A longitudinal study was performed to investigate the content of human colostrum and milk of antibodies against endotoxins of Escherichia coli, Pseudomonas aeruginosa and Salmonella minnesota during the first 6 mo of lactation. The influence of the gestational age of the newborn and the prevalence of a systemic infection in the child on maternal antibody production were observed. Colostrum of mothers of term infants who had shown signs of systemic infection contained higher antibody concentrations compared to colostrum of mothers of healthy newborns. After the first week post partum, no difference in the milk's antibody content could be observed between these two groups. Antibody titres rose from 2 wk to 6 mo post partum (p < 0.001). Milk of mothers of preterm infants with signs of systemic infection contained higher antibody titres than milk of mothers of preterm infants without infection throughout the observation period. This difference reached statistical significance 3 wk after delivery (p < 0.05). The corrected endotoxin antibody levels against all tested antigens in milk of mothers of preterm infants with infection 6 mo post partum were 6 ± 3.5 times as high as 2 wk post partum.
Conclusions: Breast milk contains anti-endotoxin antibodies. The particularly high levels of anti-endotoxin antibodies in cases of neonatal infection may present a special maternal protection for premature infants.