L-ARGININE STIMULATES HOST DEFENSES IN PATIENTS WITH BREAST-CANCER

Background. The amino acid L-arginine is known to have immunostimulato ry effects in animals and healthy human volunteers. We have studied th e effect of dietary supplementation with L-arginine (30 gm/day for 3 d ays) on host defenses in patients with breast cancer. Methods. Mitogen ic responses of peripheral blood lymphocytes to concanavalin A, phytoh emagglutinin, and pokeweed mitogen and phenotype analysis of lymphocyt e subsets and activation markers were assessed before and after 3 days of L-arginine supplementation. The effect of L-arginine supplementati on on natural killer and lymphokine-activated killer cell cytotoxicity and serum levels of the cytokines interleukin-18 and 2, interferon-ga mma, and tumor necrosis factor-alpha were also measured. Results. L-ar ginine significantly increased lymphocyte mitogenic reactivity to conc anavalin A, phytohemagglutinin, and pokeweed mitogen (mean percentage increases: 64% [p<0.001], 65% [p<0.001]. and 48% [p<0.05], respectivel y). Natural killer and lymphokine-activated killer cell cytotoxicity w as also significantly enhanced after L-arginine intake (mean percentag e increase, 81% and 107% [p<0.001]). However, no corresponding increas e in circulating CD16+ and CD56+ cells was obtained. Arginine suppleme ntation did not increase the level of serum cytokines. Conclusions. Di etary supplementation with L-arginine in patients with breast cancer s ignificantly enhances host defenses and therefore may have a role in a djuvant treatment.