Hypersensitivity- any immune response against a foreign antigen exaggerated beyond the norm. example are: ? Type I immediate ? Type ii hypersensitive ? Type iii immune complex mediated ? Type iv delay or cell-mediated Type 1 immediate Hypersensitivity o Develop within seconds. Commonly called allergies. The antigens that stimulate it are called allergens. Occurs via two processes; o Sensitization upon initial exposure to an allergen. o Degranulation of sensitized cells. o Roles of degranulating cells in an allergic reaction. o Mast cells throughout the body in connective tissue, have granules that contain inflammatory chemicals. Degranulation releases histamine, kinins, proteases, leukotrienes, and prostaglandin.