[Interleukin-2: molecular, physiological and pathophysiological bases and possible significance for clinical...

Interleukin-2, a lymphokine produced by T lymphocytes in response to antigenic or mitogenic stimulation, is necessary for the proliferation and differentiation of various cell populations including activated T lymphocytes, natural killer cells (NK), lymphokine-activated killer cells (LAK), B lymphocytes and macrophages. In addition, IL2 induces or increases the production of important cytokines and thus plays a central role in regulation of the immune response. A number of studies have demonstrated that in patients with primary and secondary immunodeficiency disease, including patients with human immunodeficiency virus infections, decreased immune response was associated with impaired production of, or abnormal reaction to, IL2. Furthermore, IL2 has been assessed, alone or in combination with IL2-activated killer cells ("adoptive immunotherapy"), for its anticancer potential in several animal models and in patients with various forms of advanced cancer. A brief synopsis of biochemical and biological properties of IL2 is presented. The potential pathophysiological role of IL2 in a variety of immunodeficiency states and its possible therapeutic use in cancer therapy are discussed.