Several types of hypersensitive reactions can be identified, reflecting differences in the effector molecules generated in the course of the reaction. Gell and Coomb described four types of hypersensitivity reactions (Types I, II, III and IV). The first three types are antibody-mediated and the fourth type is mediated mainly by T-cell and macro-phases i.e. cell-mediated (Table 11.1 and 11.2; Fig. [...]
Immune response recruits and mobilizes a series of effector molecules that induce a localized inflammatory response, which ultimately removes the antigen. This inflammatory response usually does not extensively damage the host tissues. But under certain conditions, the inflammatory response produces deleterious effects, resulting in significant tissue damage or even death; this is termed as hypersensitivity or allergy. Hypersensitive reactions may [...]
The following points highlight the four important types of hypersensitivity. The types are: 1. Type I Hypersensitivity (Anaphylaxis) 2. Type II Hypersensitivity (Cytotoxic Hypersensitivity) 3. Type III Hypersensitivity 4. Type IV Hypersensitivity. 1. Type I Hypersensitivity (Anaphylaxis): This type of hypersensitivity is the most common among all the types. About 17% of the human population may be affected, probably due [...]