SEP 10, 2015

Mast Cells and Allergy Therapies

WRITTEN BY: Kara Marker
Allergic reactions occur when the immune system overreacts to an environmental protein that's not threatening the body. Peanuts, cat dander, shellfish - these are all some typical allergens that can cause serious harm to people whose immune systems respond negatively when ingested or inhaled. The American College of Allergy, Asthma, and Immunology lists medication and immunotherapy as two treatment options for different kinds of allergies. For minor allergies, pollen allergies for example, antihistamines and decongestants are effective therapies. Immunotherapy consists of desensitizing the body by injecting increasing amounts of the allergen over time. However, this treatment has a risk of contributing to anaphylactic shock, a severe response to a large amount of allergen that causes the body tissues to release large amounts of histamine, causing airway constriction and other severe symptoms (Medline Plus). This reaction is countered by administration of epinephrine (commonly known as an "epi pen"), which is a hormone that causes an "increase in heart rate, muscle strength, blood pressure, and sugar metabolism" (University of Delaware).


So far, there are no great preventative options for people with severe allergies other than avoiding the allergen and keeping an epi pen with them at all times in case of emergencies. However, scientists from Switzerland, Japan, and the United States have been collaborating on research surrounding the idea of manipulating the action of mast cells in such a way to develop a cure for allergies. Earlier this week, the idea of utilizing regulatory T cells to suppress allergic reactions was proposed by scientists in Vienna. It seems like scientists are piecing the puzzle together, and the collaborative action of regulatory T cells and mast cells could very well lead to an effective treatment for current allergies and potential prevention for development of new allergies. 


While regulatory T cells play a central role in regulating the immune response by ensuring recognition of "self" proteins and thus preventing autoimmune reactions, mast cells play a different role. According to Respiratory Medicine, mast cells are activated by the presence of an allergen, and upon activation they signal activity of other cells like B cell production of IgE, an immunoglobulin (antibody) that doubles back to stimulate mast cells to produce inflammatory cytokines (Asthma and Allergy Foundation of America) and Th2 lymphocyte differentiation. Thus, mast cells play a huge role in initiating the inflammatory response when exposed to an allergen. How then could they be used to suppress allergies? 

Fortunately, in addition to all of their pro-inflammatory activities, mast cells also induce the release of a substance called interleukin-2. IL-2 then stimulates regulatory T cell production. Then, those regulatory T cells can get to work controlling the inflammatory action of IgE and Th2 lymphocytes. Dr. Hideaki Morita, study leader, sees this relationship between mast cells and regulatory T cells as the link that could change the future of allergy treatment and prevention. In order to make a large enough difference in the fight against allergic reactions, the regulatory T cell count would have to be much higher than is naturally instigated by IL-2 production by mast cells. Dr. Morita sees the potential of making large-scale regulatory T cell production possible using mast cells in the laboratory. As studies continue, Dr. Morita considers the discovered relationship between mast cells and regulatory T cells as "the basis for a new way to handle allergies."

Check out the video below to learn more about the action of mast cells. 


Source: Medical Xpress