Immune system disorders

A. Hypersensitivities

Type I Hypersensitivity (allergy)

  1. First exposure to an allergen: 
  2. Second and later exposures to allergen
  3. Types of allergic reactions
  4. Treatments

Type II Hypersensitivity (Cytotoxic)

  1. Autoimmune Diseases
    1. Graves' Disease
      • IgG vs. TSH receptor = overstimulate thyroid
    2. Goodpasture's Syndrome
  2. Transfusion reactions
  3. Hemolytic Disease of newborns

Type III Hypersensitivity (Immune complex)Type III (Immune Complex) Hypersensitivity- Mechanism, Examples

  1. Lupus (SLE)
  2. Rheumatoid arthritis

Type IV Hypersensitivity (delayed hypersensitivity)

  1. Exposure to antigen activates special TH1 cells called TDTH cells
  2. TD cells proliferate = sensitization
  3. Second or continued exposure: 
  4. Examples

B. Immune deficiencies

  1. B-cell deficiencies
  2. T-cell deficiencies
  3. Phagocyte deficiencies
  4. Complement deficiencies
  5. Combined immunodeficiencies
  6. Neonates
    1. Passive protection by maternal IgG
    2. Insufficient T-cell responses (immature)
      • increased severity of viral infection (Herpes)
      • decreased severity of immunopathogenesis (measles)
Are T-cell deficiencies more serious than B-cell deficiencies?

C. Cytokine storm

  1. sepsis
  2. superantigens

D. autoimmunity

  1. Override Treg effect (excess cytokines)
  2. antigen cross-reaction

E. Immune system evasion by pathogens

  1. Bacteria
    1. evasion of phagocytosis
    2. complement inactivation
    3. antibody binding/destruction
    4. intracellular life
    5. antigenic variation
  2. Viruses
    1. Hidden from immune system (latency; syncytia)
    2. antigenic variation
    3. blocking antigens
    4. IFN suppression
    5. lymphocyte death or suppression
    6. IL-10 mimics
    7. MHC reduction
    8. cytokine effect block
  3. Parasites
    1. intracellular life
    2. inhibit phagocytic killing
    3. blocking antigens
    4. antigenic variation
    5. cysts

 

Links/References
  1. Peanut allergy: http://www.allerg.qc.ca/peanutallergy.htm
  2. Graves' Disease: http://www.bio.davidson.edu/Courses/Immunology/Students/Spring2003/Breedlove/GravesDisease.html
  3. Goodpasture's: http://kidney.niddk.nih.gov/kudiseases/pubs/goodpasture/
  4. Lupus: http://cerebel.com/lupus/overview.htm
  5. SCID; http://student.biology.arizona.edu/honors2000/group08/main.html