40 - Immunopathological reactions in oral diseases

Question 1

Immunopathological reactions

Answer 1

These are protection + adaptation of the body

Types are:

• Allergic
• Autoimmune
• Immunodeficiencies

Question 2

Allergic reactions

Answer 2

Upon re-entry of the antigen the immune system responds in 3 ways:

• A protective immune response
• With increased sensitivity ⇢ an allergic reaction
• No response - Anergy

Allergen = antigen that causes an allergic reaction

There are 4 types of allergic reactions

Question 3

Type I + II

Answer 3

Type I⇢ allergic immediate reaction

• Hypersensitivity to humoral type
• Anaphylactic/Atopic
• Rapid immune response ⇢ IgE binds to mast cells

Type II - Cytotoxic

• Humoral-mediated response of immediate type
• Toxic effect on cells
• Cytolysis ⇢ IgM, IgD + complement
• Target cells ⇢ erythrocytes, leukocytes + platelets

Question 4

Type III + IV

Answer 4

Type III ⇢ antigen-antibody reaction

• Immediate reaction
• Toxic effect on antigen-antibody complex

Type IV ⇢ cell mediated DELAYED reaction

• Similar to cellular immune reactions

Question 5

Autoimmune reactions

Answer 5

Immune system is self tolerant of its own tissues + antigens

If this tolerance is breached ⇢ the body will produce antibodies against its own cells + antigens

Question 6

Adaptive immunity in mouth

Answer 6

This may be impaired:

• Commensal MOs have similar antigens
• They bind to molecules of MOs
• The MO does not perceive them as foreign + doesn’t develop a cross-immune response
• The body recognises its cells as foreign