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Mast cells - immune system and allergies

What are mast cells? Mast cells are cells produced by the body that are responsible , among other things, for the immune system . They help the body to fight off pathogens such as viruses, bacteria, fungi, or parasites , but they also play an important role in allergic reactions . Histamine, as a mast cell mediator, also plays a crucial role in immunology and allergies.

The relationship between mast cells, allergy and immune response

Allergic diseases come in numerous forms : allergic asthma, atopic dermatitis, hay fever, hives (urticaria), food allergies, and allergic alveolitis (inflammation of the alveoli). IgE-mediated allergies are classified as type I allergies . These affect an estimated 20% of the world's population. Many people with these allergies have a genetic predisposition to reacting to harmless environmental antigens.
Environmental factors such as air pollutants, viral infections, allergens, and other sensitizers also play a role. It has been proven that people who grew up on a farm or were cared for in a daycare center as toddlers are less affected by allergies. This is most likely due to the early exposure of the immune system to specific pathogens , which can prevent a predisposition to more pronounced allergic reactions.

How do mast cells trigger an allergic reaction?

Mast cells can not only exacerbate allergy symptoms but also trigger allergies . Various messenger substances , including histamine , are found within mast cells . Histamine influences the activity of mast cells during allergic reactions. Certain factors such as stress, infections, medications, alcohol, sudden temperature changes, insect bites, or foods can trigger the release of these messenger substances, including histamine, by mast cells.
Mast cells in the skin are responsible for spots, hives, swelling, itching, or blisters. Mast cells in internal organs, such as the gastrointestinal tract or liver, can lead to abdominal pain, nausea, diarrhea, or fatigue. An increased number of mast cells or altered mast cells can indicate a mast cell disorder , such as mastocytosis or mast cell activation syndrome (MCAS). This article explains how to recognize these conditions.

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How do mast cells contribute to the body's own defense system?

Mast cells are located in well-vascularized skin tissue, the gastrointestinal tract, and the respiratory system, resulting in close contact with the environment . Acute allergic reactions can occur within seconds or minutes . Allergens bind to the FcεRI receptor on basophils and mast cells via IgE molecules. Following antigen contact, the receptors cross-link, causing the cells to become extremely active .

As a result, mast cells release substances stored in their secretory granules (cells specialized for secretion), such as histamine, cytokines, proteoglycans (e.g., heparin), growth factors, and enzymes (e.g., tryptase). This occurs through a process called degranulation , in which the vesicles within a cell bind to its cell membrane and release secretions. This is actually a normal process controlled by the immune system to fight pathogens . Disruption of degranulation can also impair the immune response.


How are mast cells associated with inflammation?

Lipid mediators such as leukotrienes and prostaglandins are rapidly synthesized and released into the surrounding tissue. Growth factors and cytokines are also newly synthesized. The released histamine ultimately leads to the dilation and increased permeability of blood vessels and affects cell layers and nerves .

Symptoms include edema, skin rash , migraines , muscle pain, cold-like symptoms, diarrhea and constipation , and much more. Tryptase release can also damage connective tissue cells and the intercellular substance. This disrupts the smooth functioning of cell-cell communication. Instead, immune cells such as granulocytes (white blood cells) and goblet cells can be activated. An increased number of granulocytes can promote infections, inflammation, and chronic diseases such as rheumatoid arthritis .

Goblet cells produce mucus to defend against pathogens. However, overproduction can lead to breathing difficulties. Mast cells also secrete pro-inflammatory cytokines (pro-inflammatory polypeptides) . These play a key role in inflammatory and immune responses . With prolonged exposure to allergens, the inflammatory process can become chronic.

What medications and therapies are available?

The most important therapy for calming mast cells is an elimination diet in the form of a low-histamine diet . Additionally, there are (natural) mast cell stabilizers available in the form of medications and foods (see below). Those who have been medically diagnosed with a mast cell disorder can obtain a prescription for additive-free mast cell stabilizers.

Mast cells and a low-histamine diet

Can mast cells be influenced by diet? Indeed, certain foods can activate or even calm mast cells. Therefore, a low-histamine diet can reduce mast cell activity and allergic reactions . Natural, low-histamine mast cell stabilizers include quercetin, curcumin, and luteolin . Examples of foods that contain these include:
  • apples
  • Blueberries
  • celery
  • red leaf lettuce
  • onions
  • asparagus
  • red grapes
  • broccoli
  • Capers
  • turmeric
  • carrots
  • lettuce
  • olive oil
  • rosemary
  • thyme
  • oregano
  • Chamomile tea
broccoli
However, there are also DAO / HNMT inhibitors and foods that contribute to increased mast cell activation . These include histamine liberators, histamine-rich foods, and foods containing biogenic amines such as...
  • offal
  • Cashew nuts
  • Walnuts
  • eggs
  • Shellfish
  • avocado
  • citrus fruits
  • pineapple
  • tomatoes
  • alcohol
  • cocoa
  • sauerkraut
  • mature cheese
  • salami

Outlook for further research

The research surrounding mast cells still raises many questions. The topic of mast cell activation syndrome (MCAS) is particularly under-researched. Even certain odors, such as fragrances, can trigger anaphylactic shock in affected individuals. The MCAS Hope association, through its scientific MAGELLAN study , in collaboration with Aachen University Hospital, Charité Berlin, and FOM University of Applied Sciences Düsseldorf, has made it its mission to investigate mast cell activation syndrome from a systems medicine perspective. The aim is to gain new insights into the disease and to identify new approaches to therapy and diagnostics .


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