positive regulation of type IIa hypersensitivity

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of type IIa hypersensitivity, a type of inflammatory response. [GOC:add, ISBN:0781735149]

Type IIa hypersensitivity, also known as cytotoxic hypersensitivity, is a form of antibody-mediated immune response that involves the destruction of cells by antibodies. The process begins with the binding of antibodies to antigens on the surface of target cells. These antibodies can be of the IgG or IgM class. The binding of antibodies to antigens triggers a cascade of events that ultimately leads to cell lysis.

One of the key mechanisms of cell lysis in type IIa hypersensitivity is the activation of the complement system. Complement is a series of proteins that circulate in the blood and can be activated by the binding of antibodies to antigens. Once activated, complement proteins can form a membrane attack complex (MAC) on the surface of target cells. The MAC is a pore-forming complex that disrupts the cell membrane, leading to cell lysis.

Another mechanism of cell lysis is antibody-dependent cell-mediated cytotoxicity (ADCC). ADCC involves the binding of antibodies to antigens on target cells, followed by the recruitment of natural killer (NK) cells or other cytotoxic cells. NK cells and other cytotoxic cells express Fc receptors, which bind to the Fc portion of antibodies. This binding activates the cytotoxic cells, which then release cytotoxic granules containing enzymes that can kill target cells.

In addition to cell lysis, type IIa hypersensitivity can also lead to other pathological effects, such as inflammation and tissue damage. For example, in autoimmune hemolytic anemia, antibodies bind to red blood cells, leading to their destruction. This can cause anemia and other symptoms.

In summary, positive regulation of type IIa hypersensitivity involves the activation of the complement system and antibody-dependent cell-mediated cytotoxicity (ADCC). These processes lead to the destruction of target cells, which can cause a variety of pathological effects.'
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Compounds (3)