Hypersensitivity

Hypersensitivity

1. Type One

   • Immediate, allergies  wrong antibody choice  Anaphylactic shock  atopic- localized instead of IgA and IgG it recreates IgE which binds to the mast cells instead  Degranulation of mast cells leads to inflammation 
   • Concern Anaphylaxis
     • Mast cells are everywhere  local effects, but the later phase is systemic
   • asthama
     • Chronically inflamed respiratory tract severely overreactive to allergy chemicals like leukotrienes and serotonin
     • Treatments
       • Steroids= anti-inflammatory bronchodialator= relax the contracted muscle  **combo drugs do both 
   • Atopic Dermatitis aka eczema
     • making IgE early on infants- weepy/blistery adults- dry and thick Exposure to allergen on the skin 
   • Food and Drug Allergies
     • Starts with vomiting and diarrhea classic food allergy involves IgE and degranulation of mast cells 
   • Wheel and Flare Rxn
     • Skin testing: Just underneath the skin, Measure each of the zones  InVitro- measure elevated blood levels f tryptase and IgE, differential blood cell count, leukocyte histamine release test 
   • Treatment
     • Antihistamines
       • works on the surface of MY cels  blocks histamine by competitive inhibition 
       • Cromolyn
         • prevents mast cells from exploding 
       • Epipen
         • Epinephrine, reverts anaphylactic shock  Vasoconstrictor- for Tx anaphylaxis Bronchodialator- for Tx asthma
     • Desensitization
       • allergy drop attaches to antibody TH1 responses Shot therapy- blocking antibody shot 

2. Type Two: Cytotoxic

   • NOT misrecognition, we are fighting something that is actually foreign 
   • Blood Transfusion
   • Hemolytic disease of the newborn
     • IgG response to the RH in the pregnancy of second child  RH- mother RH+ father
     • RHOGAM
       • medication  never generates an attack binds cross-fetal cells before it effects memory
   • Drug induced
     • Haptens
       • when it binds to self-cells it appears to be foreign (destroys platelets)  Targeting the combination of self and foreign 
       • ITCP
         • easily bleeding, bruising
       • AIHA
         • Destruction of red blood cells 
   • Autoimmune AIHA
     • destruction of red blood cells  sore tongue warm= IgG//Cold Igm

3. Type Three Complexing

   • Hypersensitivity  "Misclearance"- where something that should have been cleared is targeted for a second reaction  Relocation of the antigen + antibody (activates new response which could be detrimental 
   • Systemic
     • Lupus
       • Butterfly rash 
     • Rheumatoid Arthritis
       • sand filled joints 
     • Serum sickness reaction
   • Localized
     • Glomerulonephritis aka kidney failure
     • Hypersesitivity pneumontis
     • Arthus reaction to vaccine

4. Type Four: delayed Hypersensitivity

   • Mis-response lazy macrophage syndrom 
   • Poison Ivy
     • Causes a T-Cell reaction mild-hasty inflammation  "going for the fly on the wall with a tank" Takes time because we are calling the T-Cells 
   • PPD Testing
     • strip of unique piece of tuberculosis (no big deal) and inject it, if they have never seen it before they don't care because they are "Naive" but if they have seen it before they realize where it came from and you see a greater reaction to it 
   • Why?
     • Epitope spreading- everytime they blow up a cell they find more epitopes to fight 
   • Graft rejection
     • Can eventually catch on causing a slow reaction  or Passager lymphocytes from the donor come out and attack the host
     • Auto
     • Allo
     • Xeno
   • SJS/TEN
   • Treatments
     • Corticosteriods
     • Anti-B7/anti IL-2
       • B7- co-stimulation  IL-2- T-Cell growth factor