Effects of arginine supplementation on the humoral and innate immune response of older people

Abstract

Objective: To evaluate whether oral supplementation with arginine affects the humoral and innate immune response after vaccination against Streptococcus pneumoniae in a group of people aged 60 y and older, free-living in the community.

Design: A randomized controlled trial with one supplemented group and one control group.

Setting: Older persons living in the community.

Subjects: A total of 29 adults aged 60 y and older.

Interventions: The older people were randomized into two groups, one with arginine supplementation (15 g/day) for 4 weeks after pneumococcal vaccine. The control group received only the vaccine. Anthropometric measurements and immune system function parameters: neutrophil chemotaxis and phagocytosis, natural killer cell activity, determination of serum pneumococcal polysaccharide antibodies and serum C3 and C4.

Results: Neutrophil phagocytosis and the serum concentration of complement (C3 and C4) did not differ between groups. IgG antibodies against pneumococcal polysaccharide serotypes 1, 5 and 6B increased in both groups. The following parameters increased in the arginine-supplemented group compared to the nonsupplemented group: neutrophil chemotaxis (34 vs 19 units of migration, P = 0.002), natural killer cell cytotoxicity (23.3 vs 13.4 10 M/Ul 40%, P = 0.011) and IgG against antigen 5 (12.3 vs 6.2 mug/ml, P = 0.044).

Conclusions: This study suggests that, after the pneumococcal vaccine, the intake of arginine increased neutrophil chemotaxis, natural killer cytotoxicity and serum concentration of IgG against antigen 5 in older people. These results suggest that arginine supplementation may enhance the immune response elicited by the pneumococcal vaccine in older people.

Sponsorship: Supported in part by CAPES and FAEPA.