Immunomodulatory effects of AS101 on interleukin-2 production and T-lymphocyte function of lymphocytes treated with psoralens and ultraviolet A

This study tested the immunomodulatory effects of AS101, a synthetic organotellurium compound, on interleukin (IL-2) production and functional activity of normal human lymphocytes. Normal human lymphocytes were treated in vitro with 8-methoxypsoralen alone, ultraviolet A (UVA) and psoralen plus UVA (PUVA) as well as with a combination of AS101 + phytohaemagglutinin (PHA) + phorbol myristate acetate (PMA) and the above-mentioned treatments. Following treatment IL-2 production, free IL-2 receptor (IL-2R), the ability of lymphocytes to induce a local graft-versus-host reaction (GVHR) and the ability of separated CD4 cells to induce help were tested. 8-Methoxypsoralen alone did not significantly affect either cell proliferation or IL-2 production or functional activity. However, UVA and PUVA had a high inhibitory effect on cell proliferation, IL-2 production, IL-2R release and the functional activity of T- and T-helper lymphocytes. In the present study, the addition of AS101 and PMA serve to restore the impaired IL-2 production, T- and T-helper lymphocyte functional activity, but not the IL-2R release. AS101 alone without PMA was also effective in restoring GVHR and helper activity of CD4 lymphocytes, without affecting cell proliferation.