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Human Milk Composition: Concentration of Immune Factors during the First Month Postpartum

Posted:  Thursday, September 29, 2016

Immune Factors in Breast Milk of Preterm and Term Mothers during the First Month Postpartum

A study published in the British Journal of Nutrition evaluated the effects of preterm birth on immune factors in breast milk during the 1st month postpartum.

Sixty mothers were enrolled into one of the World Health Organization-defined infant gestational age groups: extremely preterm (<28 weeks of gestation), very preterm (28–<32 weeks of gestation), moderately preterm (32–<37 weeks of gestation), or term (37–41 weeks of gestation). Colostrum, transitional milk, and mature milk samples were obtained postpartum on days 2–5, 8–12, and 26–30, respectively. Total protein, secretory IgA (sIgA), lactoferrin, α defensin 5 (HD5), β defensins 1 (HBD1) and 2 (HBD2), soluble CD14 receptor (sCD14), transforming growth factor-β2 (TGF-β2), IL-6, IL-10, IL-13, interferon-γ, TNF-α, and lysozyme (LZ) were measured in the breast milk. The effects of gestational age, lactation stage, mode of delivery, parity, maternal infection, and volume of milk expressed on milk immune factor concentrations were examined.

Lactoferrin followed by sIgA, LZ, and sCD14 were abundantly present in breast milk samples and together made up 60%, 43%, and 30% of the total proteins in colostrum, transitional milk, and mature milk, respectively. Except LZ and HD5, the concentration of all other immune factors significantly decreased during the 1st month postpartum. Furthermore, the breast milk samples of extremely preterm mothers had significantly higher concentrations of HBD1 and TGF-β2 in colostrum compared to those from term mothers. Preterm birth was associated with higher concentrations of LZ, HBD1, and sCD14 in milk samples after controlling for other variables in regression analysis.

The study concluded that the concentration of some immune proteins is significantly higher in preterm breast milk than in term breast milk.

News source - Trend S, Strunk T, Lloyd ML, et al. Levels of innate immune factors in preterm and term mothers' breast milk during the 1st month postpartum. Br J Nutr. 2016 Apr 14; 115(7):1178–93.