1Anthropology, Binghamton University (SUNY), 2Kilimanjaro Clinical Research Institute, Kilimanjaro Clinical Research Institute
April 17, 2020 4:45PM, Diamond 2
Immune factors in human milk are numerous, and together constitute the immune system of milk. The immune system of milk represents a substantial maternal investment, which is important to infant survival. We have observed that stronger pro-inflammatory responses in milk (in vitro interleukin-6, IL-6, production during incubation with Salmonella) decrease infants’ risk for infectious disease (ID). We further predict that ID in a breastfeeding infant will lead mothers to bolster milk pro-inflammatory responses. We evaluated this hypothesis among mother-infant dyads in Kilimanjaro, Tanzania. Milk IL-6 responses to Salmonella were characterized at baseline and during infant ID among 55 mother-infant dyads. The median change in IL-6 response (sick - baseline) was 0 (range: -55, 162), and it was inversely associated with the strength of the baseline visit IL-6 response (B: -7.7; p: 0.001): those with the lowest initial IL-6 responses exhibited the most positive change in IL-6 response for children undergoing an ID. This may reflect a constraint on milk immunity: the higher the initial IL-6 response, the less it could be further increased. This may also reflect a divergence in strategies: a “proactive” strategy of high milk pro-inflammatory responses to decrease infants’ risk for ID vs. a “reactive” strategy of increasing milk pro-inflammatory responses for a sick infant. Additional independent predictors of the change in IL-6 response to Salmonella were maternal anemia (B: 13.22; p: 0.064) and prior pregnancy loss (B: 15.69; p: 0.034); these may be indicators of poor maternal condition, which could push mothers toward a “reactive” strategy.
Funding for this project was provided by the Wenner-Gren Foundation, the Leakey Foundation, The American Philosophical Society, and Binghamton University (SUNY)