Dysregulation of the interleukin-2 receptor alpha- and beta-chain expression in CD4 and CD8 T cells in HIV infection.

Peripheral blood mononuclear cells were prepared from human immunodeficiency virus-positive (HIV+) individuals (n = 46) to investigate the expression of both chains of the interleukin-2 receptor. Both qualitative and quantitative changes in expression were observed. Total lymphocyte expression of the IL-2 alpha chain (CD25) was decreased compared with HIV-negative (HIV-) controls. This was due to the decrease in the CD4+ population, which favored expression of this receptor, rather than a decrease in expression, per se. CD8+ lymphocytes expressed the beta chain (CD122) in the absence of the alpha chain. However, a significant increase in the number of peripheral blood CD8+ lymphocytes expressing mainly the beta subunit was observed in HIV+ patients (P = 0.02). This was observed to a similar extent in asymptomatic and symptomatic patients and characterized a subpopulation of T lymphocytes expressing high levels of CD8. Lymphocytes from patients with advanced HIV disease failed to up-regulate both alpha and beta chains in response to mitogenic concentrations of phytohaemagglutanin. However, those cells that were able to up-regulate both of the IL-2 receptors were capable of effective signal transduction through the receptor, increasing the proliferative response to stimulation.