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| An
allergy can refer to several kinds of immune reactions including
Type I hypersensitivity in which a person's body is hyper
sensitized
and develops IgE type antibodies to typical proteins. When a person
is hypersensitive, these substances are known as allergens. The
word allergy derives from the Greek words allos meaning "other"
and ergon meaning "work". Type I hypersensitivity is
characterized
by excessive activation of mast cells and basophils by immunoglobulin
E resulting in a systemic inflammatory response that can result
in symptoms as benign as a runny nose, to life-threatening anaphylactic
shock and death. |
| Allergy
is a very common disorder and more than 50 million Americans suffer
from allergic diseases. Allergies are the 6th leading cause of chronic
disease in the United States, costing the health care system $18
billion annually. |
| Hyposensitization
is a form of immunotherapy where the patient is gradually vaccinated
against progressively larger doses of the allergen in question.
This can either reduce the severity or eliminate hypersensitivity
altogether. It relies on the progressive skewing of IgG ("the
blocking antibody") production, as opposed to the excessive
IgE production seen in hypersensitivity type I cases. Delivery can
occur via allergy injection, or sublingual immunotherapy, allergy
drops taken under the tongue. Though not commonly offered in the
U.S., sublingual immunotherapy is gaining attention internationally.
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| A
second form of immunotherapy involves the intravenous injection
of monoclonal anti-IgE antibodies. These bind to free and B-cell
IgE signalling such sources for destruction. They do not bind to
IgE already bound to the Fc receptor on basophils and mast cells
as this would stimulate the allergic inflammatory response. The
first agent in this class is omalizumab. |
| An
experimental treatment form, enzyme potentiated desensitization,
has been tried with some success but is not in widespread use. EPD
uses dilutions of allergen and an enzyme, beta-glucuronidase, to
which T-regulatory lymphocytes respond by favoring desensitization,
or down-regulation, rather than sensitization. EPD is also under
development for the treatment of autoimmune diseases.
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