Hypersensitivity reactions

Definition

Hypersensitivity reactions are exaggerated immune responses to a typically harmless substance, resulting in tissue damage or disease. They are classified into four types based on the mechanism and time taken for the reaction to occur.

5 Must Know Facts For Your Next Test

1. Type I hypersensitivity involves IgE antibodies and can cause conditions such as asthma, which directly impacts pulmonary health.
2. Type II hypersensitivity is mediated by IgG or IgM antibodies targeting cell surface antigens, leading to cell destruction or dysfunction.
3. Type III hypersensitivity involves immune complex deposition in tissues, causing inflammation and potential damage to organs like the lungs.
4. Type IV hypersensitivity is delayed and mediated by T-cells, and it can result in chronic inflammatory conditions affecting the respiratory system.
5. Nutritional status can influence hypersensitivity reactions; deficiencies in essential nutrients like vitamins A, C, and E may exacerbate these responses.

Review Questions

• What type of antibody is involved in Type I hypersensitivity reactions?
• How does Type IV hypersensitivity differ from the other types?
• Which nutrients are essential in potentially modulating hypersensitivity reactions impacting pulmonary health?

Related terms

IgE: Immunoglobulin E (IgE) is an antibody associated with allergic reactions and Type I hypersensitivity.

Asthma: A chronic respiratory condition often triggered by Type I hypersensitivity reactions involving airway inflammation.

Immune Complex: Formed when antigens bind to antibodies, these complexes can deposit in tissues leading to Type III hypersensitivity reactions.