is armed. The cell divides, sends out messenger substances and alarms other elements of the immune system. This overreaction increases inflammation and damages the skin.

Pollen, food or contact allergens repeatedly trigger strong flare-ups in atopic dermatitis, including Silja Beckmann.

Patient: "What bothers me the most is definitely the itching, which is particularly strong then, yes, when I can't use it at all, when I already have a stressful situation or something. What then is a burden, are definitely restrictions, situations that you simply avoid. In other words, things like not going to the swimming pool because water irritates the skin again and it starts to itch again, or that you sweat in summer and you notice that it is getting worse and tries to stay in the house, where it's cooler. And then what happens with neurodermatitis, simply because it's a disease that you can't hide, is that you are repeatedly forced to grapple with it, because it is visible. "

Neurodermatitis sufferers are caught in a spiral of suffering that is difficult to break. Constantly itchy eczema increases stress, and the stress exacerbates symptoms.

Prof. Schöpf: "We have known for a long time that allergic reactions, especially in neurodermatitis, but we also know this from allergic asthma, are aggravated by psychological stressful situations. We now know some substances that are released in psychological stressful situations, so-called neuropeptides, which partly affect the immune cells , which play the main role in the allergic reaction, activate and thus intensify an allergic reaction. On the other hand, in stressful situations there is the release of neurotransmitters, such as adrenaline, which tend to slow down allergic reactions. That is always a question of the balance in the organism. "

The salty waters of the Dead Sea promise relief from a number of skin diseases. In the case of neurodermatitis, success is rather questionable. Warmth usually exacerbates symptoms and pure sunlight increases the risk of cancer.

Cold light therapy has proven itself in a number of patients. Part of the solar spectrum, namely long-wave UV-A rays, is artificially generated. The light attenuates the overactive Langerhans cells in the skin and inhibits the unwanted defense reactions. Inflammation and itching, which keep many patients awake, subside. Filters not only hold back the heat rays, they also block the part of the UV-A light that is considered to be carcinogenic.

Doctor: "You can already see here that the skin is much smoother, hardly any more scratches, overall much softer than it was six or eight weeks ago."


Patient: "I came across cold light therapy by chance and it is actually very successful. The skin regenerates itself, the itching subsides. You just feel completely different, you are a different person when your skin is good again. Man dares to wear something short-sleeved again, so I'm very satisfied. "

Allergy research still offers a lot of space for new findings. Some processes that take place in the immune system have not been adequately understood. Often the doctors only have to treat the symptoms with substances that suppress inflammation in general.

As at the University Clinic in Freiburg, scientists around the world are working on influencing the misdirected immune system of allergy sufferers in a more targeted manner than before. Using genetic engineering methods, it could be possible to dissuade the immune system from its astray.

Prof. Schöpf: "One of the main thrusts is the better identification of the chemical structure of the allergens, which is responsible for the triggering of the allergies. This also has major consequences for the desensitization therapy, because it can be used to produce vaccines that are very specific and very clean, so to speak, of the triggering allergen The second main thrust is the manipulation of immunoglobulin E production in our body. Our genetic disposition as allergy sufferers leads to the fact that we excessively produce too much immunoglobulin E when we come into contact with allergens after appropriate sensitization. And This excessive IgE production can already be suppressed in certain animal models and slowed down with substances that are in hand, and I think that therapeutic developments can also be expected here for humans in the next few years ten are. "