Breast Milk and Saliva Lactoferrin Levels and Postnatal Cytomegalovirus Infection.

OBJECTIVE

Very low birth weight preterm infants are at risk for life-threatening infections in the NICU. Breast milk protects against infections but carries the risk of infection by cytomegalovirus (CMV) shed in mother's milk. Lactoferrin is a breast milk and saliva protein with potent neutralizing activity against CMV.

STUDY

DESIGN

VLBW, maternal breast milk fed infants in the NICU and their lactating mothers were enrolled and followed for 3 months/discharge. Breast milk and infant saliva samples were collected biweekly. Maternal CMV status was determined on breast milk. CMV was measured using quantitative polymerase chain reaction and lactoferrin by enzyme-linked immunosorbent assay.

RESULTS

In an in vitro neutralization assay, the IC90 of purified human lactoferrin against CMV was 2.08 ng/mL. Bovine lactoferrins were more potent, IC90s > 10-fold higher. Lactoferrin was detected in all breast milk (median: 3.3 × 106 ng/mL) and saliva (median: 84.4 ng/swab) samples. Median CMV load in breast milk was 893 copies/mL. There was no correlation between breast milk lactoferrin concentration and CMV load. Five infants acquired postnatal CMV. There was no difference in saliva or breast milk lactoferrin concentration for mother-infant pairs and postnatal CMV acquisition.

CONCLUSION

Lactoferrin neutralizes CMV in vitro, but concentrations in breast milk and saliva are likely too low for effective neutralization in vivo.