Poster Topical Area: Maternal, Perinatal and Pediatric Nutrition

Location: Hall D

Poster Board Number: 287

P13-029 - Immune Composition of Mature Human Milk in Exclusively Breastfeeding and Mixed-Feeding Mothers

Sunday, Jun 10
8:00 AM – 6:00 PM

Objective: Human milk (HM) is composed of a diverse profile of immune components, which are believed to influence infant innate and adaptive immunity. Factors such as maternal age, geography, gestational age, and lactation stage influence immune composition. However, the breadth of cytokines, chemokines, and growth factors (CCGFs) present in HM is not well-characterized, and whether breastfeeding exclusivity affects CCGF composition is unknown. The objective was to measure CCGFs in mature HM and assess differences in composition between exclusively breastfeeding (EBF) and mixed-feeding (MF) mothers.

Methods: Milk samples (EBF=44; MF=25) collected at 6 weeks postpartum from healthy mothers enrolled in the STRONG Kids 2 birth cohort study were utilized for analysis. All mothers vaginally-delivered their infants at term. Samples were analyzed for 41 CCGFs using a human cytokine/chemokine multiplex magnetic bead panel.

Results: Forty components were detectable in the milk samples. Twelve CCGFs (EGF, TGF-α, GRO, MDC, PDGF-AA, IL-15, IL-4, IL-7, IL-8, IP-10, MCP-1, VEGF) were identified in more than 94% of samples. TNF-α, Fractalkine, and IL-1α were detected in more than 78% of samples. Among this subset of 15 analytes, IL-8 was the only CCGF, within limits of detection (LOD), which differed between groups, with greater concentrations in the milk of MF relative to EBF mothers (p=0.002). EGF and GRO were above the LOD (10,000 pg/ml) in most samples. Fisher exact tests were used to determine differences in frequency of detection for all CCGFs between EBF and MF mothers. The probability of detecting Fractalkine was greater among EBF compared to MF mothers (p=0.04). The probability of detecting IL-3 (p=0.009), IL-6 (p=0.02), IL-9 (p=0.02), and MIP-1β (p=0.006) was greater among MF compared to EBF mothers.

Conclusion: While levels of many CCGFs have been shown to be higher in early lactation, results demonstrate that a wide range of immune components are present at detectable levels in mature HM. The high frequency of detection of a subset of CCGFs may point to a core immune composition in mature HM. Differences in CCGF components in HM of EBF and MF mothers suggest that breastfeeding exclusivity impacts the immune profile of HM, which may be related to differences in oral microbiota of EBF and MF infants.

Funding Source: National Dairy Council, The Gerber Foundation, The Doris Kelley Christopher Foundation, and USDA Hatch funds.

CoAuthors: Sharon Donovan, PhD, RD – University of Illinois at Urbana-Champaign

Erin Davis

Graduate Research Assistant
University of Illinois at Urbana-Champaign
Urbana, Illinois