Breast milk and transplantation tolerance.

Recent experimental and clinical studies suggest that exposure of the fetus to noninherited maternal antigens (NIMAs) during pregnancy has an impact on allogeneic transplantations performed later in life. We have reported that NIMA exposure by breastfeeding further potentiates the tolerogenic NIMA effect mediated by in utero NIMA exposure during pregnancy in mice of allogeneic hematopoietic stem cell transplantation (HSCT). Breastfeeding generates Foxp3(+) regulatory T cells that suppress anti-maternal immunity and persist until adulthood. These results reveal a previously unknown impact of breastfeeding on the outcome of allogeneic HSCT.