Hypersensitivity type II

Figure 6.32 The basis of type II hypersensitivity reactions. The antigen is part of a cell, which becomes the target for macrophages, NK cells, neutrophils, and complement. Abbreviation NK, natural killer.

Figure 7.81 Antibody-dependent phagocyte-mediated lysis of red cells in penicillin immunotoxicity (type II hypersensitivity). Abbreviation NK, natural killer cell.

Type II hypersensitivity results from the formation of antigen-antibody complexes between foreign antigen and IgM or IgG immunoglobulins. One example of this type of hypersensitivity is a blood transfusion reaction that can occur if blood is not cross-matched properly. Preformed antibodies bind to red blood cell membrane antigens that activate the complement cascade, generating a membrane attack complex that destroys the transfused red blood cells. In hemolytic disease of the newborn, anti-Rh IgG antibodies produced by an Rh-negative mother cross the placenta, bind to red... 

Trimellitic anhydride, used in chemical synthesis. Type II hypersensitivity manifested by adverse effects on blood, including hemolytic anemia and bone marrow depression, may be caused by exposure to trimellitic anhydride. This agent may also cause type III hypersensitivity, resulting from deposition of antigen-antibody complexes in tissue and causing symptoms such as rheumatoid disease or pneumonitis. 

Immune-mediated reactions to penicillin G include anaphylaxis (a type 1 hypersensitivity reaction), hemolytic anemia and thrombocytopenia (type II hypersensitivity reactions). Anaphylactic reactions can be fatal, so epinephrine... 

Cytolytic (type II) hypersensitivity Arthus-immune complex (type III) hypersensitivity Cell-mediated (type IV) hypersensitivity Immunosuppression... 

Hypersensitivity can be defined as an exaggerated response of the immune system leading to host tissue damage. However, some of the immune responses described in the hypersensitivity classification below are, in some circumstances, appropriate responses to invading antigen. For example, a component in what is an appropriate immune response to tissue transplant rejection can be defined as a type II hypersensitivity reaction. 

Localized food allergies, atopy, and asthma 2. Type II hypersensitivity (cytotoxic type)... 

As well as erythrocytes, other cells including platelets (thrombocytes) and some hanatopoietic precursor cells can be affected by drag-induced type II hypersensitivity reactions. Drag-induced thrombocytopenia for example is increasing as more drags are released and used. A number of different mechanisms appear to be involved. Drugs may bind covalently to the platelet mem-... 

The reaction is generally a type fV hypersensitivity response involving CD4+ cells, CD8+ cytotoxic lymphocytes and NK, Kupffer, and dendritic cells. Type II hypersensitivities may also sometimes occur. Knowledge of mechanisms underlying idiosyncratic drug-induced liver injury is limited. 

---