Hypersensitivities The Princess and the Pea Syndrome

Hypersensitivity refers to undesirable (damaging,intended ligand binding with the receptor or mimics the
discomfort-producing and sometimes fatal) reactionseffects of the ligand, thus impairing cell signaling and the
produced by the normal immune system.delayed hypersensitivity (DH), delayed-type
Hypersensitivity is a state of altered reactivity in whichhypersensitivity (DTH) that which takes 24 to 72 hours
the body reacts with an exaggerated immuneto develop and is mediated by T lymphocytes rather
response to a foreign agent; allergy is a synonym forthan by antibodies; usually used to denote the subset
hypersensitivity. anaphylaxis is a form ofof type IV hypersensitivity involving cytokine release
hypersensitivity. Hypersensitivity reactions require aand macrophage activation, as opposed to direct
pre-sensitized (immune) state of the host. The causescytolysis, but sometimes used more broadly, even as
of the hypersensitive are protein component, watera synonym of type IV h.
which contains the chemicals and bacteria, unawareOnly someone as refined and delicate as a princess
exposure to avery toxic chemical.would be able to feel a single pea through 23
The Gell and Coombs classification (below)mattresses. This strange statement is evolved from
distinguishes four types of hypersensitivity reactionsthe fairy that the measurement of a true princess was
based on antibody (I-III) or cell-mediated (IV) reactionsone who was sensitive enough to feel a pea under a
and constitutes a logical framework for understandingtall stack of mattresses.
hypersensitivity reactions although. Hypersensitivity toThe immune system is an integral part of human
flying insects such as flies and mosquitos is the mostprotection against disease, but the normally protective
common cause of itching in horses.  Itching is causedimmune mechanisms can sometimes cause
by the bite itself because flies have chewingdetrimental reactions in the host. Such reactions are
mouthparts and the bite is painful for the horse. known as hypersensitivity reactions, and the study of
However, it’s not only the bite as many horsesthese is termed immunopathology. Hypersensitivity is a
are hypersensitive to the saliva of the insect and thisstate of altered reactivity in which the body reacts
increases the inflammation. with an exaggerated immune response to a foreign
There are several types hypersensitivity and they aresubstance. Hypersensitivity reactions are classified as
antibody-dependent, immune complex, cell-mediated,immediate or delayed, types I and IV, respectively, in
the immediate in which this have guinea pig is injectedthe Gell and Coombs classification of immune
intravenously with an antigen. For this example, bovineresponses.
serum albumin (BSA, a protein) will be used. After twoHypersensitivity can also be a symptom of ADD and
weeks, the same antigen will be reinjected into theADHD (Symptoms of Adult ADD) and may also be
same animal.associated with certain mood disorders such as
Within a few minutes, the animal begins to suffocateschizophrenia, OCD, anxiety disorders, bipolar disorder
and dies by a process called anaphylactic shock,and as part of the cycle whenever someone
stimulatory which have binding to cell surfaceexperiences panic attacks. If you are experiencing
components, the antibodies recognize and bind to thehypersensitivity to the extent that is a health threat,
cell surface receptors, which either prevents thesee the appropriate mental health professional.