Arginine stimulates lymphocyte immune response in healthy human beings

The effect of daily dietary supplements of 30 gm of arginine HCl for 7 days on peripheral blood lymphocyte (PBL) mitogenic reactivity in vitro was measured in 21 healthy human volunteers. Arginine significantly increased stimulation indices of PBL following concanavalin A (Con A) (57.9 ± 11.4 versus 216.9 ± 46.6, P < 0.01) and phytohemagglutinin (PHA) (84.1 ± 12.8 versus 307.0 ± 59.4, P < 0.001) stimulation in a microculture assay utilizing RPMI 1640 medium supplemented with 10% heat-inactivated autologous serum. Similar enhanced blastogenesis was observed using medium supplemented with 10% heat-inactivated pooled AB normal human serum. In six volunteers studied following 3 days of similar arginine supplementation, blastogenic responses of their peripheral blood lymphocytes were already significantly enhanced, although not as greatly as after 7 days. Arginine had no effect on total peripheral blood lymphocyte counts and on T- and B-cell ratios. The effects of supplemental dietary arginine could not be duplicated in vitro by increasing the arginine concentration in the culture medium. Furthermore, dietary arginine supplementation did not increase cell viability in culture. Minimal side effects were noted, such as nausea or diarrhea, which responded to lowering the dose ingested at one time. No deleterious effects were noted on liver function test results. We conclude that supplemental dietary arginine is a safe nutritional stimulator of lymphocyte immune reactivity in healthy human beings.