MICROANATOMY

Detailed explanation-1: -Histamine is an endogenous mediator contained in the granules of mast cells and basophils, and is released upon activation by IgE crosslinking (Kinet, 1999).

Detailed explanation-2: -Mast cells and basophils represent the most relevant source of histamine in the immune system.

Detailed explanation-3: -Human eosinophils induce histamine release from antigen-activated rat peritoneal mast cells: A possible role for mast cells in late-phase allergic reactions.

Detailed explanation-4: -Eosinophils develop in the bone marrow, where they differentiate from hematopoietic progenitor cells into mature eosinophils. Factors that control this process have not been fully defined; however, IL-3, IL-5, and GM-CSF are important in eosinophil expansion during conditions of hypereosinophilia.

Detailed explanation-5: -What enzymes do basophils release? During allergic reactions, basophils release two enzymes, histamine and heparin. Histamine enlarges your blood vessels to improve blood flow and heal the affected area. Histamine opens pathways for other cells in your immune system to quickly target and respond to the allergen.