Type III hypersensitivity disease

Although the antibodies of type Ⅲ hypersensitivity are similar to those of type Ⅱ hypersensitivity, they are mainly IgG and IgM antibodies, but the difference is that these antibodies heterogeneously bind to the corresponding soluble antigen to form an antigen-antibody complex (immune complex) ), And deposited under certain conditions in the glomerular basement membrane, blood vessel wall, skin or synovial tissue. Immune complex activates the complement system, produces allergic toxins and attracts neutrophils for local infiltration; polymerizes platelets, releases vasoactive amines or forms thrombus; activates Mphi; causes release of cytokines such as IL-1. As a result, inflammatory reactions and tissue damage characterized by congestive edema, local necrosis, and neutrophil infiltration are caused. This type of hypersensitivity is also known as immune complex-mediated hypersensitivity.