Evolutionary Anthropology Society
Oral Presentation Session
Sami Kanaan (Fred Hutchinson Cancer Research Center)
Nanette Mayol (University of San Carlos)
Josephine Avila (University of San Carlos)
Lee Nelson (Fred Hutchinson Cancer Research Center)
Dan Eisenberg (University of Washington)
Microchimerism (Mc) refers to the presence of a small number of cells or DNA from a genetically disparate individual and occurs naturally with bidirectional maternal-fetal exchange during pregnancy. Mc can persist for decades after delivery with positive or negative implications for the health of the person harboring Mc, such as autoimmune disorders, infectious diseases, cancer, and reproduction. Mc is a growing area in biomedical research, but little is known about why some individuals have more detectable Mc than others. We examined potential developmental determinants of maternal-origin Mc (MMc) in young adult women in the Philippines: gestation duration (in utero exposure to MMc), history of being breastfed or not (postpartum exposure to MMc), and maternal telomere length (maternal cells’ ability to replicate and persist in the study participant). Statistical models evaluating each predictor separately demonstrated trends toward decreased MMc with increased gestation duration and among those who were breastfed, and we found significantly decreased MMc with increased maternal telomere length. When we included all three predictors in the same statistical model, only history of being breastfed remained a significant predictor of decreased MMc. Our findings diverge from experimental findings in mice of breastmilk-derived MMc and human organ transplantation studies that showed increased immune tolerance of maternal grafts with history of being breastfed. Potential alternative, but not mutually exclusive, determinants of MMc in adulthood include fluctuation in immune regulation throughout the life course, which may impact MMc persistence or detectability.