- Mast cells are immune cells that help defend the body against infections, toxins, and allergic reactions.
- Mast cells release substances like histamine, heparin, cytokines, and growth factors when activated by a specific stimulus.
- Mast cell levels may change in conditions like allergies, parasitic or bacterial infections, mastocytosis, and mast cell activation syndrome.
Mast cells are immune cells that develop in the bone marrow. They help defend the body against infections caused by parasites and bacteria, play a key role in allergic reactions, support normal immune function, and help maintain cardiovascular health.
Mast cells can perform these functions because they store active substances in granules inside the cell and on the cell membrane. These substances include histamine, heparin, cytokines, proteases, and growth factors, which are released according to the specific type of stimulus.
Mast cells are released from the bone marrow as immature progenitor cells. When a stimulus occurs, these cells travel to the site where they are needed and mature there so they can perform their function.
Main functions
The main functions of mast cells are:
- Defending the body against parasites and bacteria by releasing substances that coordinate the immune response and help eliminate these microorganisms
- Protecting the body from toxins and venoms, as mast cells can be activated by these substances and help break them down
- Identifying foreign agents in the body and starting a defense response by activating other immune system cells
- Helping fight allergic reactions by releasing histamine and leukotrienes when activated
- Helping form new blood vessels by stimulating angiogenesis, which is the formation of new vessels and can affect blood flow in tissues
Mast cells are activated when there is inflammation in the body. This causes the substances stored in their granules to be released, which helps reduce inflammation and stimulate the activity of other immune defense cells.
Mature mast cells are found throughout the body, especially in the skin, lungs, and gastrointestinal tract. Under normal conditions, mature mast cells do not circulate in the bloodstream and are only activated and differentiated when there is an inflammatory signal that causes them to move to the site where they are needed.
How mast cells are detected
Mast cells can be detected through specific tests. A skin biopsy is usually recommended, as mast cells are found in higher amounts in the skin.
In addition, tests may be ordered to measure substances released by mast cells during their activity, such as tryptase or histamine. This can be done with a blood test.
However, mast cell testing is not commonly performed. Other tests are often more useful for evaluating overall health and the body’s response to inflammation or infection, such as a complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).
What causes abnormal mast cell levels
Mast cell levels may be higher or altered in conditions such as:
1. Allergies
Mast cells work together with basophils to trigger and amplify allergic reactions. They increase blood vessel permeability, cause muscle contraction, and increase mucus production, leading to typical allergy symptoms such as a runny nose, watery eyes, itching, and swelling.
In addition, mast cells are found in higher amounts in cases of anaphylaxis. This is a severe allergic reaction that can be life-threatening, as it may cause difficulty breathing due to excessive contraction of the respiratory muscles and intense localized swelling.
2. Parasitic and bacterial infections
Mast cell levels can also increase in cases of parasitic infections, especially helminth infections, and bacterial infections.
This is because mast cells regulate the activity of antigen-presenting cells, such as dendritic cells, which present infectious agents to other immune system cells so they can be eliminated by macrophages.
3. Mastocytosis
Mastocytosis is a rare condition characterized by an abnormal accumulation of mast cells in the skin and/or other organs, according to the National Organization for Rare Disorders. It can cause symptoms depending on where mast cells are most concentrated, such as red spots on the skin, excessive itching, numbness in the fingertips, headache, dizziness, or diarrhea.
4. Mast cell activation syndrome
Mast cell activation syndrome is a rare condition that affects the immune system. According to the NIH Genetic and Rare Diseases Information Center, it causes repeated severe allergy-like symptoms that can affect several body systems, including the skin, gastrointestinal tract, heart, and respiratory system.
In mast cell activation syndrome, a person may have excessive itching, redness, swelling, increased heart rate, low blood pressure, nausea, vomiting, cramps, runny nose, and difficulty breathing. Wheezing may also be noticed when breathing.