Immunoglobulin A concentration is lower in mothers' own milk and infant stool in infants who develop necrotising...

Immunoglobulin A (IgA) binding gut bacteria may modulate necrotising enterocolitis (NEC). In infants <32 weeks gestation exclusively receiving their mother's own milk (MOM) who either did or did not develop NEC, we explored IgA concentration in MOM and infant stool.

We quantified IgA and secretory IgA (sIgA) concentration by enzyme linked immunosorbent assay (ELISA). 41 NEC (median onset day 22) and 44 matched control infants, median gestation 25 weeks, contributed 202 MOM and 92 stool samples.

IgA and sIgA in MOM were significantly lower for the first three weeks in infants developing NEC compared to control infants (median IgA 499 μg/ml vs 1261 µg/ml, sIgA 481 µg/ml versus 1023 µg/ml, adjusted p < 0.001 between 0-6 and 7-13 days of life, adjusted p = 0.029 days 14-20). Stool IgA concentration before disease was also significantly lower in NEC infants compared with control infants (262 µg/ml versus 491 µg/ml, p = 0.045), but there was no statistical difference in sIgA.

IgA and sIgA are lower in early MOM (before week 3 of life) received by infants who go on to develop NEC, reflected in lower stool IgA. Potential mechanisms require further elucidation. Targeted use of high IgA donor milk to preterm infants may be beneficial.

This is the first published work that evaluates both milk and stool IgA and sIgA in control preterm infants and those developing NEC and has the benefit of samples taken before disease onset for some infants. In this study, IgA and sIgA are lower in early MOM (before week 3 of life) received by infants who go on to develop NEC, reflected in lower stool IgA. Targeted use of high IgA donor milk to preterm infants may be beneficial. Clinical practice in the interim should focus on maximising fresh MOM delivery to preterm babies.