Lower Proportion of CD45R0⁺ Cells and Deficient Interleukin‐10 Production by Formula‐Fed Infants, Compared With Human‐Fed, Is Corrected With Supplementation of Long‐Chain Polyunsaturated Fatty Acids

Abstract

BackgroundThe immune consequences of adding 20:4n‐6 and 22:6n‐3 fatty acids to preterm infant formula are not known.MethodsThe effect of feeding preterm infants (14–42 days of age) human milk (Human Milk group), infant formula (Formula group), or formula with added long‐chain polyunsaturated fatty acids 20:4n‐6 and 22:6n‐3 (Formula + LCP group) on isolated peripheral blood lymphocytes (by flow cytometry) and lipid composition (by gas–liquid chromatography) was determined. Lymphocytes were stimulated in vitro with phytohemagglutinin to measure soluble interleukin (sIL)‐2R and IL‐10 production (by enzyme‐linked immunosorbent assay).ResultsWith age, the percentage of CD3+CD4+ T cells and the percentage of CD20+ cells increased in the Human Milk and Formula + LCP groups (P < 0.05), but not in the unsupplemented Formula group. Compared with the Formula group, CD4+ cells from the Formula + LCP and Human Milk groups expressed more CD45R0 (antigen mature) and less CD45RA (antigen naive) at 42 days of age (P < 0.05). At 42 days, IL‐10 production was lower (P < 0.05) in cells of the Formula group than in cells of the Human Milk group. Production of IL‐10 by the cells of the Formula + LCP group was not different from that produced by the Human Milk group cells. An age‐related decrease (P < 0.05) in sIL‐2R production by Formula + LCP lymphocytes was observed, but sIL‐2R production at 42 days in the Formula + LCP group did not differ significantly from that in the Human Milk group. Compared with Formula alone, adding LCP to formula resulted in a lower C18:2n‐6 and higher C20:4n‐6 content in lymphocyte phospholipids (P < 0.05).ConclusionsAdding LCP to a preterm infant formula resulted in lymphocyte populations, phospholipid composition, cytokine production, and antigen maturity that are more consistent with that in human milk–fed infants. This may affect the ability of the infant to respond to immune challenges.