L-arginine stimulates host defenses in patients with breast cancer.

BACKGROUND

The amino acid L-arginine is known to have immunostimulatory effects in animals and healthy human volunteers. We have studied the effect of dietary supplementation with L-arginine (30 gm/day for 3 days) on host defenses in patients with breast cancer.

METHODS

Mitogenic responses of peripheral blood lymphocytes to concanavalin A, phytohemagglutinin, and pokeweed mitogen and phenotype analysis of lymphocyte subsets and activation markers were assessed before and after 3 days of L-arginine supplementation. The effect of L-arginine supplementation on natural killer and lymphokine-activated killer cell cytotoxicity and serum levels of the cytokines interleukin-1 beta and 2, interferon-gamma, and tumor necrosis factor-alpha were also measured.

RESULTS

L-arginine significantly increased lymphocyte mitogenic reactivity to concanavalin A, phytohemagglutinin, and pokeweed mitogen (mean percentage increases: 64% [p < 0.001], 65% [p < 0.001], and 48% [p < 0.05], respectively). Natural killer and lymphokine-activated killer cell cytotoxicity was also significantly enhanced after L-arginine intake (mean percentage increase, 81% and 107% [p < 0.001]). However, no corresponding increase in circulating CD16+ and CD56+ cells was obtained: Arginine supplementation did not increase the level of serum cytokines.

CONCLUSIONS

Dietary supplementation with L-arginine in patients with breast cancer significantly enhances host defenses and therefore may have a role in adjuvant treatment.