Premature Delivery Influences the Immunological Composition of Colostrum and Transitional and Mature Human Milk

Human breast milk is the ideal nutrition for the newborn, and in addition to its nutritional contribution, necessary for infant growth and development, it contains various immune bioactive factors that confer some of the numerous beneficial effects of breastfeeding. The current study analyzed the concentrations of IgA, growth factors such as epidermal growth factor (EGF), TGF beta 1, and TGF beta 2, cytokines IL-6, IL-8, IL-10, IL-13, and TNF alpha, and TNF-receptor I (TNF-RI) in colostrum and transitional and mature milk from mothers with mature, premature, and very premature infants. Human milk samples were collected from mothers delivering at term (T), preterm (PT), and very preterm (VPT). Milk from all the mothers was collected at 3 different time points after delivery corresponding to colostrum and transitional and mature milk. After obtaining milk whey, IgA, EGF, TGF beta 1, and TGF beta 2 were determined by ELISA and IL-6, IL-8, IL-10, IL-13, TNF alpha and TNF-RI by cytometric bead array immunoassay. The colostrum of the PT group was extremely rich in most of the factors studied, but higher concentrations than in the T group were only found for IL-6 (P = 0.051), TGF beta 1, and TGF beta 2 (P < 0.05). Conversely, the colostrum of the VPT group had lower concentrations of IgA, IL-8, IL-10, and TNF alpha than those in the T group (P < 0.05). Results suggest that maternal lactogenic compensatory mechanisms accelerating the development of immature breast-fed preterm infants may take effect only after wk 30 of gestation. J. Nutr. 141: 1181-1187, 2011.