You may not have heard of the name 'Mast Cells' before, right? But these are a very important type of cell that protects our body. Like little guards inside our bodies. However, sometimes when these guards get a little too excited, we get into trouble. Today, let's talk in detail, very simply, about what these mast cells are, how they work in our bodies, and what conditions they can cause.
What are Mast Cells?
Simply put, mast cells are special soldiers in our immune system . They are produced in our bone marrow . They then travel through our bloodstream and settle in various tissues throughout the body. Like sentinels stationed in different parts of the country, these mast cells are stationed in various parts of our body, ready to protect us from external threats. They can fight off various infections and help regulate the functioning of our body’s organs.
However, sometimes these mast cells become overprotective and start reacting to things that are actually harmless to us. If you have seasonal allergies or allergic asthma, one reason for this is because of mast cell activity. In some severe cases, mast cell activation can even cause a sudden, serious allergic reaction called anaphylaxis . So it's important to be aware of this.
What do mast cells do to our bodies?
Mast cells act like our body's 'alert system' . They protect our bodies from outside invaders, such as pathogens such as viruses, bacteria and parasites , as well as toxins such as snake venom and bee venom. They also fight against anything they think is harmful, even if it's not. That's when we get allergic reactions .
Unlike many other types of white blood cells, mast cells do not directly destroy pathogens. Instead, they sit on guard inside our tissues, waiting for a signal that something harmful has entered the body.
How do mast cells work?
Imagine that something you don't like, for example, a dust particle, pollen, or a food you are allergic to, enters your body. Another special type of cell in our immune system, called B cells, recognizes this invader. Once recognized, they start making a special type of protein, called antibodies, to fight it. The special antibody that is produced at this time is called Immunoglobulin E (IgE) .
These IgE antibodies quickly travel to and attach to specific receptors on the surface of mast cells, like a cat's claw. The next time the same invader (e.g. pollen, dust) comes into the body again, the IgE on the mast cells will grab it.
That's when the mast cells are "activated." It's like a fire alarm being rung.
When mast cells are activated in this way, they suddenly release a chemical called histamine and many other chemicals stored in tiny sacs (storage granules) inside those cells. This is called degranulation .
It is these histamines and other chemicals that cause allergy symptoms. These include:
- Our blood vessels dilate, and fluid accumulates in the surrounding tissues, causing swelling . This allows immune cells to quickly rush to the site of infection, carrying the invaders to the lymph nodes to destroy them.
- Mucus (phlegm) production increases.
- The smooth muscles in our respiratory tract and gastrointestinal system (intestines) contract and try to push harmful substances out with a wave-like movement (peristalsis).
These things can cause your skin to become red, swollen, and itchy. You may have a runny nose, sneeze, or cough. Sometimes you may even have diarrhea or vomiting. In very severe cases, this process can cause the airways to swell, making it difficult to breathe, and cause a dangerous drop in blood pressure, which can even lead to severe anaphylaxis, a life-threatening condition.
Mast cells and homeostasis
In addition to causing allergies, mast cells help balance various processes in our body, that is, maintain a state of 'homeostasis' . Here are a few examples:
- Blood vessel growth.
- Bone growth.
- Growth and repair of respiratory tract cells.
Where are mast cells located in our body?
Compared to other types of white blood cells, mast cells are very few in our blood. Most of the time, we are exposed to something harmful by breathing it in, eating it, or through a skin wound. That's why mast cells are most often found in:
- In our respiratory tract and lungs .
- Our digestive system (GI tract) (stomach, intestines).
In addition, these mast cells are also located around our blood vessels and nerves.
What are the parts of a mast cell?
If you take a mast cell, it has a nucleus in the center, which is the "brain" of the cell. Around this nucleus are hundreds of small sacs called granules . These granules store various chemical messengers (mediators) . These messengers are what send signals to the body to respond when something harmful comes into contact with it. Some of the main ones are:
- Histamine: We've talked about this before. It dilates blood vessels, allowing fluids and immune cells to enter tissues. It also constricts the airways and gastrointestinal tract, producing mucus to help push out pathogens.
- Proteases: (Examples: tryptase, chymase, carboxypeptidase A). Proteases are a type of enzyme that breaks down proteins. They help break down connective tissue, which allows immune cells to more easily reach the area.
