Interleukin-2 was discovered back in 1983 as an autocrine growth factor for cultured T cells and was the first biological product created through the use of recombinant DNA. IL-2 tumor immunotherapy performed the first historical clinical demonstration of the possibility to cause an effective anticancer immune reaction, mediated by cytotoxic lymphocytes activated from IL-2 stimulation. The Interleukin 2 receptor is a heterotrimeric protein that is composed of three peptide chains: the alpha chain, the beta chain and the gamma chain of the common cytokine receptor. There are 3 majors’ ways of interfering with the IL-2/IL-2R to use it as treatments: Antibodies, Aptamers, and punctual mutagenesis. Recent studies have shown, that Il-2 therapies for cancer, specifically targets restoring the individual’s natural antitumor immune response. HIV directed treatments have demonstrated the necessity of introducing the IL-2 complemented with the patient’s antiretroviral therapy.

Adenosine deaminase deficiency (ADA) represents an immune system disorder producing abnormalities in humoral and cellular immune responses due to the lack of adenosine deaminase (ADA) enzyme. PEG-ADA therapy tries to counteract ADA deficiency by conjugates conformed of numerous mono-methoxy polyethyleneglycol chains linked non-covalently, and ADA enzymes, which are bound by lysine residues. PEG-ADA protects from any proteolytic attack, and presentation of antigens, increasing their lifespan within the organism. Enzyme replacement therapy with PEGylated ADA provides metabolic correction and improvement in immune function and clinical parameters. Its effectiveness is confirmed by the increase of B and T lymphocytes in questionable time ranges.