Autologous lymphocyte proliferation in multiple sclerosis and the effect of intravenous ACTH

The proliferative response of peripheral blood T cells to autologous non-T cells, a reaction called the autologous mixed lymphocyte reaction (MLR), was significantly increased in 17 patients with active multiple sclerosis (MS) compared to age- and sex-matched individuals with other neurological diseases (OND). Following a 10-day course of intravenous adrenocorticotropic hormone (ACTH) therapy the values were reduced to control levels. No differences were noted between MS patients and controls in their response to alloantigens. The increased autologous MLR in patients with active MS appeared to result from an increased stimulatory capacity of non-T cells rather than from an intrinsically greater T cell proliferative potential. ACTH appeared to induce a change in the populations of circulating non-T cells such that these cells had a decreased stimulatory capacity in both autologous and allogeneic MLR. The decrease in stimulatory capacity in autologous MLR was, however, significantly greater than the decrease in allogeneic stimulatory capacity, suggesting a functional decrease of specific non-T cell-enriched subpopulations. No significant changes in the numbers of myeloperoxidase-positive (MP+) cells were noted in the blood of MS patients before and after ACTH therapy. Since the autologous MLR results in generation of cells that regulate immune responsiveness, the changes noted provide additional evidence for abnormal immune regulation in MS.