Type IV or Delayed-Type Hypersensitivity (DTH)
Type IV hypersensitivity is also called Delayed-Type Hypersensitivity (DTH). It is a cell mediated hypersensitivity reaction. It is due to T lymphocytes. It is not due to antibody. It is called delayed type because the reaction appears late. Usually it appears after 48 to 72 hours. Sometimes more time also needed. This delay is due … Read more