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Glossary of mast cell related terms: P-Z

Parasympathetic nervous system: Part of the autonomic nervous system.  Regulates digestion and other functions.

Prostaglandin D2 (PGD2): The dominant prostaglandin produced by mast cells.

9a,11b-PGF2: a breakdown product of prostaglandin D2; can be measured to assess level of mast cell activation

Platelet activating factor (PAF): a mast cell mediator that correlates with severity of anaphylaxis; induces degranulation and release of leukotrienes and prostaglandins

Postural orthostatic tachycardia (POTS): increase of 30 bpm or more when standing in the absence of orthostatic hypotension.

Premedication: taking medication in advance of an event in order to suppress an undesirable reaction during the event, such as premedicating before surgery

Pre-stored: as relates to mast cell biology, mediators that are made inside the cell and stored in granules to be released at a later time

Progenitor cell: a cell that develops into another type of cell

Proliferation: growth and expansion of a cell population

Prostaglandin: a type of eicosanoid with wide ranging biological effects; PGD2 is the prostaglandin most abundantly produced by mast cells

Protracted anaphylaxis: a long episode of anaphylaxis symptoms despite treatment

Rare disease: a disease that affects only a small amount of people in a population; in the US, defined as affecting 200,000 people or less in the US

Rebound: a resurgence of symptoms after quelling symptoms earlier

Receptor: a protein on the outside of cells that bind specific molecules, causing a specific action to occur

Secretion: the release of molecules from inside the cell to the outside environment without degranulation

Sensitization: production of IgE specific to an allergen without obvious allergic reaction to the allergen

Serotonin: a neurotransmitter released by a number of cell types, including mast cells

Smouldering systemic mastocytosis (SSM): a form of SM in which organ damage and failure could eventually occur; diagnosed when someone with SM has two or more B findings

Splenomegaly: swelling of the spleen

Stem cell factor (SCF): a mast cell growth factor; SCF binds to CKIT and tells mast cells to stay alive and make more mast cells

Sympathetic nervous system: Part of the autonomic nervous system.  Controls the fight or flight response

Systemic mastocytosis (SM): a proliferative mast cell disease in which too many mast cells are produced

Systemic mastocytosis with associated clonal hematologic non-mast cell lineage disease (SM-AHNMD): co-occurrence of SM with another proliferative blood cell disorder, such as essential thrombocythemia or chronic myelogenous leukemia

Tachycardia: rapid heartbeat

Third spacing: when fluid is forced out of a place the body can use it and becomes trapped, such as ascites or angioedema

TLR: toll like receptor; receptors on the outside of many cells (including mast cells) that activate immune response to infections

Telangiectasia macularis eruptive perstans (TMEP): a less common form of cutaneous mastocytosis.  Found almost exclusively in adults.

Tryptase: a mast cell mediator; when tested outside of a symptomatic episode, it is used to measure the baseline amount of mast cells present ; when tested during a symptomatic episode, it can be used to identify mast cell activation

Urticaria pigmentosa (UP): also called maculopapular cutaneous mastocytosis (MPCM).  The most common form of cutaneous mastocytosis.

Urticaria: hives

Wheal and flare response: a reaction marked by redness and raised, taut skin due to histamine release