Changes

Cell mediated hypersensitivity:

Cell mediated hypersensitivity:

Type IV hypersensitivity involves cytokines being secreted from the Th-I cells, which cause the activation of macrophages and other T cells.

Type IV hypersensitivity also known as delayed hypersensitivity involves [[Cytokines - WikiBlood|cytokines]] being secreted from the Th-I cells, which cause the activation of [[Macrophages - WikiBlood|macrophages]] and other T cells.

* CD4+ T cell mediated:

* [[Lymphocytes - WikiBlood#Helper CD4+|'''CD4+ (helper)''']] mediated:

** Abnormal activation of macrophages in healthy tissues.

** Abnormal activation of macrophages in healthy tissues.

** Macrophage production of inflammatory mediators and MMP (matrix metalloproteinase) enzymes cause tissue damage.

** Macrophage production of inflammatory mediators and MMP (matrix metalloproteinase) enzymes cause tissue damage.