Anaphylaxis primary mediators

The elevation of luftg histamine levels during both immunization and immunization with anaphylaxis would be expected since histamine is the primary mediator of anaphylactic shock. However, the observed increase in spleen histamine in both groups is unique, and might suggest the spleen as a target organ for anaphylaxis in the mouse. 

Although human anaphylaxis is a systemic reaction, the mouse model of passive cutaneous anaphylaxis (PGA) has been used extensively to enhance our understanding of mechanisms which also may contribute to systemic anaphylaxis. Unlike systemic anaphylaxis in the mouse, PGA appears to be entirely dependent on mast cells [4,6]. While IgE appears to be the primary antibody isotype that mediates PCA reactions in actively immunized mice, activation of FcyRIII by a fraction of IgGl antibodies (called anaphylactic IgGl) can also mediate PCA reactions in mice [4]. 

Initial features are mostly pulselessness, difficulty in ventilation, desaturation, and a decreased end-tidal CO2. Cutaneous symptoms are observed in 66-70% of patients in case of IgE-mediated reactions but in more than 90% in non-IgE-mediated reactions. On the contrary, cardiovascular collapse and bronchospasm are more frequent in IgE-dependent reactions (table 2). Severe anaphylaxis may be a primary cardiac arrest [9]. 

IgE -mediated urticarial/angioedema reactions and anaphylaxis are associated with aspirin and NSAIDs. Urticaria is the most common form of IgE-mediated reaction. This class is second only to fi-lactams in causing anaphylaxis. The potential for cross-reactivity between agents in IgE-mediated reactions appears small, but caution is advised. Because aspirin therapy is highly beneficial in primary and secondary prevention in... 

Release of histamine The release of histamine may be the primary response to some stimuli, but most often, histamine is just one of several chemical mediators released. Stimuli causing the release of histamine from tissues include the destruction of cells as a result of cold, bacterial toxins, bee sting venoms, or trauma. Allergies and anaphylaxis can also trigger release of histamine. 

---