Effect of Dietary Ribonucleotides on Infant Immune Status. Part 2 Immune Cell Development

The objective of this study was to determine whether dietary ribonucleotides alter immune cell phenotypes or function in the first year of life. Newborn term infants in a double-blind, 12-mo, multicenter trial were randomized to cow milk formula groups with (FN, n138) or without (F, n147) 72 mg/L supplemental ribonucleotides. A nonrandomized HMF cohort (n192) was concurrently enrolled. Eighty-eight immune blood cell types were characterized by flow cytometry. Data were analyzed by multivariate ANOVA (MANOVA), ANOVA, and repeated measures analysis (RMA), with adjustments made for multiple comparisons. Ribonucleotide feeding changed subpopulations of T and natural killer (NK) cells. FN had higher numbers and percentages of memory/effector (M/E) cytotoxic/suppressor (CD45R0CD8, RMA) T, FasM/E (CD45R0CD95CD3, 6 mo) T, and CD56CD16−NK cells (CD56CD16−CD3−CD8−, 12 mo), and higher percentages of M/E helper (CD45R0CD4, RMA) T, Tc1 (IFNCD4−CD3, RMA), total interferon (IFN)T (IFNCD4/−CD3, RMA), Th2 (IL-4CD4CD3, 7 mo), and CD57NK-T cells (CD57CD56−CD3, 6 mo, 7 mo) compared with F. Percentages of naive helper T (CD45RACD4, 12 mo) and numbers and percentages of CD56NK-T cells (CD56CD16−CD3CD8−, 2 mo, 6 mo) were lower in FN than F. Percentages of M/E cytotoxic/suppressor, Th2, and CD56CD16−NK cells in FN were significantly higher than F but were not different from HMF, whereas F was significantly lower than HMF. Ribonucleotide supplementation of infant formula supported increased T-cell maturation and affected immunoregulatory NK cell subsets. These FN-associated immune cell profiles either did not differ from those infants fed HMF or tended to be more like those fed HMF than those fed F.