Zusammenfassung der Ressource
HYPERSENSITIVITY
- type 1
- immediate @ anaphylactic
- localized & systemic
- allergy
- 2 part mechanisms
- sensitization upon initial exposure
- degranulation of sensitized cells
- reexposures -> allergen bind to allergen-specific -> cross linkage -> sensitized cell activation -> synthesis of newly formed mediators
- may lead to ANAPHYLAXIS REACTION ( shock )
- type 2
- cytotoxic h/s
- IgM / IgG react with antigens on cell/tissue
- 3 syndromes
- blood transfusion reaction
- blood A, B, AB, O
- differ on surface antigen of RBC
- ntigen bind to transfused RBC -> complement pathway -> lysis of blood cells
- haemolysis diseases
- due to rhesus antigen of RBC
- Rh(+)- with rh antigen
- Rh(-) - no rh antigen
- Rhogam - anti-Rh serum
- Drug-induced hypersensitivity
- drugs -> complex formed -> foreign to host -> antibodies produced -> complenet lysis or phagocytosis
- destruction of platelets - inhibit ability clotting blood correctly
- type 3
- immune complex h/s
- complex escape phagocytosis and complement -> circulate -> trap in organ, joint and tissue -> trigger mast cells to degranulate -> damage the site
- 1. localized immune complex disease
- 2. systematic immune complex disease
- type 4
- cell mediated type h/s
- DTH responses -> Th1 secrete cytokinesis -> recruited cells secrete lytic enzymes -> damage to tissue
- occured in response to small chemical encountered with skin
- contact hypersensitivity
- too small to stimulate immune response in free form
- CH response : similar to DTH
- Autoimmune Disease
- immune response againts one or more self antigen
- Classifications
- 1. Organ specific AD
- 2. Non-organ specific AD
- it happens by :
- 1. complement-mediated lysis
- 2. Opsonisation
- 3. Inhibition of receptor function
- 4. Stimulation of receptors
- 5. Blockage of biological function
- 6. Deposition of immune complexes
- Causes of AD
- 1. Genetic
- 2. Environmental
- a) infectious agent
- b) drugs
- c) toxins & pollutants
- 3. Loss of immunotolerance
- caused by :
- a) production of high-affinity autoantibody
- b) Generation of autoreactive T cells
- c) Autoantibodies produced by autoreactive B cells in absence of T cells