Hypersensitivity - Complete

Question 1

What are the 4 hypersensitivity in regards to ABCD

Answer 1

• I = Allergic Anaphylaxis and Atropy
• II = AntiBody
• III = Immune Complex
• IV = Delayed

Question 2

explain type 1 hypersensitivity

Answer 2

• Allergies
• IgE mediated.
• Mast cell degranulation (Release of histamines, leukotrienes, and prostaglandins)
• In response to an allergen – an antigen which causes an allergic reaction.
• People have specific genes that cause their T helper cells more hypersensitive to antigens.

Question 3

Explain type 2 hypersensitivity

Answer 3

• Antibody-mediated
• Bind to cell surface – THIS DIFFERENTIATES IT FROM TYPE III
• Tissue-specific (specific to organ or tissue)
• T or B cells “Escape” the thymus or bone marrow and attack their cells.
• B cells produce IgM, or, with the help of CD4, T cells have IgG and attach to the antigen on the host cell.
• For example, it will attach to a red blood cell to form an antigen-antibody complex that activates the complement system and kills RBC, leading to haemolytic anaemia.

Question 4

What conditions are included in type II hypersensitivity

Answer 4

• Good pastures syndrom e
• Rheumatic fever
• Myasthenia Gravis
• Hemolytic anemia

Question 5

Explain type III hypersensitivity

Answer 5

• Immune complex, aka antigen-antibody complexes.
• This happens when antigen-antibody complexes deposit in blood vessel walls and cause inflammation and tissue damage.
• Eg lupus – AUTOANTIBODY AGAINST NUCLEAR COMPONENTS.

Question 6

Explain type IV hypersensitivity

Answer 6

• DELAYED!!
• Mediated by T cells and macrophages of NK cells.
• Contact dermatitis
• Organ rejection
• Granulomas
• Tuberculosis, leprosy, sarcoidosis, and chrons disease.