Hypersensitivity and Autoimmune disorders
Hypersensitivity
It means tissue damage due to reaction between immune system and
endogenous or exogenous antigen.
Types of Hypersensitivity
Type I
Type II
Type III
Type IV
= Anaphylaxis
= Cytotoxic antibodies reaction.
= Arthus reaction (locally) or Serum Sickness Systemic.
= Delayed hypersensitivity.
Hypersensitivity type I = Anaphylaxis = Immediate
Hypersensitivity
Occurs in people, genetically has ability to produce high level of
immunoglobulin type IgE.
Most IgE molecules are bound to the surface of mast cells and blood
basophils.
Mast cells in many respects are similar to basophils. Their cytoplasm is
filled secretary granules. These granules contain chemical mediators such as
histamine and proteoglycan.
Histamine is a potent vasodilator, increase permeability of blood vessels,
bronchial contraction and enhance inflammation.
Mast cells present in connective tissues of all the body, specially in the
skin, respiratory tract, and intestine.
