What Is Delayed Hypersensitivity?

Delayed hypersensitivity is a type IV cell-mediated delayed allergy. After injecting tuberculin into the infected person, the sensitized T-lymphocytes bind to the antibody, causing a local hypersensitivity inflammatory reaction mainly with lymphocyte and monocyte infiltration accompanied by cell degeneration and necrosis and granulomas. Redness, induration, and even blisters and necrosis. This reaction is usually the most obvious 48-72 hours after the injection, hence the name of delayed-type hypersensitivity. The release of lymphokines, chemotaxis and migration inhibitory factors keep immune cells in the injection site and cause lymphocytes and macrophages to multiply and produce necrosis. ^[1]