Interleukin 2 (IL-2) is a 15 kDa glycoprotein that, in humans, is encoded by a single gene located in the q26-28 region of chromosome 4. It is a class of signaling molecules in the immune system that regulates activity against immunocompetent white blood cells (leukocytes, usually lymphocytes).IL-2 is the body’s natural response to microbial infections, distinguishing between foreign and self-antigens.IL-2 functions by interacting with the IL-2 receptor, which consists of three chains, the alpha (CD25), beta (CD122) and gamma chains ( CD132). Monitoring serum levels of IL-2 provides a more detailed perspective on a variety of pathologies, including cancer, infectious diseases, transplant rejection, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, and type I diabetes.