Use of interleukin-2 in immunotherapy of human immunodeficiency virus infection.

Interleukin-2 (IL-2) is a cytokine produced by activated T cells. Its stimulatory activity allows T cells, B cells and natural killer cells to proliferate and to release cytokines and antibodies which protect the host against invading organisms. IL-2 plays a critical role in the prevention of apoptosis of HIV-infected cells, and the addition of IL-2 to a culture medium will increase the survival of T cells and will upregulate IL-2 receptor function. Clinical studies of the administration of exogenous IL-2 to HIV-infected patients have demonstrated that it can be given in well tolerated doses and that it can increase and sustain the number of CD4+ cells while only transiently affecting viral proliferation, especially when given to patients with CD4+ counts >200 cells/mm(3). Further investigations are required to determine the optimal use of exogenous IL-2 in HIV-infected patients. There may also be an important role for IL-2 as an adjunct to gene therapy and preventive vaccines against HIV infection.