Which substances are typically released by the immune system during an allergic reaction?

During an allergic reaction, histamines play a crucial role in the body's response to allergens. They are chemicals released primarily by mast cells and basophils, which are types of white blood cells. When the immune system identifies a harmless substance as a threat, it triggers the release of histamines to signal other immune responses. This response can lead to various symptoms associated with allergies, such as itching, swelling, and inflammation.

Histamines function by binding to specific receptors in various tissues, resulting in blood vessel dilation and increased permeability, which can lead to the classical symptoms of an allergic reaction. This mechanism underscores their importance in the body's defense against perceived threats, even though, in the case of allergies, the reaction is exaggerated and inappropriate.

While antibodies, cytokines, and white blood cells also play significant roles in the immune response, they do not specifically characterize the immediate reaction associated with allergies as prominently as histamines do. Antibodies may be involved in the sensitization phase of allergies, cytokines mediate various immune responses, and white blood cells are essential in defending against infections and parasites but are not the primary substances responsible for the immediate symptoms of allergic reactions.