The effect of supplemental beta-carotene on immunologic indices in patients with AIDS: a pilot study.
Patients with the acquired immunodeficiency syndrome (AIDS) are characterized by a decrease in the number of T helper cells, a defect that is linked to the impaired immunologic competence. Vitamin A and its dietary precursor, beta-carotene, increase absolute T helper cell counts as well as indices of T cell function in both human and animal models. To determine if short-term beta-carotene treatment affects T lymphocyte subsets in patients with AIDS, a single-blind, non-randomized clinical trial of beta-carotene was performed in seven patients with AIDS. Enrollment criteria included no evidence of: a) active opportunistic infection: b) greater than 1 kilogram change in weight in the month preceding enrollment; c) chronic diarrhea or malabsorption; and d) hepatic disease or significant anemia. Beta-carotene was given with meals in two divided doses of 60 mg/day for four weeks; this was followed by no therapy for six weeks. Samples for total white blood cell, lymphocyte and T lymphocyte subset counts were measured at baseline, at the end of four weeks of treatment and another six weeks after treatment had stopped. P24 antigen, beta-2 microglobulin and liver function tests were also measured. All subjects tolerated the treatment well without evidence of toxicity. In response to beta-carotene, total lymphocyte counts rose by 66 percent (.05 < p < .10), and CD4+ cells rose slightly, but insignificantly, in the entire group. In all three of the patients who had baseline CD4+ cells greater than 10/microliters, however, the mean absolute increase in CD4+ cells in response to beta-carotene was 53 +/- 10 cells/microliters (p < .01). Six weeks off beta-carotene treatment, the absolute CD4+ cell count returned to pretreatment levels (p < .01). No change was observed in CD8+ cells. P24 antigen and beta-2 microglobulin did not change during treatment. These preliminary observations suggest that short-term treatment with beta-carotene may increase CD4+ cell counts in patients with AIDS who have greater than 10 cells/microliters.