Quantitation and clinical implications of lactadherin in human breast milk

Background Lactadherin (also known as milk fat globule-EGF factor 8, MFG-E8) is a major bioactive component of the milk fat globule membrane (MFGM) in human milk and plays important roles in immune regulation, intestinal homeostasis, and host defense. However, data regarding lactadherin concentrations in human milk and the maternal factors influencing its levels remain limited. This study aimed to characterize lactadherin concentrations across different lactation stages, identify potential determinants of lactadherin variation, and explore its associations with infant health outcomes. Methods A total of 91 Chinese mother-infant pairs were enrolled in this prospective cohort study. Maternal and infant demographic characteristics and clinical information were collected through medical records and structured questionnaires. Colostrum and mature milk samples were collected, and lactadherin concentrations were quantified using a modified enzyme-linked immunosorbent assay (ELISA). Infants were followed up to 6 months after birth through telephone interviews to record feeding patterns and the occurrence of common infantile diseases. Results Lactadherin concentrations were significantly higher in colostrum than in mature milk (median: 112.79 μg/mL vs. 10.51 μg/mL, respectively; P < 0.0001), indicating a substantial decline in lactadherin levels during lactation. Maternal allergy history was identified as an independent factor associated with lactadherin concentrations. Specifically, maternal allergy history was associated with lower lactadherin concentrations in colostrum (β= −53.16, P = 0.039) but higher concentrations in mature milk (β = 7.38, P = 0.024). Furthermore, a significant interaction between maternal allergy history and lactation stage was observed ( P = 0.0007), suggesting a stage-dependent association between maternal allergy history and lactadherin levels. No significant associations were observed between lactadherin concentrations in human milk and the incidence of infantile diseases during the follow-up period. Conclusions Lactadherin concentration in human milk varies substantially across lactation stages and is influenced by maternal allergy history. Further studies are needed to elucidate the underlying mechanisms governing lactadherin dynamics and to determine their implications for infant health and nutritional applications.