What is Hypersensitivity and How Does it Affect Tissue?
Hypersensitivity reactions are inappropriate or exaggerated immune responses that can cause tissue damage. There are four types:
1. Type I (Immediate): Mediated by IgE antibodies and involves mast cells and basophils. Common in allergic reactions. 2. Type II (Cytotoxic): Involves IgG or IgM antibodies directed against cell surface antigens, leading to cell destruction. 3. Type III (Immune Complex): Involves immune complexes that deposit in tissues and cause inflammation. 4. Type IV (Delayed): Mediated by T cells and macrophages, leading to tissue damage over time.
Histological examination can reveal the extent and nature of tissue damage in hypersensitivity reactions.
