Which of the following is a local type III reaction?
The Ahus reaction is a type of local type III hypersensitivity reaction. Type III hypersensitivity reactions are immune complex-mediated and involve the deposition of antigen/antibody complexes mainly in the vascular walls, serosa (pleura, pericardium, synovium) and glomeruli. Type 1 HSR- Production of IgE- immediate release of vasoactive amines; later recruitment of inflammatory cells. Ex: Anaphylaxis; Bronchial asthma, Atopic Dermatitis Type 2 HSR- Production of IgG, IgM which binds to antigen on target cell causing phagocytosis of target cell by activated complement; recruitment of leukocytes. eg-ITP Type 3 HSR- Deposition of antigen-antibody complexes -complement activation - recruitment of leukocytes by complement products and Fc receptors -release of enzymes and other toxic molecules Ex: SLE, Serum sickness (Generalized), Ahus reaction (localized) Type 4 HSR- Activated T lymphocytes - (1) release of cytokines, inflammation and macrophage activation; (2) T cell-mediated cytotoxicity Ex: Type 1 DM, Contact dermatitis
Atopic dermatitis
DTH
Serum sickness
Ahus reaction
Miscellaneous QBank