Mast cell

A mast cell is a type of white blood cell called a granulocyte. Mast cells are present in most tissues surrounding blood vessels and nerves, and are play an important role in the mucosal immune system and allergic response.

They release histamine and heparin.

Physiology

Degranulation

Mast cells are activated by a transient rise in calcium in the cytosol.

Infection

In a mouse model of myocarditis, Coxsackievirus infection was found to upregulate Toll-like receptor 4 on mast cells and macrophages immediately following infection. It also increased numbers of mast cells.

Central nervous system

Mast cells play an important role in the gut-brain axis. They are found throughout the gastrointestinal tract near sensory nerve fibers. In the nervous system, they are found on the blood-brain barrier, in the dural layer of the meninges, and in areas of the brain responsible for pain or neuroendocrine functions including the pituitary stalk, pineal gland, thalamus, and hypothalamus.

They are the main effector cells though which intestinal pathogens can affect the brain.

Mast cell activation disorder

Mast cell activation disorder (MCAD) is a disorder where mast cells are normal in number but over-responsive to dietary and environmental triggers. Cells release excess histamine and other signaling molecules, causing symptoms. It is often found in patients with Ehlers-Danlos syndrome (EDS) and postural orthostatic tachycardia syndrome (POTS), a form of orthostatic intolerance.

Mastocytosis

Mastocytosis is a genetic disorder of excessive populations of mast cells.

Chronic fatigue syndrome

One study found that moderate and severe ME/CFS patients had higher levels of naive mast cells than healthy controls.

Notable studies

• 2016, Novel characterisation of mast cell phenotypes from peripheral blood mononuclear cells in chronic fatigue syndrome/myalgic encephalomyelitis patients (Donald Staines, Sonya Marshall-Gradisnik)

mouse model The use of special strains of mice to study a human disease or condition, and how to prevent and treat it

central nervous system (CNS) - One of the two parts of the human nervous system, the other part being the peripheral nervous system. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system consists of nerves that travel from the central nervous system into the various organs and tissues of the body.

postural orthostatic tachycardia syndrome (POTS) - A form of orthostatic intolerance where the cardinal symptom is excessive tachycardia due to changing position (e.g. from lying down to sitting up).

mastocytosis A type of mast cell disease in which chronic symptoms are related to overproduction or over-accumulation of mast cells. Not to be confused with Mast Cell Activation Syndrome (MCAS), where there are normal numbers of mast cells, but abnormal activity.

dysautonomia disorders of the autonomic nervous system that cause disturbances in all or some autonomic functions, may cause problems regulating autonomic functions, including heart rate, blood pressure, body temperature, and digestion. Can cause symptoms including lightheadedness, fainting, unstable blood pressure, and orthostatic intolerance.