Hypersensitivity and Autoimmune Disease Flashcards
What is a Hypersensitivity
A condition in which the immune system, which normally serves a protective role, has a harmful effect
Allergy
Abnormal immunological response to an otherwise harmless environmental stimulus
Autoimmune disease
An abnormal immunological response directed against an antigen that is part of the body
Type I
Preformed IgE antibodies coating mast cells and basophils are crosslinked by contact with free antigen.
Mast cells and basophils in type I ______ and release _____
Degranulate and Histamine and other inflammatory mediators
Hypersensitivity response
Allergy - Type I
Cytotoxic- Type II
Immune Complexes - Type III
Delayed (Cell mediated) Type IV
Causes of Type I
Drug reactions
Food allergies
Insect venom
Atopy
Type II
IgM and IgG antibodies bond to antigen on the self tissue (e.g. RBC). This leads to complement activation and lysis and phagocytosis
Causes of Type II
Acute haemolytic transfusion Autoimmune anaemia Good Pasture's syndrome Graves disease Thrombocytopenia
Type III
Antibodies bind to antigen in circulation and form complexes and are deposited in particular tissues
What do the deposition in Type III cause
Inflammation
Consequences of Type III
Glomerulophritis
Systemic Lupus
Type IV
Contact with antigen with presensitised T lymphocytes release cytokines that drive immune response
Consequences of Type IV
Graft vs host disease
Rheumatoid arthritis
Type 1 diabetes
Atopy
Genetic tendency to develop allergic diseases such as asthma
Purpose of Neutrophils
Release cytokines which amplify inflammatory response
How do T cells cause tissue damage
Cytokines which are produced by CD4+ T cells and Direct cell cytoxicity mediated by CD8+ T cells
Immune tolerance
Failure to mount an immune response to an antigen
Central tolerance
Main way the immune system learns to discriminate self from non-self
Two types of autoimmune diseases
Systemic
Organ specific
Systemic
Lupus, Rheumatoid arthritis
Organ specific
Good Pasture’s
Hashimoto’s Thyroiditis
Type 1 diabetes
Type V
Antibodies bind to cell surface and prevents the intended ligand binding with the receptor
