Mast cell activation syndrome

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Mast cell activation syndrome
Specialty Immunology (Allergy)

Mast cell activation syndrome (MCAS) is a term referring to one of two types of mast cell activation disorder (MCAD); the other type is idiopathic MCAD. [1] MCAS is an immunological condition in which mast cells, a type of white blood cell, inappropriately and excessively release chemical mediators, such as histamine, resulting in a range of chronic symptoms, sometimes including anaphylaxis or near-anaphylaxis attacks. [2] [3] [4] Primary symptoms include cardiovascular, dermatological, gastrointestinal, neurological, and respiratory problems. [3] [5]

Contents

MCAS is an umbrella term that describes a set of symptoms; it is not a specific diagnosis. [1] [6] Multiple diagnostic schemes for MCAS have been proposed. MCAS has been increasingly over-diagnosed or misdiagnosed. [7] [8]

Signs and symptoms

Because degranulation events can be triggered in various locations within the body, MCAS can present with a wide range of symptoms in multiple body systems. These symptoms may range from digestive discomfort to chronic pain, mental issues, or full-scale anaphylactic reactions. Symptoms typically wax and wane over time, varying in severity and duration. Many signs and symptoms are the same as those for mastocytosis, because both conditions result in too many mediators released by mast cells. [5] [9]

Common symptoms include: [10]

Causes

There are many causes of mast cell activation, including allergy. Genetics may play a role. In particular, mutations of the KIT gene (which codes for the KIT protein that regulates cell growth), specifically around codon 816 with the common one being asp816val, have been suspected to be associated with MCAS and is also associated to most systemic mastocytosis patients. [5] [11] [12] It has been found that people with MCAS tend to have a wider range of KIT mutations around all domains of the protein and multiple at the same time rather than a single one, which could be a potential cause of the heterogeneity of the presenting symptoms of MCAS. Symptoms of MCAS are caused by excessive chemical mediators released by mast cells. [13] Mediators include leukotrienes, histamines, prostaglandin, and tryptase. [14]

Pathophysiology

Mast cell activation syndrome can be categorized into three subclasses depending on the trigger which "activates" the degranulation of cells. In Primary MCAS, researchers theorize that the threshold for chemical mediator release, also called degranulation, is lower, meaning it takes less outside stimulation to cause a reaction. [15] Other research has demonstrated that some patients, specifically those with Monoclonal Mast Cell Activation Disorder and those with Mastocytosis have something of an 'overpopulation' of mast cells in the bone marrow, which leads to stronger response when triggered [16] . Secondary MCAS is far more common, and involve an unclear etiology, though not directly related to monoclonal cells. In these cases, reactions occur as a result of IgE-mediated (an environmental allergen, such as food or medication and non-IgE-mediated (such as exercise) mechanisms [17] . Idiopathic MCAS occurs in patients who have an unremarkable workup, including a benign bone marrow biopsy, which suggests that there are no allergic causes or clonal mast cell diseases [17]

Mast cell activation can be localized or systemic, but a diagnosis of MCAS requires systemic symptoms. [18] [19] Some examples of tissue specific consequences of mast cell activation include urticaria, allergic rhinitis, and wheezing. Systemic mast cell activation presents with symptoms involving two or more organ systems (skin: urticaria, angioedema, and flushing; gastrointestinal: nausea, vomiting, diarrhea, and abdominal cramping; cardiovascular: hypotensive syncope or near syncope and tachycardia; respiratory: wheezing; naso-ocular: conjunctival injection, pruritus, and nasal stuffiness). This can result from the release of mediators from a specific site, such as the skin or mucosal tissue, or activation of mast cells around the vasculature. [20]

Diagnosis

MCAS is often difficult to identify due to the heterogeneity of symptoms and the "lack of flagrant acute presentation". [10] Many of the numerous symptoms are non-specific in nature. Diagnostic criteria were proposed in 2010 [3] and revised in 2019. [19] Mast cell activation was assigned an ICD-10 code (D89.40, along with subtype codes D89.41-43 and D89.49) in October 2016. [21]

According to the American Academy of Allergy, Asthma, and Immunology (AAAI), the most precise method of diagnosing MCAS is through a bone marrow biopsy and aspirate. [19] This method is commonly used to diagnose systemic mastocytosis, and the presence of SM increases the possibility of subsequently having MCAS. In addition, other common laboratory tests including KIT-D816X mutational analysis and flow cytometry analysis seeking co-expression of CD117 and CD25 are also commended for diagnosing clonal MCAS. [22]

Although different diagnostic criteria are published, a commonly used strategy to diagnose patients is to use all three of the following:[ citation needed ]

  1. Symptoms consistent with chronic/recurrent mast cell release:
    Recurrent abdominal pain, diarrhea, flushing, itching, nasal congestion, coughing, chest tightness, wheezing, lightheadedness (usually a combination of some of these symptoms is present)
  2. Laboratory evidence of mast cell mediator (elevated serum tryptase, N-methyl histamine, prostaglandin D2 or 11-beta- prostaglandin F2 alpha, leukotriene E4 and others)
  3. Improvement in symptoms with the use of medications that block or treat elevations in these mediators

The World Health Organization has not published diagnostic criteria.

Treatment

Pharmacological treatments include:

Prognosis

The prognosis of MCAS is uncertain. [19]

History

The condition was hypothesized by the pharmacologists Oates and Roberts of Vanderbilt University in 1991, and named in 2007, following a build-up of evidence featured in papers by Sonneck et al. [26] and Akin et al. [27] [9]

See also

Related Research Articles

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Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions.

Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of the use of emergency medication on site. It typically causes more than one of the following: an itchy rash, throat closing due to swelling that can obstruct or stop breathing; severe tongue swelling that can also interfere with or stop breathing; shortness of breath, vomiting, lightheadedness, loss of consciousness, low blood pressure, and medical shock. These symptoms typically start in minutes to hours and then increase very rapidly to life-threatening levels. Urgent medical treatment is required to prevent serious harm and death, even if the patient has used an epipen or has taken other medications in response, and even if symptoms appear to be improving.

<span class="mw-page-title-main">Mastocytosis</span> Medical condition

Mastocytosis, a type of mast cell disease, is a rare disorder affecting both children and adults caused by the accumulation of functionally defective mast cells and CD34+ mast cell precursors.

<span class="mw-page-title-main">Mast cell</span> Cell found in connective tissue

A mast cell is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a part of the immune and neuroimmune systems. Mast cells were discovered by Paul Ehrlich in 1877. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing, angiogenesis, immune tolerance, defense against pathogens, and vascular permeability in brain tumors.

<span class="mw-page-title-main">Immunoglobulin E</span> Immunoglobulin E (IgE) Antibody

Immunoglobulin E (IgE) is a type of antibody that has been found only in mammals. IgE is synthesised by plasma cells. Monomers of IgE consist of two heavy chains and two light chains, with the ε chain containing four Ig-like constant domains (Cε1–Cε4). IgE is thought to be an important part of the immune response against infection by certain parasitic worms, including Schistosoma mansoni, Trichinella spiralis, and Fasciola hepatica. IgE is also utilized during immune defense against certain protozoan parasites such as Plasmodium falciparum. IgE may have evolved as a defense to protect against venoms.

<span class="mw-page-title-main">Food allergy</span> Hypersensitivity reaction to a food

A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe, it is known as anaphylaxis. A food intolerance and food poisoning are separate conditions, not due to an immune response.

<span class="mw-page-title-main">Omalizumab</span> Monoclonal antibody medication

Omalizumab, sold under the brand name Xolair among others, is an injectable medication to treat severe persistent allergic forms of asthma, nasal polyps, urticaria (hives), and immunoglobulin E-mediated food allergy.

<span class="mw-page-title-main">Aspirin-exacerbated respiratory disease</span> Chronic inflammatory disease affecting the sinuses and lungs

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<span class="mw-page-title-main">Tryptase</span> Class of enzymes

Tryptase is the most abundant secretory granule-derived serine proteinase contained in mast cells and has been used as a marker for mast cell activation. Club cells contain tryptase, which is believed to be responsible for cleaving the hemagglutinin surface protein of influenza A virus, thereby activating it and causing the symptoms of flu.

<span class="mw-page-title-main">Soy allergy</span> Type of food allergy caused by soy

Soy allergy is a type of food allergy. It is a hypersensitivity to ingesting compounds in soy, causing an overreaction of the immune system, typically with physical symptoms, such as gastrointestinal discomfort, respiratory distress, or a skin reaction. Soy is among the eight most common foods inducing allergic reactions in children and adults. It has a prevalence of about 0.3% in the general population.

<span class="mw-page-title-main">Milk allergy</span> Type of food allergy caused by milk

Milk allergy is an adverse immune reaction to one or more proteins in cow's milk. Symptoms may take hours to days to manifest, with symptoms including atopic dermatitis, inflammation of the esophagus, enteropathy involving the small intestine and proctocolitis involving the rectum and colon. However, rapid anaphylaxis is possible, a potentially life-threatening condition that requires treatment with epinephrine, among other measures.

<span class="mw-page-title-main">Solitary mastocytoma</span> Medical condition

Solitary mastocytoma, also known as cutaneous mastocytoma, may be present at birth or may develop during the first weeks of life, originating as a brown macule that urticates on stroking. Solitary mastocytoma is a round, erythematous, indurated lesion measuring 1-5 cm in diameter. It can be mildly itchy or asymptomatic and develops over time. Predilection is the head and neck, followed by the trunk, extremities, and flexural areas.

<span class="mw-page-title-main">Chronic spontaneous urticaria</span> Medical condition

Chronic spontaneous urticaria(CSU) also known as Chronic idiopathic urticaria(CIU) is defined by the presence of wheals, angioedema, or both for more than six weeks. The most common symptoms of chronic spontaneous urticaria are angioedema and hives that are accompanied by itchiness.

Kounis syndrome is defined as acute coronary syndrome caused by an allergic reaction or a strong immune reaction to a drug or other substance. It is a rare syndrome with authentic cases reported in 130 males and 45 females, as reviewed in 2017; however, the disorder is suspected of being commonly overlooked and therefore much more prevalent. Mast cell activation and release of inflammatory cytokines as well as other inflammatory agents from the reaction leads to spasm of the arteries leading to the heart muscle or a plaque breaking free and blocking one or more of those arteries.

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Peter Valent is an Austrian hematologist and stem cell researcher. Since 1990 he leads a research group at the Medical University of Vienna. From 2002 he coordinates the European Competence Network on Mastocytosis and since 2008 he is Scientific Director of the Ludwig Boltzmann Institute for Hematology and Oncology of the Ludwig Boltzmann Society in Austria.

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<span class="mw-page-title-main">Sesame allergy</span> Food allergy caused by sesame seeds

A food allergy to sesame seeds has prevalence estimates in the range of 0.1–0.2% of the general population, and are higher in the Middle East and other countries where sesame seeds are used in traditional foods. Reporting of sesame seed allergy has increased in the 21st century, either due to a true increase from exposure to more sesame foods or due to an increase in awareness. Increasing sesame allergy rates have induced more countries to regulate food labels to identify sesame ingredients in products and the potential for allergy. In the United States, sesame became the ninth food allergen with mandatory labeling, effective 1 January 2023.

References

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