Hypersensitivity
Excessive, undesirable reactions produced by the normal
immune system.There are four type of
hypersensitivity reactions.
Type 1 – Anaphylaxis reaction
Occur after ten to fifteen minutes of exposure. Primary involve
cellular component in this type is basophil or mast cell and involve antibody
is IgE.
eg: - allergy, asthma, anaphylaxis
Type 2 – Cytotoxic reaction
This is an antibody mediated reaction and mainly involves
IgG and IgM.
eg: - Blood transfusion reaction, Hemolytic disease of new
born, Autoimmune hemolytic anemia….
Type 3 – Immune complex mediated reaction.
This is due to deposition of antigen –antibody complex in
tissues.
eg: - Systemic lupus erythematosus, Serum sickness, Arthus
reaction, Post Streptococcal Glomerulonephritis.
Type 4 – Delayed type reaction
This is a cell mediated reaction and activated T lymphocytes
are mainly involved.
eg: - Contact dermatitis, Multiple sclerosis, Type 1
diabetic, Rheumatoid arthritis…..