- Cytokines/chemokines: These are small proteins that signal other immune cells to make more copies of themselves, to make blood vessels "sticky" so that immune cells can be transported to tissues, and to recruit cells to clean and repair damaged areas.
- Heparin: This prevents blood from clotting, so it helps keep blood vessels open.
Mast cell receptors
Mast cells have many different receptors on their surface. These are specially shaped proteins. Like a key fits a lock, these receptors interact with other signaling proteins to activate the mast cells.
Of these, the IgE receptor, which we discussed earlier, is the most well-known. In addition, mast cells also have receptors for other types of antibodies (e.g., Immunoglobulin G / IgG) and for direct recognition of pathogens (e.g., Toll-like receptors).
What are the most common conditions associated with mast cells?
Some of the common conditions we see related to mast cells are:
- Environmental allergies (e.g., dust, pollen, pet dander)
- Asthma
- Food allergies
- Heat Blisters/ Hives
Rare mast cell diseases
In addition, there are several rare conditions associated with mast cells:
- Mast cell activation syndrome (MCAS): This is a condition in which, for no apparent reason, symptoms of allergy or anaphylaxis occur repeatedly.
- Sometimes there is an excessive increase in the number of mast cells in the body (Mastocytosis).
- Hereditary alpha-tryptasemia / familial hypertryptasemia: This is a condition that is passed down from person to person. It causes the body to have elevated levels of an enzyme called tryptase, which is produced by mast cells. However, many people with this genetic condition do not experience symptoms.
What are the common symptoms of mast cell disease?
Histamine released in mast cell disease can cause symptoms such as:
- Skin discoloration, redness, or itching.
- Swelling (edema) .
- Difficulty breathing.
- Recurrent anaphylaxis .
What tests are done to diagnose these conditions?
If a doctor suspects that you have a mast cell disorder, they may do tests like these to see if your mast cells are activated:
- Urine tests.
- Blood tests.
- Bone marrow tests.
- Skin tests.
A doctor can do allergy skin tests or blood tests to identify triggers. Sometimes a lab can also do genetic testing to see if your symptoms are caused by a hereditary condition.
What are the treatments for this?
Treatment for mast cell disease depends on your symptoms and what's causing them. Treatment may include:
- Avoiding known allergy triggers .
- Medications to control symptoms. These may include antihistamines , acid reducers, and leukotriene-modifying medications (e.g., montelukast).
- Mast cell stabilizers. These drugs prevent the release of chemicals such as histamine from mast cells.
- Medications to reduce or treat anaphylaxis. These include medications such as epinephrine and omalizumab .
- Cytoreductive therapy/chemotherapy . For severe cases of mastocytosis, chemotherapy drugs that are usually used to kill cancer cells are sometimes used.
So, are mast cells good or bad?
Most people only hear about mast cells when something goes wrong with them, so you might think that mast cells are a bad thing. But actually, they help protect our bodies from harmful invaders and regulate our organs. So, most of the time, they're good.
Imagine, sirens go off. The security team arrives at the scene. Your mast cells sound the alarm, and your immune system races to save the day. They are an essential part of our body's defense system. But we usually pay most attention to mast cells when they are a little too enthusiastic about their job. But they also strengthen our defenses and help regulate our blood vessels and organs. So, the next time you sneeze, have a runny nose, or feel a little itchy, don't forget to thank your mast cells for their vigilance!
Things to remember in summary
So, the most important thing to remember from all of this is that mast cells are very important little sentinels in our immune system. They protect us from various diseases and toxins from outside. But, sometimes when they become a little too sensitive, they can react to things that are actually harmless, and cause us conditions like allergies.
If you are experiencing frequent allergy symptoms, such as itchy skin, hives, runny nose, sneezing, or difficulty breathing, the best thing to do is to see a doctor and get advice without ignoring it. Don't worry, there are treatments available today that can help control many of these conditions.
` Mast cells, immune system, allergy, histamine, anaphylaxis, cell function, symptoms
💬 අදහස් (0)
තවමත් කිසිදු අදහසක් පළ කර නොමැත. ඔබේ අදහස පළමු වරට මෙහි එක් කරන්න.
ඔබේ අදහස එක් කරන්න