Human recombinant interleukin-2 partly reconstitutes deficient in-vitro immune responses of lymphocytes from patients with AIDS.

The lymphokine interleukin-2 is required for the development of various cell-mediated immune functions that are known to be deficient in patients with acquired immunodeficiency syndrome (AIDS). The effects of pure human recombinant interleukin-2 (rIL-2), produced by Escherichia coli containing the cloned human gene, on in-vitro immune responses were studied in 16 patients with AIDS and 10 age-matched healthy heterosexual men. Exposure of lymphocytes from most AIDS patients to 1-100 U/ml rIL-2, increased mitogen and alloantigen induced proliferation and augmented natural killer (NK) cell function in a dose-dependent manner. NK activity was the function most consistently improved, with deficient patient responses uniformly restored to normal after incubation of effector cells with rIL-2. Patient responsiveness to rIL-2 did not appear to depend upon the primary manifestation of disease (opportunistic infection, Kaposi's sarcoma, or both) or other clinical variables. rIL-2 also augmented the responses of lymphocytes from health subjects, but to a lesser degree. Pure rIL-2 seems capable of at least partly reconstituting some in-vitro immunological defects characteristic of AIDS. The availability of highly purified rIL-2 makes in-vivo testing feasible.