Allergic Reaction
An allergic reaction is when the immune system contains B cells which recognise what would normally be harmless, such as dust, pollen and some types of food like nuts, shellfish, milk, eggs etc. Because of this immune responses to environmental agents, which aren’t normally harmful are now known as being hypersensitivities or allergens. And when people with allergies are exposed to these typically harmless substances now have exaggerated responses which can lead to death.
The components of the immune system that lead to allergic reactions are to an extent B plasma cells and majority mast cells. The B plasma cell release antibodies that in an allergic reaction are attached to mast cells which due to the antibodies on its external surface are now hypersensitive. This hypersensitivity no causes which are extravagant in comparison to the ‘allergen’ the body is fighting.
The specific immune system is the part at fault here, as mast cells due to the production of antibodies known as IgE from B plasma cells have stuck to the external surface of the mast cell making it hypersensitive. This hypersensitivity causes the mast cells to release amounts of histamine when the IgEs on its external surface come into contact with the ‘allergen.’ This excessive release of histamine causes the blood vessels to increase in permeability, which leads to swelling and redness. This large amount of widespread histamine can also cause the contraction of smooth muscle tissue like that found in the lungs, which makes breathing difficult, also known as anaphylaxis. There is treatment for these reactions. Drugs such as antihistamines can suppress the reactions caused by the unnecessary amount of histamine. However if these drug aren’t taken in time then the sufferer can die.
Video on IgE and Allergic Responses:
http://highered.mcgraw-hill.com/olc/dl/120110/micro38.swf
Video on IgE and Allergic Responses:
http://highered.mcgraw-hill.com/olc/dl/120110/micro38.swf