Breast milk: a source of stem cells and protective cells for the infant

Microchimerism, the result of homing of foreign cells into our tissues, can occur during pregnancy and lactation. Although this natural transfer of viable cells including stem cells and immune protective cells from the mother to the infant and vice versa is likely to have a functional significance, this is yet unknown. New studies provide conclusive evidence of this phenomenon during the breastfeeding period. This review will summarise the current knowledge on breast milk cells and will present the potential significance and applications of these cells in the fields of lactation and medicine.